Vera Lukić, Ružica Micić, Biljana Arsić, Bojan Nedović and Živana Radosavljević

Overview of the major classes of new psychoactive substances, psychoactive effects, analytical determination and conformational analysis of selected illegal drugs

De Gruyter | 2021

Abstract

The misuse of psychoactive substances is attracting a great deal of attention from the general public. An increase use of psychoactive substances is observed among young people who do not have enough awareness of the harmful effects of these substances. Easy access to illicit drugs at low cost and lack of effective means of routine screening for new psychoactive substances (NPS) have contributed to the rapid increase in their use. New research and evidence suggest that drug use can cause a variety of adverse psychological and physiological effects on human health (anxiety, panic, paranoia, psychosis, and seizures). We describe different classes of these NPS drugs with emphasis on the methods used to identify them and the identification of their metabolites in biological specimens. This is the first review that thoroughly gives the literature on both natural and synthetic illegal drugs with old known data and very hot new topics and investigations, which enables the researcher to use it as a starting point in the literature exploration and planning of the own research. For the first time, the conformational analysis was done for selected illegal drugs, giving rise to the search of the biologically active conformations both theoretically and using lab experiments.

Abbreviations

NMR

nuclear magnetic resonance

MS

mass spectrometry

NPS

new psychoactive substances

USA

United States of America

GABA

γ-aminobutyric acid

EU

European Union

LSD

lysergic acid diethylamide

LSA

lysergamide

UK

United Kingdom

DMT

N,N-dimethyltryptamine

NE

norepinephrine

5-HT

5-hydroxytryptamine

ENT

ears, nose and throat

IV

intravenous

GC-MS

gas chromatography-mass spectrometry

IR

infra-red

CNS

central nervous system

MEA

microelectrode arrays

hDAT

human dopamine reuptake transporter

hNET

human norepinephrine reuptake transporter

SPE

solid-phase extraction

QuEChERS

quick (Qu), easy (E), cheap (Ch), effective (E), rugged (R) and safe (S)

LLE

liquid–liquid extraction

dSPE

dispersive solid phase extraction

ELISA

enzyme-linked immunosorbent assay

UHPLC

ultrahigh-performance liquid chromatography

TOF

time-of-flight

UV-Vis

ultraviolet-visible

PDA

photodiode array detector

HPLC

high-performance liquid chromatography

LC-HRMS

liquid chromatography–high-resolution mass spectrometry

CYP2D6

cytochrome P450 2D6

FMO3

flavin-containing monooxygenase 3

NAT1

N-acetyltransferase 1

NAT2

N-acetyltransferase 2

SGK1

serum/glucocorticoid regulated kinase 1

PER2

period circadian regulator 2

CB

cannabinoid receptor

EMCDDA

European monitoring centre for drugs and drug addiction

CBD

cannabidiol

CBN

cannabinol

GPCR

G protein-coupled receptor

CB1R

cannabinoid receptor type 1

CB2R

cannabinoid receptor type 2

pHLM

pooled human liver microsome assay

SARs

structure–activity relationships

AAI

aminoalkylindole

SCs

synthetic cannabinoids

UGT

UDP glucuronosyl transferase

HEK293

human embryonic kidney 293

HNK

hydroxy-norketamine

NPD

nitrogen–phosphorus detector

CIMS

chemical ionization mass spectrometry

HS-SPME

headspace-solid phase microextraction

AMT

alpha-methyltryptamine

DIPT

diisopropyltryptamine

MAO

monoamine oxidase

NSO

new synthetic opioids

LOD

limit of detection

DBZD

designer benzodiazepines

US-LDS-DLLME

ultra-assisted low-density solvent dispersive liquid–liquid microextraction

QSAR

quantitative structure–activity relationship

DFT

density functional theory

UPLC

ultra-performance liquid chromatography

DART

direct analysis in real time

TLC

thin layer chromatography

EIA

enzyme immunoassay

APCI

atmospheric pressure chemical ionization

NACE

nonaqueous capillary electrophoresis

UPC2 SFC-PDA

ultraperformance convergence chromatography supercritical fluid chromatography–photodiode array

NIRS

near-infrared spectroscopy

HPTLC

high-performance thin-layer chromatography

FID

flame-ionization detection

ECD

electrochemical detection

DESI-MS

desorption electrospray ionization mass spectrometry

HSCCC

high-speed counter-current chromatography

4-MMC

4-methylmethcathinone

MDPV

3,4-methylenedioxypyrovalerone

4-MEC

4-methylethcathinone

4-MePPP

4′-methyl-α-pyrrolidinopropiophenone

α-PVP

α-pyrrolidinopentiophenone

4-FMC

4-fluoromethcathinone

3-FMC

3-fluoromethcathinone

α-PBP

α-pyrrolidinobutiophenone

3-MMC

3-methylmethcathinone

MDMA

3,4-methylenedioxymethamphetamine

MDPBP

3′,4′-methylenedioxy-α-pyrrolidinobutyrophenone

3,4-DMMC

3,4-dimethylmethcathinone

PV9

1-phenyl-2-(pyrrolidin-1-yl)octan-1-one

IS

internal standard

TM5

transmembrane helix 5

TM6

transmembrane helix 6

r5-HT 2AR

rat HT2A receptor

BZP

benzylpiperazine

1 Introduction

The number of health-related incidents caused by the use of illegal drugs is increasing rapidly, and so is the need for better understanding of their physiological effects and fast identification [1].

These substances can be grouped depending on the chemical structure into synthetic cannabinoids, synthetic cathinones, phenethylamines, arylcyclohexylamines, tryptamines, indolalkylamines, new synthetic opioids, piperazines and designer benzodiazepines [2,3], and on the basis of their origin on psychoactive drugs of natural origin and synthetic molecules. Previous studies have been limited to the analytical and toxicological data related to only some classes, and their representatives [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30], reviews of the particular group [31,32,33,34,35], or particular topic [36], but failed to address all aspects: identification, quantification, synthesis, case reports, and statistics. The last few years have witnessed research on origin and the trafficking route for various psychoactive molecules (using both 13C NMR spectrometry and 13C, 15N MS) [37], and the use of machine learning to predict the similarity of new psychoactive substances (NPS) with the classical NPS [38]. This article seeks to address the topic in the broadest spectrum available.

2 Psychoactive drugs of natural origin

Numerous plants possess psychoactive properties. Areca catechu, Argyreia nervosa, Ayahuasca, Catha edulis, Ipomoea violacea, Mandragora officinarum, Mitragyna speciosa, Pausinystalia johimbe, Piper methisticum, Psilocybe, Rivea corymbosa, Salvia divinorum, Sceletium tortuosum, Lactuca virosa, and Lophophora williamsii have been receiving much attention due to their common misuse [34]. Mainly found in Asia and South America, the misuse of these plants is underestimated due to religious and traditional practices [34]. Catha edulis (common name: khat; mainly in the USA and the Netherlands), Mitragyna speciosa (common name: kratom; mainly in Asia), and Salvia divinorum are monitored by the United Nation Office on Drugs and Crime [34].

2.1 Areca catechu

Areca catechu belongs to Arecaceae family, and it is a native palm tree in Sri Lanka and Malaysia, abounded in Asia and Africa and exported to USA and Europe by the Asian communities. The fruit of this plant (areca nut) is traditionally chewed and represents one of the most used drugs (after caffeine, ethanol, and nicotine) [32]. It is consumed either in combination with other substances (“betel quid”) or alone giving the stimulation and relaxation during ceremonies and as a traditional remedy in China [39]. The psychoactive property of the plant is mainly caused due to the presence of arecoline, a GABA competitive inhibitor inducing agitation and euphoria [40,41,42]. The available data on the analytical determination of the active component are presented in Table 1.

Table 1

Techniques used for the detection of new psychoactive substances of natural origin

Plant The main detected compound Biological matrices Method used References
Areca catechu Arecoline Plant material HPLC [41]
Arecoline Human plasma [84,85,86,87,88,89,90,91,92]
Saliva GC
Hair HPLC
Buccal cells UPLC
Meconium DART-MS/MS
Cord serum
Breast milk
Argyreia nervosa, Ipomea violacea, and Rivea corymbose LSA Human blood urine UPLC [93,94]
LSA Plant material (seeds) HPLC [44,95,96,97]
TLC
Capsules GC
Banisteropsis capii and Psychotria viridis Plant material HPLC [98,99,100,101,102,103,104,105,106]
GC
Harmine GC
Harmaline LC
DMT DART-HRMS
HPLC
Harmine Human urine UHPLC [98,107,108,109,110,111]
Harmaline Plasma LC
DMT Hair HPLC
GC
Chata edulis Cathinone Plant material (leaves and green) HPLC [112,113,114]
Cathine GC
Human urine Immunoassay [115,116,117,118]
Cathinone Hair HPLC
Cathine Blood GC
Oral fluid
Mandragora officinarum Hyoscyamine Human blood urine GC [119,120,121,122,123,124,125]
Scopolamine Plasma HPLC
Plant material EIA
Mytragina speciosa Mitragynine Human blood HPLC [126,127,128,129,130,131,132,133,134,135,136,137,138,139,140]
7-OH-mitragynine Urine 1H-NMR
Rat plasma 13C-NMR
HPLC
Mitragynine Plant material HPLC, GC, NMR, HPLC, DART-HRMS, HPLC [140,141,142,143,144,145,146]
7-OH-mitragynine Kratom products
Pausinystalia johimbe Yohimbine Plant material TLC, HPLC [147,148,149,150,151,152,153,154,155,156]
Yohimbine HPLC [157,158]
Urine NACE
Blood GC
Plasma UPLC
UHPLC
Piper methysticum Kawain Kawa samples (powder or liquid) UPLC [159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181]
HPLC
Plant material UPC2 SFC detector, NIRS
Food supplement HPTLC
GC
UHPLC
FTIR
Kawain Human urine blood GC [182,183,184,185,186]
Serum LC
Hair LC
GC
Psylocibe spp. Psilocin Human urine LC [69,93,109,187,188,189,190,191,192,193,194,195]
Psilocybin glucuronide Plasma HPLC
Serum
Psilocin Plant material (sclerotia) LC [174]
Psilocybin
Salvia divinorum Salvinorin A Plant material TLC/DESI-MS [196,197,198,199,200,201,202,203]
GC
HPLC
TLC/GC
HPLC
Salvinorin A Plasma GC [73,74,204]
Urine
Saliva
Sweat
Sceletium tortuosum Mesembrine Plant material EC-MS [205,206,207,208]
Mesembrenone UPLC
HSCCC
Mesembrine Rat urine and plasma GC [209,210]
LC
Mesembrenone Human liver LC, UHPLC
Lactuca virosa LC Plant material HPLC [211,212,213,214]
LCP HPLC
Lophophora williamsii Mescaline Plant material HPLC [215,216,217,218]
LC
Ion-interaction HPLC
HPLC

There are no measures regarding the use of the Areca catechu or its active compounds in the EU and the USA [34].

2.2 Argyreia nervosa, Ipomea violacea and Rivea corymbosa

Argyreia nervosa (common names: Hawaiian Baby Woodrose, Adhoguda or Vidhara, Elephant Creeper, and Woolly Morning Glory), Ipomea violacea (common name: morning glory), and Rivea corymbosa are plants with characteristic pink flowers with the origin at the Indian subcontinent and transferred to Africa, Europe, and subtropical America [43]. The psychoactive alkaloids (isoergine and ergine) are mainly found in the plant seeds, and they show psychoactive effects quite similar to lysergic acid diethylamide (LSD), but not so intensive [3,44]. Similarly to ergot alkaloids, ergine is assumed to bind to D2-dopamine receptors [45]. The available data on the analytical determination of the active components are presented in Table 1.

There are specific national regulations regarding LSA in Italy and UK. In the USA, the LSA and its related products are controlled (Schedule III drug in the Controlled Substances Act) as a depressant, and LSA is also on the list of U.S. Code of Federal Regulations as a possible LSD forerunner, but the plant and the seeds can be bought without any problem [34].

2.3 Banisteropsis caapi and Psychotria viridis

Ayahuasca (Quechua word meaning “soul rope”) is a brew characteristic for the South America used for religious and therapeutic purposes in Northwestern Amazonian countries for many centuries, and now by some religious sects (Santo Daime, Baraquinha; prepared from Banisteropsis caapi stems mixed with P. viridis, Mimosa hostiles, Mimosa tenuiflorea, Anadenanthera spp., and/or other plants with psychoactive compounds) [10,46]. The psychoactive compound found in Ayahuasca is DMT that behaves as 5HTA/2c receptor agonist [47].

According to Hamill et al. [48], Ayahuasca has effect on the pupil size, body temperature, cardiovascular system, endocrine system, immune system but has shown no addiction potential. The most common side effects are agitation, hypertension, tachycardia, mydriasis, and vomiting.

The available data on the analytical determination of the active components are presented in Table 1.

There is a controversy about the control status of Ayahuasca because of its composition. Consumption of β-carbolines and P. viridis are not forbidden [34].

2.4 Chata edulis

Chata edulis (common name: khat) belongs to the Celestraceae family, and it is a native plant of Ethiopia, Arabian Peninsula, East Africa and used widely in Yemen [49]. Its use is forbidden in Denmark, Germany, France, Ireland, the United States, and Canada, while it is used as a recreational and traditional habit in Ethiopia, Yemen, Israel, Somalia [49]. S-(−)-Cathinone is the main alkaloid in khat leaves [50]. Symptoms of psychosis and violent behaviors are widely displayed in khat chewers, particularly heavy consumers [34]. Identified toxic effects on the gastrointestinal system, respiratory, cardiovascular, endocrine, and genitourinary system cause increased blood pressure, tachycardia, constipation, insomnia, general malaise, headache, irritability, and impaired sexual potency are found in men [50,51,52].

The available data on the analytical determination of the active components are presented in Table 1.

2.5 Mandragora officinarum

Mandragora officinarum (common name: mandrake) is a native in the area of the eastern Mediterranean, but it is also abundant in the Middle East, southern Europe, northern Africa, and Himalayas [53]. It possesses aphrodisiac, healing, hallucinogenic, and poisonous properties [34].

The available data on the analytical determination of the active components are presented in Table 1.

In EU and USA, there are no legal measures regarding the use of the Mandragora officinarum or active compounds isolated from the plant [34].

2.6 Mytragina speciosa

Mytragina speciosa (common name: kratom) originated in South East Asia [47,54]. Fresh leaves are traditionally chewed, and the dried leaves can be smoked or chewed. Although the molecular structure of the active components (mitragynine, speciogynine, paynantheine, and speciociliatine) is different from opioids, they possess the affinity for opioid receptors leading to the analgesic effect (mytragynine to supraspinal μ-opioid receptors and δ-opioid receptors). The second mechanism of action is the inhibition of pain involving the release of the neurotransmitters by reversible blocking of the Ca2+ channels [55]. Gastrointestinal effects, anti-inflammatory properties, antidepressant activity, and antioxidant properties have also been published [56,57,58].

The available data on the analytical determination of the active components are presented in Table 1.

Mytragina speciosa and isolated active compounds are currently under control only in Latvia, Lithuania, Denmark, Romania, Poland, Sweden, and Italy. There is a narcotic law in Malaysia, Australia, Myanmar, and Thailand against kratom, and in New Zealand, Medicines Amendment Regulations control Mytragina speciosa and mitragynine. In the USA, the Drug Enforcement Administration has labelled kratom on its list as a “drug of concern.”

2.7 Pausinystalia johimbe

Pausinystalia johimbe (from the family Rubiaceae) is native to tropical West Africa, and widely grows mainly in Cameroon [59]. Yohimbine, the major alkaloid found in the bark of this plant, is an α2-adrenoreceptor blocker and a weak α1-antagonist [60]. It is known to cause increase in heart rate, blood pressure, and plasma norepinephrine [60]. Yohimbine induces the increase in plasma NE levels by the increase in the rate of norepinephrine release from sympathetic nerves [60].

The use of yohimbe bark and its preparations is prohibited in foods or food supplements in UK, Ireland, the Netherlands, Belgium, Denmark, Czech Republic, Canada, Australia, and New Zealand, while in the USA, it is possible to possess it without license or prescription [34].

2.8 Piper methysticum Forst

Kava is a Pacific beverage traditionally used and made from the stems and roots of Piper methysticum, which belongs to the pepper family [61,62,63]. It is known to decrease anxiety and fatigue; it gives the user the sense of a sociable attitude, induces sleep, and relieves pain [51]. Six major kavalactones induce changes, interacting with GABA activity, inhibiting monoamine oxidase B, and reuptaking noradrenaline and dopamine [64].

The available data on the analytical determination of the active components are presented in Table 1.

Kava is legal in many countries; the use of the plant and the preparations containing kava lactones are legally regulated. The sale of Piper methysticum is controlled in France, Switzerland, and the Netherlands. Pharmaceutical preparations of the plant are prescription drugs in Germany. The UK government in 2002 clearly prohibited the sale, importation, and supply of kava-containing products. The possession of kava was strictly illegal in Poland until August 2018 [34].

2.9 Psylocibe

“Magic mushrooms” are the most common name for hallucinogenic fungi which contain psychoactive alkaloids psilocin and psilocybin. These alkaloids are two psychedelic substances with effects similar to LSD and mescaline [65,66,67,68].

The available data on the analytical determination of the active components are presented in Table 1.

Psylocin and psylocibine are considered as Schedule I drugs under the United Nations 1971 Convention on Psychotropic Substances and, therefore, mushroom containing them are not legal in the majority of worldwide countries. In the Netherlands, mushroom is illegal since December 2008. Mushroom and its active compounds are listed in Table 1 of the Republic Presidential Decree 309/90 and following updates in Italy [34].

2.10 Salvia divinorum

Salvia divinorum is an endemic plant in Mexico (the northeastern Sierra mazateca mountain) [69]. The chewing of fresh leaves or using it to make tea is known for centuries, while the dried leaves can be smoked or chewed [34].

Salvinorin A is the main active molecule of Salvia divinorum, and it is a potent hallucinogenic [70]. Different mechanism of action is shown by comparing it with classical hallucinogens, such as Δ9-tetrahydrocannabinol, LSD, or ketamine, due to no interaction with the 5-hydroxytryptamine receptor, N-methyl-d-aspartate receptor, and cannabinoid receptor [71,72].

The available data on the analytical determination of the active component are presented in Table 1.

Recently, both Salvia divinorum and salvinorin A have been brought under control in Belgium, Italy, Denmark, Lithuania, Latvia, Romania, Sweden, Japan, and Australia. Salvia divinorum has also been included recently in the list of “drugs of concern” by United States Drug Enforcement Administration. Germany, Croatia, Poland, and Spain put the control on the plant. Salvia divinorum is under medicines legislation in Finland, Estonia, and Norway. Without authorization under the Natural Health Products Regulation, it is impossible to sell Salvia in Canada [34].

2.11 Sceletium tortuosum

Sceletium tortuosum (common names: channa, kanna, sceletium) is a plant that belongs to Mesembryanthemum family. It is grown and used (as quid) in southern Africa to elevate mood and to relieve thirst and hunger. On the websites, it is sold as capsules or tablets, and it is highly recommended for the treatment of depression and anxiety, to quit smoking, and among students during the intense study periods [34]. The psychoactivity is attributed to alkaloids, mainly mesembrine. It was isolated by Zwicky in 1914, and structurally solved in 1960 [73,74]. In vitro experiments reveal various pharmacological roles, such as an effective inhibition of 5-HT reuptake, while mesembrenone inhibits both phosphodiesterase type 4 isoenzyme and 5-HT reuptake [75,76].

Sceletium tortuosum induces lethargy, strong headaches, loss of appetite, and depression [77].

The available data on the analytical determination of the active components are presented in Table 1.

There are no measures regarding the use of the S. tortuosum or active compounds isolated from the plant in the EU as well as in the USA [34].

2.12 Lactuca virosa

Lactuca virosa (wild lettuce) is a plant which can be found in Europe and in Asia [78]. Various preparations of Lactuca virosa have been used traditionally as a natural diuretic, analgesic, antitussive, and sedative [78,79].

The available data on the analytical determination of the active components are presented in Table 1.

There are no measures regarding the use of the plant or its active compounds in the EU as well as in the USA [34].

2.13 Lophophora williamsii

The illicit administration of Lophophora williamsii is less common, and the licit consumption is associated with the rituals of religious nature connected to Native American Church. The pharmacodynamic mechanisms of action involve the interaction with 5-HT2A-C receptors, inducing euphoria, hallucinations, depersonalization, and different psychoses [80]. However, it was shown to stimulate blood pressure, sleep, hunger, and thirst [81]. It was found that it contains different alkaloids, such as mescaline, pellotine, anhalonidine, lophophorin, anhalonin, anhalamin, N-methyl mescaline, N-acetyl mescaline, anhalidin, O-methylanhalonidine, and anhalin [82]. Mescaline was identified in 1896 and first synthesized in 1919 [80].

The available data on the analytical determination of mescaline are presented in Table 1.

Peyote is illegal in Brazil, Italy, France, and other countries, and it is not under control in Canada if it is not prepared for ingestion. The peyote use is only permitted when related to the Native American Church in the US legislation. The peyote cactus is not strictly prohibited or regulated in Mexico [83].

3 Synthetic molecules

3.1 Synthetic cathinones

Synthetic cathinones (“bath salts” in the USA and “plant food” or “research chemicals” in Europe) were synthesized in 1920s and were used for the treatment of patients with symptoms of Parkinson disease, obesity, and depression [219,220]. Lately, due to their psychoactive properties (empathy, euphoria, increased alertness, talkativeness, openness in communication, intensification of sensory experiences, reduced appetite, music sensitivity, increased sociability, insomnia, and capacity to work) [33], they were used as recreational drugs. However, synthetic cathinones possess somatic (cardiovascular system: hypovolemia, tachycardia, chest pain, hypertension, ST segment (the period when the myocardium maintains contraction to expel blood from the ventricles) alterations, myocarditis, cardiac arrest; central nervous system: insomnia, dizziness, headache, seizures, confusion altered mental status, tremor, confusion, dizziness, collapse, dystonia, hyperreflexia, drowsiness, myoclonus, paraesthesias; hematologic system: disseminated intravascular coagulation, anemia, thrombocytopenia; gastrointestinal and hepatic system: nausea, emesis, abnormal liver function tests, abdominal pain, liver failure; pulmonary system: tachypnea, shortness of breath, respiratory failure and arrest, respiratory acidosis; renal system: increased renal creatinine, kidney damage, hyponatremia, hyperkalemia, acute renal failure, hyperuricemia; musculoskeletal system: elevated creatinine kinase, peripheral vasoconstriction, rhabdomyolysis; ophthalmic system: mydriasis, nystagmus, blurred vision; ENT: epistaxis, tongue disorder, oral and pharyngeal effects, bruxism, trismus; consequences of IV use: vein blockage, local infection, skin erosion, scab, lump, abscess, gangrenous tissue, blood clots, and large holes at overused injecting sites) and psychiatric adverse effects (aggression, anxiety, agitation, anorexia, paranoia, depersonalization, visual and auditory hallucinations, paranoid delusion, psychosis, depression, suicidal thoughts, anhedonia, self-harm, cognitive disorders: long-term cognitive impairments, place and time, loosening of association, disorientation to names, addiction, withdrawal, and tolerance). Two pioneering representatives are methcathinone (CAT; in the 1930s and 1940s it was used in Russia as an antidepressant) and 4-methylmethcathinone ([4-MMC] mephedrone). The second most popular drug, methylone (3,4-methylenedioxy-N-methylcathinone), is usually combined with mephedrone (first synthesized in 1929), and 3,4-methylenedioxypyrovalerone (MDPV) is used due to reinforcing properties and the activation of brain rewarding circuitry [220,221,222]. Some new cathinones are used as substitute medications in therapy and treatment (e.g., bupropion (trade names Wellbutrin, Zyban) is prescribed as a smoking-cessation aid and for the treatment of depression) [223]. Pyrovalerone was intended to be a prescription drug to treat chronic fatigue, lethargy and obesity but was withdrawn from the legal market due to abuse in users [224,225,226]. 4-MEC, 4-MePPP, α-PVP, butylone (β-keto-N-methylbenzodioxolylbutanamine), pentedrone (α-methylamino-valerophenone), pentylone (β-keto-methylbenzodioxolylpentanamine), 3-FMC, 4-FMC, naphyrone (naphthylpyrovalerone), and α-PBP have no currently accepted medical use in treatment [227]. 3-MMC (metaphedrone) first appeared in Sweden in 2012 without any therapeutic use [228,229], and it is present on the illegal market as white powder or crystals, and according to users, it is less potent and intense than MDMA and 4-MMC [230]. Power et al. synthesized and analyzed 3-MMC using GC-MS, IR, and NMR in 2011 [231]. Christie et al. used Raman spectrometry to distinguish regioisomers, and it is fast and reliable, and, therefore, it can be used at airports [232].

Based on their chemical structures, cathinone derivatives are divided into four groups. The first group is a group of N-alkyl compounds, and compounds with a halogen or an alkyl substituent at any position of the aromatic ring: ephedrone, ethcathinone, flephedrone, mephedrone, buphedrone, and pentedrone (Table 2). The second group consists of compounds with substituents at any position of the aromatic ring as pentylone, methylone, and butylone, i.e., methylenedioxy-substituted compounds (Table 2). The third group is a group of natural cathinone analogs with N-pyrrolidinyl substituent. Finally, the fourth group consists of compounds that include both N-pyrrolidinyl and methylenedioxyl substituents.

Table 2

Cathinone derivatives

Chemical name Common name Chemical structure
[2-(N-Methylamino)butan-1-onyl]-benzene Buphedrone, α-methylaminobutyrophenone
[2-(N-Ethylamino)-propan-1-onyl]-benzene Ethcathinone, ETCAT, N-ethylcathinone
[2-(N-Methylamino)-propan-1-onyl]-benzene Ephedrone, methcathinone, CAT, α-methylaminopropiophenone
1-[2-(N-Methylamino)-propan-1-onyl]-4-fluorobenzene Flephedrone, 4-FMC, 4-fluoromethcathinone
1-[2-(N-Methylamino)-propan-1-onyl]-4-methylbenzene Mephedrone, 4-MMC, 4-methylmethcathinone
[2-(N-Methylamino)-pentan-1-onyl)]-benzene Pentedrone, α-methylaminovalerophenone
1-[2-(N-Methylamino)-propan-1-onyl]-3,4-dimethylbenzene 3,4-DMMC, 3,4-dimethylmethcathinone
1-[2-(N-Methylamino)-butan-1-onyl]-(3,4-methylenedioxy)-benzene Butylone, bk-MBDB, β-keto-methylbenzodioxolylbutanamine
1-[2-(N-Ethylamino)-propan-1-onyl]-(3,4-methylenedioxy)-benzene Ethylone, bk-MDEA, 3,4-methylenedioxy-N-ethylcathinone
1-[2-(N-Methylamino)-propan-1-onyl]-(3,4-methylenedioxy)-benzene Methylone, bk-MDMA, 3,4-methylenedioxy-N-methylcathinone
1-[2-(N-Methylamino)-pentan-1-onyl]-(3,4-methylenedioxy)-benzene Pentylone, bk-MBDP
1-[2-(Pyrrolidin-1-yl)-hexan-1-onyl]-4-methylbenzene MPHP, 4-methyl-α-pyrrolidinohexanophenone
1-[2-(Pyrrolidin-1-yl)-pentan-1-onyl]-benzene α-PVP, α-pyrrolidinovalerophenone
1-[2-Pyrrolidin-1-yl)-pentan-1-onyl]-4-methylbenzene Pyrovalerone, 4-methyl-α-pyrrolidinovalerophenone
1-[2-(Pyrrolidin-1-yl)-butan-1-onyl]-3,4-methylenedioxybenzene MDPBP, 3,4-methylenedioxy-α-pyrrolidinobutiophenone
1-[2-(Pyrrolidin-1-yl)-propan-1-onyl]-3,4-methylenedioxybenzene MDPPP, 3,4-methylenedioxy-α-pyrrolidinopropiophenone
1-[2-(Pyrrolidin-1-yl)-pentan-1-onyl]-3,4-methylenedioxybenzene MDPV, 3,4-methylenedioxypyrovalerone

Synthetic cathinones easily cross the blood–brain barrier (in vitro experiments) [221]. Also, β-keto-amphetamines cause CNS stimulating and sympathomimetic effects characterized by increased blood pressure, heart rate, mydriasis, and hyperthermia [50,233,234,235,236,237,238,239,240]. They are inhibitors of monoamine transporters. Their selectivity for serotonin receptors, norepinephrine transporter, and dopamine transporters is quite different. The mechanism of cathinone on neurotransmission consists of triggering of presynaptic dopamine release and reduction in the reuptake of dopamine which is similar to the mechanism of amphetamines. Interestingly, although they are binding to dopamine and serotonin receptors, the cathinone shows the highest affinity for norepinephrine receptors. It was also found that cathinone induces serotonin release and the inhibition of its reuptake [241].

Cathinones exist in two stereoisomeric forms, and each of them may possess different potency [222]. S-Enantiomers are present in khat. However, most ring-substituted psychoactive substances are present as racemic mixtures [242].

Regarding the potency of their inhibition of noradrenaline, dopamine, and serotonin reuptake and the ability to release these compounds, Simmler et al. [221] divided synthetic cathinones into three groups based on in vitro experiments:

  1. Cathinones that act like cocaine and MDMA (cocaine-MDMA-mixed cathinones). The mode of action of compounds from this group consists of nonselective inhibition of monoamine reuptake, which exhibits better selectivity toward the dopamine transporter and promotion of serotonin release (similarity to MDMA). Methylone, mephedrone, ethylone, butylone, and naphyrone are cathinones from this group [221,233,235,236,237,239].

  2. Cathinones that act like methamphetamine (methamphetamine-like cathinones). Their mechanism of action consists of the preferential reuptake inhibition of catecholamines and the release of dopamine. Flephedrone, methcathinone, and clephedrone (4-chloromethcathinone) are cathinones from this group [221,234].

  3. Synthetic cathinones with pyrovalerone-based structures (pyrovalerone cathinones). The members of this group, MDPBP and MDPV, are very selective and potent inhibitors of the catecholamine reuptake with no neurotransmitter release effect [221,234].

The strength and the action of cathinone on the central nervous system are wide depending on numerous factors (e.g., age, sex, general health condition, degree of addiction, taking other psychoactive substances, use of medication, and use of alcohol) [35,243]. They all elicit psychomotor excitation, euphoria, feeling of increased empathy, increased interpersonal openness and self-assurance, and increased libido [50,220,222,244]. Overdose can result in numerous adverse effects (e.g., panic and aggression, memory disturbances, hallucinations, memory loss, depression, and suicidal thoughts) [221]. The combination of measurements (MEA recordings and neuronal activity) with specific assays (monoamine reuptake transporter inhibition) shows as the primary mode of action the inhibition in hDAT and hNET of the investigated synthetic cathinones (4-MEC, 4-MMC, 3-MMC, pentedrone, methylone, α-PVP, and MDPV) [245].

Meyer et al. [237] proposed the mechanism of mephedrone metabolism involving N-demethylation to basic amines followed by the ketone functionality reduction, and methyl substituent hydroxylation of the aromatic ring (which enables its oxidation to the carboxylic acid). Uralets et al. [246] investigated the metabolites of 16 synthetic cathinones found in human urine upon their division into three groups according to their metabolization:

  1. Buphedrone, mephedrone, 4-methylbuphedrone, 4-methylethcathinone, pentedrone, 3,4-DMMC, flephedrone, ethcathinone, and N-ethyl-buphedrone belong to the first group. Their metabolism follows the pattern of the synthetic cathinone precursors (i.e., cathinone and methcathinone). In urine of recreational drug users, metabolites were detected from the processes of β-ketone reduction and N-dealkylation (ephedrines and norephedrines as the main metabolites).

  2. The second group includes 3,4-methylenedioxy-substituted cathinones (butylone, methylone, and ethylone), which are less prone to the β-keto reduction compared to the compounds of the first group. One of the explanations can be the existence of the 3,4-methylenedioxyl substituent in the aromatic ring. In the analyzed urine, the parent molecules were found [35].

  3. α-Pyrrolidinophenones, such as α-PBP and α-PVP, which were initially thought not to further metabolize followed by the reduction of the ketone group or not to be changed in the urine, are the representatives of the third group [237,246,247]. Shima et al. [248] showed that the main α-pyrrolidinophenones metabolic pathways depend on the length of the parent molecule alkyl chain in humans. PV9 metabolism differs significantly from α-PVP and α-PBP, and it includes (1) reduction of the ketone group to the alcohol, (2) oxidation of the pyrrolidine ring to the pyrrolidone, (3) aliphatic oxidation of the terminal carbon atom to the carboxylate, (4) hydroxylation at the penultimate carbon atom to the alcohol, (5) oxidation to the ketone, and (6) combinations of the above steps [248].

Dickson et al. [249] described the preparation method of autopsy material for basic drug search: to 1 or 2 mL of the sample in the liquid state, a phosphate buffer (pH 6), and the internal standard (ethylmorphine or mepivacaine at the concentration of 0.5 mg/L) were added. The mixture was then ultrasonicated for 15 min and centrifuged. They were subsequently put on the top of the SPE cartridges (mixed-mode silica-based SPE), which were previously treated with 3 mL deionized water, 3 mL methanol, and 2 mL of the same phosphate buffer. Afterward, the cartridges were washed with 2 mL deionized water, 2 mL 20% aqueous acetonitrile, and 2 mL 0.1 M acetic acid. In the end, the cartridges were dried for 3 min in a vacuum, then in 3 mL methanol and 2 mL hexane, and again dried for 10 min in a vacuum. The elution afterward was performed with 3 mL dichloromethane/isopropanol/ammonium hydroxide (78:20:2, v/v/v), and after the evaporation of the solvent under nitrogen and the residue dissolution in 50 µL acetonitrile, the samples were made ready for the instrumental analysis. The introduction of QuEChERS technique into the toxicological analysis is mentioned in the majority of recent reports on the determination of synthetic cathinones from postmortem samples. Its use has several advantages compared to LLE and SPE, which are prone to the possible contamination of samples giving rise to the possibilities of inaccurate results and negative matrix results on analytical instruments. Usui et al. [250] used QuEChERS for the rapid extraction of psychoactive substances from human blood, demonstrating selectivity compared to SPE and simplicity as LLE. Also, QuEChERS is often cheaper and faster comparing to LLE and SPE. In the extraction/partitioning step, liquid samples are triple diluted with distilled water, followed by the placement in plastic test tubes containing 0.5 g of a commercial mixture (sodium acetate and magnesium sulfate), a stainless-steel bead, and 1 mL acetonitrile with IS. The content of the tube is vigorously mixed and centrifuged. In the case of acidic analytes, the acetonitrile layer can be used directly for the instrumental analysis. Contrary, for basic compounds, additional step, dSPE, must be performed, which requires 600 µL of acetonitrile supernatant into a test tube that contains a commercially obtained mixture of N-propylethylenediamine, then an amount of an end-capped octadecylsilane, and magnesium sulfate, for the purification. Afterward, the content of the test tube should be mixed and centrifuged, and the upper layer taken for the instrumental analysis.

The identification of cathinone derivatives always begins with the application screening methods that are not specific. In the case of powders, tablets, and capsules, colorimetric methods are used [251,253]. The most frequently used test for nitrogen-containing compounds (used for the identification of amphetamine) is the Marquis reagent (formaldehyde and sulfuric acid). It does not give positive reaction for synthetic cathinones derived from mephedrone. Positive results are obtained with the compounds containing the methylenedioxyl substituent (e.g., MDPV). For MDPV, the additional test with the Chen reagent (copper monosulfide, acetic acid, and sodium hydroxide) can also be applied, and this test was considered as good for the ephedrine derivatives, too [252]. Colorimetric tests are good because they are fast and easy for the application. However, the disadvantage of this test is that it provides the identification only of the single structural part of a molecule, which is not sufficient for the identification of a compound. Immunoenzymatic assays are used for the screening of the biological material. The most commonly used assay is ELISA [253,254], but it was shown as nonspecific because of cross reactions (e.g., the reaction between MDPV and butylone) [254]. For synthetic cathinones, primarily GC [251,255,256,257,258,259,260,261] and LC were used coupled with different spectroscopic techniques [262,263,264]. CI is sometimes applied, but EI is mostly used [251,255,256,257,258,259,260,261]. GC-MS gave a simple mass spectrum in the positive ionization mode characterized by signals derived from iminium ions. Zuba [260] proposed a new method for the identification of synthetic cathinones using GC-EI-MS. Recently the distinguishing of regioisomers becomes possible due to the application of GC-EI-MS/MS [255]. LC-MS is used in the toxicological analysis because of its high selectivity and sensitivity [265,266,267]. UHPLC coupled with the time-of-flight mass spectrometry (TOF-MS) [268] and its quadrupole TOF (QTOF) is an extra technique for the high accuracy analysis of the active compounds in designer drugs [269]. The less-used detection system, for biological samples and drug products, is LC coupled with ultraviolet-visible (UV-Vis) spectroscopy using diode array or PDA detection which can be used only for screening [267,270,271,272,273]. Screen-printed graphite electrodes can be used for the detection of two metabolites of 4-MMC (4-methylcathinone and 4-methylephedrine) and, therefore, is a potential portable analytical sensor for the fast, cheap, reliable, and accessible detection and quantification of synthetic cathinone metabolites mainly for on-site analysis [274]. HPLC-MS/MS in combination with micro-solid-phase extraction as a preparation process using membrane-protected molecularly imprinted polymer (high selectivity) can also be used for synthetic cathinones monitoring in urine [275].

3.1.1 MDPV

The alkaloid cathinone is the main psychoactive compound of the khat plant (Catha edulis), which has been used as a stimulant in the Arabian Peninsula and parts of Africa for hundreds of years. Its psychoactive properties are known for centuries by inhabitants of East Africa and north-eastern parts of the Arabian Peninsula [235,276,277,278]. It was found that members of this class stimulate the release of dopamine and norepinephrine [279] and inhibit dopamine and norepinephrine transporters with a negligible effect on serotonin reuptake [280,281]. MDPV was first synthesized in 1969 and is structurally closely related to cathinone [282,283]. Also, it is a locomotor stimulant, approximately ten times more potent than cocaine [234,284].

Mephedrone and MDPV show excellent blood–brain barrier permeability in an in vitro model (Table 3) [221].

Table 3

Blood–brain barrier permeability for selected psychoactive substances [221]

Pe ratio
Apical to basolateral Basolateral to apical Permeability Active transporta ClogPb
MDMA 6.0 ± 0.56 7.4 ± 2.4 + No 1.85
Mephedrone 14.0 ± 10.4 12.2 ± 6.1 ++ No 1.67
Methylone 6.1 ± 2.8 5.3 ± 1.3 + No 1.39
Methcathinone 5.9 ± 2.8 8.5 ± 3.2 + No 1.19
Amphetamine 6.3 ± 3.7 5.2 ± 1.3 + No 1.74
Methamphetamine 5.4 ± 1.1 6.4 ± 3.0 + No 1.74
MDPV 37.2 ± 11.3 12.0 ± 11.2 ++ Yes 3.80

Data are expressed as mean ± SD (n = 3–9).

Pe ratios shows the blood–brain permeability of the drug in relation to the extracellular marker Lucifer yellow (Pe = 1).

+, high permeability (Pe ratio > 3). ++, very high permeability (Pe ratio > 10).

Users of this and similar drugs have experienced euphoria, alertness, talkativeness, sexual arousal, and positivity 30–45 min after oral intake, which lasts 1–3 h. The side effects are numerous and consist of insomnia, anxiety, mydriasis, fatigue, agitation, aggression, panic, combative behavior, disorientation, memory loss, confusion, blackouts, excited delirium, myoclonus, paranoia, hallucinations, chest pain, increased suicidal intention, and hypertension. According to medical records, users of these drugs (including MDPV) are out of control and very violent [285].

MDPV shares structural similarities and pharmacodynamics with MDMA. Recreational use of more than one drug is quite common [286]. Frequently, NPS are often combined with other drugs, particularly ethanol [287,288,289]. The MDPV levels in 23 postmortem cases ranged 10–640 ng/mL in blood [285].

3.2 Phenethylamines

Phenethylamines are compounds which are relatives of amphetamines and MDMA. Their skeleton is an aromatic ring with two-carbon side-chains ending with an amine group (Figure 1) and can undergo two main changes: (1) substitution of the α-carbon by a methyl produces amphetamine derivatives (Figure 1) [290] and (2) substitution of the benzene cycle at positions 2 and 5 with methoxy groups and position 4 with a substituent on phenethylamine or amphetamine (Figure 1) [290,291,292]. Tetrahydrobenzodifuranyl and benzodifuranyl (“FLY”) are analogs of these series [293]. NBOMe series, which consists of N-benzyl derivatives of the 2 C series (Figure 1) was recently made [294,295].

Figure 1 Chemical structures of some members of the phenethylamines family of drugs [296]. Reprinted from Drug and Alcohol Dependence, 154, Gael Le Roux, Chloe Bruneau, Benedicte Lelievre, Marie Bretaudeau Deguigne, Alain Turcant, Patrick Harry, David Boels, Recreational phenethylamine poisonings reported to a French poison control center, 46–53, 2015, with permission from Elsevier.

Figure 1

Chemical structures of some members of the phenethylamines family of drugs [296]. Reprinted from Drug and Alcohol Dependence, 154, Gael Le Roux, Chloe Bruneau, Benedicte Lelievre, Marie Bretaudeau Deguigne, Alain Turcant, Patrick Harry, David Boels, Recreational phenethylamine poisonings reported to a French poison control center, 46–53, 2015, with permission from Elsevier.

It has been demonstrated that ring substitutions increase the affinity of compounds for 5HT2a receptors [297]. The substitution of the aromatic ring with a methylenedioxy group at positions 3 and 4 gives MDMA and its derivatives. They belong to a new pharmacological class – entactogens.

MDMA switches on central α2A adrenoceptors and peripheral α1 adrenoceptors inducing vasoconstriction to restrict heat loss, and β3 adrenoceptors in brown adipose tissue increasing the generation of heat. The hyperthermia happening in recreational users of MDMA can be fatal (the first investigations in 1998 [298]); furthermore, the literature data indicate that there are small chances that any pharmaceutical agent will be effective in reversing the hyperthermia [298]. Although it was found that hypothermia is the major effect when 10 mg kg−1 was injected in mice, hyperthermia followed by hypothermia is observed when doses of 30 mg kg−1 were applied [299]. The reason for that phenomenon may be the vasodilation of the tail veins [300]. Generally, MDMA and its derivatives do not cause hallucinations but promote the feeling of socialization in consumers [301,302,303].

Adverse reactions upon the consumption of phenethylamines are feelings of distress and anxiety, emotional disturbances, unpleasant hallucinations, tachycardia and hypertension, frequent agitation, tremors, and seizures [296]. It has been suggested that alcohol-induced effects are reduced by MDMA without any improvement in psychomotor performance. Effects of MDMA was prolonged in combination with alcohol [304], but it reduces hyperthermia induced by MDMA [115]. Cannabis consumption combined with phenethylamines is frequent and recommended in Internet forums for avoiding “come down” (e.g., negative symptoms or aggressive behavior) [305].

Both in vivo and in vitro investigations of selected “FLY” analogs (2C-T-7-FLY, 2C-E-FLY, 2C-EF-FLY) using LC-HRMS/MS gave 32 metabolites with the major metabolic steps consisted of hydroxylation and N-acetylation; phase I was catalyzed by CYP2D6, 3A4, and FMO3 and N-acetylation using NAT1 and NAT2 [306]. LC-MS/MS methods for the thermally labile (25-NBOH drugs) were developed [307]. Pharmacokinetic profile of new amphetamines (1-(2,3,6,7-tetrahydrofuro[2,3-f][1]benzofuran-4-yl)propan-2-amine and 2-(2,3,6,7-tetrahydrofuro[2,3-f][1]benzofuran-4-yl)ethanamine) were investigated using LC-MS/MS [308]. Developed ELISA for the detection of 2C-B and similar hallucinogenic phenethylamines was confirmed as a good tool for screening before confirmation with UHPLC-MS-MS [309].

The fragmentations of NBOMe derivatives were analyzed using LC-QTOF/MS; the halogen-substituted methoxybenzylethanamine-type derivatives showed a characteristic product ion of a radical cation [14]. Fully validated LC-tandem mass spectrometry method was developed for the quantification of seven NBOMes (25B-, 25C-, 25D-, 25E-, 25G-, 25H-, and 25I-NBOMe) in blood, with the previous refrigeration of the whole blood (up to 90 days) or freezing of samples for longer storage [310].

3.2.1 25I-NBOMe

25I-NBOMe is a derivative of the 2C-X series of phenethylamines. NBOMe compounds are known as hallucinogens and stimulants, and potent agonists of the human 5HT2A receptor [311].

Theoretical studies revealed expected interactions of partial agonists (hallucinogens like ergolines, phenylisopropylamines, and substituted tryptamines) with the 5HT2A receptor (e.g., with a cluster of aromatic amino acids in TM5 and TM6, and serines in TM3 and TM5). The highly conserved Asp1553.32 [312,313]; the serines Ser1593.36, Ser2395.43, and Ser2425.46 (h5-HT2AR, Ala242 in r5-HT2AR) [314,315,316]; and the phenylalanines Phe2435.47, Phe2445.48, and Phe3406.52 [317,318,319] are shown as important for efficacy and binding of agonists and partial agonists for 5HT2AR (superscripts show the generic numbering scheme of amino acids in TMs 1–7 proposed by Ballesteros and Weinstein [320]).

Dopamine level increased in mice after taking 25I-NBOMe, and the expression levels of SGK1 and PER2 changed [321].

3.2.2 MDMA

MDMA is the main constituent of the widely used recreational drug ecstasy [322]. It was first made in the lab in 1912 by Merck KGaA (Darmstadt, Germany) in the project aimed the identification of new hemostatic (blood-clotting) agents [322]. Its first major toxicological study in animals was performed in the 1950s at the University of Michigan in a classified USA Army contract [322]. In 1973, the results were declassified and made public by Hardman et al. [323]. In 1978, Alexander Shulgin together with David Nichols from Purdue University published the first report on the effects of MDMA in humans [324].

The positive effects of MDMA consumption include arousal, euphoria, increased sociability, enhanced mood, and heightened perceptions [322]. Adverse effects consist of headache, nausea, bruxism, tachycardia, and trismus [322]. The acute effects of MDMA are ascribed to increase the release and inhibit the reuptake of norepinephrine and serotonin with the possibility of the release of the neuropeptide oxytocin [322].

MDMA is a Schedule I compound by the Drug Enforcement Agency, but MDMA-assisted psychotherapy for patients with chronic, treatment-resistant posttraumatic stress disorder is currently under investigation [322].

3.3 Cannabinoids

Based on the origin, cannabinoids can be classified into (1) phytocannabinoids, (2) endocannabinoids, and (3) synthetic cannabinoids [325].

In the 1980s, cannabinoid receptors were found and labeled with CB and numbered according to their discovery by a subscript (CB1 and CB2). These receptors differ based on their predicted amino acid sequence, tissue distribution, and signaling mechanisms [326].

HPLC-UV approach was shown as the gold standard for the quantitation of the synthetic cannabinoids with highly conjugated chromophores [327]. Synthetic and natural cannabinoids were found in oral fluid using solid-phase microextraction coupled to gas chromatography/mass spectrometry [328].

Synthetic cannabinoids can be grouped based on their structures by the National Forensic Services: naphthylindoles, phenylacetylindoles, benzoylindoles, cyclopropylindoles, aminocarbonylindazoles, adamantylindoles, adamantylindazoles, quinolinylindoles, CP-47,497 homologs, and cyclopropylthiazoles [1,329,330,331] (Figure 2).

Figure 2 Sample structures for synthetic cannabinoids: (a) JWH-018, a simple naphthoylindole; (b) JWH-167, a simple phenylacetylindole; (c) AM-1241, a chemical from benzoylindole family; (d) APICA (2NE1, SDB-001), a drug from adamantylindole group; (e) APINACA (AKB48), a drug from adamantylindazoles family; (f) general structure for quinolinylindole.

Figure 2

Sample structures for synthetic cannabinoids: (a) JWH-018, a simple naphthoylindole; (b) JWH-167, a simple phenylacetylindole; (c) AM-1241, a chemical from benzoylindole family; (d) APICA (2NE1, SDB-001), a drug from adamantylindole group; (e) APINACA (AKB48), a drug from adamantylindazoles family; (f) general structure for quinolinylindole.

The first synthetic cannabinoid was detected at the end of 2008, and since then, more than 130 synthetic cannabinoids have been registered at the EMCDDA [332].

3.3.1 Marijuana (cannabis)

Phytocannabinoids are present in significant quantities in plant cannabis [333]. The medicinal use of marijuana, a complex plant, for its analgesic, anticonvulsant, and anti-inflammatory properties is known [334]. The first medical data on this plant (the relief of cramps and pain) are coming from China around 5,000 years ago [335]. Few phytocannabinoids, especially CBD, has a beneficial effect in numerous pathological conditions (inflammation, cancer, addiction, and epilepsy) [336,337,338,339]. The various pharmacological properties of marijuana have inspired drug discovery programs intending to produce new cannabinoids with therapeutic potential.

However, a number of epidemiological research shows the connection between dose-related marijuana use and an increased risk of the development of symptoms of depression and anxiety [340]. Studies showed that the negative effect of cannabis is more pronounced in individuals with predispositions for psychosis and personality and psychosis susceptibility genes [340].

3.3.2 Synthetic cannabinoids

Synthetic cannabinoids are mimetic of Δ9-tetrahydrocannabinol, the primary active substance in cannabis. Other cannabinoids present in cannabis are CBD and CBN [333,341]. They are full agonists of the CB1 receptor, a GPCR [342]. Several other receptors, ranging from other GPCRs to ion channel and nuclear receptors, have been reported to have the interaction with cannabinoids [326,343]. The full-length CB1R dominates in the skeletal muscle and brain, whereas the CB1Rb shows high expression level in pancreatic islet cells and the liver [344] (Figure 3a). In human body, two isoforms of the CB2R are as follows: the first is mainly expressed in testis and at lower levels in brain reward regions, whereas the second is predominantly expressed in the spleen and at the lower levels in the brain [345] (Figure 3a).

Figure 3 (a) The main localization sites and related functions of the CB1R in the human body; (b) subcellular localization of the CB1R [335].

Figure 3

(a) The main localization sites and related functions of the CB1R in the human body; (b) subcellular localization of the CB1R [335].

Similarly to other GPCRs, the CB1R is mainly localized in cell membrane. However, the predominant localization of CB1Rs is inside the cell, including transfected nonneuronal cells, cultured hippocampal neurons, and undifferentiated neuronal cells [346]. Intracellular CB1Rs are in acid-filled endo/lysosomes [347] (Figure 3b). Also, there is another subpopulation of CB1Rs expressed in mitochondria.

Synthetic cannabinoids have similar effects with the natural cannabinoids, including alteration in perception and mood, increased pulse, and xerostomia [348].

In vitro phase I of PX-1 (5F-APP-PICA) showed ten identified metabolites, which enable medical professionals and analytical scientists to detect PX-1 and make a prediction of the metabolites of synthetic cannabinoids with the similar structural pattern [349]. Synthetic cannabinoids with an alkene functional group at the alkyl side chain, chosen for in vitro and in vivo investigations (MDMB-4en-PINACA, methyl (S)-3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate) show a total of 32 metabolites (11 in hepatocyte samples, 31 in human liver microsomes, 1 in blood and 2 in urine), and the main metabolic pathway happens through the terminal alkene group of the pentenyl side chain consisting of dihydrodiol formation (via epoxidation probably) [350]. It was found that the major hydrolysis metabolites of ADB-CHMICA, 5F-AB-PINACA, ADB-FUBICA, ADB-CHMINACA, and their ethylester and methyl-derivatives do not induce any CB1 activation at concentrations lower than 1 μM [351]. On the contrary, metabolites of 5F-ADB-PINACA, AB-CHMINACA, and ADB-FUBINACA show activity, but it is significantly reduced compared to the parent compounds (EC50 > 100 nM) [351]. 5F-CUMYL-P7AICA metabolites were identified in three urine samples, where the major biotransformation steps in humans were oxidative defluorination followed by carboxylation and monohydroxylation followed by sulfation and glucuronidation [264]. Metabolism of the new synthetic cannabinoid 7′N-5F-ADB in human, rat, and pooled human S9 was studied by means of hyphenated high-resolution mass spectrometry [352]. UHPLC-QTOF-MS was used for screening, quantification, and confirmation of synthetic cannabinoid (AB-FUBINACA, AB-CHMINACA, AB-PINACA, AM-2201, 5F-AKB48, AKB48, JWH-018, BB-22, JWH-081, JWH-073, JWH-122, JWH-203, JWH-250, 5F-PB-22, RCS-4, PB-22, THJ-2201, and UR-144) metabolites in urine [353]. Incubation of APP-CHMINACA with human liver macrosomes, followed by analysis with HRMS gave 12 metabolites with the predominant biotransformation in the form of hydrolysis of the distal amide group and hydroxylation of the cyclohexylmethyl substituent [354]. Analysis of pHLM and urine samples revealed that in case of 5F-AB-P7AICA the main metabolites were generated by amide hydrolysis, hydroxylation, and hydrolytic defluorination [355].

Huffman and colleagues at Clemson University extensively explored SARs within the AAI class of SCs, resulting in highly simplified analogs exemplified by JWH-018, which shows high affinity for CB1 receptor (Ki = 9.0 nM) [356,357,358,359]. Auwarter et al. identified JWH-018 and the n-octyl homolog of CP 47497 as the psychoactive components of “Spice” [360].

3.3.2.1 JWHs

The first “JWH” compounds were made by Huffman et al. [357] researching the effects of JWHs on CB1 and CB2 receptors. They reported higher affinities than those reported for cannabis [359]. JWH-018 (1-alkyl-3-(1-naphthoyl) indole) was detected for the first time in 2008 in “Spice” products [360]. JWH-018 metabolite exerts higher toxicity compared to the parent drug, suggesting a non-CB1 receptor-mediated toxicological mechanism [361]. The first generation of JWHs consists of JWH-073, JWH-018, JWH-250, and CP 47,497. The synthesis of these drugs is straightforward, so it has been continued with second generation (RCS-4, JWH-122, and AM2201) [362].

Various JWHs were detected in seized materials [363,364,365,366,367], such as oral fluid [368], hair [369], serum, or whole blood [370,371,372,373,374]. In vivo studies consisted of the investigation of phases I and II metabolites in the rat urine after exposure and in human urine postadministration [375,376,377,378,379,380,381,382,383]. It was shown that hydroxylation and carboxylation are typical phase I biotransformations prior to conjugation [384]. JWH-018 is metabolized through phases I and II enzymes [385]. There are indications that CYP1A2 and CYP2C9 catalyze JWH-018 oxidation [386,387], while hepatic UGT1A9, UGT1A1, and UGT2B7 and extra-hepatic UGT1A10 are the enzymes that perform the catalysis of the conjugation of glucuronic acid to phase I JWH-018 metabolites [386]. JWH-018 hydroxylated metabolites bind to CB1 with more “love” than Δ9 THC [388,389], and JWH-018 phase I metabolites also like CB2 receptor [389].

Investigations of toxicological profiles of synthetic cannabinoids have shown cannabinoid receptor independent and dependent cytotoxic effects on cell lines [390,391,392]. Koller et al. [391] found that JWH-018 induces damage to the cell membranes of buccal (TR146)- and breast (MCF-7)-derived cells at concentrations of ≥75–100 µM. JWH-018 N-(3-hydroxypentyl) phase I metabolite is toxic for HEK293T and SH-SY5Y cell lines contrary to its parent compound. JWH-018 metabolite causes mitochondrial damage and membrane disruption on both cell lines [361].

Different spectrometric techniques were used for the identification: GC-MS [236,364,377], GC-MS/MS [382], LC-MS [364], and LC-MS/MS [371,372,374,375,376,377,378,379,380,382,383,385]. Shanks et al. (2012) [373] developed the method for the analysis of the concentrations of JWH-018 and JWH-073 in human blood using UPLC-MS-MS. Concentrations ranged from 0.1 to 199 ng/mL for JWH-018, and 0.1–68.3 ng/mL for JWH-073 in postmortem forensic cases.

3.4 Arylcyclohexylamines

3.4.1 Ketamine and norketamine

Ketamine is a medical anesthetic agent used in veterinary medicine and also in humans [393,394] and pediatric practice [395]. Arylcyclo-alkylamine skeleton produces hallucinogenic effects [396].

Ketamine biotransformation mechanism of ketamine was established by Chang and Glazko (1972) [397]. In phase I, the ketamine oxidation process occurred (heteroatom demethylation), giving norketamine, followed by a hydroxylation process (here the product is HNK); and in phase II the biotransformation reaction, it undergoes glucuronidation and conjugation with glutathione and amino acid.

For the detection of ketamine, GC/NPD [398], GC/MS (first derivatized with heptafluorobutyric anhydride) [399], and GC/CIMS [400] were used. The same derivatization procedure was used for HS-SPME-GC/MS [401], LC/UV [402,403], and LC/MS single mass, tandem mass [404].

3.4.2 BZP

Stimulant properties of BZP, a piperazine derivative, are similar to those produced by amphetamine but less potent [405]. It is listed as Schedule I drug in the USA and Schedule III in Canada but banned in all Australian states, New Zealand, and Japan [406].

It has many adverse effects, such as palpitations, agitation, anxiety, confusion, dizziness, tremor, headache, urine retention, insomnia, and vomiting [407].

3.5 Tryptamines

Numerous biologically active derivatives contain the tryptamine nucleus as a building block, such as neurotransmitter serotonin or antimigraine drugs of the tryptan series. N,N-Dialkylation on nitrogen side chain may result in derivatives with psychoactive and hallucinogenic properties acting primarily as agonists of the 5-HT2A receptor [408]. The story of synthetic tryptamines started with LSD in mid-1900s, with AMT 5-MeO-DMT (5-methoxy-N,N-dimethyltryptamine) and 5-MeO-DIPT as the next-generation designer drugs to replace LSD [408].

Key properties in the interpretation of mass spectra of this class of illegal drugs include the formation of iminium ion CnH2n+2N+ in substituted CH2═N+(R1R2) species. Soft-ionization techniques, such as electrospray, are used to give strong [3-vinylindole]+-type species, reflecting the extent of the substitution on the indole ring [409].

Figure 4 represents a generalized tryptamine structure. Psychoactivity is highly affected by the substitution in positions 4 and 5 of the indole ring and the alkylation of the side-chain nitrogen and the side-chain carbon [410]. Interestingly, numerous naturally occurring psychoactive tryptamines are N,N-dimethylated derivatives: DMT, psilocybin (found in many mushroom species [411]), psilocin (4-OH-DMT), and 5-methoxy- and 5-hydroxy-DMT (bufotenin).

Figure 4 Generalized structure of a tryptamine derivative [409]. Reprinted from TrAC Trends in Analytical Chemistry, 29, Claudia P. B. Martins, Sally Freeman, John F. Alder, Torsten Passie, Simon D. Brandt, Profiling psychoactive tryptamine-drug synthesis by focusing on detection using mass spectrometry, 285–296, 2010, with permission from Elsevier.

Figure 4

Generalized structure of a tryptamine derivative [409]. Reprinted from TrAC Trends in Analytical Chemistry, 29, Claudia P. B. Martins, Sally Freeman, John F. Alder, Torsten Passie, Simon D. Brandt, Profiling psychoactive tryptamine-drug synthesis by focusing on detection using mass spectrometry, 285–296, 2010, with permission from Elsevier.

The pharmacology of tryptamine derivatives is complex, but it seems that 5-HT1A & 2A receptor subtypes are involved [412,413,414]. It was found that DMT also serves as an agonist at the sigma-1 receptor [415]. Szara showed that DMT induces spatial distortions, visual hallucinations, speech disturbance, and euphoria when it is used intramuscularly in humans [416]. Numerous N,N-dialkylated tryptamines were discovered to be substrates at the vesicle monoamine transporter and the plasma membrane serotonin transporter [417].

LSD was synthesized in 1938 by Hofmann, and hallucinogenic properties were determined a few years later [418,419]. AMT was developed in the Soviet Union as an antidepressant under the name of Indopan in the 1960s. Although today it does not have any therapeutic applicability, its popularity as a “designer drug” increased in 1990s [420]. Tryptamine derivatives can be found as a free base or salt, tablets, or powders [421,422].

An increased impulsiveness and abnormal behaviors occurred after taking tryptamine. The study on rats was performed regarding the effect on body temperature. During the period of the administration, they showed hypothermia, followed by hyperthermia [408].

DMT metabolic pathway in humans is sketched in Figure 5. It is inactivated by MAO enzymes in gut and liver.

Figure 5 (a) Minor (blue arrows) and major (red arrows) metabolic pathways for DMT in humans; (b) metabolic pathways for psilocybin in humans [408].

Figure 5

(a) Minor (blue arrows) and major (red arrows) metabolic pathways for DMT in humans; (b) metabolic pathways for psilocybin in humans [408].

The analysis of urine from LSD shows five metabolites: 2-oxo-LSD, 2-oxo-3-hydroxy-LSD, N-desmethyl-LSD, 13- and 14-hydroxy-LSD glucuronides [423,424,425]. It is suggested that 2-oxo-3-hydroxy-LSD could be made through dehydrogenation of the 2,3-dihydroxy-LSD intermediate, which is probably formed from LSD 2,3-epoxide [408]. Due to the fact that urine samples contain the parent compounds in small quantities or may not even be excreted, it is better to investigate the metabolites of NPS using pooled human liver S9 fraction. Such analysis of nine LSD derivatives (1-acetyl-LSD (ALD-52), 1-butyryl-LSD (1B-LSD), 1-propionyl-LSD (1P-LSD), N6-ethyl-nor-LSD (ETH-LAD), N6-allyl-nor-LSD (AL-LAD), 1-propionyl-N6-ethyl-nor-LSD (1P-ETH-LAD), N-ethyl-N-cyclopropyl lysergamide (ECPLA), lysergic acid morpholide (LSM-775), and (2′S, 4′S)-lysergic acid 2,4-dimethylazetidide (LSZ)) enables the identification of monooxygenase enzymes involved in the initial metabolic steps [426]. It was found that 1-acyl-substitution reduces the affinity of LSD for the majority of monoamine receptors (including 5-HT2A sites) [427]. 1P-LSD, ALD-52, and 1B-LSD have weak efficiency as antagonists in Ca2+ mobilization assays [427].

3.6 New synthetic opioids

NSO can be divided into two groups: (1) pharmaceutical (e.g., sufentanyl, fentanyl, remifentanyl, carfentanyl, and alfentanyl) and (2) nonpharmaceutical fentanyls (e.g., ocfentanyl and butylfentanyl). A new generation of NSOs, with structures different from fentanyls, appeared on the drug market in 2010: MT-45 (piperazine analogue), AH-7921 (benzamide analogue), isotonitazene, and U-47,700 (isomer of AH-7921) (Figure 6). They are characterized by different characteristics, such as availability on the Internet, purity, low price, legality, and lack of detection in laboratory tests [419]. NSOs can be found in tablet, powder, or liquid forms [428].

Figure 6 Structures and potencies of NSOs [428]

Figure 6

Structures and potencies of NSOs [428]

Their number is increasing. The synthetic opioid U-47700, μ-opioid receptor agonist, emerged on the illicit drug market, and it is sold as a “research chemical” with a potency of approximately 7.5 times that of morphine [418]. Its structure is similar to the synthetic opioid AH-7921.

Isotonitazene (N,N-diethyl-2-[5-nitro-2-({4-[(propan-2-yl)oxy]phenyl}methyl)-1H-benzimidazol-1-yl]ethan-1-amine) was identified recently using GC-MS and LC-QTOF-MS (m/z = 411.2398) with the confirmation of the region – isomer with 1H and 13C NMR [429]. Assessment of the in vitro biological activity at the μ-opioid receptor showed its high potency (EC50 = 11.1 nM) and efficacy (Emax 180% of hydromorphone) [429]. In vivo experiments show four metabolites identified using LC-QTOF-MS: N- and O-dealkylation products (N-desethyl-isotonitazene and N-desethyl-O-desalkyl-isotonitazene) were determined as urinary biomarkers, while 5-amino-isotonitazene was found in the majority of the investigated blood samples [430].

Potential use of NSO causes side effects, such as sedation, miosis, hypothermia, respiratory depression, inhibition of gastrointestinal propulsion, death (overdose) [431]. Sometimes reagents used in the synthesis can cause symptoms like discoloration of the nails, loss and depigmentation of hair, extensive folliculitis and dermatitis, bilateral hearing loss, elevated liver enzymes, and eye irritation followed by bilateral secondary cataracts requiring surgery, after the administration of MT-45 [432,433].

As a pharmaceutical medicine, fentanyl is used in anaesthesia and for the management of severe pain. In anaesthesia, sufentanyl, remifentanil, and alfentanil can also be used. On the other hand, carfentanyl (at the moment the most powerful synthetic opioid-10,000 times more potent than fentanyl) is used in veterinary medicine (trade name Wildnil®). However, it was most likely used to free hostages in Moscow by the government [434]. Pharmaceutical forms include lozenges, transdermal patch, sublingual tablets, and solutions for the infusion [435].

Up to 17 opioid receptors have been reported, but three classes are the most important in humans: μ, κ, and δ [436]. Fentanyl, made in 1959 by Jansen, is a complete μ receptor agonist. Metabolism of this drug, mediated by the CYP450 isoenzyme system, makes inactive norfentanyl [437]. Carfentanyl and its metabolites can be detected in urine (LOD is 0.20 ng/mL for carfentanyl and LOD for carfentanyl metabolite is 0.01 ng/mL) [438]. Carfentanyl amides were found as potent compounds with less hazardous side effects associated with traditional opioids [439]. MT-45 acts on opioid (δ and κ) and nonopioid receptors. Its mechanism is not well investigated yet, and it can be responsible for special reported effects (e.g., profound loss of consciousness and ototoxicity) [440]. The psychiatric effects of opioids are related to the localization of receptors in the central nervous system [441]. κ receptors contribute to dysphoria, and they are present in the brain stem, spinal cord, and in the limbic and other diencephalic areas. Euphoria is connected to μ-opioid agonist effect in the medial thalamus and brain stem. The duration varies depending on the drug and its half-life (1–8 h). The psychiatric effects from opioid abuse are similar to those of heroin: a sense of well-being, relaxation, and euphoria, followed by a peaceful, dream-like state [428]. Naloxone is a short-acting semisynthetic competitive opioid receptor antagonist with the highest activity for the μ receptor and can be administered by intramuscular, intravenous, subcutaneous, and intranasal routes [428].

Routine urine drug tests cannot detect them yet. They show extreme potency, and very small quantities are enough to obtain a result [428]. The fragmentation pattern of frequently used NSO (fentanyl derivatives, AH series opioids, 4U series opioids, 4W series opioids, and MT-45) was investigated with the aim to be applied to a nontargeted screening workflow [442]. Metabolic fate of three NSOs (trans-4-bromo-N-[2-(dimethylamino)cyclohexyl]-N-methyl-benzamide (U-47931E), trans-3,4-dichloro-N-[2-(dimethylamino)cyclohexyl]-N-methyl-benzenacetamide (U-51754), and 2-methoxy-N-phenyl-N-[1-(2-phenylethyl)piperidin-4-yl]acetamide (methoxyacetylfentanyl)) was found using high-resolution mass spectrometry after pooled human S9 fraction incubation and in the urine of rats after oral intake, and the following main reactions occurred: (1) demethylation of the amine moiety for U-51754 and U-47931E, (2) N-hydroxylation of the hexyl ring, (3) combinations of O-demethylation, N-dealkylation, and hydroxylation at the alkyl part for methoxyacetylfentanyl [443]. Miniaturized ion mobility spectrometer with a dual-compression tristate ion shutter for on-site rapid screening of fentanyl drug mixtures was used [444]. Raman spectroscopy can also be used to distinguish fentanyls from morphines [445]. Analytical toxicology and toxicokinetic studies of the new synthetic opioids cyclopentanoyl-fentanyl (CP-F) and tetrahydrofuranyl-fentanyl (THF-F) revealed 12 phase I metabolites of CP-F and 13 of THF-F, among them 9 metabolites were described for the first time, with the N-dealkylations, hydroxylations, and dihydroxylations as the main metabolic reactions using LC-HRMS/MS [446]. Three fluorofentanyl isomers with the incubation with pooled human hepatocytes give as the major metabolite N-dealkylation product norfluorofentanyl, with 14 different metabolites for each fluorofentanyl isomer [447].

3.6.1 AH-7921

AH-7921 was reported first by EMCDDA in 2012. It was detected in synthetic cannabinoid products as well [1].

AH-7921 (3,4-dichloro-N-[(1-dimethylamino)cyclohexylmethyl]benzamide) is a µ-opioid receptor agonist developed in 1974 by Allen and Hanburys Ltd. [448] and patented 2 years later as a potential analgesic agent [449]. The reported analgesic activity in mice is equal or slightly higher than that in morphine [450,451]. Studies on animals show that AH-7921 is approximately equipotent to morphine regarding antinociception, respiratory depression, sedation, Straub tail, decrease in pupil diameter, decrease in body temperature, and inhibition of gut propulsion [452].

AH-7921 has never been sold as a medicine due to its addictive properties [453], and it has no other industrial use.

Studies show that AH-7921 acts as an agonist at the κ and μ opioid receptors with a Ki of 50 and 10 nM, respectively [454].

3.7 Designer benzodiazepines

The DBZD include pharmaceutical drug candidates never been approved for medical use (deschloroetizolam, clonazolam, flubromazepam, diclazepam, pyrazolam, and meclonazepam) derivatives obtained by a simple modification of the registered drugs (flubromazolam), and some metabolites of registered benzodiazepines (desmethylflunitrazepam and 3-hydroxydesmethylflunitrazepam) [455] (Table 4).

Table 4

Chemical structures and names of designer benzodiazepines [455]

Chemical structure Names
Cloniprazepam (5-(2-chlorophenyl)-1-(cyclopropylmethyl)-7-nitro-1,3-dihydro-2H-benzo[e][1,4]diazepin-2-one
Desmethylflunitrazepam or norflunitrazepam or Ro-4435 or fonazepam (5-(2-fluorophenyl)-7-nitro-1,3-dihydro-2H-1,4-benzodiazepin-2-one)
Diclazepam or 2-Chlorodiazepam (7-chloro-5-(2-chlorophenyl)-1-methyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one
4′-Chlorodiazepam or Ro5-4864 (7-chloro-5-(4-chlorophenyl)-1-methyl-3H-1,4-benzodiazepin-2-one
Flubromazepam (7-bromo-5-(2-fluorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one
Meclonazepam or (S)-3-methylclonazepam (3S)-5-(2-chlorophenyl)-3-methyl-7-nitro-1,3-dihydro-2H-1,4-benzodiazepin-2-one
Nifoxipam or 3-hydroxydesmethylflunitrazepam (5-(2-fluorophenyl)-3-hydroxy-7-nitro-2,3-dihydro-1H-1,4-benzodiazepin-2-one
Nitemazepam (3-hydroxy-1-methyl-7-nitro-5-phenyl-2,3-dihydro-1H-1,4-benzodiazepin-2-one
Phenazepam (7-bromo-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one)
3-Hydroxyphenazepam (7-bromo-5-(2-chlorophenyl)-3-hydroxy-1,3-dihydro-2H-1,4-benzodiazepin-2-one
Adinazolam or Deracyn® or Adinazolamum (1-(8-chloro-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine-1-yl)-N,N-dimethylmethanamine
Bromazolam (8-bromo-1-methyl-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine
Clonazolam or Clonitrazolam (6-(2-chlorophenyl)-1-methyl-8-nitro-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine
Flualprazolam (8-chloro-6-(2-fluorophenyl)-1-methyl-4H-benzo[f][1,2,4]triazolo[4,3-a][1,4]diazepine
Flubromazolam (8-bromo-6-(2-fluorophenyl)-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine
Flunitrazolam (6-(2-fluorophenyl)-1-methyl-8-nitro-4H-[1,2,4]triazolo[4,3-a][1,4] benzodiazepine
Nitrazolam or NitrazolaM (1-methyl-8-nitro-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4] benzodiazepine
Pyrazolam (8-bromo-1-methyl-6-(pyridine-2-yl)-4H-[1,2,4]triazolo[4,3-a][1,4] benzodiazepine
Zapizolam (8-chloro-6-(2-chlorophenyl)-4H-pyrido[2,3-f][1,2,4]triazolo [4,3-a][1,4] diazepine
Etizolam (4-(2-chlorophenyl)-2-ethyl-9-methyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine
Deschloroetizolam (4-phenyl-2-ethyl-9-methyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine
Metizolam or desmethyletizolam (4-(2-chlorophenyl)-2-ethyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine
Fluclotizolam (2-chloro-4-(2-fluorophenyl)-9-methyl-6H-thieno[3,3-f][1,2,4]triazoleo[4,3-a]diazepine

*Phenazepam is used as a prescription medicine in Russian Federation, Estonia, Latvia, Lithuania and Belarus [456], and etizolam is used as a prescription medicine in Japan, India and Italy [457].

Reprinted from NeuroToxicology, 73, Jolanta B. Zawilska, Jakub Wojcieszak, An expanding world of new psychoactive substances-designer benzodiazepines, 8–16, 2019, with permission from Elsevier.

They appeared in early 1960s, and it was found that they act as positive allosteric modulators of GABA-A receptors, with the binding site at the α/γ subunit interface [455]. In medicine, DBZD are widely applied in the therapy of neurological and psychiatric disorders (e.g., panic attacks, anxiety, muscle spasms, insomnia, epilepsy, and alcohol withdrawal), and as a premedication prior to surgery and intraoperative medications [455].

The first recreationally used benzodiazepine was phenazepam in 2007, which was followed by etizolam in 2011 [457]. Phenazepam was created in the Soviet Union in the 1970s for the treatment of anxiety and alcohol withdrawal [456]. Etizolam was made initially in Japan (Depas) in 1984 as an anxiolytic medicine [455].

They are sold as tablets, capsules, pills, pellets, blotters, powders, and liquids [458,459,460,461].

Biological effects caused by benzodiazepines include increased muscle relaxation, sociability, feelings of well-being, and euphoria [455]. The common adverse effects of DBZD include impaired balance, somnolence, ataxia, impaired thinking and self-assessment capability, loss of coordination, slurred speech, muscle weakness, confusion, amnesia, dizziness, blurred vision, drowsiness, fatigue, lethargy, and palpitations [455]. High doses can induce auditory and visual hallucinations, delirium, deep sleep, seizures, and coma [455]. Long-acting flubromazolam users have sleeping paralysis, unpleasant night dreams, and somnambulistic states persisted for several days [462].

Three main ways are used to investigate the metabolism of DBZD like in the case of other NPS: (1) incubation of DBZD with human liver microsomes followed by the analysis of the metabolites, (2) analysis of urine samples of a large number of NPS users, and (3) analysis of urine samples in controlled self-administration studies [455]. The major biotransformation pathway for DBZD is in general oxidation and glucuronidation (Table 5) [463].

Table 5

Metabolism of designer benzodiazepines [463]

Compound Metabolites Reference
Adinazolam In vitro (HLM): N-desmethyladinazolam, N,N-didesmethyladinazolam [464]
Diclazepam In vitro (HLM): monohydroxylation → delorazepam, desmethylation → lormetazepam [465]
Human urine: delorazepam, lorazepam, lormetazepam [465,466]
Human serum: delorazepam
Etizolam In vitro (HLM): three monohydroxylated metabolites, keto-metabolite, etizolam glucuronide [465,467]
Post-mortem blood: α-hydroxyetizolam, 8-hydroxyetizolam [468]
Deschloroetizolam In vitro (HLM): hydroxydeschloroetizolam, dihydroxydeschloroetizolam, deschloroetizolam glucuronide [465,467]
Flubromazolam In vitro (HLM, human hepatocytes): 4-hydroxyflubromazolam, α-hydroxyflubromazolam, dihydroxyflubromazolam, flubromazolam glucuronide [465,467,469,470]
Human urine: α-hydroxyflubromazolam, 4-hydroxyflubromazolam, α-hydroxyflubromazolam glucuronide, α,4-dihydroxyflubromazolam, flubromazolam glucuronide [469,470,471,472]
Metizolam In vitro (HLM): 2-hydroxymetizolam, N-hydroxymetizolam, metizolam glucuronide [464,467,473]
Human urine: 2-hydroxymetizolam, N-hydroxymetizolam, 2-hydroxymetizolam glucuronide [473]
Norflurazepam In vitro (HLM): hydroxynorflurazepam, dihydroxynorflurazepam [474]
Phenazepam Human urine: 3-hydroxyphenazepam, 5-bromo-(2-chlorophenyl)-2-aminobenzophenone (ABPH), 6-bromo-(2-chlorophenyl) quinazoline-2-one (QNZ) [456]
Pyrazolam Human urine: pyrazolam glucuronide [472]
Clonazolam In vitro (HLM): aminoclonazolam, desmethylclonazolam, hydroxyclonazolam [465]
Human urine: 7-aminoclonazolam, 7-acetaminoclonazolam, hydroxyclonazolam, 7-aminoclonazolam glucuronide, 7-acetaminoclonazolam glucuronide, hydroxyclonazolam glucuronide [475]
Cloniprazepam In vitro (HLM): 7-aminocloniprazepam, hydroxycloniprazepam, dihydroxycloniprazepam, 3-ketocloniprazepam, clonazepam, 7-aminoclonazepam, hydroxyclonazepam, 3-hydroxy-7-aminoclonazepam, hydroxycloniprazepam glucuronide [464,476]
Flunitrazolam In vitro (HLM): hydroxyflunitrazolam, dihydroxyflunitrazolam, aminoflunitrazolam, flunitrazolam glucuronide [467,474]
Human urine: desnitroflunitrazolam, 7-aminoflunitrazolam, 7-acetamidoflunitrazolam, hydroxyflunitrazolam [477]
Fonazepam (norflunitrazepam) In vitro (HLM): 7-aminofonazepam (7-aminonorflunitrazepam), 3-hydroxyfonazepam (3-hydroxynorflunitrazepam; nifoxipam) [464]
Meclonazepam In vitro (HLM): aminomeclonazepam, hydroxymeclonazepam [465]
Human urine: 7-aminomeclonazepam, 7-acetaminomeclonazepam [475,478]
Nifoxipam In vitro (HLM): 7-aminonifoxipam, denitro-nifoxipam, nifoxipam glucuronide [465,467]
Nitrazolam In vitro (HLM): 8-aminonitrazolam, 4-hydroxynitrazolam/α-hydroxynitrazolam [464]

A solid-phase extraction and liquid-liquid extraction are used for sample clean-up and the extraction of DBZD. Certain DBZD have been found in blood and urine using immunochemical assays with high cross-reactivity (e.g., cloned enzyme donor immunoassay, enzyme multiplied immunoassay technique, enzyme-linked immunosorbent assay, and kinetic interaction of microparticles in solution) [467,479,480]. Immunochemical screening of biological specimens for DBZD has three major drawbacks: (1) NPS, especially the newest may be not detected when screened by immunoassay if they are not in the scope of the confirmation panel of benzodiazepines, (2) blood/serum levels of DBZD can be extremely low to be detected by immunoassays, and (3) cross-contamination [463,480].

Recently, an US-LDS-DLLME in combination with gas chromatography-triple quadruple mass spectrometry (GC-QQQ-MS) [481] and a nonaqueous capillary electrophoresis-tandem mass spectrometry [482] have been used for the detection of DBZD in urine and serum, respectively.

4 Statistical data on the use of illegal drugs

It seems that policies (especially reducing the open trade) on NPS have had an impact on the decrease in its number of the first detections in European countries. Currently, around 50 new substances are reported each year (55 in 2018), with over 730 reported to the EU Early Warning System [332]. Among the 731 registered today from 1997, there are 190 synthetic cannabinoids, 138 cathinones, 99 phenethylamines, 49 opioids, 42 tryptamines, 36 arylalkylamines, 28 benzodiazepines, 18 arylcyclohexylamines, 17 piperazines, 14 piperidines and pyrrolidines, 8 plants and extracts, 5 aminoindanes, and 87 other substances [332]. The number of users of NPS among young adults (15–34) goes from 0.1% in Norway to 3.2% in the Netherlands [332].

There are published papers on the detection of NPS in wastewater [483] or as a part of the doping control [38].

5 Conformational analysis

For the first time we show the spatial occupation and arrangements of the groups of illicit drugs. The investigated drugs (mephedrone, AH-7921, 25B-NBOMe, 25C-NBOMe, 25I-NBOMe, BZP, AM-2201, MDPV, methylone, JWH-018, and 2C-B) are relatively simple and small molecules, so conformational analysis is a reliable tool for the prediction of biologically active conformations (Table 6). The conformational analysis starting from the drawn structures of the illegal drugs (mephedrone, AH-7921, 25B-NBOMe, 25C-NBOMe, 25I-NBOMe, BZP, AM-2201, MDPV, methylone, JWH-018, and 2C-B) was performed in Macromodel, Schrodinger Suite 2016-1 [484] using MMFFs force field in water and chloroform. Initially drawn structures were first minimized in 10,000 steps, and then put for the conformational search. Nonbonded van der Waals cut-off was 8.0 Å, and all structures within 5 kcal/mol far from global minimum were saved. All other parameters were adjusted according to our previous investigations [485]. Images in Table 6 represent the most probable look of the investigated molecules in 3D. Also, the information about the energies of the global minima is presented. Obtained structures can be the initial steps in the further investigations of the interactions of illicit drugs with various biological targets.

Table 6

Structures of the global minima and their energies

Name and structure of the global minimum of the compound The energy of the global minimum, kJ/mol
Mephedrone
276.15
AH-7921
153.56
25B-NBOMe
244.92
25C-NBOMe
252.04
25I-NBOMe
244.16
BZP
307.50
AM-2201
345.15
MDPV
265.43
Methylone
243.09
JWH-018
340.96
2C-B
143.71

We used before conformational analysis to predict physicochemical properties of selected illegal drugs [486].

Computational modeling was also performed to explain the interactions established between NPS (substituted cathinones and benzofurans) and transporters indicating the main amino acids in the binding pockets of transporters that effect drug affinities [487]. Similarly, molecular docking was used to predict interactions of selected synthetic cathinones with a complex of SAP97 PDZ2 with 5-HT2A receptor peptide [488]. Also, three QSAR models were developed for the prediction of affinity of μ-opioid receptor ligands [489]. DFT calculations were shown as an efficient tool for the prediction of infrared and Raman spectra of newly synthesized cathinones [490].

6 Conclusion

This review article is an attempt to summarize the current state on the major used illicit drugs: their types, synthesis, metabolism, and identification. Currently, the number of reported NPS is decreasing each year due to the new EU policies with 50 new compounds in average. Investigations of NPS are increasing, so now we have a large and deep pool of data worldwide, both on natural and on synthetic NPS. Many of NPS were initially released from the official labs as medications against various diseases or were known for their use for religious or medicinal purposes. Searching for more efficient and less harmful antidotes should be a priority now. To the best of our knowledge, we are the first who performed the conformational analysis of selected NPS giving rise to the search of the biologically active conformations both theoretically and using lab experiments.

Acknowledgments

Special thanks to Rita Podzuna from Schrodinger for providing the trial version of the Schrodinger Suite.

References

[1] Uchiyama N, Matsuda S, Kawamura M, Kikura-Hanajiri R, Goda Y. Two new-type cannabimimetic quinolinyl carboxylates, QUPIC and QUCHIC, two new cannabimimetic carboxamide derivatives, ADB-FUBINACA and ADBICA, and five synthetic cannabinoids detected with a thiophene derivative α-PVT and an opioid receptor agonist AH-7921 identified in illegal products. Forensic Toxicol. 2013;31:223–40. Search in Google Scholar

[2] Chung H, Lee J, Kim E. Trends of novel psychoactive substances (NPSs) and their fatal cases. Forensic Toxicol. 2016;34:1–11. Search in Google Scholar

[3] Riley AL, Nelson KH, To P, Lopez-Arnau R, Xu P, Wang D, et al. Abuse potential and toxicity of the synthetic cathinones (i.e., “Bath salts”). Neurosci Biobehav Rev. 2020;110:150–73. Search in Google Scholar

[4] Bade R, Tscharke BJ, White JM, Grant S, Mueller JF, O’Brien J, et al. LC-HRMS suspect screening to show spatial patterns of New Psychoactive Substances use in Australia. Sci Total Environ. 2019;650(Part 2):2181–7. Search in Google Scholar

[5] Birk L, Franco de Oliveira SE, Mafra G, Brognoli R, Carpes MJS, Scolmeister D, et al. A low-voltage paper spray ionization QTOF-MS method for the qualitative analysis of NPS in street drug blotter samples. Forensic Toxicol. 2020;38(1):227–31. Search in Google Scholar

[6] Celma A, Sancho JV, Salgueiro-Gonzalez N, Castiglioni S, Zuccato E, Hernandez F, et al. Simultaneous determination of new psychoactive substances and illicit drugs in sewage: potential of micro-liquid chromatography tandem mass spectrometry in wastewater-based epidemiology. J Chromatogr A. 2019;1602:300–9. Search in Google Scholar

[7] Fabresse N, Larabi IA, Stratton T, Mistrik R, Pfau G, Lorin de la Grandmaison G, et al. Development of a sensitive untargeted liquid chromatography-high resolution mass spectrometry screening devoted to hair analysis through a shared MS2 spectra database: a step toward early detection of new psychoactive substances. Drug Test Anal. 2019;11(5):697–708. Search in Google Scholar

[8] Fernandez P, Regenjo M, Ares A, Fernandez AM, Lorenzo RA, Carro AM. Simultaneous determination of 20 drugs of abuse in oral fluid using ultrasound-assisted dispersive liquid-liquid microextraction. Anal Bioanal Chem. 2019;411(1):193–203. Search in Google Scholar

[9] Gerace E, Caneparo D, Borio F, Salomone A, Vincenti M. Determination of several synthetic cathinones and an amphetamine-like compound in urine by gas chromatography with mass spectrometry. Method validation and application to real cases. J Sep Sci. 2019;42(8):1577–84. Search in Google Scholar

[10] Graziano S, Orsolini L, Rotolo MC, Tittarelli R, Schifano F, Pichini S. Herbal highs, review on psychoactive effects and neuropharmacology. Curr Neuropharmacol. 2017;15:750–61. Search in Google Scholar

[11] Jurasek B, Bartunek V, Huber S, Kuchar M. X-ray powder diffraction-a non-destructive and versatile approach for the identification of new psychoactive substances. Talanta. 2019;195:414–8. Search in Google Scholar

[12] Kadkhodaei K, Kadisch M, Schmid MG. Successful use of a novel lux i-Amylose-1 chiral column for enantioseparation of “legal highs” by HPLC. Chirality. 2020;32(1):42–52. Search in Google Scholar

[13] Lopez-Garcia E, Postigo C, de Alda Lopez M. Psychoactive substances in mussels: analysis and occurrence assessment. Mar Pollut Bull. 2019;146:985–92. Search in Google Scholar

[14] Malaca S, Busardo FP, Gottardi M, Pichini S, Marchei E. Dilute and shoot ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis of psychoactive drugs in oral fluid. J Pharm Biomed Anal. 2019;170:63–67. Search in Google Scholar

[15] Mannocchi G, Di Trana A, Tini A, Busardo FP, Zaami S, Gottardi M, et al. Development and validation of fast UHPLC-MS/MS screening method for 87 NPS and 32 other drugs of abuse in hair and nails: application to real cases. Anal Bioanal Chem. 2020;412:5125–45. 10.1007/s00216-020-02462-6. Search in Google Scholar

[16] Margalho C, Almeida P, Tiago R, Francisco CR, Gallardo E. Determination of new psychoactive substances in whole blood using microwave fast derivatization and gas chromatography/mass spectrometry. J Anal Toxicol. 2020;44(1):92–102. Search in Google Scholar

[17] Mesihaa S, Rasanen I, Pelander A, Ojanpera I. Quantitative estimation of 38 illicit psychostimulants in blood by GC-APCI-QTOFMS with nitrogen chemiluminescence detection based on three external calibrators. J Anal Toxicol. 2019;44(2):163–72. 10.1093/jat/bkz055. Search in Google Scholar

[18] Nisbet LA, Wylie FM, Logan BK, Scott KS. Gas chromatography-mass spectrometry method for the quantitative identification of 23 new psychoactive substances in blood and urine. J Anal Toxicol. 2019;43(5):346–52. Search in Google Scholar

[19] Omar J, Slowikowski B, Guillou C, Reniero F, Holland M, Boix A. Identification of new psychoactive substances (NPS) by Raman spectroscopy. J Raman Spectrosc. 2019;50(1):41–51. Search in Google Scholar

[20] Ong RS, Kappatos DC, Russell SGG, Poulsen HA, Banister SD, Gerona RR, et al. Simultaneous analysis of 29 synthetic cannabinoids and metabolites, amphetamines, and cannabinoids in human whole blood by liquid chromatography-tandem mass spectrometry-A New Zealand perspective of use in 2018. Drug Test Anal. 2020;12(2):195–214. Search in Google Scholar

[21] Qian Z, Liu C, Huang J, Deng Q, Hua Z. Identification of the designer benzodiazepine 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine (flualprazolam) in an anesthesia robbery case. Forensic Toxicol. 2020;38(1):269–76. Search in Google Scholar

[22] Rajšić I, Javorac D, Tatović S, Repić A, Đukić-Ćosić D, Đorđević S, et al. Effect of urine adulterants on commercial drug abuse screening test strip results. Arh Hig Rada Toksikol. 2020;71:87–93. Search in Google Scholar

[23] Richter LHJ, Beck A, Flockerzi V, Maurer HH, Meyer MR. Cytotoxicity of new psychoactive substances and other drugs of abuse studied in human HepG2 cells using an adopted high content screening assay. Toxicol Lett. 2019;301:79–89. Search in Google Scholar

[24] Shirley Lee HZ, Koh HB, Tan S, Goh BJ, Lim R, Lim JLW, et al. Identification of closely related new psychoactive substances (NPS) using solid deposition gas-chromatography infra-red detection (GC-IRD) spectroscopy. Forensic Sci Int. 2019;299:21–33. Search in Google Scholar

[25] Salgueiro-Gonzalez N, Castiglioni S, Gracia-Lor E, Bijlsma L, Celma A, Bagnati R, et al. Flexible high resolution-mass spectrometry approach for screening new psychoactive substances in urban wastewater. Sci Total Environ. 2019;689:679–90. Search in Google Scholar

[26] Segawa H, Fukuoka T, Itoh T, Imai Y, Iwata YT, Yamamuro T, et al. Rapid detection of synthetic cannabinoids in herbal highs using surface-enhanced Raman scattering produced by gold nanoparticle co-aggregation in a wet system. Analyst. 2019;144(23):6928–35. Search in Google Scholar

[27] Sorribes-Soriano A, Esteve-Turrillas F, Armenta S, Amoros P, Herrero-Martinez JM. Amphetamine-type stimulants analysis in oral fluid based on molecularly imprinting extraction. Anal Chim Acta. 2019;1052:73–83. Search in Google Scholar

[28] Sorribes-Soriano A, Valencia A, Esteve-Turrillas FA, Armenta S, Herrero-Martinez JM. Development of pipette tip-based poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith for the extraction of drugs of abuse from oral fluid samples. Talanta. 2019;205:120158. Search in Google Scholar

[29] Vincenti F, Montesano C, Cellucci L, Gregori A, Fanti F, Comagnone D, et al. Combination of pressurized liquid extraction with dispersive liquid liquid micro extraction for the determination of sixty drugs of abuse in hair. J Chromatogr A. 2019;1605:360348. Search in Google Scholar

[30] Wozniak MK, Banaszkiewicz L, Wiergowski M, Tomczak E, Kata M, Szpiech B, et al. Development and validation of a GC-MS/MS method for the determination of 11 amphetamines and 34 synthetic cathinones in whole blood. Forensic Toxicol. 2020;38(1):42–58. Search in Google Scholar

[31] Concalves JL, Alves VL, Aguiar J, Teixeira HM, Camara JS. Synthetic cathinones: an evolving class of new psychoactive substances. Crit Rev Toxicol. 2019;49(7):549–66. Search in Google Scholar

[32] Gupta PC, Warnakulasuriya S. Global epidemiology of areca nut usage. Addict Biol. 2002;7:77–83. Search in Google Scholar

[33] Karila L, Megarbane B, Cottencin O, Lejoyeux M. Synthetic cathinones: a new public health problem. Curr Neuropharmacol. 2015;13:12–20. Search in Google Scholar

[34] Lo Faro AF, Di Trana A, La Maida N, Tagliabracci A, Giorgetti R, Busardo FP. Biomedical analysis of new psychoactive substances (NPS) of natural origin. J Pharm Biomed Anal. 2020;179:112945. Search in Google Scholar

[35] Majchrzak M, Celinski R, Kus P, Kowalska T, Sajewicz M. The newest cathinone derivatives as designer drugs: an analytical and toxicological review. Forensic Toxicol. 2018;36:33–50. Search in Google Scholar

[36] Kraemer M, Boehmer A, Madea B, Maas A. Death cases involving certain new psychoactive substances: a review of the literature. Forensic Sci Int. 2019;298:186–267. Search in Google Scholar

[37] Joubert V, Trebuchet M, Mikic M, Silvestre V, Schiphorst A-M, Loquet D, et al. Isotopomics by isotope ratio monitoring by 13C nuclear magnetic resonance spectrometry on cutting agents in heroin: a new approach for illicit drugs trafficking route elucidation. Drug Test Anal. 2020;12(4):449–57. 10.1002/dta.2745. Search in Google Scholar

[38] Olesti E, De Toma I, Ramaekers JG, Brunt TM, Carbo M, Fernandez-Aviles C, et al. Metabolomics predicts the pharmacological profile of new psychoactive substances. J Psychopharmacol. 2019;33(3):347–54. Search in Google Scholar

[39] Peng W, Liu YJ, Wu N, Sun T, He XY, Gao YX, et al. Areca catechu L. (Arecaceae): a review of its traditional uses, botany, phytochemistry, pharmacology and toxicology. J Ethnopharmacol. 2015;164:340–56. Search in Google Scholar

[40] Coppola M, Mondola R. Potential action of betel alkaloids on positive and negative symptoms of schizophrenia: a review. Nord J Psychiatry. 2012;66:73–8. Search in Google Scholar

[41] Li HJ, Mcleish J. High-performance liquid chromatographic determination of the alkaloids in betel nut. J Chromatogr. 1989;475:447–50. Search in Google Scholar

[42] Papke RL, Horenstein NA, Stokes C. Nicotinic activity of arecoline, the psychoactive element of “betel nuts”, suggests a basis for habitual use and anti-inflammatory activity. PLoS One. 2015;10:1–18. Search in Google Scholar

[43] Austin DF, Huaman Z. A synopsis of Ipomoea (Convolvulaceae) in the Americas. Taxon. 1996;45:3–38. Search in Google Scholar

[44] Paulke A, Kremer C, Wunder C, Wurglics M, Schubert-Zsilavecz M, Toennes SW. Studies on the alkaloid composition of the Hawaiian Baby Woodrose Argyreia nervosa, a common legal high. Forensic Sci Int. 2015;249:281–93. Search in Google Scholar

[45] Larson BT, Harmon DL, Piper EL, Griffis LM, Bush LP. Alkaloid binding and activation of D2 dopamine receptors in cell culture. J Anim Sci. 1999;77:942. Search in Google Scholar

[46] dos Santos RG, Hallak JEC. Ayuhuasca, an ancient substance with traditional and contemporary use in neuropsychiatry and neuroscience. Epilepsy Behav. 2019;2–7. 10.1016/j.yebeh.2019.04.053. Search in Google Scholar

[47] Tittarelli R, Mannocchi G, Pantano F, Romolo F. Recreational use, analysis and toxicity of tryptamines. Curr Neuropharmacol. 2014;13:26–46. Search in Google Scholar

[48] Hamill J, Hallak J, Dursun SM, Baker G. Ayahuasca: psychological and psysiologic effects, pharmacology and potential uses in addiction and mental illness. Curr Neuropharmacol. 2018;17:108–28. Search in Google Scholar

[49] El-Menyar A, Mekkodathil A, Al-Thani H, Al-Motarreb A. Khat use: history and heart failure. Oman Med J. 2015;30:77–82. Search in Google Scholar

[50] Feyissa AM, Kelly J. A review of the neuropharmacological properties of khat. Prog Neuropsychopharmacol Biol Psychiat. 2008;32:1147–66. Search in Google Scholar

[51] Pantano F, Tittarelli R, Mannocchi G, Zaami S, Ricci S, Giorgetti R, et al. Hepatotoxicity induced by “the 3Ks”: kava, kratom and khat. Int J Mol Sci. 2016;17(4):580. Search in Google Scholar

[52] Wabe NT. Chemistry, pharmacology, and toxicology of khat (Catha edulis forsk): a review. Addict Heal. 2011;3:137–49. Search in Google Scholar

[53] Hanus LO, Rezanka T, Spizek J, Dembitsky VM. Substances isolated from Mandragora species. Phytochemistry. 2005;66:2408–17. Search in Google Scholar

[54] Pichini S, Marchei E, Ilaria P, Pellegrini M, Pacifici R, Zuccaro P. Smart drugs; 2011. Search in Google Scholar

[55] Lu J, Wei H, Wu J, Jamil MFA, Tan ML, Adenan MI, et al. Evaluation of the cardiotoxicity of mitragynine and its analogues using human induced pluripotent stem cell-derived cardiomyocytes. PLoS One. 2014;9:e115648. Search in Google Scholar

[56] Farah Idayu N, Taufik Hidayat M, Moklas MAM, Sharida F, Nurul Raudzah AR, Shamima AR, et al. Antidepressant-like effect of mitragynine isolated from Mitragyna speciosa Korth in mice model of depression. Phytomedicine. 2011;18:402–7. Search in Google Scholar

[57] Tsuchiya S, Miyashita S, Yamamoto M, Horie S, Sakai S-I, Aimi N, et al. Effect of mitragynine, derived from Thai folk medicine, on gastric acid secretion through opioid receptor in anesthetized rats. Eur J Pharmacol. 2002;443:185–8. Search in Google Scholar

[58] Utar Z, Majid MIA, Adenan MI, Jamil MFA, Lan TM. Mitragynine inhibits the COX-2 mRNA expression and prostaglandin E2 production induced by lipopolysaccharide in RAW264.7 macrophage cells. J Ethnopharmacol. 2011;136:75–82. Search in Google Scholar

[59] Wink VM, van Wyk B, Wink C. Handbuch der giftigen und psychoaktiven Pflanzen. Pharm Unserer Zeit. 2009;38:288–9. Search in Google Scholar

[60] Murburg MM, Villacres EC, Ko GN, Veith RC. Effect of yohimbine on human sympathetic nervous system function. J Clin Endocrinol Metab. 1991;73:861–5. Search in Google Scholar

[61] Li XZ, Ramzan I. Role of ethanol in kava hepatotoxicity. Phyther Res. 2010;24:475–80. Search in Google Scholar

[62] Shimoda LMN, Park C, Stokes AJ, Gomes HH, Turner H. Pacific Island’ awa (kava) extracts but not isolated kavalactones, promote proinflamatory responses in model mast cells. Phyther Res. 2012;26:1934–41. Search in Google Scholar

[63] Showman AF, Baker JD, Linares C, Naeole CK, Borris R, Johnston E, et al. Contemporary pacific and western perspectives on ‘awa (Piper methysticum) toxicology. Fitoterapia. 2015;100:56–67. Search in Google Scholar

[64] Tescke R, Qiu SX, Lebot V. Herbal hepatotoxicity by kava: update on pipermethystine, flavokavain B, and mould hepatotoxins as primarily assumed culprits. Dig Liver Dis. 2011;43:676–81. Search in Google Scholar

[65] Griffiths RR, Richards WA, McCann U, Jesse R. Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance. Psychopharmacology (Berl). 2006;187:268–83. Search in Google Scholar

[66] Griffiths RR, Johnson MW, Richards WA, Richards BD, McCann U, Jesse R. Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects. Psychopharmacology (Berl). 2011;218:649–65. Search in Google Scholar

[67] Hasler F, Grimberg U, Benz MA, Huber T, Vollenweider FX. Acute psychological and psysiological effects of psilocybin in healthy humans: a double-blind, placebo-controlled dose? Effect study. Psychopharmacology (Berl). 2004;172:145–56. Search in Google Scholar

[68] Wittmann M, Carter O, Hasler F, Cahn BR, Grimberg U, Spring P, et al. Effects of psilocybin on time perception and temporal control of behavior in humans. J Psychopharmacol. 2007;21:50–64. Search in Google Scholar

[69] Valdes LJ, Diaz JL, Paul AG. Ethnopharmacology of ska Maria Pastora (Savia divinorum, Epling and Jativa-M.). J Ethnopharmacol. 1983;7:287–312. Search in Google Scholar

[70] Roth BL, Baner K, Westkaemper R, Siebert D, Rice KC, Steinberg S, et al. Salvinorin A, a potent naturally occurring nonnitrogenous kappa opioid selective agonist. Proc Natl Acad Sci USA. 2002;99:11934–9. Search in Google Scholar

[71] Vortherms TA, Roth BL, Salvinorin A, from natural product to human therapeutics. Mol Interv. 2006;6:257–65. Search in Google Scholar

[72] Walentiny DM, Vann RE, Warner JA, King LS, Seltzman HH, Navarro HA, et al. Kappa opioid mediation of cannabinoid effects of the potent hallucinogen, salvinorin A, in rodents. Psychopharmacology (Berl). 2010;210:275–84. Search in Google Scholar

[73] Gericke N, Viljoen AM. Sceletium-a review update. J Ethnopharmacol. 2008;119:653–63. Search in Google Scholar

[74] Patnala S, Kanfer I. Investigations of the phytochemical content of Sceletium tortuosum following the preparation of “Kougoed” by fermentation of plant material. J Ethnopharmacol. 2009;121:86–91. Search in Google Scholar

[75] Harvey AL, Young LC, Viljoen AM, Gericke NP. Pharmacological actions of the South African medicinal and functional food plant Sceletium tortuosum and its principal alkaloids. J Ethnopharmacol. 2011;137:1124–9. Search in Google Scholar

[76] Terburg D, Syal S, Rosenberger LA, Heany S, Phillips N, Gericke N, et al. Acute effects of Sceletium tortuosum (Zembrin), a dual 5-HT reuptake and PDE4 inhibitor, in the human amygdale and its connection to the hypothalamus. Neuropsychopharmacology. 2013;38:2708–16. Search in Google Scholar

[77] Smith MT, Crouch NR, Gericke N, Hirst M. Psychoactive constituents of the genus Sceletium N.E.Br. and other Mesembryanthemaceae: a review. J Etnopharmacol. 1996;50:119–30. Search in Google Scholar

[78] Besharat S, Besharat M, Jabbari A. Wild lettuce (Lactuca virosa) toxicity. Case Rep. 2009;2009. Search in Google Scholar

[79] Gromek D, Kisiel W, Klodzinska A, Chojnacka-Wojcik E. Biologically active preparations from Lactuca virosa L. Phyther Res. 1992;6:285–7. Search in Google Scholar

[80] Dinis-Oliveira RJ, Pereira CL, Dias da Silva D. Pharmacokinetic and pharmacodynamic aspects of peyote and mescaline: clinical and forensic repercussions. Curr Mol Pharmacol. 2019;12(3):184–94. Search in Google Scholar

[81] Franco-Molina M, Gomez-Flores R, Tamez-Guerra P, Tamez-Guerra R, Castillo-Leon L, Rodriguez-Padilla C. In vitro immunopotentiating properties and tumour cell toxicity induced by Lophophora williamsii (peyote) cactus methanolic extract. Phytother Res: PTR. 2003;17(9):1076–81. Search in Google Scholar

[82] Becker H. Composition of cactus Lophophora williamsii. Pharm Unserer Zeit. 1985;14(5):129–37. Search in Google Scholar

[83] https://www.iceers.org/peyote-basic-info/ Search in Google Scholar

[84] Cox S, Piatkov I, Vickers ER, Ma G. High-performance liquid chromatographic determination of arecoline in human saliva. J Chromatogr A. 2004;1032:93–5. Search in Google Scholar

[85] Franke AA, Biggs L, Yew JY, Lai JF. Areca alkaloids measured from buccal cells using DART-MS serve as accurate biomarkers for areca nut chewing. Drug Test Anal. 2019;11(6):906–11. Search in Google Scholar

[86] Franke AA, Li X, Custer LJ, Lai JF. Chemical markers for short- and long-term Areca nut exposure. Subst Use Misuse. 2020;55(9):1395–402. Search in Google Scholar

[87] Gheddar L, Ricaut F, Ameline A, Brucato N, Tsang R, Leavesley M, et al. Testing of betel nut alkaloids in hair of Papuans abusers using UPLC-MS/MS and UPLC-Q-Tof-MS. J Anal Toxicol. 2020;44(1):41–8. Search in Google Scholar

[88] Hayes MJ, Khemani L, Bax M, Alkalay D. Quantitative determination of arecoline in plasma by gas chromatography chemical ionization mass spectrometry. Biomed Environ Mass Spectrom. 1989;18:1005–9. Search in Google Scholar

[89] Lee HH, Chen LY, Wang HL, Chen BH. Quantification of salivary arecoline, arecaidine and N-methylnipecotic acid levels in volunteers by liquid-chromatography-tandem mass spectrometry. J Anal Toxicol. 2015;39:714–9. Search in Google Scholar

[90] Marchei E, Durgbanshi A, Rossi S, Garcia-Algar O, Zuccaro P, Pichini S. Determination of arecoline (areca nut alkaloid) and nicotine in hair by high-performance liquid chromatography/electrospray quadrupole mass spectrometry. Rapid Commun Mass Spectrom. 2005;19:3416–8. Search in Google Scholar

[91] Pellegrini M, Marchei E, Rossi S, Vagnarelli F, Durgbanshi A, Garcia-Algar O, et al. Liquid chromatography/electrospray ionization tandem mass spectrometry assay for determination of nicotine and metabolites, caffeine and arecolin in breast milk. Rapid Commun Mass Spectrom. 2007;21:2693–709. Search in Google Scholar

[92] Pichini S, Pellegrini M, Pacifici R, Marcheil E, Murillo J, Puig C, et al. Quantification of arecoline (Areca nut alkaloid) in neonatal biological matrices by high-performance liquid chromatography/electrospray quadrupole mass spectrometry. Rapid Commun Mass Spectrom. 2003;17:1958–64. Search in Google Scholar

[93] Bjornstad K, Beck O, Helander A. A multi-component LC-MS/MS method for detection of ten plant-derived psychoactive substances in urine. J Chromatogr B Anal Technol Biomed Life Sci. 2009;877:1162–8. Search in Google Scholar

[94] Klinke HB, Muller IB, Steffenrud S, Dahl-Sorensen R. Two cases of lysergamide intoxication by ingestion of seeds from Hawaiian Baby Woodrose. Forensic Sci Int. 2010;197:e1–e5. Search in Google Scholar

[95] Chao J-M, Der Marderosian AH. Ergoline alkaloidal constituents of Hawaiian baby wood rose, Argyreia nervosa (Burm. F.) Bojer. J Pharm Sci. 1973;62:588–91. Search in Google Scholar

[96] Hylin JW, Watson DP. Ergoline alkaloids in tropical wood roses. Science. 1965;148:499–500. Search in Google Scholar

[97] Mercurio I, Melai P, Capano D, Ceraso G, Carlini L, Bacci M. GC/MS analysis of morning glory seeds freely in commerce: can they be considered “herbal highs”? Egypt J Forensic Sci. 2017;7:16. Search in Google Scholar

[98] Callaway JC, Brito GS, Neves ES. Phytochemical analyses of banisteriopsis caapi and Psychotria viridis. J Psychoact Drugs. 2005;37:145–50. Search in Google Scholar

[99] Gambelunghe C, Aroni K, Rossi R, Moretti L, Bacci M. Identification of N,N-dimethyltryptamine and β-carbolines in psychotropic ayahuasca beverage Cristiana. Biomed Chromatogr. 2008;22:1056–9. Search in Google Scholar

[100] Gaujac A, Dempster N, Navickiene S, Brandt SD, De Andrade JB. Determination of N,N-dimethyltryptamine in beverages consumed in religious practices by headspace solid-phase microextraction followed by gas chromatography ion trap mass spectrometry. Talanta. 2013;106:394–8. Search in Google Scholar

[101] Huhn C, Neusuß C, Pelzing M, Pyell U, Mannhardt J, Putz M. Capillary electrophoresis-laser induced fluorescence-electrospray ionization-mass spectrometry: a case study. Electrophoresis. 2005;26:1389–97. Search in Google Scholar

[102] Lesiak AD, Musah RA. Application of ambient ionization high resolution mass spectrometry to determination of the botanical provenance of the constituents of psychoactive drug mixtures. Forensic Sci Int. 2016;266:271–80. Search in Google Scholar

[103] McIlhenny EH, Pipkin KE, Standish LJ, Wechkin HA, Strassman R, Barker SA. Direct analysis of psychoactive tryptamine and harmala alkaloids in the Amazonian botanical medicine ayahuasca by liquid chromatography-electrospray ionization-tandem mass spectrometry. J Chromatogr A. 2009;1216:8960–8. Search in Google Scholar

[104] Pires APS, De Oliveira CDR, Moura S, Dorr FA, Silva WAE, Yonamine M. Gas chromatographic analysis of dimethyltryptamine and β-carboline alkaloids in Ayahuasca, an Amazonian psychoactive plant beverage. Phytochem Anal. 2009;20:149–53. Search in Google Scholar

[105] Santos MC, Navickiene S, Gaujac A. Determination of tryptamines and β-carbolines in Ayahuasca beverage consumed during Brazilian religious ceremonies. J AOAC Int. 2017;100:820–4. Search in Google Scholar

[106] Wang YH, Samoylenko V, Tekwani BL, Khan IA, Miller LS, Chaurasiya ND, et al. Composition, standardization and chemical profiling of Banisteriopsis caapi, a plant for the treatment of neurodegenerative disorders relevant to Parkinson’s disease. J Ethnopharmacol. 2010;128:662–71. Search in Google Scholar

[107] McIlhenny EH, Riba J, Barbanoj MJ, Strassman R, Barker SA. Methodology for and the determination of the major constituents and metabolites of the Amazonian botanical medicine ayahuasca in human urine. Biomed Chromatogr. 2011;25:970–84. Search in Google Scholar

[108] McIlhenny EH, Riba J, Barbanoj MJ, Strassman R, Barker SA. Methodology for determining major constituents of ayahuasca and their metabolites in blood. Biomed Chromatogr. 2012;26:301–13. Search in Google Scholar

[109] Pichini S, Marchei E, Garcia-Algar O, Gomez A, Di Giovannandrea R, Pacifici R. Ultra-high-pressure liquid chromatography tandem mass spectrometry determination of hallucinogenic drugs in hair of psychedelic plants and mushrooms consumers. J Pharm Biomed Anal. 2014;100:284–9. Search in Google Scholar

[110] Pope JD, Choy KW, Drummer OH, Schneider HG. Harmala alkaloids identify ayahausca intoxication in a urine drug screen. J Anal Toxicol. 2019;43:e23–7. Search in Google Scholar

[111] Rodrigues Oliveira CD, Goncalves Okai G, Luiz da Costa J, Menck de Almeida R, Oliveira-Silva D, Yonamine M. Determination of dimethyltryptamine and β-carbolines (ayahuasca alkaloids) in plasma samples by LC-MS/MS. Bioanalysis. 2012;14:1731–8. Search in Google Scholar

[112] Atlabachew M, Chandravanshi BS, Redi-Abshiro M. Preparative HPLC for large scale isolation, and salting-out assisted liquid-liquid extraction based method for HPLC-DAD determination of khat (Catha edulis Forsk) alkaloids. Chem Cent J. 2017;11:1–10. Search in Google Scholar

[113] Krizevski R, Dudai N, Bar E, Lewinsohn E. Development patterns of phenylpropylamino alkaloids accumulation in khat (Catha edulis, Forsk.). J Ethnopharmacol. 2007;114:432–8. Search in Google Scholar

[114] Laussmann T, Meier-Giebing S. Forensic analysis of hallucinogenic mushrooms and khat (Catha edulis Forsk) using cation-exchange liquid chromatography. Forensic Sci Int. 2010;195:160–4. Search in Google Scholar

[115] Mohamed WM, Ben Hamida S, Cassel JC, De Vasconcelos AP, Jones BC. MDMA: interactions with other psychoactive drugs. Pharmacol Biochem Behav. 2011;99:759–74. Search in Google Scholar

[116] Sørensen LK. Determination of cathinones and related ephedrines in forensic whole-blood samples by liquid-chromatography-electrospray tandem mass spectrometry. J Chromatogr B Anal Technol Biomed Life Sci. 2011;879:727–36. Search in Google Scholar

[117] Sporkert F, Pragst F, Bachus R, Masuhr F, Harms L. Determination of cathinone, cathine and norephedrine in hair of Yemenite khat chewers. Forensic Sci Int. 2003;133:39–46. Search in Google Scholar

[118] Toennes SW, Kauert GF. Excretion and detection of cathinone, cathine, and phenylpropanolamine in urine after kath chewing. Clin Chem. 2002;48:1715–9. Search in Google Scholar

[119] Auriola S, Martinsen A, Oksman-Caldentey KM, Naaranlahti T. Analysis of tropane alkaloids with thermospray high-performance liquid chromatography-mass spectrometry. J Chromatogr B Biomed Sci Appl. 1991;562:737–44. Search in Google Scholar

[120] Deutsch J, Soncrant TT, Greig NH, Rapoport SI. Electron-impact ionization detection of scopolamine by gas chromatography-mass spectrometry in rat plasma and brain. J Chromatogr B Biomed Sci Appl. 1990;528:325–31. Search in Google Scholar

[121] Fliniaux MA, Manceau F, Jacquin-Dubreuil A. Simultaneous analysis of l-hyoscyamine, l-scopolamine and dl-tropic acid in plant material by reversed-phase high-performance liquid chromatography. J Chromatogr A. 1993;644:193–7. Search in Google Scholar

[122] Nikolaou P, Papoutsis I, Stefanidou M, Dona A, Maravelias C, Spiliopoulou C, et al. Accidental poisoning after ingestion of “aphrodisiac” berries: diagnosis by analytical toxicology. J Emerg Med. 2012;42:662–5. Search in Google Scholar

[123] Oertel R, Richter K, Ebert U, Kirch W. Determination of scopolamine in human serum by gas chromatography-ion trap tandem mass spectrometry. J Chromatogr B Biomed Appl. 1996;682:259–64. Search in Google Scholar

[124] Papadoyannis IN, Samanidou VF, Theodoridis GA, Vasilikiotis GS, van Kempen GJM, Beelen GM. A simple and quick solid phase extraction and reversed phase hplc analysis of some tropane alkaloids in feedstuffs and biological samples. J Liq Chromatogr. 1993;16:975–98. Search in Google Scholar

[125] Yashiki M, Namera A, Tani T, Kojima T, Hirose Y, Yamaji S. Quantitative analysis of tropane alkaloids in biological materials by gas chromatography-mass spectrometry. Forensic Sci Int. 2002;130:34–43. Search in Google Scholar

[126] Arndt T, Claussen U, Gussregen B, Schrofel S, Sturzer B, Werle A, et al. Kratom alkaloids and O-desmethyltramadol in urine of a “Krypton” herbal mixture consumer. Forensic Sci Int. 2011;208:47–52. Search in Google Scholar

[127] Lee MJ, Ramanathan S, Mansor SM, Yeong KY, Tan SC. Method validation in quantitative analysis of phase I and phase II metabolites of mitragynine in human urine using liquid chromatography-tandem mass spectrometry. Anal Biochem. 2018;543:146–61. Search in Google Scholar

[128] Fu H, Cid F, Dworkin N, Cocores J, Shore G. Screening and identification of mitragynine and 7-hydroxymitragynine in human urine by LC-MS/MS. Chromatography. 2015;2:253–64. Search in Google Scholar

[129] Fu H. A mass spectrometric study of kratom compounds by direct infusion electrospray ionization triple quadrupole mass spectrometry. Detection. 2016;4:66–72. Search in Google Scholar

[130] Janchawee B, Keawpradub N, Chittrakarn S, Prasettho S, Wararatananurak P, Sawangjareon K. A high-performance liquid chromatographic method for determination of mitragynine in serum and its application to a pharmacokinetic study in rats. Biomed Chromatogr. 2007;21:176–83. Search in Google Scholar

[131] Le D, Goggin MM, Janis GC. Analysis of mitragynine and metabolites in human urine for detecting the use of the psychoactive plant kratom. J Anal Toxicol. 2012;36:616–25. Search in Google Scholar

[132] Lu S, Tran BN, Nelsen JL, Aldous KM. Quantitative analysis of mitragynine in human urine by high performance liquid chromatography-tandem mass spectrometry. J Chromatogr B Anal Technol Biomed Life Sci. 2009;877:2499–505. Search in Google Scholar

[133] Kronstrand R, Roman M, Thelander G, Eriksson A. Unintentional fatal intoxications with mitragynine and O-desmethyltramadol from the herbal blend krypton. J Anal Toxicol. 2011;35:242–7. Search in Google Scholar

[134] Neerman MF, Frost RE, Deking J. A drug fatality involving kratom. J Forensic Sci. 2013;58:278–9. Search in Google Scholar

[135] Parthasarathy S, Ramanathan S, Ismail S, Adenan MI, Mansor SM, Murugaiyah V. Determination of mitragynine in plasma with solid-phase extraction and rapid HPLC-UV analysis, and its application to a pharmacokinetic study in rat. Anal Bioanal Chem. 2010;397:2023–30. Search in Google Scholar

[136] Philipp AA, Wissenbach DK, Zoerntlein SW, Klein ON, Kanogsunthornrat J, Maurer HH. Studies on the metabolism of mitragynine, the main alkaloid of the herbal drug Kratom, in rat and human urine using liquid chromatography-linear ion trapmass spectrometry. J Mass Spectrom. 2009;44:1249–61. Search in Google Scholar

[137] Philipp AA, Wissenbach DK, Weber AA, Zapp J, Zoerntlein SW, Kanogsunthornrat J, et al. Use of liquid chromatography coupled to low- and high-resolution linear ion trap mass spectrometry for studying the metabolism of paynantheine, an alkaloid of the herbal drug Kratom in rat and human urine. Anal Bioanal Chem. 2010;396:2379–91. Search in Google Scholar

[138] Philipp AA, Wissenbach DK, Weber AA, Zapp J, Maurer HH. Metabolism studies of the Kratom alkaloids mitraciliatine and isopaynantheine, diastereomers of the main alkaloids mitragynine and paynantheine, in rat and human urine using liquid chromatography-linear ion trap-mass spectrometry. J Chromatogr B Anal Technol Biomed Life Sci. 2011;879:1049–55. Search in Google Scholar

[139] Sudheedibu SK, Jangher RL, Kaive AH, Naickereebu NJ. Qualification and quantitation of kratom compounds in human urine by high performance liquid chromatography-tandem mass spectrometry. Am J Chem. 2016;6:60–4. Search in Google Scholar

[140] Chittrakarn S, Penjamras P, Keawpradub N. Quantitative analysis of mitragynine, codeine, caffeine, chlorpheniramine and phenylephrine in a kratom (Mitragyna speciosa Korth.) cocktail using high-performance liquid chromatography. Forensic Sci Int. 2012;217:81–6. Search in Google Scholar

[141] Fowble KL, Musah RA. A validated method for the quantification of mitragynine in sixteen commercially available Kratom (Mitragyna speciosa) products. Forensic Sci Int. 2019;299:195–202. Search in Google Scholar

[142] Kikura-Hanajiri R, Kawamura M, Maruyama T, Kitajima M, Takayama H, Goda Y. Simultaneous analysis of mitragynine, 7-hydroxymitragynine, and other alkaloids in the psychotropic plant “kratom” (Mitragyna speciosa) by LC-ESI-MS. Forensic Toxicol. 2009;27:67–74. Search in Google Scholar

[143] Kowalczuk AP, Lozak A, Zjawiony JK. Comprehensive methodology for identification of Kratom in police laboratories. Forensic Sci Int. 2013;233:238–43. Search in Google Scholar

[144] Parthasarathy S, Ramanathan S, Murugiyah V, Hamdan MR, Mohd Said MI, Lai CS, et al. A simple HPLC-DAD method for the detection and quantification of psychotropic mitragynine in Mitragyna speciosa (ketum) and its products for the application in forensic investigation. Forensic Sci Int. 2013;226:183–7. Search in Google Scholar

[145] Sharma A, Kamble SH, Leon F, Chear NJ-Y, King TI, Berthold EC, et al. Simultaneous quantification of ten key Kratom alkaloids in Mitragyna speciosa leaf extracts and commercial products by ultra-performance liquid chromatography-tandem mass spectrometry. Drug Test Anal. 2019;11(8):1162–71. Search in Google Scholar

[146] Wang M, Carrell EJ, Ali Z, Avula B, Avonto C, Parcher JF, et al. Comparison of three chromatographic techniques for the detection of mitragynine and other indole and oxindole alkaloids in Mitragyna speciosa (kratom) plants. J Sep Sci. 2014;37:1411–8. Search in Google Scholar

[147] Chen P, Bryden N. Determination of yohimbine in yohimbe bark and related dietary supplements using UHPLC-UV/MS: single-laboratory validation. J AOAC Int. 2015;98:896–901. Search in Google Scholar

[148] Chen Q, Li P, Zhang Z, Li K, Liu J, Li Q. Analysis of yohimbine alkaloid from Pausinystalia yohimbe by non-aqueous capillary electrophoresis and gas chromatography-mass spectrometry. J Sep Sci. 2008;31:2211–8. Search in Google Scholar

[149] Friesen K, Palatnick W, Tenenbein M. Benign course after massive ingestion. J Emerg Med. 1993;11:287–8. Search in Google Scholar

[150] Le Hir A, Goutarel R, Janot M-M. Extraction et separation de la yohimbine et de ses stereoisomers. Ann Pharm Fr. 1953;11:546–64. Search in Google Scholar

[151] Linden CH, Vellman WP, Rumack B, Denver C. Yohimbine: a new street drug. Ann Emerg Med. 1985;14(10):1002–4. Search in Google Scholar

[152] van der Meulen TH, van der Kerck GJ. Alkaloids in Pausinystalia yohimbe (K. Schum.) ex pierre: part I. The paper-chromatographic identification of alkaloids occurring in some yohimbine-containing barks. Recl Trav Chim Pays-Bas. 1964;83:141–7. Search in Google Scholar

[153] Raman V, Avula B, Galal AM, Wang YH, Khan IA. Microscopic and UPLC-UV-MS analyses of authentic and commercial yohimbe (Pausinystalia johimbe) bark samples. J Nat Med. 2013;67:42–50. Search in Google Scholar

[154] Ruck B, Shih RD, Marcus SM. Hypertensive crisis from herbal treatment of impotence. J Emerg Med. 1999;17:317–8. Search in Google Scholar

[155] Varkey S. Overdose of yohimbine. BMJ. 1992;34:548. Search in Google Scholar

[156] Zanolari B, Ndjoko K, Ioset J, Marston A, Hostettmann K. Qualitative and quantitative determination of yohimbine in authentic yohimbe bark and in commercial aphrodisiacs by HPLC-UV-API/MS methods. Phytochem Anal. 2003;201:193–201. Search in Google Scholar

[157] Giampreti A, Lonati D, Locatelli C, Rocchi L, Campailla MT. Acute neurotoxicity after yohimbine ingestion by a body builder. Clin Toxicol. 2009;47:827–9. Search in Google Scholar

[158] Myers A, Barrueto F. Refractory priapism associated with ingestion of yohimbe extract. J Med Toxicol. 2009;5:223–5. Search in Google Scholar

[159] Bilia AR, Bergonzi MC, Lazari D, Vincieri FF. Characterization of commercial kava-kava herbal drug and herbal drug preparations by means of nuclear magnetic resonance spectroscopy. J Agric Food Chem. 2002;50:5016–25. Search in Google Scholar

[160] Bilia AR, Scalise L, Bergonzi MC, Vincieri FF. Analysis of kavalactones from Piper methysticum (kava-kava). J Chromatogr B. 2004;812:203–14. Search in Google Scholar

[161] Bobeldijk I, Boonzaaijer G, Spies-Faber EJ, Vaes WHJ. Determination of kava lactones in food supplements by liquid chromatography-atmospheric pressure chemical ionisation tandem mass spectrometry. J Chromatogr A. 2005;1067:107–14. Search in Google Scholar

[162] Coates PM. Encyclopedia of dietary supplement. New York: Marcel Dekker; 2005. Search in Google Scholar

[163] Erickson MD. Analytical chemistry of PCBs. Boca Raton: CRC/Lewis Publ; 1997. Search in Google Scholar

[164] Ganzera M, Khan IA. Analytical techniques for the determination of lactones in Piper methysticum forst. Chromatographia. 1999;50:649–53. Search in Google Scholar

[165] Gaub M, Roeseler C, Roos G, Kovar K-A. Analysis of plant extracts by NIRS: simultaneous determination of kavapyrones and water in dry extracts of Piper methysticum Forst. J Pharm Biomed Anal. 2004;36:859–64. Search in Google Scholar

[166] Gracza L, Ruff P. Hocleistungs-Flssigkeitschromatographische Trennung und quantitative Bestimmung von pflanzlichen Stillbenderivaten. J Chromatogr A. 1984;287:462–5. Search in Google Scholar

[167] He X, Lin L, Lian L. Electrospray high performance liquid chromatography-mass spectrometry in phytochemical analysis of kava (Piper methysticum) extract. Planta Med. 1997;63:70–4. Search in Google Scholar

[168] Herath HMPD, Preston S, Jabbar A, Garcia-Bustos J, Addison RS, Hayes S, et al. Selected α-pyrones from the plants Cryptocarya novoguineensis (Lauraceae) and Piper methysticum (Piperaceae) with activity against Haemonchus contortus in vitro. Int J Parasitol Drugs Drug Resist. 2019;9:72–9. Search in Google Scholar

[169] Hu L, Jhoo J-W, Ang CY, Dinovi M, Mattia A. Determination of six kavalactones in dietary supplements and selected functional foods containing Piper methysticum by iscratic liquid chromatography with internal standard. J AOAC Int. 2005;88:16–25. Search in Google Scholar

[170] Lasme P, Davrieux F, Montet D, Lebot V. Quantification of kavalactones and determination of kava (Piper methysticum) chemotypes using near-infrared reflectance spectroscopy for quality control in Vanuatu. J Agric Food Chem. 2008;56:4976–81. Search in Google Scholar

[171] Lebot V, Levesque J. Evidence for conspecificity of Piper methysticum forst. f. and Piper wichmannii C. DC. Biochem Syst Ecol. 1996;24:775–82. Search in Google Scholar

[172] Lechtenberg M, Quandt B, Kohlenberg F-J, Nahrstedt A. Qualitative and quantitative micellar electrokinetic chromatography of kavalactones from dry extracts of Piper methysticum Forst. and commercial drugs. J Chromatogr A. 1999;848:457–64. Search in Google Scholar

[173] Liu Y, Lund JA, Murch SJ, Brown PN. Single-lab validation for determination of Kavalactones and flavokavains in Piper methysticum (Kava). Planta Med. 2018;84:1213–8. Search in Google Scholar

[174] Martin AC, Johnson E, Xing C, Hegeman AD. Measuring the chemical and cytotoxic variability of commercially available kava (Piper methysticum G. Forster). PLoS One. 2014;9:e111572. Search in Google Scholar

[175] Murauer A, Ganzera M. Quantitative determination of lactones in Piper methysticum (Kava-Kava) by supercritical fluid chromatography. Planta Med. 2017;83:1053–7. Search in Google Scholar

[176] Petersen GE, Tang Y, Fields C. Chemical and in vitro toxicity analysis of a supercritical fluid extract of Kava kava (Piper methysticum). J Ethnopharmacol. 2019;235:301–8. Search in Google Scholar

[177] Schmidt AH, Molnar I. Computer-assisted optimization in the development of a high-performance liquid chromatographic method for the analysis of kava pyrones in Piper methysticum preparations. J Chromatogr A. 2002;948:51–63. Search in Google Scholar

[178] Shao Y, He K, Zheng B, Zheng Q. Reversed-phase high-performance liquid chromatographic method for quantitative analysis of the six major kavalactones in Piper methysticum. J Chromatogr A. 1998;825:1–8. Search in Google Scholar

[179] Wang J, Qu W, Jun S, Bittenbender HC, Li QX. Rapid determination of six kavalactones in kava root and rhizome samples using Fourier transform infrared spectroscopy and multivariate analysis in comparison with gas chromatography. Anal Methods. 2010;2:492–8. Search in Google Scholar

[180] Wang J, Qu W, Bittenbender HC, Li QX. Kavalactone content and chemotype of kava beverages prepared from roots and rhizomes of Isa and Mahakea varieties and extraction efficiency of kavalactones using different solvent. J Food Sci Technol. 2015;52:1164–9. Search in Google Scholar

[181] Young RL, Hylin JW, Plucknett DL, Kawano Y, Nakayama RT. Analysis for kawa pyrones in extracts of Piper methysticum. Phytochemistry. 1966;5:795–8. Search in Google Scholar

[182] Duffield AM, Jamieson DD, Lidgard RO, Duffield PH, Bourne DJ. Identification of some human urinary metabolites of the intoxicating beverage kava. J Chromatogr A. 1989;475:273–81. Search in Google Scholar

[183] Koppel C, Tenczer J. Mass spectral characterization of urinary metabolites of D,L-kawain. J Chromatogr. 1991;562:207–11. Search in Google Scholar

[184] Tarbah F, Mahler H, Kardel B, Weinmann W, Hafner D, Daldrup T. Kinetics of kavain and its metabolites after oral application. J Chromatogr B Analyt Technol Biomed Life Sci. 2003;789:115–30. Search in Google Scholar

[185] Tarbah F, Barguil Y, Muller C, Rickert A, Weinmann W, Nour M, et al. Chromatographic hair analysis for natural kavalactones and their metabolites. A preliminary study. Ann Toxicol Anal. 2013;25:109–19. Search in Google Scholar

[186] Villain M, Cirimele V, Tracqui A, Ricaut FX, Ludes B, Kintz P. Testing for kavain in human hair using gas chromatography-tandem mass spectrometry. J Chromatogr B. 2003;798:351–4. Search in Google Scholar

[187] Albers C, Khler H, Lehr M, Brinkmann B, Beike J. Development of a psilocin immunoassay for serum and blood samples. Int J Legal Med. 2004;118:326–31. Search in Google Scholar

[188] Del Mar Ramirez Fernandez M, Laloup M, Wood M, De Boeck G, Lopez-Rivadulla M, Wallemacq P, et al. Liquid chromatography-tandem mass spectrometry method for the simultaneous analysis of multiple hallucinogens, chlorpheniramine, ketamine, ritalinic acid, and metabolites, in urine. J Anal Toxicol. 2007;31:497–504. Search in Google Scholar

[189] Grieshaber AF, Moore KA, Levine B. The detection of psilocin in human urine. J Forensic Sci. 2001;46:627–30. Search in Google Scholar

[190] Hasler F, Bourquin D, Brenneisen R, Bar T, Vollenweider FX. Determination of psilocin and 4-hydroxyindole-3-acetic acid in plasma by HPLC-ECD and pharmacokinetic profiles of oral and intravenous psilocybin in man. Pharm Acta Helv. 1997;72:175–84. Search in Google Scholar

[191] Hasler F, Bourquin D, Brenneisen R, Vollenweider FX. Renal excretion profiles of psilocin following oral administration of psilocybin: a controlled study in man. J Pharm Biomed Anal. 2002;30:331–9. Search in Google Scholar

[192] Kamata T, Nishikawa M, Katagi M, Tsuchihashi H. Optimized glucuronide hydrolysis for the detection of psilocin in human urine samples. J Chromatogr B Analyt Technol Biomed Life Sci. 2003;796:421–7. Search in Google Scholar

[193] Kamata T, Nishikawa M, Katagi M, Tsuchihashi H. Direct detection of serum psilocin glucuronide by LC/MS and LC/MS/MS: time-courses of total and free (unconjugated) psilocin concentrations in serum specimens of a “magic mushroom” user. Forensic Toxicol. 2006;24:36–40. Search in Google Scholar

[194] Lindenblatt H, Kramer E, Holzmann-Erens P, Gouzoulis-Mayfrank E, Kovar K-A. Quantitation of psilocin in human plasma by high-performance liquid chromatography and electrochemical detection: comparison of liquid-liquid extraction with automated on-line solid-phase extraction. J Chromatogr B Biomed Sci Appl. 1998;709:255–63. Search in Google Scholar

[195] Valdes LJ, Butler WM, Hatfield GM, Paul AG, Koreeda M, Divinorin A, a psychotropic terpenoid, and divinorin B from the hallucinogenic Mexican mint, Salvia divinorum. J Org Chem. 1984;49:4716–20. Search in Google Scholar

[196] Gruber JW, Siebert DJ, Der Marderosian AH, Hock RS. High performance liquid chromatographic quantification of salvinorin A from tissues of Salvia divinorum Epling and Jativa-M. Phytochem Anal. 1999;10:22–5. Search in Google Scholar

[197] Lin PX, Li JH, Chen SH, Chang HC, McKetin R. Quantitative determination of salvinorin A, a natural hallucinogen with abuse liability, in Internet-available Salvia divinorum and endemic species of Salvia in Taiwan. J Food Drug Anal. 2014;22:370–8. Search in Google Scholar

[198] McDonough PC, Holler JM, Vorec SP, Bosy TZ, Magluilo J, Past MR. The detection and quantitative analysis of the psychoactive component of Salvia divinorum, salvinorin a, in human biological fluids using liquid chromatography-mass spectrometry. J Anal Toxicol. 2008;32:417–21. Search in Google Scholar

[199] Medana C, Massolino C, Pazzi M, Baiocchi C. Determination of salvinorins and divinatorins in Salvia divinorum leaves by liquid chromatography/multistage mass spectrometry. Rapid Commun Mass Spectrom. 2006;20:131–6. Search in Google Scholar

[200] Munro TA, Rizzacasa MA, Salvinorins D-F, new neoclerodane diterpenoids from Salvia divinorum, and an improved method for the isolation of salvinorin A. J Nat Prod. 2003;66:703–5. Search in Google Scholar

[201] Pichini S, Abanades S, Farre M, Pellegrini M, Marchei E, Pacifici R, et al. Quantification of the plant-derived hallucinogen salvinorin A in conventional and non-conventional biological fluids by gas chromatography/mass spectrometry after Salvia divinorum smoking. Rapid Commun Mass Spectrom. 2005;19:1649–56. Search in Google Scholar

[202] Siebert DJ. Localization of salvinorin A and related compounds in glandular trichomes of the psychoactive sage, Salvia divinorum. Ann Bot. 2004;93:763–71. Search in Google Scholar

[203] Wolowich WR, Perkins AM, Cienki JJ. Analysis of the psychoactive terpenoid salvinorin A content in five Salvia divinorum herbal products. Pharmacotherapy. 2006;26(9):1268–72. Search in Google Scholar

[204] Schmidt MD, Schmidt MS, Butelman ER, Harding WW, Tidgewell K, Murry DJ, et al. Pharmacokinetics of the plant-derived κ-opioid hallucinogen salvinorin A in nonhuman primates. Synapse. 2005;58:208–10. Search in Google Scholar

[205] Marston A, Hostettmann K. Developments in the application of counter-current chromatography to plant analysis. J Chromatogr A. 2006;1112:181–94. Search in Google Scholar

[206] Meyer GMJ. Herbal drugs of abuse Glaucium flavum and Sceletium tortuosum: metabolism and toxicological detectability of their alkaloids glaucine, mesembrine and mesembrenone studied in rat urine and human liver preparations using GC-MS, LC-MS, LC-HR-MSn, and NMR. PhD Thesis. Technischen Fakultät III – Chemie, Pharmazie, Bio- und Werkstoffwissenschaften der Universität des Saarlandes; 2014. Search in Google Scholar

[207] Meyer GMJ, Wink CSD, Zapp J, Maurer HH. GC-MS, LC-MSn, LC-high resolution-MSn, and NMR studies on the metabolism and toxicological detection of mesembrine and mesembrenone, the main alkaloids of the legal high “Kanna” isolated from Sceletium tortuosum. Anal Bioanal Chem. 2015;407:761–78. Search in Google Scholar

[208] Shikanga EA, Viljoen A, Combrinck S, Marston A. Isolation of Sceletium alkaloids by high-speed countercurrent chromatography. Phytochem Lett. 2011;4:190–3. Search in Google Scholar

[209] Meyer GMJ, Meyer MR, Wissenbach DK, Maurer HH. Studies on the metabolism and toxicological detection of glaucine, an isoquinoline alkaloid from Glaucium flavum (Papaveraceae), in rat urine using GC-MS, LC-MS and LC-high-resolution MS. J Mass Spectrom. 2013;48:24–41. Search in Google Scholar

[210] Welter J, Meyer MR, Wolf E, Weinmann W, Kavanagh P, Maurer HH. 2-Methiopropamine, a thiophene analogue of methamphetamine: studies on its metabolism and detectability in the rat and human using GC-MS and LC-(HR)-MS technologies. Anal Bioanal Chem. 2013;405:3125–35. Search in Google Scholar

[211] Bischoff TA, Kelley CJ, Karchesy Y, Laurantos M, Nguyen-Dinh P, Arefi AG. Antimalarial activity of lactucin and lactucopicrin: sesquiterpene lactones isolated from Cichorium intybus L. J Ethnopharmacol. 2004;95:455–7. Search in Google Scholar

[212] Michalska K, Szneler E, Kisiel W. Complete NMR spectral assignments of two lactucin-type sesquiterpene lactone glycosides from Picris conyzoides. Magn Reason Chem. 2011;49:753–6. Search in Google Scholar

[213] Tamura Y, Mori T, Nakabayashi R, Kobayashi M, Saito K, Okazaki S, et al. Metabolomic evaluation of the quality of leaf lettuce grown in practical plant factory to capture metabolite signature. Front Plant Sci. 2018;9:1–11. Search in Google Scholar

[214] Yang X, Wei S, Liu B, Guo D, Zheng B, Feng L, et al. A novel integrated non-targeted metabolomic analysis reveals significant metabolite variations between different lettuce (Lactuca sativa L.). Hortic Res. 2018;5:1–14. Search in Google Scholar

[215] Hulsey D, Kalam A, Daley P, Terry M. Mescaline concentrations in Chihuahuan desert vs. Tamaulipan thornscrub populations of Lophophora williamsii (peyote). 66th Northwest regional meeting of the American chemical society, Portland, OR, United States, June 26–29; 2011. NORM-159. Search in Google Scholar

[216] Casado R, Uriarte I, Cavero RY, Calvo MI. LC-PAD determination of mescaline in cactus peyote (Lophophora williamsii). Chromatographia. 2008;67(7/8):665–7. Search in Google Scholar

[217] Gennaro MC, Gioannini E, Giacosa D, Siccardi D. Determination of mescaline in hallucinogenic Cactaceae by ion-interaction HPLC. Anal Lett. 1996;29(13):2399–409. Search in Google Scholar

[218] Helmlin H-J, Bourquin D, Brenneisen R. Determination of phenylethylamines in hallucinogenic cactus species by high-performance liquid chromatography with photodiode-array detection. J Chromatogr. 1992;623(2):381–5. Search in Google Scholar

[219] Kelly JP. Cathinone derivatives: a review of their chemistry, pharmacology and toxicology. Drug Test Anal. 2011;3:439–53. Search in Google Scholar

[220] Zawilska JB, Wojcieszak J. Designer cathinones-an emerging class of novel recreational drugs. Forensic Sci Int. 2013;231:42–53. Search in Google Scholar

[221] Simmler LD, Buser TA, Donzelli M, Schramm Y, Dieu L-H, Huwyler J, et al. Pharmacological characterization of designer cathinones in vitro. Br J Pharmacol. 2013;168:458–70. Search in Google Scholar

[222] Valente MJ, Guedes de Pinho P, de Lourdes Bastos M, Carvalho F, Carvalho M. Khat and synthetic cathinones: a review. Arch Toxicol. 2014;88:15–45. Search in Google Scholar

[223] Prosser JM, Nelson LS. The toxicology of bath salts: a review of synthetic cathinones. J Med Toxicol. 2012;8:33–42. Search in Google Scholar

[224] Gardos G, Cole JO. Evaluation of pyrovalerone in chronically fatigued volunteers. Curr Ther Res Clin Exp. 1971;13(10):631–5. Search in Google Scholar

[225] Goldberg J, Gardos G, Cole JO. A controlled evaluation of pyrovalerone in chronically fatigued volunteers. Int Pharmacopsychiatry. 1973;8(1):60–9. Search in Google Scholar

[226] Kriikku P, Wilhelm L, Schwarz O, Rintatalo J. New designer drug of abuse: 3,4-methylenedioxypyrovalerone (MDPV). Findings from apprehended drivers in Finland. Forensic Sci Int. 2011;210(1–3):195–200. Search in Google Scholar

[227] Department of justice, drug enforcement administration. 21 CFR part 1308, [Docket no. DEA–386], schedules of controlled substances: temporary placement of 10 synthetic cathinones into Schedule I, federal register, vol. 79, No. 45/Friday, March 7, 2014/rules and regulations; 2014. p. 12938–42 Search in Google Scholar

[228] Backberg M, Lindeman E, Beck O, Helander A. Characteristics of analytically confirmed 3-MMC-related intoxications from the Swedish STRIDA project. Clin Toxicol. 2015;53(1):46–53. Search in Google Scholar

[229] WHO. Critical review project of 3-methylmethcathinone (3-MMC) for 38th ECDD meeting; 2016. Search in Google Scholar

[230] Adamowicz P, Gieron J, Gil D, Lechowicz W, Skulska A, Tokarczyk B. 3-Methylmethcathinone – interpretation of blood concentrations based on analysis of 95 cases. J Anal Toxicol. 2016;40:272–6. Search in Google Scholar

[231] Power JD, McGlynn P, Clarke K, McDermott SD, Kavanagh P, O’Brien J. The analysis of substituted cathinones. Part 1: chemical analysis of 2-, 3- and 4-methylmethcathinone. Forensic Sci Int. 2011;212(1–3):6–12. Search in Google Scholar

[232] Christie R, Horan E, Fox J, O’Donnell C, Byrne HJ, McDermott S, et al. Discrimination of cathinone regioisomers, sold as ‘legal highs’, by Raman spectroscopy. Drug Test Anal. 2014;6(7–8):651–7. Search in Google Scholar

[233] Baumann MH, Ayestas MAJr, Partilla JS, Sink JR, Shulgin AT, Daley P, et al. The designer methcathinone analogs, mephedrone and methylone, are substrates for monoamine transporters in brain tissue. Neuropsychopharmacology. 2012;37:1192–203. Search in Google Scholar

[234] Baumann MH, Partilla JS, Lehner KR, Thorndike EB, Hoffman AF, Holy M, et al. Powerful cocaine-like actions of 3,4-methylenedioxypyrovalerone (MDPV), a principal constituent of psychoactive “bath salts” products. Neuropsychopharmacology. 2013;38:552–62. Search in Google Scholar

[235] Lopez-Arnau R, Martinez-Clemente J, Pubill D, Escubedo E, Camarasa J. Comparative neuropharmacology of three psychostimulant cathinone derivatives: butylone, mephedrone and methylone. Br J Pharmacol. 2012;167:407–20. Search in Google Scholar

[236] Martinez-Clemente J, Escubedo E, Pubill D, Camarasa J. Interaction of mephedrone with dopamine and serotonin targets in rats. Eur Neuropsychopharmacol. 2012;22:231–6. Search in Google Scholar

[237] Meyer MR, Wilhelm J, Peters FT, Maurer HH. Beta-keto amphetamines: studies on the metabolism of the designer drug mephedrone and toxicological detection of mephedrone, butylone, and methylone in urine using gas chromatography-mass spectrometry. Anal Bioanal Chem. 2010;397:1225–33. Search in Google Scholar

[238] Gibbons S, Zloh M. An analysis of the “legal high” mephedrone. Bioorg Med Chem. 2010;20:4135–9. Search in Google Scholar

[239] Dargan PI, Sedefov R, Gallegos A, Wood DM. The pharmacology and toxicology of the synthetic cathinone mephedrone (4-methylmethcathinone). Drug Test Anal. 2011;3:454–63. Search in Google Scholar

[240] Liechti M. Novel psychoactive substances (designer drugs): overview and pharmacology of modulators of monoamine signalling. Swiss Med Wkly. 2015;145(w):14043. Search in Google Scholar

[241] Dasgupta A. Abuse of magic mushroom, peyote cactus, LSD, khat, and volatiles. Critical issues in alcohol and drugs of abuse testing. 2nd edn; 2019. Search in Google Scholar

[242] https://www.emcdda.europa.eu/publications/drug-profiles/synthetic-cathinones_en. Accessed 14/07/2020. Search in Google Scholar

[243] Papaseit E, Perez-Mana C, de Sousa Fernandes Perna EB, Olesti E, Mateus J, Kuypers KP, et al. Mephedrone and alcohol interactions in humans. Front Pharmacol. 2020;10:1588. Search in Google Scholar

[244] Katz DP, Bhattacharya D, Bhattacharya S, Deruiter J, Clark CR, Suppiramaniam V, et al. Synthetic cathinones: a khat and mouse game. Toxicol Lett. 2014;229:349–56. Search in Google Scholar

[245] Zwartsen A, Olijhoek ME, Westerink RHS, Zwartsen A, Hondebrink L. Hazard characterization of synthetic cathinones using viability, monoamine reuptake, and neuronal activity assays. Front Neurosci. 2020;14:9. Search in Google Scholar

[246] Uralets V, Rana S, Morgan S, Ross W. Testing for designer stimulants: metabolic profiles of 16 synthetic cathinones excreted free in human urine. J Anal Toxicol. 2014;38:233–41. Search in Google Scholar

[247] Lusthof KJ, Oosting R, Maes A, Verschraagen M, Dijkhuizen A, Sprong AGA. A case of extreme agitation and death after the use of mephedrone in The Netherlands. Forensic Sci Int. 2011;206:e93–5. Search in Google Scholar

[248] Shima N, Kakehashi H, Matsuta S, Kamata H, Nakano S, Sasaki K, et al. Urinary excretion and metabolism of the α-pyrrolidinophenone designer drug 1-phenyl-2-(pyrrolidine-1-yl)octan-1-one (PV9) in humans. Forensic Toxicol. 2015;33:279–94. Search in Google Scholar

[249] Dickson AJ, Vorce SP, Levine B, Past MR. Multiple-drug toxicity caused by the coadministration of 4-methylmethcathinone (mephedrone) and heroin. J Anal Toxicol. 2010;34:162–8. Search in Google Scholar

[250] Usui K, Hayashizaki Y, Hashiyada M, Funayama M. Rapid drug extraction from human whole blood using a modified QuEChERS extraction method. Leg Med. 2012;14:286–96. Search in Google Scholar

[251] Namera A, Kawamura M, Nakamoto A, Saito T, Nagao M. Comprehensive review of the detection methods for synthetic cannabinoids and cathinones. Forensic Toxicol. 2015;33:175–94. Search in Google Scholar

[252] Toole KE, Fu S, Shimmon RG, Kraymen N, Taflaga S. Color test for the preliminary identification of methcathinone and analogues of methcathinone. Microgram J. 2012;9:27–32. Search in Google Scholar

[253] Ellefsen KN, Anizan S, Castaneto MS, Desrosiers NA, Martin LTM, Klette CKL, et al. Validation of the only commercially available immunoassay for synthetic cathinones in urine: Randox Drugs of Abuse V Biochip Array technology. Drug Test Anal. 2014;6:728–38. Search in Google Scholar

[254] Swortwood MI, Hearn WL, DeCaprio AP. Cross-reactivity of designer drugs, including cathinone derivatives, in commercial enzyme-linked immunosorbent assays. Drug Test Anal. 2014;6:716–27. Search in Google Scholar

[255] Kohyama E, Chikumoto T, Kitaichi K, Horiuchi T, Ito T. Differentiation of the isomers of N-alkylated cathinones by GC-EI-MS-MS and LC-PDA. Anal Sci. 2016;32:831–7. Search in Google Scholar

[256] Kudo K, Usumoto Y, Usui K, Hayashida M, Kurisaki E, Saka K, et al. Rapid and simultaneous extraction of acidic and basic drugs from human whole blood for reliable semiquantitative NAGINATA drug screening by GC-MS. Forensic Toxicol. 2013;32:97–104. Search in Google Scholar

[257] Rojek S, Klys M, Strona M, Maciow M, Kula K. “Legal Highs”-toxicity in the clinical and medico-legal aspect as exemplified by suicide with bk-MDMA administration. Forensic Sci Int. 2012;22:e1–6. Search in Google Scholar

[258] Westphal F, Junge T, Klein B, Fritschi G, Girreser U. Spectroscopic characterization of 3,4-methylenedioxypyrrolidinobutyrophenone: a new designer drug with α-pyrrolidinophenone structure. Forensic Sci Int. 2011;209:126–32. Search in Google Scholar

[259] Westphal F, Junge T, Girreser U, Greibl W, Doering C. Mass, NMR and IR spectroscopic characterization of pentedrone and pentylone and identification of their isocathinone by-products. Forensic Sci Int. 2012;217:157–67. Search in Google Scholar

[260] Zuba D. Identification of cathinones and other active components of “legal highs” by mass spectrometric methods. Trends Anal Chem. 2012;32:15–30. Search in Google Scholar

[261] Zweipfenning PG, Wilderink AH, Horsthuis P, Franke JP, de Zeeuw RA. Toxicological analysis of whole blood samples by bond-elut certify columns and gas chromatography with nitrogen-phosphorus detection. J Chromatogr A. 1994;674:87–95. Search in Google Scholar

[262] Adamowicz P, Malczyk A. Stability of synthetic cathinones in blood and urine. Forensic Sci Int. 2019;295:36–45. Search in Google Scholar

[263] Lopez-Rabunal A, Lendoiro E, Concheiro M, Lopez-Rivadulla M, Cruz A, de Castro Lios A. A LC-MS/MS method for the determination of common synthetic cathinones in meconium. J Chromatogr B Analyt Technol Biomed Life Sci. 2019;1124:349–55. Search in Google Scholar

[264] Staeheli SN, Veloso VP, Bovens M, Bissig C, Kraemer T, Poetzsch M, et al. Liquid chromatography-tandem mass spectrometry screening method using information-dependent acquisition of enhanced product ion mass spectra for synthetic cannabinoids including metabolites in urine. Drug Test Anal. 2019;11(9):1369–76. Search in Google Scholar

[265] Fornal E. Identification of substituted cathinones: 3,4-methylenedioxy derivatives by high performance liquid chromatography-quadrupole time of flight mass spectrometry. J Pharm Biomed Anal. 2013;81–2:13–9. Search in Google Scholar

[266] Jankovics P, Varadi A, Tolgyesi L, Lohner S, Nemeth-Palotas J, Koszegi-Szalai H. Identification and characterization of the new designer drug 4′-methylethcathinone (4-MEC) and elaboration of a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening method for seven different methcathinone analogs. Forensic Sci Int. 2011;210:213–20. Search in Google Scholar

[267] Majchrzak M, Rojkiewicz M, Celinski R, Kus P, Sajewicz M. Identification and characterization of new designer drug 4-fluoro-PV9 and α-PHP in the seized materials. Forensic Toxicol. 2016;34:115–24. Search in Google Scholar

[268] Lukic V, Micic R, Denic K, Jokic A, Arsic B. Toxicological screening for drugs of abuse in hair using LC–QTOF-MS. 54th meeting of the Serbian chemical society and 5th conference of young chemists of Serbia, 29–30th September 2017, Belgrade, Republic of Serbia, 6; 2017. Search in Google Scholar

[269] Ibanez M, Sancho JV, Bijlsma L, van Nuijs ALN, Covaci A, Hernandez F. Comprehensive analytical strategies based on high-resolution time-of-flight mass spectrometry to identify new psychoactive substances. Trends Anal Chem. 2014;57:107–17. Search in Google Scholar

[270] Uchiyama N, Matsuda S, Kawamura M, Shimokawa Y, Kikura-Hanajiri R, Aritake K, et al. Characterization of four new designer drugs, 5-chloro-NNEI, NNEI indazole analog, α-PHPP and α-POP, with 11 newly distributed designer drugs in illegal products. Forensic Sci Int. 2014a;243:1–13. Search in Google Scholar

[271] Uchiyama N, Matsuda S, Kawamura M, Kikura-Hanajiri R, Goda Y. Identification of two new-type designer drugs, piperazine derivative MT-45 (I-C6) and synthetic peptide Noopept (GVS-111), with synthetic cannabinoid A-834735, cathinone derivative 4-methoxy-α-PVP, and phenethylamine derivative 4-methyl-buphedrine from illegal products. Forensic Toxicol. 2014b;32:9–18. Search in Google Scholar

[272] Uchiyama N, Shimokawa Y, Kawamura M, Kikura-Hanajiri R, Hakamatsuka T. Chemical analysis of a benzofuran derivative, 2-(2-ethylaminopropyl)benzofuran (2-EAPB), eight synthetic cannabinoids, five cathinone derivatives, and five other designer drugs newly detected in illegal products. Forensic Toxicol. 2014c;32:266–81. Search in Google Scholar

[273] Uchiyama N, Shimokawa Y, Kikura-Hanajiri R, Demizu Y, Goda Y, Hakamatsuka T. A synthetic cannabinoid FDU-NNEI, two 2H-indazole isomers of synthetic cannabinoids AB-CHMI-NACA and NNEI indazole analog (MN-18), a phenethylamine derivative N-OH-EDMA, and a cathinone derivative dimethoxy-α-PHP, newly identified in illegal products. Forensic Toxicol. 2015;33:244–59. Search in Google Scholar

[274] Elbardisy HM, Garcia-Miranda Ferrari A, Foster CW, Sutcliffe OB, Brownson DAC, Belal TS, et al. Forensic electrochemistry: the electroanalytical sensing of mephedrone metabolites. ACS Omega. 2019;4(1):1947–54. Search in Google Scholar

[275] Sanchez-Gonzalez J, Odoardi S, Bermejo AM, Bermejo-Barrera P, Romolo FS, Moreda-Pineiro A, et al. HPLC-MS/MS combined with membrane-protected molecularly imprinted polymer micro-solid-phase extraction for synthetic cathinones monitoring in urine. Drug Test Anal. 2019;11(1):33–44. Search in Google Scholar

[276] Brenneisen R, Fisch HU, Koelbing U, Geisshusler S, Kalix P. Amphetamine-like effects in humans of the khat alkaloid cathinone. Br J Clin Pharmacol. 1990;30:825–8. Search in Google Scholar

[277] Patel NB. “Natural amphetamine” khat: a cultural tradition or a drug of abuse? Int Rev Neurobiol. 2015;120:235–55. Search in Google Scholar

[278] Szendrei K. The chemistry of khat. Bull Narc. 1980;32:5–35. Search in Google Scholar

[279] Fauquet JP, Morel E, Demarty C, Rapin JR. Role of central catecholamines in the psychostimulant activity of pyrovalerone. Arch Int Pharmacodyn Ther. 1976;224:325–37. Search in Google Scholar

[280] Meltzer PC, Butler D, Deschamps JR, Madras BK. 1-(4-Methylphenyl)-2-pyrrolidin-1-yl-pentan-1-one (Pyrovalerone) analogues: a promising class of monoamine uptake inhibitors. J Med Chem. 2006;49:1420–32. Search in Google Scholar

[281] Rickli A, Kopf S, Hoener MC, Liechti ME. Pharmacological profile of novel psychoactive benzofurans. Br J Pharmacol. 2015;172(13):3412–25. Search in Google Scholar

[282] German CL, Fleckenstein AE, Hanson GR. Bath salts and synthetic cathinones: An emerging designer drug phenomenon. Life Sci. 2014;97:2–8. Search in Google Scholar

[283] Koppe H, Ludwig G, Zeile K. 1-(3′,4′-Methylenedioxy-phenyl)-2-pyrrolidino-alkanones-(1). US Patent 3478050; 1969. Search in Google Scholar

[284] Gatch MB, Taylor CM, Forster MJ. Locomotor stimulant and discriminative stimulus effects of “bath salt” cathinones. Behav Pharmacol. 2013;24:437–47. Search in Google Scholar

[285] Marinetti LJ, Antonides HM. Analysis of synthetic cathinones commonly found in bath salts in human performance and postmortem toxicology: method development, drug distribution and interpretation of results. J Anal Toxicol. 2013;37:135–46. Search in Google Scholar

[286] Pedersen W, Skrondal A. Ecstasy and new patterns of drug use: a normal population study. Addiction. 1999;94:1695–706. Search in Google Scholar

[287] Elliott S, Evans J. A 3-year review of new psychoactive substances in casework. Forensic Sci Int. 2014;243C:55–60. Search in Google Scholar

[288] Zivkovic VB, Nikolic SD, Lukic V, Zivadinovic N, Babic DD. The effects of a new traffic safety law in the Republic of Serbia on driving under the influence of alcohol. Toxicol Lett. 2008;180:S163. Search in Google Scholar

[289] Zivkovic VB, Nikolic SD, Lukic V, Zivadinovic N, Babic DD. The effects of a new traffic safety law in the Republic of Serbia on driving under the influence of alcohol. Accid Anal Prev. 2013;53:161–5. Search in Google Scholar

[290] Hill SL, Thomas SH. Clinical toxicology of newer recreational drugs. Clin Toxicol (Phila). 2011;49:705–19. Search in Google Scholar

[291] Maurer HH. Chemistry, pharmacology, and metabolism of emerging drugs of abuse. Ther Drug Monit. 2010;32:544–9. Search in Google Scholar

[292] Shulgin A. Pihkal: a chemical love story. Berkeley: Transform Press; 1991. Search in Google Scholar

[293] Corazza O, Schifano F, Farre M, Deluca P, Davey Z, Torrens M, et al. Designer drugs on the internet: a phenomenon out-of-control? The emergence of hallucinogenic drug Bromo-Dragonfly. Curr Clin Pharmacol. 2011;6:125–9. Search in Google Scholar

[294] Elz S, Klas T, Warnke U, Pertz H. Development of highly potent partial agonists and chiral antagonists as tools for the study of 5-HT2A-receptor mediated function. Naunyn-Schmiedeberg’s Arch Pharmacol. 2002;365(1 Suppl):R29. Search in Google Scholar

[295] Heim R. Synthese und pharmakologiepotenter 5-HT2A-rezeptoragonisten mit N-2-methoxybenzyl-partialstruktur. Berlin: Freien Universitat Berlin; 2003. Search in Google Scholar

[296] Le Roux G, Bruneau C, Lelievre B, Deguigne MB, Turcant A, Harry P, et al. Recreational phenethylamine poisonings reported to a French poison control center. Drug Alcohol Depend. 2015;154:46–53. Search in Google Scholar

[297] Trachsel D. Fluorine in psychedelic phenethylamines. Drug Test Anal. 2012;4:577–90. Search in Google Scholar

[298] Docherty JR, Green AR. The role of monoamines in the changes in body temperature induced by 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) and its derivatives. Br J Pharmacol. 2010;160:1029–44. Search in Google Scholar

[299] O’Shea E, Esteban B, Camarero J, Green AR, Colado MI. Effect of GBR 12909 and fluoxetine on the acute and long term changes induced by MDMA (‘ecstasy’) on the 5-HT and dopamine concentrations in mouse brain. Neuropharmacology. 2001;40:65–74. Search in Google Scholar

[300] Romanovsky AA, Ivanov AI, Shimansky YP. Ambient temperature for experiments in rats: a new method for determining the zone of thermal neutrality. J Appl Physiol. 2002;92:2667–79. Search in Google Scholar

[301] Freudenmann RW, Spitzer M. The neuropsychopharmacology and toxicology of 3,4-methylenedioxy-N-ethyl-amphetamine (MDMA). CNS Drug Rev. 2004;10:89–116. Search in Google Scholar

[302] Ghysel-Laporte M-H, Sibille P, Milan N. Amphetamines et derives. In: Kintz P, ed., Traite de toxicologie medico- judiciaire. Issy-les-Moulineaux: Elsevier Masson S. A. S.; 2012. Search in Google Scholar

[303] Gouzoulis-Mayfrank E. Differential actions of an entactogen compared to a stimulant and a hallucinogen in healthy humans. In: Nichols DE, ed. The Heffter review of psychedelic research. Santa Fe: Heffter Research Institute; 2001. Search in Google Scholar

[304] Hernandez-Lopez C, Farre M, Roset PN, Menoyo E, Pizarro N, Ortuno J, et al. 3,4-Methylenedioxymethamphetamine (ecstasy) and alcohol interactions in humans: psychomotor performance, subjective effects, and pharmacokinetics. J Pharmacol Exp Ther. 2002;300:236–44. Search in Google Scholar

[305] Porcu A, Castelli MP. Cannabis and the use of amphetamine-like substances. Handbook of cannabis and related pathologies: biology, pharmacology, chapter: e10, editors: AP; 2017. p. e101–10. Search in Google Scholar

[306] Wagmann L, Hempel N, Richter LHJ, Brandt SD, Stratford A, Meyer MR. Phenethylamine-derived new psychoactive substances 2C-E-FLY, 2C-EF-FLY, and 2C-T-7-FLY: Investigations on their metabolic fate including isoenzyme activities and their toxicological detectability in urine screenings. Drug Test Anal. 2019;11(10):1507–21. Search in Google Scholar

[307] Chia XWS, Ong MC, Yeo YYC, Ho YJ, Binte Ahmad Nasir EI, Tan L-LJ, et al. Simultaneous analysis of 2Cs, 25-NBOHs, 25-NBOMes and LSD in seized exhibits using liquid chromatography-tandem mass spectrometry: a targeted approach. Forensic Sci Int. 2019;301:394–401. Search in Google Scholar

[308] Baralla E, Nieddu M, Burrai L, Varoni MV, Demontis MP, Boatto G. LC-MS/MS analysis of two new designer drugs (FLY serie) in rat plasma and its application to a pharmacokinetic study. Leg Med. 2019;38:58–63. Search in Google Scholar

[309] Sulakova A, Fojtikova L, Holubova B, Bartova K, Lapcik O, Kuchar M. Two immunoassays for the detection of 2C-B and related hallucinogenic phenethylamines. J Pharmacol Toxicol Methods. 2019;95:36–46. Search in Google Scholar

[310] da Cunha KF, Eberlin MN, Huestis MA, Costa JL. NBOMe in whole blood. Forensic Toxicol. 2019;37(1):82–89. Search in Google Scholar

[311] Kueppers VB, Cooke CT. 25I-NBOMe related death in Australia: a case report. Forensic Sci Int. 2015;249:e15–e18. Search in Google Scholar

[312] Sealfon SC, Chi L, Ebersole BJ, Rodic V, Zhang D, Ballesteros J, et al. Related contribution of specific helix 2 and 7 residues to conformational activation of the serotonin 5-HT2A receptor. J Biol Chem. 1995;28:16683–8. Search in Google Scholar

[313] Wang CD, Gallaher TK, Shih JC. Site-directed mutagenesis of the serotonin 5-hydroxytryptamine2 receptor: identification of amino acids necessary for ligand binding and receptor activation. Mol Pharmacol. 1993;43:931–40. Search in Google Scholar

[314] Almaula N, Ebersole BJ, Zhang D, Weinstein H, Sealfon SC. Mapping the binding site pocket of the serotonin 5-Hydroxytryptamine2A receptor. Ser3.36 (159) provides a second interaction site for the protonated amine of serotonin but not of lysergic acid diethylamide or bufotenin. J Biol Chem. 1996;271:14672–5. Search in Google Scholar

[315] Johnson MP, Loncharich RJ, Baez M, Nelson DL. Species variations in transmembrane region V of the 5-hydroxytryptamine type 2A receptor alter the structure-activity relationship of certain ergolines and tryptamines. Mol Pharmacol. 1994;45:277–86. Search in Google Scholar

[316] Johnson MP, Wainscott DB, Lucaites VL, Baez M, Nelson DL. Mutations of transmembrane IV and V serines indicate that all tryptamines do not bind to the rat 5-HT2A receptor in the same manner. Mol Brain Res. 1997;49:1–6. Search in Google Scholar

[317] Braden MR, Parrish JC, Naylor JC, Nichols DE. Molecular interaction of serotonin 5-HT2A receptor residues Phe339 (6.51) and Phe340 (6.52) with superpotent N-benzyl phenethylamine agonists. Mol Pharmacol. 2006;70:1956–64. Search in Google Scholar

[318] Choudhary MS, Craigo S, Roth BL. A single point mutation (Phe340 → Leu340) of a conserved phenylalanine abolishes 4-[125I]iodo-(2,5-dimethoxy)phenylisopropylamine and [3H] mesulergine but not [3H] ketanserin binding to 5-hydroxytryptamine2 receptors. Mol Pharmacol. 1993;43:755–61. Search in Google Scholar

[319] Choudhary MS, Sachs N, Uluer A, Glennon RA, Westkaemper RB, Roth BL. Differential ergoline and ergopeptine binding to 5-hydroxytryptamine2A receptors: ergolines require an aromatic residue at position 340 for high affinity binding. Mol Pharmacol. 1995;47:450–7. Search in Google Scholar

[320] Ballesteros JA, Weinstein H. Integrated methods for the construction of three-dimensional models and computational probing of structure-function relations in G protein-coupled receptors. Methods Neurosci. 1995;25:366–428. Search in Google Scholar

[321] Jeon SY, Kim Y-H, Kim SJ, Suh SK, Cha HJ. Abuse potential of 2-(4-iodo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl) ethanamine (25I-NBOMe); in vivo and ex vivo approaches. Neurochem Int. 2019;125:74–81. Search in Google Scholar

[322] Meyer JS. 3,4-methylenedioxymethamphetamine (MDMA): current perspectives. Subst Abuse Rehabil. 2013;4:83–99. Search in Google Scholar

[323] Hardman HF, Haavik CO, Seevers MH. Relationship of the structure of mescaline and seven analogs to toxicity and behavior of five species of laboratory animals. Toxicol Appl Pharmacol. 1973;25(2):299–309. Search in Google Scholar

[324] Shulgin AT, Nichols DE. Characterization of three new psychotomimetics. In: Stillman RC, Willette RE, eds., The psychopharmacology of hallucinogens. New York: Pergamon Press; 1978. p. 74–83. Search in Google Scholar

[325] Sun Y, Bennett A. Cannabinoids: a new group of agonists of PPARs. PPAR Res. 2007;2007:23513. Search in Google Scholar

[326] Howlett AC, Barth F, Bonner TI, Cabral G, Casellas P, Devane WA, et al. International union of pharmacology. XXVII. Classification of cannabinoid receptors. Pharmacol Rev. 2002;54:161–202. Search in Google Scholar

[327] Ciolino LA. Quantitation of synthetic cannabinoids in plant materials using high performance liquid chromatography with UV detection (validated method). J Forensic Sci. 2015;60:1171–81. Search in Google Scholar

[328] Anzillotti L, Marezza F, Calo L, Andreoli R, Agazzi S, Bianchi F, et al. Determination of synthetic and natural cannabinoids in oral fluid by solid-phase microextraction coupled to gas chromatography/mass spectrometry: a pilot study. Talanta. 2019;201:335–41. Search in Google Scholar

[329] Chung H, Choi H, Heo S, Kim E, Lee J. Synthetic cannabinoids abused in South Korea: drug identifications by the 123 national forensic service from 2009 to June 2013. Forensic Toxicol. 2014;32:82–88. Search in Google Scholar

[330] Uchiyama N, Kawamura M, Kikura-Hanajiri R, Goda Y. Identification of two new-type synthetic cannabinoids, N-(1-adamantyl)-1-pentyl-1H-indole-3-carboxamide (APICA) and N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (APINACA), and detection of five synthetic cannabinoids, AM-1220, AM-2233, AM-1241, CB-13 (CRA-13), and AM-1248, as designer drugs in illegal products. Forensic Toxicol. 2012;30:114–25. Search in Google Scholar

[331] Vikingsson S, Josefsson M, Gre´en H. Identification of AKB-48 and 5F-AKB-48 metabolites in authentic human urine samples using human liver microsomes and time of flight mass spectrometry. J Anal Toxicol. 2015;39:426–35. Search in Google Scholar

[332] European Monitoring Centre for Drugs and Drug Addiction, Europol; 2019. EU drug markets report. https://www.emcdda.europa.eu/system/files/publications/12078/20192630_TD0319332ENN_PDF.pdf. Accessed 06/07/2020. Search in Google Scholar

[333] Grotenhermen F. Pharmacology of cannabinoids. Neuroendocrinol Lett. 2004;25:14–23. Search in Google Scholar

[334] Zuardi AW. History of cannabis as a medicine: a review. Rev Bras Psiquiatr. 2006;28:153–7. Search in Google Scholar

[335] Zou S, Kumar U. Cannabinoid receptors and the endocannabinoid system: signaling and function in the central nervous system. Int J Mol Sci. 2018;19:833. Search in Google Scholar

[336] Hill AJ, Williams CM, Whalley BJ, Stephens GJ. Phytocannabinoids as novel therapeutic agents in cns disorders. Pharmacol Ther. 2012;133:79–97. Search in Google Scholar

[337] Izzo AA, Borrelli F, Capasso R, di Marzo V, Mechoulam R. Non-psychotropic plant cannabinoids: new therapeutic opportunities from an ancient herb. Trends Pharmacol Sci. 2009;30:515–27. Search in Google Scholar

[338] Mechoulam R, Sumariwalla PF, Feldmann M, Gallily R. Cannabinoids in models of chronic inflammatory conditions. Phytochem Rev. 2005;4:11–8. Search in Google Scholar

[339] Patil KR, Goyal SN, Sharma C, Patil CR, Ojha S. Phytocannabinoids for cancer therapeutics: recent updates and future prospects. Curr Med Chem. 2015;22:3472–501. Search in Google Scholar

[340] Atakan Z. Cannabis, a complex plant: different compounds and different effects on individuals. Ther Adv Psychopharmacol. 2012;2(6):241–54. Search in Google Scholar

[341] Pertwee RG. Cannabinoid pharmacology: the first 66 years. Br J Pharmacol. 2006;147:163–71. Search in Google Scholar

[342] Shen M, Piser TM, Seybold VS, Thayer SA. Cannabinoid receptor agonists inhibit glutamatergic synaptic transmission in rat hippocampal cultures. J Neurosci. 1996;16:4322–34. Search in Google Scholar

[343] Kano M, Ohno-Shosaku T, Hashimotodani Y, Uchigashima M, Watanabe M. Endocannabinoid-mediated control of synaptic transmission. Physiol Rev. 2009;89:309–80. Search in Google Scholar

[344] Gonzalez-Mariscal I, Krzysik-Walker SM, Doyle ME, Liu QR, Cimbro R, Calvo SSC, et al. Human CB1 receptor isoforms, present in hepatocytes and β-cells, are involved in regulating metabolism. Sci Rep. 2016;6:33302. Search in Google Scholar

[345] Liu QR, Pan CH, Hashimoto A, Li CY, Xi ZX, Llorente-Berzal A, et al. UhlGR.Species differences in cannabinoid receptor 2 (CNR2 gene): identification of novel human and rodent CB2 isoforms, differential tissue expression and regulation by cannabinoid receptor ligands. Genes Brain Behav. 2009;8:519–30. Search in Google Scholar

[346] Rozenfeld R. Type I cannabinoid receptor trafficking: all roads lead to lysosome. Traffic. 2011;12:12–8. Search in Google Scholar

[347] Rozenfeld R, Devi LA. Regulation of CB1 cannabinoid receptor trafficking by the adaptor protein ap-3. FASEB J. 2008;22:2311–22. Search in Google Scholar

[348] Gunderson EW, Haughey HM, Ait-Daoud N, Joshi AS, Hart CL. “Spice” and “K2” herbal highs: a case series and systematic review of the clinical effects and biopsychosocial implications of synthetic cannabinoid use in humans. Am J Addict. 2012;21:320–6. Search in Google Scholar

[349] Presley BC, Logan BK, Jansen-Varnum SA. Phase I metabolism of synthetic cannabinoid receptor agonist PX-1 (5F-APP-PICA) via incubation with human liver microsomes and UHPLC-HRMS. Biomed Chromatogr. 2020;34(3):e4786. 10.1002/bmc.4786. Search in Google Scholar

[350] Watanabe S, Vikingsson S, Aastrand A, Green H, Kronstrand R. Biotransformation of the new synthetic cannabinoid with an alkene, MDMB-4en-PINACA, by human hepatocytes, human liver microsomes, and human urine and blood. AAPS J. 2020;22(1):13. Search in Google Scholar

[351] Wouters E, Mogler L, Cannaert A, Auwaerter V, Stove C. Functional evaluation of carboxy metabolites of synthetic cannabinoid receptor agonists featuring scaffolds based on L-valine or L-tert-leucine. Drug Test Anal. 2019;11(8):1183–91. Search in Google Scholar

[352] Richter LHJ, Maurer HH, Meyer MR. Metabolic fate of the new synthetic cannabinoid 7′N-5F-ADB in rat, human, and pooled human S9 studied by means of hyphenated high-resolution mass spectrometry. Drug Test Anal. 2019;11(2):305–17. Search in Google Scholar

[353] Gundersen POM, Spigset O, Josefsson M. Screening, quantification, and confirmation of synthetic cannabinoid metabolites in urine by UHPLC-QTOF-MS. Drug Test Anal. 2019;11(1):51–67. Search in Google Scholar

[354] Presley BC, Jansen-Varnum SA, Logan BK. In vitro metabolic profile elucidation of synthetic cannabinoid APP-CHMINACA (PX-3). J Anal Toxicol. 2019;44:bkz086. 10.1093/jat/bkz086. Search in Google Scholar

[355] Giorgetti A, Mogler L, Haschimi B, Halter S, Franz F, Westphal F, et al. Detection and phase I metabolism of the 7-azaindole-derived synthetic cannabinoid 5F-AB-P7AICA including a preliminary pharmacokinetic evaluation. Drug Test Anal. 2020;12(1):78–91. Search in Google Scholar

[356] Aung MM, Griffin G, Huffman JW, Wu M-J, Keel C, Yang B, et al. Influence of the N-1 alkyl chain length of cannabimimetic indoles upon CB(1) and CB(2) receptor binding. Drug Alcohol Depend. 2000;60:133–40. Search in Google Scholar

[357] Huffman JW, Dai D, Martin BR, Compton DR. Design, synthesis and pharmacology of cannabimimetic indoles. Bioorg Med Chem Lett. 1994;4:563–6. Search in Google Scholar

[358] Huffman JW, Mabon R, Wu M-J, Lu J, Hart R, Hurst DP, et al. 3-Indolyl-1-naphtylmethanes: new cannabimimetic indoles provide evidence for aromatic stacking interactions with the CB(1) cannabinoid receptor. Bioorg Med Chem. 2003;11:539–49. Search in Google Scholar

[359] Huffman JW, Zengin G, Wu M-J, Lu J, Hynd G, Bushell K, et al. Structure-activity relationships for 1-alkyl-3-(1-naphthoyl)indoles at the cannabinoid CB1 and CB2 receptors: steric and electronic effects of naphthoyl substituents. New highly selective CB2 receptor agonists. Bioorg Med Chem. 2005;13:89–112. Search in Google Scholar

[360] Auwarter V, Dresen S, Weinmann W, Muller M, Putz M, Ferreiros N. “Spice” and other herbal blends: harmless incense or cannabinoid designer drugs. J Mass Spectrom. 2009;44:832–7. Search in Google Scholar

[361] Couceiro J, Bandarra S, Sultan H, Bell S, Constantino S, Quintas A. Toxicological impact of JWH-018 and its phase I metabolite N-(3-hydroxypentyl) on human cell lines. Forensic Sci Int. 2016;264:100–5. Search in Google Scholar

[362] Dunham SJB, Hooker PD, Hyde RM. Identification, extraction and quantification of the synthetic cannabinoid JWH-018 from commercially available herbal marijuana alternatives. Forensic Sci Int. 2012;223:241–4. Search in Google Scholar

[363] Dresen S, Ferreiros N, Putz M, Westphal F, Zimmermann R, Auwarter V. Monitoring of herbal mixtures potentially containing synthetic cannabinoids as psychoactive compounds. J Mass Spectrom. 2010;45:1186–94. Search in Google Scholar

[364] Chiyama NU, Anajiri RKI, Awahara NK, Aishima YH, Oda YG. Identification of a cannabinoid analog as a new type of designer drug in a herbal product. Chem Pharm Bull. 2009;57:439–41. Search in Google Scholar

[365] Lindigkeit R, Boehme A, Eiserloh I, Luebbecke M, Wiggermann M, Ernst L, et al. Spice: a never ending story. Forensic Sci Int. 2009;191:58–63. Search in Google Scholar

[366] Uchiyama N, Kikura-Hanajiri R, Ogata J, Goda Y. Chemical analysis of synthetic cannabinoids as designer drugs in herbal products. Forensic Sci Int. 2010;198:31–8. Search in Google Scholar

[367] Lukić V, Jokić A, Sejmanović D, Micić R. Identification and quantitative analysis of synthetic cannabinoid JWH-018 in plant materials. XXIV congress of chemists and technologists of Macedonia, AC 013, 11–14 September 2016, Ohrid, Republic of North Macedonia; 2016. Search in Google Scholar

[368] Strano-Rossi S, Anzillotti L, Castrignano E, Romolo FS, Chiarotti M. Ultra high performance liquid chromatography – electrospray ionization – tandem mass spectrometry screening method for direct analysis of designer drugs, “spice” and stimulants in oral fluid. J Chromatogr A. 2012;1258:37–42. Search in Google Scholar

[369] Hutter M, Kneisel S, Auwarter V, Neukamm M. Determination of 22 synthetic cannabinoids in human hair by liquid chromatography – tandem mass spectrometry. J Chromatogr B Anal Technol Biomed Life Sci. 2012;903:95–101. Search in Google Scholar

[370] Ammann J, McLaren JM, Gerostamoulos D, Beyer J. Detection and quantification of new designer drugs in human blood: part 1 – synthetic cannabinoids. J Anal Toxicol. 2012;36:372–80. Search in Google Scholar

[371] Dresen S, Kneisel S, Weinmann W, Zimmermann R, Auwarter V. Development and validation of a liquid chromatography–tandem mass spectrometry method for the quantitation of synthetic cannabinoids of the aminoalkylindole type and methanandamide in serum and its application to forensic samples. J Mass Spectrom. 2011;46:163–71. Search in Google Scholar

[372] Kacinko SL, Xu A, Homan JW, McMullin MM, Warrington DM, Logan BK. Development and validation of a liquid chromatography – tandem mass spectrometry method for the identification and quantification of JWH-018, JWH- 073, JWH-019, and JWH-250 in human whole blood. J Anal Toxicol. 2011;35:386–96. Search in Google Scholar

[373] Shanks KG, Dahn T, Terrell AR. Detection of JWH-018 and JWH-073 by UPLC–MS–MS in postmortem whole blood casework. J Anal Toxicol. 2012;36:145–52. Search in Google Scholar

[374] Teske J, Weller J-P, Fieguth A, Rothamel T, Schulz Y, Troger HD. Sensitive and rapid quantification of the cannabinoid receptor agonist naphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-018) in human serum by liquid chromatography–tandem mass spectrometry. J Chromatogr B. 2010;878:2659–63. Search in Google Scholar

[375] Beuck S, Moller I, Thomas A, Klose A, Schlorer N, Schanzer W, et al. Structure characterisation of urinary metabolites of the cannabimimetic JWH-018 using chemically synthesised reference material for the support of LC–MS/MS-based drug testing. Anal Bioanal Chem. 2011;401:493–505. Search in Google Scholar

[376] De Jager AD, Warner JV, Henman M, Ferguson W, Hall A. LC–MS/MS method for the quantitation of metabolites of eight commonly-used synthetic cannabinoids in human urine – an Australian perspective. J Chromatogr B Anal Technol Biomed Life Sci. 2012;897:22–31. Search in Google Scholar

[377] Grigoryev A, Savchuk S, Melnik A, Moskaleva N, Dzhurko J, Ershov M, et al. Chromatography-mass spectrometry studies on the metabolism of synthetic cannabinoids JWH-018 and JWH-073, psychoactive components of smoking mixtures. J Chromatogr B Anal Technol Biomed Life Sci. 2011;879:1126–36. Search in Google Scholar

[378] Jang M, Yang W, Choi H, Chang H, Lee S, Kim E, et al. Monitoring of urinary metabolites of JWH-018 and JWH-073 in legal cases. Forensic Sci Int. 2013;231:13–9. Search in Google Scholar

[379] Logan BK, Kacinko SL, Ms MMM, Xu A, Robert A. Technical bulletin: identification of primary JWH-018 and JWH-073 metabolites in human urine. NMS Labs; 2011. Online website: http://www.nmslabs.com/uploads/PDF/JWH_ metabolites_Technical_Bulletin_Final_v1.1.pdf Search in Google Scholar

[380] Moran CL, Le V-H, Chimalakonda KC, Smedley AL, Lackey FD, Owen SN, et al. Quantitative measurement of JWH-018 and JWH-073 metabolites excreted in human urine. Anal Chem. 2011;83:4228–36. Search in Google Scholar

[381] Poklis JL, Amira D, Wise LE, Wiebelhaus JM, Haggerty BJ, Poklis A. Detection and disposition of JWH-018 and JWH-073 in mice after exposure to “Magic Gold” smoke. Forensic Sci Int. 2012;220:91–6. Search in Google Scholar

[382] Sobolevsky T, Prasolov I, Rodchenkov G. Detection of JWH-018 metabolites in smoking mixture post-administration urine. Forensic Sci Int. 2010;200:141–7. Search in Google Scholar

[383] Wohlfarth A, Scheidweiler KB, Chen X, Liu H, Huestis MA. Qualitative confirmation of 9 synthetic cannabinoids and 20 metabolites in human urine using LC–MS/MS and library search; 2013. Search in Google Scholar

[384] Ozturk YE, Yeter O, Alpertunga B. Validation of JWH-018 and its metabolites in blood and urine by UPLC-MS/MS: monitoring in forensic cases. Forensic Sci Int. 2015;248:88–93. Search in Google Scholar

[385] Wintermeyer A, Moller I, Thevis M, Jubner M, Beike J, Rothschild MA. In vitro phase I metabolism of the synthetic cannabimimetic JWH-018. Anal Bioanal Chem. 2010;398(5):2141–53. Search in Google Scholar

[386] Chimalakonda KC, Bratton SM, Le VH, Yiew KH, Dineva A, Moran CL, et al. Conjugation of synthetic cannabinoids JWH-018 and JWH-073, metabolites by human UDP-glucuronosyltransferases. Drug Metab Dispos. 2011;39:1967–76. Search in Google Scholar

[387] Stout SM, Cimino NM. Exogenous cannabinoids as substrates, inhibitors, and inducers of human drug metabolizing enzymes: a systematic review. Drug Metab Rev. 2014;46:86–95. Search in Google Scholar

[388] Brents LK, Reichard EE, Zimmerman SM, Moran JH, Fantegrossi WE, Prather PL. Phase I hydroxylated metabolites of the K2 synthetic cannabinoid JWH-018 retain in vitro and in vivo cannabinoid 1 receptor affinity and activity. PLoS ONE. 2011;6:e21917. Search in Google Scholar

[389] Rajasekaran M, Brents LK, Franks LN, Moran JH, Prather PL. Human metabolites of synthetic cannabinoids JWH-018 and JWH-073 bind with high affinity and act as potent agonists at cannabinoid type-2 receptors. Toxicol Appl Pharmacol. 2013;269:100–8. Search in Google Scholar

[390] Gustafsson SB, Lindgren T, Jonsson M, Jacobsson SO. Cannabinoid receptor-independent cytotoxic effects of cannabinoids in human colorectal carcinoma cells: synergism with 5-fluorouracil. Cancer Chemother Pharmacol. 2009;63:691–701. Search in Google Scholar

[391] Koller VJ, Ferk F, Al-Serori H, Misik M, Nersesyan A, Auwarter V, et al. Genotoxic properties of representatives of alkylindazoles and aminoalkyl-indoles which are consumed as synthetic cannabinoids. Food Chem Toxicol. 2015;80:130–6. Search in Google Scholar

[392] Tomiyama, K-i, Funada, M, Cytotoxicity of synthetic cannabinoids on primary neuronal cells of the forebrain: the involvement of cannabinoid CB1 receptors and apoptotic cell death. Toxicol Appl Pharmacol. 2014;274:17–23. Search in Google Scholar

[393] Reich DL, Silvay G. Ketamine: an update on the first twenty-five years of clinical experience. Can J Anaesth. 1989;36:186–97. Search in Google Scholar

[394] White PF, Way WL, Trevor AJ. Ketamine – its pharmacology and therapeutic uses. Anesthesiology. 1982;56:119–36. Search in Google Scholar

[395] Petrillo TM, Fortenberry JD, Linzer JF, Simon HK. Emergency department use of ketamine in pediatric status asthmaticus. J Asthma. 2001;38(8):657–64. Search in Google Scholar

[396] Smith KM, Larive LL, Romanelli F. Club drug: methylenedioxymethamphetamine, flunitrazepam, ketamine hydrochloride, and gamma-hydroxybutyrate. Am J Health Syst Pharm. 2002;59(11):1067–76. Search in Google Scholar

[397] Chang T, Glazko AJ. A gas chromatographic assay for ketamine in human plasma. Anesthesiology. 1972;36:401–4. Search in Google Scholar

[398] Moore KA, Kilbane EM, Jones R, Kunsman GW, Levine B, Smith M. Tissue distribution of ketamine in a mixed drug fatality. J Forensic Sci. 1997;2(6):1183–5. Search in Google Scholar

[399] Domino EF, Zsigmond EK, Domino LE, Domino KE, Kothary SP, Domino SE. Plasma levels of ketamine and two of its metabolites in surgical patients using a gas chromatographic mass fragmentographic assay. Anesth Analog. 1982;61:87–92. Search in Google Scholar

[400] Kochhar MM. The identification of ketamine and its metabolites in biologic fluids by gas chromatography–mass spectrometry. Clin Toxicol. 1977;11(2):265–75. Search in Google Scholar

[401] Spokert F, Pragst F. Use of headspace solid-phase microextraction (HS-SPME) in hair analysis for organic compounds. Forensic Sci Int. 2000;107:129–48. Search in Google Scholar

[402] Needham LL, Kochhar MM. Determination of ketamine and some in vivo metabolites using high pressure liquid chromatography. J Chromatogr. 1975;114:220–2. Search in Google Scholar

[403] Yanagihara Y, Ohtani M, Kariya S, Uchino K, Aoyama T, Yamamura Y, et al. Stereoselective high-performance liquid chromatographic determination of ketamine and its active metabolite, norketamine, in human plasma. J Chromatogr B. 2000;746:227–31. Search in Google Scholar

[404] Moore KA, Sklerov J, Levine B, Jacobs AJ. Urine concentrations of ketamine and norketamine following illegal consumption. J Anal Toxicol. 2001;25:583–8. Search in Google Scholar

[405] Schep LJ, Gee P, Tingle M, Galea S, Newcombe D. Regulating new psychoactive drugs: innovation leading to compromise. BMJ. 2014;349:g5085. Search in Google Scholar

[406] Zamengo L, Frison G, Bettin C, Sciarrone R. Understanding the risks associated with the use of new psychoactive substances (NPS): High variability of active ingredients concentration, mislabelled preparations, multiple psychoactive substances in single products. Toxicol Lett. 2014;229:220–8. Search in Google Scholar

[407] Schep LJ, Slanghter RJ, Vale JA, Beasley DMG, Gee P. The clinical toxicology of the designer “party pills” benzylpiperazine and trifluoromethylphenylpiperazine. Clin Toxicol. 2011;49:131–41. Search in Google Scholar

[408] Araujo AM, Carvalho F, de Lourdes Bastos M, Guerdes de Pinho P, Carvalho M. The hallucinogenic world of tryptamines: an updated review. Arch Toxicol. 2015;89:1151–73. Search in Google Scholar

[409] Martins CPB, Freeman S, Alder JF, Passie T, Brandt SD. Profiling psychoactive tryptamine-drug synthesis by focusing on detection using mass spectrometry. Trends Analyt Chem. 2010;29:285–96. Search in Google Scholar

[410] Callaway JC, McKenna DJ. Neurochemistry of psychedelic drugs. In: Karch SB, ed., Drug abuse handbook. Boca Raton, FL: CRC Press; 1998. 485. Search in Google Scholar

[411] Gartz J. Magic mushrooms around the world. Los Angeles: LIS Publications; 1996. Search in Google Scholar

[412] Fantegrossi WE, Murnane KS, Reissig CJ. The behavioural pharmacology of hallucinogens. Biochem Pharmacol. 2008;75:17–33. Search in Google Scholar

[413] Nichols DE. Hallucinogens. Pharmacol Ther. 2004;101:131–81. Search in Google Scholar

[414] Winter JC. Hallucinogens as discriminative stimuli in animals: LSD, phenethylamines, and tryptamines. Psychopharmacology. 2009;203:251–63. Search in Google Scholar

[415] Fontanilla D, Johannessen M, Hajipour AR, Cozzi NV, Jackson MB, Ruoho AE. The hallucinogen N,N-dimethyltryptamine (DMT) is an endogenous sigma-1 receptor regulator. Science. 2009;323:934–7. Search in Google Scholar

[416] Szara S. Dimethyltryptamin: its metabolism in man; the relation to its psychotic effect to the serotonin metabolism. Experientia. 1956;12(11):441–2. Search in Google Scholar

[417] Cozzi NV, Gopalakrishnan A, Anderson LL, Feih JT, Shulgin AT, Daley PF, et al. Dimethyltryptamine and other hallucinogenic tryptamines exhibit substrate behavior at the serotonin uptake transporter and the vesicle monoamine transporter. J Neural Transm. 2009;116:1591–9. Search in Google Scholar

[418] Fels H, Lottner-Nau S, Sax T, Roider G, Graw M, Auwaerter V, et al. Postmortem concentrations of the synthetic opioid U-47700 in 26 fatalities associated with the drug. Forensic Sci Int. 2019;301:e20–8. Search in Google Scholar

[419] Hagenbach D, Werthmuller L. Mystic chemist: the life of Albert Hofmann and his discovery of LSD. Santa Fe, New Mexico: Synergetic Press; 2011. Search in Google Scholar

[420] Boland DM, Andallo W, Hime GW, Hearn WL. Fatality due to acute alpha-methyltryptamine intoxication. J Anal Toxicol. 2005;29(5):394–7. Search in Google Scholar

[421] Alatrash G, Majhail NS, Pile JC. Rhabdomyolysis after ingestion of “foxy”, a hallucinogenic tryptamine derivative. Mayo Clin Proc. 2006;81(4):550–1. Search in Google Scholar

[422] Corkery JM, Durkin E, Elliott S, Schifano F, Ghodse AH. The recreational tryptamine 5-MeO-DALT (N,N-diallyl-5-methoxy-tryptamine): a brief review. Prog Neuropsychopharmacol Biol Psychiatry. 2012;39(2):259–62. Search in Google Scholar

[423] Poch GK, Klette KL, Hallare DA, Manglicmot MG, Czarny RJ, McWhorter LK, et al. Detection of metabolites of lysergic acid diethylamide (LSD) in human urine specimens: 2-oxo-3-hydroxy-LSD, a prevalent metabolite of LSD. J Chromatogr B Biomed Sci Appl. 1999;724(1):23–33. Search in Google Scholar

[424] Reuschel SA, Eades D, Foltz RL. Recent advances in chromatographic and mass spectrometric methods for determination of LSD and its metabolites in physiological specimens. J Chromatogr B Biomed Sci Appl. 1999;733(1–2):145–59. Search in Google Scholar

[425] Sklerov JH, Magluilo J Jr, Shannon KK, Smith ML. Liquid chromatography-electrospray ionization mass spectrometry for the detection of lysergide and a major metabolite, 2-oxo-3-hydroxy-LSD, in urine and blood. J Anal Toxicol. 2000;24(7):543–9. Search in Google Scholar

[426] Wagmann L, Richter LHJ, Kehl T, Wack F, Bergstrand MP, Brandt SD, et al. In vitro metabolic fate of nine LSD-based new psychoactive substances and their analytical detectability in different urinary screening procedures. Anal Bioanal Chem. 2019;411(19):4751–63. Search in Google Scholar

[427] Halberstadt AL, Chatha M, Klein AK, McCorvy JD, Meyer MR, Wagmann L, et al. Pharmacological and biotransformation studies of 1-acyl-substituted derivatives of d-lysergic acid diethylamide (LSD). Neuropharmacology. 2020;172:107856. Search in Google Scholar

[428] Karila L, Marillier M, Chaumette B, Billieux J, Franchitto N, Benyamina A. New synthetic opioids: part of a new addiction landscape. Neurosci Biobehav Rev. 2019;106:133–40. Search in Google Scholar

[429] Blanckaert P, Cannaert A, Van Uytfanghe K, Hulpia F, Deconinck E, Van Calenbergh S, et al. Report on a novel emerging class of highly potent benzimidazole NPS opioids: chemical and in vitro functional characterization of isotonitazene. Drug Test Anal. 2020;12(4):422–30. Search in Google Scholar

[430] Krotulski AJ, Papsun DM, Kacinko SL, Logan BK. Isotonitazene quantitation and metabolite discovery in authentic forensic casework. J Anal Toxicol. 2020;44:521–30. 10.1093/jat/bkaa016. Search in Google Scholar

[431] Lovrecic B, Lovrecic M, Gabrovec B, Carli M, Pacini M, Maremmani AGI, et al. Non-medical use of novel synthetic opioids: a new challenge to public health. Int J Environ Res Public Health. 2019;16(2):E177. Search in Google Scholar

[432] Helander A, Backberg M, Signell P, Beck O. Intoxications involving acryl-fentanyl and other novel designer fentanyls-results from the Swedish STRIDA project. Clin Toxicol. 2017a;55(6):589–99. Search in Google Scholar

[433] Helander A, Bradley M, Hasselblad A, Norlen L, Vassilaki L, Backberg M, et al. Acute skin and hair symptoms followed by severe, delayed eye complications in subjects using the synthetic opioid MT-45. Br J Dermatol. 2017b;176(4):1021–7. Search in Google Scholar

[434] Booij LHDJ. The agent used to free the hostages in Moscow and the insufficient Dutch preparations in case of a terrorist chemical disaster. Nederlands tijdschrift voor geneeskunde. 2002;146(50):2396–401. Search in Google Scholar

[435] EMCDDA. Fentanyl in Europe, EMCDDA trendspotter study report. Luxembourg: Publication Office for the European Union; 2012. Search in Google Scholar

[436] Waldhoer M, Bartlett SE, Whistler JL. Opioid receptors. Annu Rev Biochem. 2004;73(1):953–90. Search in Google Scholar

[437] Stanley T. The fentanyl story. J Pain. 2014;15(12):1215–26. Search in Google Scholar

[438] Che J, Yuan M, Zhu X, Zhang X, Liu Z. Method for detecting carfentanyl and carfentanyl metabolite. Faming Zhuanli Shenqing; 2020. CN 111175395 A 20200519. Search in Google Scholar

[439] Varadi A, Subrath JJ, LeRouzic V, Pasternak GW, Marrone G, Majumdar S. Opioid scaffolds obtained by the Ugi multi-component reaction. 248th ACS National Meeting and Exposition, San Francisco, CA, United States, August 10–14; 2014. Search in Google Scholar

[440] Prekupec MP, Mansky PA, Baumann MH. Misuse of novel synthetic opioids: a deadly new trend. J Addict Med. 2017;11(4):256–65. Search in Google Scholar

[441] Ventura L, Carvalho F, Dinis-Oliveira RJ. Opioids in the frame of new psychoactive substances network: a complex pharmacological and toxicological issue. Curr Mol Pharmacol. 2018;11(2):97–108. Search in Google Scholar

[442] Klingberg J, Cawley A, Shimmon R, Fu S. Collision-induced dissociation studies of synthetic opioids for non-targeted analysis. Front Chem. 2019;7:331. Search in Google Scholar

[443] Nordmeier F, Richter LHJ, Schmidt PH, Schaefer N, Meyer MR. Studies on the in vitro and in vivo metabolism of the synthetic opioids U-51754, U-47931E, and methoxyacetylfentanyl using hyphenated high-resolution mass spectrometry. Sci Rep. 2019;9(1):1–17. Search in Google Scholar

[444] Chen H, Chen C, Huang W, Li M, Xiao Y, Jiang D, et al. Miniaturized ion mobility spectrometer with a dual-compression tristate ion shutter for on-site rapid screening of fentanyl drug mixtures. Anal Chem. 2019;91(14):9138–46. Search in Google Scholar

[445] Wang K, Xu B, Wu J, Zhu Y, Guo L, Xie J. Elucidating fentanyls differentiation from morphines in chemical and biological samples with surface-enhanced Raman spectroscopy. Electrophoresis. 2019;40(16–17):2193–203. Search in Google Scholar

[446] Gampfer TM, Wagmann L, Richter MJ, Meyer MR, Fischmann S, Westphal F. Toxicokinetic studies and analytical toxicology of the new synthetic opioids cyclopentanoyl-fentanyl and tetrahydrofuranyl-fentanyl. J Anal Toxicol. 2020;44(5):449–60. 10.1093/jat/bkaa010. Search in Google Scholar

[447] Gundersen POM, Astrand A, Green H, Gundersen M, Spigset O, Vikingsson S. Metabolite profiling of ortho-, meta- and para-fluorofentanyl by hepatocytes and high-resolution mass spectrometry. J Anal Toxicol. 2020;44(2):140–8. 10.1093/jat/bkz081. Search in Google Scholar

[448] Harper NJ, Veitch GB, Wibberley DG. 1-(3,4-Dichlorobenzamidomethyl)cyclohexyldimethylamine and related compounds as potential analgesics. J Med Chem. 1974;17:1188–93. Search in Google Scholar

[449] Ujvary I. AH-7921, technical description, information note on AH-7921.pdf. https://ednd.emcdda.europa.eu/assets/upload/showfile?filename=EMCDDA Search in Google Scholar

[450] Brittain RT, Kellett DN, Neat ML, Stables R. Proceedings: anti-nociceptive effects in N-substituted cyclohexylmethylbenzamides. Br J Pharmacol. 1973;49:158–9. Search in Google Scholar

[451] Tyers MB. A classification of opiate receptors that mediate antinociception in animals. Br J Pharmacol. 1980;69:503–12. Search in Google Scholar

[452] Hayes AG, Tyers MB. Determination of receptors that mediate opiate side effects in the mouse. Br J Pharmacol. 1983;79:731–6. Search in Google Scholar

[453] Coppola M, Mondola R. AH-7921: from potential analgesic medicine to recreational drug. Int J High Risk Behav Addict. 2017;6(2):e22593. Search in Google Scholar

[454] Loew G, Lawson J, Toll L, Frenking G, Berzetei-Gurske I, Polgar W. Structure activity studies of two classes of beta-amino-amides: the search for kappa-selective opioids. In: Harris LS, ed., Problems of drug dependence 1988. NIDA research monograph 90: proceedings of the 50th annual scientific meeting. Rockville, Maryland: US Department of Health and Human Services; 1988. p. 144–51. Search in Google Scholar

[455] Zawilska JB, Wojcieszak J. An expanding world of new psychoactive substances-designer benzodiazepines. Neurotoxicology. 2019;73:8–16. Search in Google Scholar

[456] WHO. Phenazepam, pre-review report, agenda item 5.8, expert committee on drug dependence thirty-seventh meeting, Geneva, 16–20 November 2015; 2015. http://www.who.int/medicines/access/controlled-substances/5.8_Phenazepam_PreRev.pdf Search in Google Scholar

[457] WHO. ETIZOLAM critical review report, agenda item 4.13, expert committee on drug dependence thirty-ninth meeting Geneva, 6–10 November 2017; 2017. http://www.who.int/medicines/access/controlled-substances/CriticalReview_Etizolam.pdf Search in Google Scholar

[458] Abouchedid R, Gilks T, Dargan PI, Archer JRH, Wood DM. Assessment of the availability, cost, and motivations for use over time of the new psychoactive substances-benzodiazepines diclazepam, flubromazepam, and pyrazolam-in the UK. J Med Toxicol. 2018;14(2):134–43. Search in Google Scholar

[459] Corkery JM, Schifano F, Ghodse AH. Phenazepam abuse in the UK: an emerging problem causing serious adverse health problems, including death. Hum Psychopharmacol. 2012;27(3):254–61. Search in Google Scholar

[460] Pope JD, Choy KW, Drummer OH, Schneider HG. Novel benzodiazepines (clonazolam and flubromazolam) identified in candy-like pills. J Appl Lab Med. 2018;3(1):48–55. Search in Google Scholar

[461] US Department of Justice Drug Enforcement Administration. Blotter acid mimic (actually containing phenazepam) in North Carolina. Microgram Bulletin. 2009;42:94. Search in Google Scholar

[462] Anderson M, Kjeligren A. The slippery slope of flubromazolam: experiences of a novel psychoactive benzodiazepine as discussed on a Swedish online forum. Nordic Studies Alc Drugs. 2017;34(3):217–29. Search in Google Scholar

[463] Moosmann B, Auwater V. Designer benzodiazepines: another class of new psychoactive substances. Handb Exp Pharmacol. 2018;252:383–410. Search in Google Scholar

[464] Moosmann B, Bisel P, Franz F, Huppertz LM, Auwarter V. Characterization and in vitro phase I microsomal metabolism of designer benzodiazepines-an update comprising adinazolam, cloniprazepam, fonazepam, 3-hydroxyphenazepam, metizolam and nitrazolam. J Mass Spectrom. 2016;51(11):1080–9. Search in Google Scholar

[465] El Balkhi S, Chaslot M, Picard N, Dulaurent S, Delage M, Mathieu O, et al. Characterization and identification of eight designer benzodiazepine metabolites by incubation with human liver microsomes and analysis by a triple quadrupole mass spectrometer. Int J Legal Med. 2017;131(4):979–88. Search in Google Scholar

[466] Moosmann B, Bisel P, Auwarter V. Characterization of the designer benzodiazepine diclazepam and preliminary data on its metabolism and pharmacokinetics. Drug Test Anal. 2014;6(7–8):757–63. Search in Google Scholar

[467] Pettersson Bergstrand M, Richter LHJ, Maurer HH, Wagmann L, Meyer MR. In vitro glucuronidation of designer benzodiazepines by human UDP-glucuronyltransferases. Drug Test Anal. 2019;11(1):45–50. Search in Google Scholar

[468] Nakamae T, Shinozuka T, Sasaki C, Ogamo A, Murakami-Hashimoto C, Irie W, et al. Case report: Etizolam and its major metabolites in two unnatural death cases. Forensic Sci Int. 2008;182:e1–6. Search in Google Scholar

[469] Noble C, Mardal M, Bjerre Holm N, Stybe Johansen S, Linnet K. In vitro studies on flubromazolam metabolism and detection of its metabolites in authentic forensic samples. Drug Test Anal. 2017;9(8):1182–91. Search in Google Scholar

[470] Wohlfarth A, Vikingsson S, Roman M, Andersson M, Kugelberg FC, Green H, et al. Looking at flubromazolam metabolism from four different angles: metabolite profiling in human liver microsomes, human hepatocytes, mice and authentic human urine samples with liquid chromatography high-resolution mass spectrometry. Forensic Sci Int. 2017;274:55–63. Search in Google Scholar

[471] Huppertz LM, Moosmann B, Auwarter V. Flubromazolam-basic pharmacokinetic evaluation of a highly potent designer benzodiazepine. Drug Test Anal. 2018;10(1):206–11. Search in Google Scholar

[472] Pettersson Bergstrand M, Meyer MR, Beck O, Helander A. Human urinary metabolic patterns of the designer benzodiazepines flubromazolam and pyrazolam studied by liquid chromatography high resolution mass spectrometry. Drug Test Anal. 2018;10(3):496–506. Search in Google Scholar

[473] Kintz P, Richeval C, Jamey C, Ameline A, Allorge D, Gaulier JM, et al. Detection of the designer benzodiazepine metizolam in urine and preliminary data on its metabolism. Drug Test Anal. 2017a;9(7):1026–33. Search in Google Scholar

[474] Moosmann B, Bisel P, Westphal F, Wilde M, Kempf J, Angerer V, et al. Characterization and in vitro phase I microsomal metabolism of designer benzodiazepines-an update comprising flunitrazolam, norflurazepam and 4′-chlorodiazepam (Ro5-4864). Drug Test Anal. 2019;11(3):541–9. Search in Google Scholar

[475] Meyer MR, Pettersson Bergstrand M, Helander A, Beck O. Identification of main human urinary metabolites of the designer nitrobenzodiazepines clonazolam, meclonazepam, and nifoxipam by nano-liquid chromatography-high-resolution mass spectrometry for drug testing purposes. Anal Bioanal Chem. 2016;408(13):3571–91. Search in Google Scholar

[476] Mortele O, Vervliet P, Gys C, Degreef M, Cuykx M, Maudens K, et al. In vitro phase I and phase II metabolism of the new designer benzodiazepine cloniprazepam using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. J Pharm Biomed Anal. 2018;153:158–67. Search in Google Scholar

[477] Ameline A, Richeval C, Gaulier J-M, Raul J-S, Kintz P. Detection of the designer benzodiazepine flunitrazolam in urine and preliminary data on its metabolism. Drug Test Anal. 2019;11(2):223–9. Search in Google Scholar

[478] Vikingsson S, Wohlfarth A, Andersson M, Green H, Roman M, Josefsson M, et al. Identifying metabolites of meclonazepam by high-resolution mass spectrometry using human liver microsomes, hepatocytes, a mouse model, and authentic urine samples. AAPS J. 2017;19(3):736–42. Search in Google Scholar

[479] O’Connell CW, Sadler CA, Tolia VM, Ly BT, Saitman AM, Fitzgerald RL. Overdose of etizolam: the abuse and rise of a benzodiazepine analog. Ann Emerg Med. 2015;65(4):465–6. Search in Google Scholar

[480] Pettersson Bergstrand M, Helander A, Hansson T, Beck O. Detectability of designer benzodiazepines in CEDIA, EMIT II Plus, HEIA, and KIMS II immunochemical screening assays. Drug Test Anal. 2017;9(4):640–5. Search in Google Scholar

[481] Meng L, Zhu B, Zheng K, Fu S. Ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction for the determination of 4 designer benzodiazepines in urine samples by gas chromatography-triple quadrupole mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci. 2017;1053:9–15. Search in Google Scholar

[482] Švidrnoch M, Boranova B, Tomkova J, Ondra P, Maier V. Simultaneous determination of designer benzodiazepines in human serum using non-aqueous capillary electrophoresis-tandem mass spectrometry with successive multiple ionic-polymer layer coated capillary. Talanta. 2018;176:69–76. Search in Google Scholar

[483] O’Rourke C, Subedi B. Near real-time determination of the prevalence of illicit drugs, cannabinoids, cathinones, and synthetic opioids in four rural counties in Illinois using wastewater-based epidemiology, abstracts of papers. 259th ACS national meeting and exposition, Philadelphia, PA, United States, March 22–26; 2020. Search in Google Scholar

[484] Schrödinger release 2016-1: MacroModel, Schrödinger. New York, NY: LLC; 2016. Search in Google Scholar

[485] Arsic B, Aguilar JA, Bryce RA, Barber J. Conformational study of tylosin A in water and full assignments of 1H and 13C spectra of tylosin A in D2O and tylosin B in CDCl3. Magn Reson Chem. 2017;55:367–73. Search in Google Scholar

[486] Lukic V, Micic R, Arsic B, Jokic A, Sejmanovic D. Prediction of physico-chemical properties of illegal drugs using the conformational analysis. 6th IAPC meeting (sixth world conference on physico-chemical methods in drug discovery and third world conference on ADMET and DMPK), 4–7th September 2017, Zagreb, Croatia, 41; 2017. Search in Google Scholar

[487] Eshleman AJ, Nagarajan S, Wolfrum KM, Reed JF, Swanson TL, Nilsen A, et al. Structure-activity relationships of bath salt components: substituted cathinones and benzofurans at biogenic amine transporters. Psychopharmacology. 2019;236(3):939–52. Search in Google Scholar

[488] Kostic EJ, Arsic BB, Milosavljevic BS, Vujovic MM. Docking analysis of selected cathinones on a complex of SAP97 PDZ2 with 5-HT2A receptor peptide. Sixth international conference on novel psychoactive substances, 8–9th April 2019, Maastricht, The Netherlands; 2019. Search in Google Scholar

[489] Floresta G, Rescifina A, Abbate V. Structure-based approach for the prediction of μ-opioid binding affinity of unclassified designer fentanyl-like molecules. Int J Mol Sci. 2019;20(9):2311. Search in Google Scholar

[490] Vujović M, Ragavendran V, Arsić B, Kostić E, Mladenović M. DFT calculations as an efficient tool for prediction of Raman and infra-red spectra and activities of newly synthesized cathinones. Open Chem. 2020;18:185–95. Search in Google Scholar