Liquid chromatography tandem mass spectrometry determination of selected synthetic cathinones and two piperazines in oral fluid. Cross reactivity study with an on-site immunoassay device

Simple and selective screening method for the synthetic cathinone MDPT in forensic samples using carbon nanofiber screen-printed electrodes

3',4'-Methylenedioxy-N-tert-butylcathinone (MDPT), also known as tBuONE or D-Tertylone, is a synthetic cathinone (SC) frequently abused for recreational purposes due to its potent stimulant effects and similarity to illegal substances like methamphetamine and ecstasy. The structural diversity and rapid introduction of new SC analogs to the market poses significant challenges for law enforcement and analytical methods for preliminary screening of illicit drugs. In this work, we present, for the first time, the electrochemical detection of MDPT using screen-printed electrodes modified with carbon nanofibers (SPE-CNF). MDPT exhibited three electrochemical processes (two oxidations and one reduction) on SPE-CNF. The proposed method for MDPT detection was optimized in 0.2 mol L-1 Britton-Robinson buffer solution at pH 10.0 using differential pulse voltammetry (DPV). The SPE-CNF showed a high stability for electrochemical responses of all redox processes of MDPT using the same or different electrodes, with relative standard deviations less than 4.7% and 1.5% (N = 3) for peak currents and peak potentials, respectively. Moreover, the proposed method provided a wide linear range for MDPT determination (0.90-112 μmol L-1) with low LOD (0.26 μmol L-1). Interference studies for two common adulterants, caffeine and paracetamol, and ten other illicit drugs, including amphetamine-like compounds and different SCs, showed that the proposed sensor is highly selective for the preliminarily identification of MDPT in seized forensic samples. Therefore, SPE-CNF with DPV can be successfully applied as a fast and simple screening method for MDPT identification in forensic analysis, addressing the significant challenges posed by the structural diversity of SCs.

Green analytical toxicology method for determination of synthetic cathinones in oral fluid samples by microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry

PURPOSE

We developed and validated a method for quantitative analysis of ten synthetic cathinones in oral fluid (OF) samples, using microextraction by packed sorbent (MEPS) for sample preparation followed by liquid chromatography‒tandem mass spectrometry (LC‒MS/MS).

METHOD

OF samples were collected with a Quantisal™ device and 200 µL was extracted using a C18 MEPS cartridge installed on a semi-automated pipette and then analyzed using LC‒M/SMS.

RESULTS

Linearity was achieved between 0.1 and 25 ng/mL, with a limit of detection (LOD) of 0.05 ng/mL and a limit of quantification (LOQ) of 0.1 ng/mL. Imprecision (% relative standard deviation) and bias (%) were better than 11.6% and 7.5%, respectively. The method had good specificity and selectivity against 9 different blank OF samples (from different donors) and 68 pharmaceutical and drugs of abuse with concentrations varying between 400 and 10,000 ng/mL. No evidence of carryover was observed. The analytes were stable after three freeze/thaw cycles and when kept in the autosampler (10 °C) for up to 24 h. The method was successfully applied to quantify 41 authentic positive samples. Methylone (mean 0.6 ng/mL, median 0.2 ng/mL), N-ethylpentylone (mean 16.7 ng/mL, median 0.35 ng/mL), eutylone (mean 39.1 ng/mL, median 3.6 ng/mL), mephedrone (mean 0.5 ng/mL, median 0.5 ng/mL), and 4-chloroethcathinone (8.1 ng/mL) were quantified in these samples.

CONCLUSION

MEPS was an efficient technique for Green Analytical Toxicology purposes, which required only 650 µL organic solvent and 200 µL sodium hydroxide, and the BIN cartridge had a lifespan of 100 sample extractions.

Sweat Testing for the Detection of Methylone after Controlled Administrations in Humans

The aim of this study was to determine the excretion of methylone and its metabolites in sweat following the ingestion of increasing controlled doses of 50, 100, 150 and 200 mg of methylone to twelve healthy volunteers involved in a clinical trial. Methylone and its metabolites 4-hydroxy-3-methoxy-N-methylcathinone (HMMC) and 3,4-methylenedioxycathinone (MDC) were analyzed in sweat patches by liquid chromatography-tandem mass spectrometry. Methylone and MDC were detected in sweat at 2 h and reached their highest accumulation (C_max) at 24 h after the administration of 50, 100, 150 and 200 mg doses. In contrast, HMMC was not detectable at any time interval after each dose. Sweat proved to be a suitable matrix for methylone and its metabolites' determination in clinical and toxicological studies, providing a concentration that reveals recent drug consumption.

Usefulness of Oral Fluid for Measurement of Methylone and Its Metabolites: Correlation with Plasma Drug Concentrations and the Effect of Oral Fluid pH

The aim of this study was to investigate methylone and its metabolites concentration in oral fluid following controlled increasing doses, focusing on the effect of oral fluid pH. Samples were obtained from a clinical trial where twelve healthy volunteers participated after ingestion of 50, 100, 150 and 200 mg of methylone. Concentration of methylone and its metabolites 4-hydroxy-3-methoxy-N-methylcathinone (HMMC) and 3,4-methylenedioxycathinone in oral fluid were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pharmacokinetic parameters were estimated, and the oral fluid-to-plasma ratio (OF/P) at each time interval was calculated and correlated with the oral fluid pH using data from our previous study in plasma. Methylone was detected at all time intervals after each dose; MDC and HMMC were not detectable after the lowest dose. Oral fluid concentrations of methylone ranged between 88.3-503.8, 85.5-5002.3, 182.8-13,201.8 and 214.6-22,684.6 ng/mL following 50, 100, 150 and 200 mg doses, respectively, peaked between 1.5 and 2.0 h, and were followed by a progressive decrease. Oral fluid pH was demonstrated to be affected by methylone administration. Oral fluid is a valid alternative to plasma for methylone determination for clinical and toxicological studies, allowing for a simple, easy and non-invasive sample collection.

A Quantitative LC–MS/MS Method for the Detection of 16 Synthetic Cathinones and 10 Metabolites and Its Application to Suspicious Clinical and Forensic Urine Samples

Background: Synthetic cathinones currently represent one of the most predominant (sub)-classes of new psychoactive substance (NPS) in illicit drug markets. Despite the increased concerns caused by the constant introduction of new analogues, these drugs are not commonly assayed in routine drug testing procedures and may not be detected in standard screening procedures. This study presents a validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the detection and quantification of 16 synthetic cathinones and 10 metabolites in human urine. Methods: The method was validated for all analytes using published guidelines. The evaluated parameters achieved acceptable values according to the set criteria. Potential abuse of synthetic cathinones was investigated in suspicious urine samples from Saudi Arabia originating from workplace drug testing, pre-employment and Accident & Emergency (A&E). Such samples generated a presumptive positive immunoassay for amphetamine; however, they yielded a negative LC–MS/MS confirmation for this analyte, following the recommended cutoff values of Substance of Abuse and Mental Health Services Administration (SAMHSA) guidelines. Results: 5.8% of the analyzed samples were found to contain at least one target analyte, namely mephedrone and N-ethylpentylone, as well as their dihydro-metabolites. The results also revealed polydrug use with the synthetic cathinones being present together with other classical stimulant drugs. Conclusions: This is the first report of NPS use in Saudi Arabia with respect to designer stimulant drugs. Confirmatory urine analyses for suspicious stimulant use should extend beyond classical stimulants to cover a broad range of NPSs and their metabolites in order to report any otherwise potentially undetected/new analyte.

Simple Analytical Strategy for Screening Three Synthetic Cathinones (α-PVT, α-PVP, and MDPV) in Oral Fluids

Synthetic cathinones are analogue compounds of the plant based stimulant cathinone. Its use, abuse, and related consumption complications have steadily increased in the last years. For this reason, there is a need for innovative analytical approaches that enable its rapid screening in biological matrices (e.g., oral fluids). The present work proposes a new analytical methodology by combining bar adsorptive microextraction followed by microliquid desorption and gas chromatography coupled to mass spectrometry (BAµE-µLD/GC-MS) for screening three synthetic cathinones (α-PVP, α-PVT, and MDPV) in oral fluids. The optimization of the BAµE-µLD/GC-MS methodology was successfully applied for the analysis of the target compounds in oral fluids. The results show average recoveries between 43.1 and 52.3% for the three synthetic cathinones. Good selectivity was also noticed. The developed methodology presents itself as an alternative tool to screen these compounds in oral fluids. To the best of our knowledge, this is the first work that combines a microextraction sorption-based technique followed by GC-MS analysis for the screening of synthetic cathinones in oral fluids.

A Fast Analytical Method for Determining Synthetic Cathinones in Oral Fluid by Liquid Chromatography-Tandem Mass Spectrometry

In this paper, we present a method for simultaneously determining 11 synthetic cathinones in oral fluid (OF) by liquid chromatography-tandem mass spectrometry. Synthetic cathinones, a wide variety of which are available on the market, are constantly evolving. It is therefore important to provide efficient methods for determining cathinones in different matrices. A common matrix for detecting recent drug intake is OF, which can easily be collected using one of numerous commercial devices. Most methods aimed at determining drugs in biological samples such as OF require labor-intensive and time-consuming sample-preparation steps. However, the pretreatment of complex samples is often a challenge in the development of a method. For this reason, in this paper, we present a simple, easy-to-handle alternative that uses a Salivette® device and pretreats the sample in the same device. Matrix-matched calibration curves were used to cover the concentration range at which these substances are usually present in the OF from drug consumers. The method detection limits ranged from 0.003 to 0.03 ng/g, and the method quantification limits were set at 0.075 ng/g. This is a simple, rapid and sensitive method with good potential for determining recent drug consumption in OF.

Simultaneous Quantitation of Seven Phenethylamine-Type Drugs in Forensic Blood and Urine Samples by UHPLC-MS/MS

Abuse of new psychoactive substances (NPSs) has become a health and social issue of global concern. p-Methoxyamphetamine (PMA)/p-methoxymethamphetamine (PMMA) with fluoro- or chloro-derivatives of amphetamine and methamphetamine were among the most common drugs found in specimens from fatal cases in Taiwan during the January 2011 to December 2018 period. A liquid-liquid extraction sample preparation protocol with highly sensitive ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) approach was developed for the simultaneous analysis of seven phenethylamine-type drugs - PMA, PMMA, p-methoxyethylamphetamine (PMEA), 4-fluoroamphetamine (4-FA), 4-fluoromethamphetamine (4-FMA), 4-chloroamphetamine (4-CA), and 4-chloromethamphetamine (4-CMA) - in postmortem blood and urine specimens. Separation by liquid chromatography was performed by Agilent Zorbax SB-Aq column. Tandem mass spectrometry was operated in Agilent Jet Stream Technology electrospray ionization in positive-ion multiple reaction monitoring (MRM) mode. An analytical methodology was evaluated using drug-free blood and urine after fortification with 100-2000 ng/mL of the seven target analytes. Average extraction recoveries were >80%; slightly higher ion suppression was observed for PMA and 4-CA; intra-/inter-day precision (%CV) and accuracy were in the ranges of 0.52-12.3% and 85-110%, respectively. Limit of detection (LOD) and lower limit of quantitation (LLOQ) for these seven analytes were both in the 0.5-5 ng/mL range. Interference and carryover were not significant. This relatively simple methodology was found effective and reliable for routine identification and quantitation of these seven analytes in postmortem and antemortem blood and urine specimens received in 2018. Analytical data obtained from these actual cases indicated: (i) compared to findings reported during the 2007-2011 period, the use of substituted phenethylamine-type drugs decreased in 2018; (ii) ketamine and 7-aminonimetazepam (the main metabolite of nimetazepam) were the most common co-ingested substances in specimens containing PMA/PMMA, 4-FA/4-FMA, or 4-CA/4-CMA; and (iii) in drug fatalities, the concentration of PMA was significantly higher than the concentration of PMMA in both urine and blood, while the reverse was true in urine specimens from antemortem cases.

3,4-Methylenedioxypyrovalerone (MDPV) Sensing Based on Electropolymerized Molecularly Imprinted Polymers on Silver Nanoparticles and Carboxylated Multi-Walled Carbon Nanotubes

3,4-methylenedioxypyrovalerone (MDPV) is a harmful and controlled synthetic cathinone used as a psychostimulant drug and as sport-enhancing substance. A sensor was developed for the direct analysis of MDPV by transducing its oxidation signal by means of an electropolymerized molecularly imprinted polymer (e-MIP) built in-situ on the screen-printed carbon electrode's (SPCE) surface previously covered with multi-walled carbon nanotubes (MWCNTs) and silver nanoparticles (AgNPs). Benzene-1,2-diamine was used as the functional monomer while the analyte was used as the template monomer. Each step of the sensor's development was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in a solution containing ferricyanide, however no redox probe was required for the actual MDPV measurements. The interaction between the poly(o-phenylenediamine) imprinted polymer and MDPV was studied by density-functional theory (DFT) methods. The SPCE-MWCNT-AgNP-MIP sensor responded adequately to the variation of MDPV concentration. It was shown that AgNPs enhanced the electrochemical signal by around a 3-fold factor. Making use of square-wave voltammetry (SWV) the developed sensor provided a limit of detection (LOD) of 1.8 μmol L-1. The analytical performance of the proposed sensor paves the way to the development of a portable device for MDPV on-site sensing to be applied in forensic and doping analysis.

Stability of synthetic cathinones in clinical and forensic toxicological analysis-Where are we now?

Understanding the stability of analyzed drugs in biological samples is a crucial part for an appropriate interpretation of the analytical findings. Synthetic cathinones, as psychoactive stimulants, belong to a major class of new psychoactive substances. As they are subject to several degradation pathways, they are known to clinical and forensic toxicologists as unstable analytes in biological samples. When interpreting analytical data of synthetic cathinones in biological samples, analysts must be aware that the concentration of analytes may not accurately reflect the levels at the time they were acquired owing to many factors. This review provides (i) an overview of the current scientific knowledge on the stability of synthetic cathinones and/or metabolites in various human biological samples with a focus on factors that may deteriorate their stability-such as storage temperature, length of storage, matrix, pH, type of preservatives, concentration of analytes, and the chemistry of the analytes-and (ii) possible solutions on how to avoid such degradation. The PubMed database as well as Google Scholar was thoroughly searched to find published studies on the stability of synthetic cathinones since 2007 by searching specific keywords. A total of 23 articles met the inclusion criteria and were included in this review. Synthetic cathinones that carry methylenedioxy or N-pyrrolidine ring showed higher degradation resistance over other substituted groups. Acidification of samples pH plays a crucial role at increasing the stability of cathinones even with analytes that were frequently considered as poorly stable. This review also provides several recommendations for best practice in planning the experimental design, preservation, and storage conditions in order to minimize synthetic cathinones' degradation in human biological samples.

Determination of Synthetic Cathinones in Urine and Oral Fluid by Liquid Chromatography High-Resolution Mass Spectrometry and Low-Resolution Mass Spectrometry: A Method Comparison

Synthetic cathinones have become very popular recreational drugs. Therefore, determining them in biological samples is now a matter of concern. In recent years, different methods that have been developed can determine these drugs at low-concentration levels. In general, liquid chromatography mass spectrometry detection plays an important role in these methods and the trend is to use low-resolution and high-resolution mass spectrometry. In this article, for the first time, we compare these two analyzers using an Orbitrap and a triple quadrupole mass spectrometer in order to determine a group of synthetic cathinones in urine and oral fluid samples. For this comparison, we evaluated and compared different parameters: Method detection and quantification limits, linearity, apparent recoveries, matrix effect, repeatability (intra-day), reproducibility (inter-day), and accuracy. Similar results were obtained for the two analyzers for the apparent recoveries and matrix effect. However, triple quadrupole showed higher sensitivity compared to Orbitrap for both urine and oral fluid samples. The quantification limits in urine and the detection limits in saliva were two times lower for triple quadrupole. Finally, when blind samples were analyzed to study the accuracy, similar results were obtained for both analyzers.

Screening of 104 New Psychoactive Substances (NPS) and Other Drugs of Abuse in Oral Fluid by LC–MS-MS

New psychoactive substances (NPS) are a major public health problem, primarily due to the increased number of acute poisoning cases. Detection of these substances is a challenge. The aim of this research was to develop and validate a sensitive screening method for 104 drugs of abuse, including synthetic cannabinoids, synthetic cathinones, fentanyl analogues, phenethylamines and other abused psychoactive compounds (i.e., THC, MDMA, LSD and their metabolites) in oral fluid by liquid chromatography–tandem mass spectrometry (LC–MS-MS). The Quantisal™ oral fluid device was used to collect oral fluid samples. The oral fluid–elution buffer mixture (500-μL sample) was extracted with t-butyl methyl ether, and chromatographic separation was performed on a Raptor™ biphenyl column (100 × 2.1 mm ID, 2.7 μm), with a total run time of 13.5 min. Limits of detection were established at three concentrations (0.05, 0.1 or 1 ng/mL) for most analytes, except for acetyl norfentanyl and mescaline (5 ng/mL). Matrix effects were generally <20% and overall extraction recoveries >60%. The highest matrix effect was observed within the synthetic cannabinoid group (PB22, −55.5%). Lower recoveries were observed for 2C-T (47.2%) and JWH-175 (58.7%). Recoveries from the Quantisal™ device were also evaluated for all analytes (56.7–127%), with lower recoveries noted for 25I-NBOMe, valerylfentanyl and mCPP (56.7, 63.0 and 69.9%, respectively). Drug stability in oral fluid was evaluated at 15, 60 and 90 days and at 25, 4 and −20°C. As expected, greater stability was observed when samples were stored at −20°C, but even when frozen, some NPS (e.g., synthetic cannabinoids) showed more than 20% degradation. The method was successfully applied to the analysis of seven authentic oral fluid samples positive for 17 different analytes. The method achieved good sensitivity and simultaneous detection of a wide range of NPS.

Computational aided acetaminophen - phthalic acid molecularly imprinted polymer design for analytical determination of known and new developed recreational drugs

In recent times, abuse drug consumption rates have been increasing. In addition, authorities have detected a trend in the development of new substances expressly created to avoid legislation. These novel psychoactive substances (NPS) are non-registered formulations, closely chemically related to outlawed ones to maintain the same psychotropic effects while circumventing legal restrictions. This issue arises enormous social, sanitary, and road safety problems since there is no way to detect nor quantify these non-registered substances. The aim of this work is the development of a high selective material able to pre-concentrate and detect NPS. On that account, molecularly imprinted polymers (MIPs) designed with an imprinted cavity that matches the cathinones structural shape were proposed to detect both conventional and new cathinone derived recreational drugs. The increasing number of illicit drug modifications that is being reported requires developing a receptor valid for not only known molecules but also for incoming ones; thus, a virtual procedure must be carried out to take a step forward towards future modifications. Accordingly, a computational MIP design is proposed as the most appropriated method to effectively design this receptor. By means of molecular dynamics and molecular docking, several combinations are studied regarding their pre-polymerization complex stability but also their rebinding capacity against the proposed analytes. Hence, a phthalic acid - acetaminophen MIP is selected as the most well-suited receptor, valid for current and forthcoming cathinone recreational drugs.

Psychoactive Bath Salts and Neurotoxicity Risk

Synthetic cathinones are new designer drugs that possess hallucinogenic and psychostimulant properties, and are designed to mimic the effects of illegal substances such as cocaine, amphetamines, and 3.4-methylenedioxymethamphetamine (ecstasy) and to produce rewarding effects, circumventing existing laws and penalties. Synthetic cathinones, also referred to as 'bath salts', have become popular particularly among young people since the mid-2000s. Similar to other psychomotor stimulants, synthetic cathinones have the potential to increase monoamine concentration in the synaptic cleft by targeting the plasma membrane transporters of dopamine, norepinephrine, and serotonin. Because of their structural similarities to amphetamines, it has been suggested that synthetic cathinones may have a neurotoxicity profile similar to that of their amphetamine congeners. Therefore, it has been hypothesized that synthetic cathinones may induce neurotoxicity on monoamine nerve endings in the striatum, hippocampus, and cortex. To date, with regard to synthetic cathinone neurotoxicity, parameters such as monoamine depletion, biosynthetic enzyme inhibition, cytotoxicity, generation of reactive oxygen species, pro-oxidation status, and the ability to induce neuroinflammation were investigated in both in vitro and in vivo experimental studies. Compared with amphetamines, synthetic cathinones appear to have more moderate effects than their amphetamine congeners in terms of neurotoxic effects. However, many synthetic cathinone users take these substances simultaneously with other substances such as benzodiazepines, amphetamines, ecstasy, tetrahydrocannabinol, and ethanol and this abuse can modify their neurotoxic effects. Hence, it is important to understand the underlying mechanism of early neurotoxic effects in case of polysubstance use. In this review, we aimed to present up-to-date information on the abuse potential of synthetic cathinones, their legal status, mechanism of action, and particularly their neurotoxic effects.

Determination of New Psychoactive Substances in Whole Blood Using Microwave Fast Derivatization and Gas Chromatography/Mass Spectrometry

The production and consumption of new psychoactive substances (NPSs) has been raising a major concern worldwide. Due to easy access and available information, many NPSs continue to be synthesized with an alarming increase of those available to purchase, despite all the control efforts created. A new analytical method was developed and validated to determine a group of phenethylamines and synthetic cathinones: cathinone, flephedrone, buphedrone, 4-MTA, α-PVP, methylone, 2C-P, ethylone, pentylone, MDPV and bromo-dragonFLY in whole blood. A mixed-mode solid phase extraction was applied to 250 μL of sample, and the extracts were derivatized with fast microwave technique before being analyzed by gas chromatography-mass spectrometry (GC-MS). The validation procedure followed the Scientific Working Group for Forensic Toxicology (SWGTOX) guidelines with parameters that included selectivity, linearity, limits of detection and quantification, intra- and inter-day precision and accuracy, recoveries and stability. The method presented linearity between 5 and 500 ng/mL for cathinone, buphedrone, 4-MTA, methylone, 2C-P and bromo-dragonFLY, 10-500 ng/mL for flephedrone, ethylone, pentylone and MDPV, and 40-500 ng/mL for α-PVP, with determination coefficients above 0.99 for all analytes. Recoveries ranged between 70.3% and 116.6%, and regarding intra- and inter-day precision, the relative mean errors were typically lower than 8.6%. The method was successfully applied to over 100 authentic samples from the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.

Oral Fluid Drug Testing: Analytical Approaches, Issues and Interpretation of Results

With advances in analytical technology and new research informing result interpretation, oral fluid (OF) testing has gained acceptance over the past decades as an alternative biological matrix for detecting drugs in forensic and clinical settings. OF testing offers simple, rapid, non-invasive, observed specimen collection. This article offers a review of the scientific literature covering analytical methods and interpretation published over the past two decades for amphetamines, cannabis, cocaine, opioids, and benzodiazepines. Several analytical methods have been published for individual drug classes and, increasingly, for multiple drug classes. The method of OF collection can have a significant impact on the resultant drug concentration. Drug concentrations for amphetamines, cannabis, cocaine, opioids, and benzodiazepines are reviewed in the context of the dosing condition and the collection method. Time of last detection is evaluated against several agencies' cutoffs, including the proposed Substance Abuse and Mental Health Services Administration, European Workplace Drug Testing Society and Driving Under the Influence of Drugs, Alcohol and Medicines cutoffs. A significant correlation was frequently observed between matrices (i.e., between OF and plasma or blood concentrations); however, high intra-subject and inter-subject variability precludes prediction of blood concentrations from OF concentrations. This article will assist individuals in understanding the relative merits and limitations of various methods of OF collection, analysis and interpretation.

A LC-MS/MS method for the determination of common synthetic cathinones in meconium

New psychoactive substances have been introduced into the market in the last years due to their unregulated status. Synthetic cathinones are one of their main representatives, and they have shown to produce neonatal complications. It is important to have objective tools to identify in utero exposure to drugs that have shown to produce neonatal complications. An analytical method was developed and fully validated for the determination of common synthetic cathinones, including methylone, methedrone, mephedrone, 3,4-methylenedioxypyrovalerone (MDPV), (±)-4-fluoromethamphetamine and 4-fluoromethcathinone in meconium. Meconium (0.25 ± 0.02 g) was homogenized with methanol by sonication for 30 min. After centrifugation, the sample was extracted with Oasis MCX columns. The analysis was performed by LC-MS/MS using an Atlantis T3 column (3 μm, 2.1 × 50 mm) and a gradient with acetonitrile and 0.1% formic acid in water. Method validation included the following parameters: selectivity (no endogenous or exogenous interferences), limits of detection (n = 3, 0.5-1 ng/g) and quantification (n = 3, 1-2 ng/g), linearity (n = 5, LOQ-200 ng/g), imprecision (n = 15, 0% to 10%), accuracy (n = 15, 87.3% to 97.8%), matrix effect (n = 10, -76% to -28.1%), extraction efficiency (n = 6, 63.7% to 91.3%), total process efficiency (n = 6, 16% to 60.2%) and stability for 72 h in the autosampler (n = 3, %loss = -6.7% to 5.1%). The method was applied to 28 meconium specimens.

Analytical quantification, intoxication case series, and pharmacological mechanism of action for N-ethylnorpentylone (N-ethylpentylone or ephylone)

Synthetic cathinones continue to proliferate in clandestine drug markets worldwide. N-ethylnorpentylone (also known as N-ethylpentylone or ephylone) is a popular emergent cathinone, yet little information is available about its toxicology and pharmacology. Here we characterize the analytical quantification, clinical presentation, and pharmacological mechanism of action for N-ethylnorpentylone. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to quantify N-ethylnorpentylone in blood obtained from human cases. Clinical features exhibited by the intoxicated individuals are described. The activity of N-ethylnorpentylone at plasma membrane transporters for dopamine (DAT), norepinephrine (NET) and 5-HT (SERT) was assessed using in vitro assays measuring uptake inhibition and evoked release of [3 H] neurotransmitters in rat brain synaptosomes. Our LC-MS/MS method assayed N-ethylnorpentylone concentrations with limits of detection and quantification of 1 and 5 ng/mL, respectively. Quantitation was linear from 5 to 500 ng/mL, and the method displayed specificity and reproducibility. Circulating concentrations of N-ethylnorpentylone ranged from 7 to 170 ng/mL in clinical cases, and the associated symptoms included palpitations, tachycardia, agitation, hallucinations, coma and death. N-Ethylnorpentylone was a potent inhibitor at DAT (IC50  = 37 nM), NET (IC50  = 105 nM) and SERT (IC50  = 383 nM) but displayed no transporter releasing activity. We present a validated method for quantifying N-ethylnorpentylone in human case work. The drug is a psychomotor stimulant capable of inducing serious cardiovascular and neurological side-effects which can be fatal. In vitro findings indicate that N-ethylnorpentylone exerts its effects by potent blockade of DAT and NET, thereby elevating extracellular levels of dopamine and norepinephrine in the brain and periphery.

Crystal structure of a host-guest complex between mephedrone hydro-chloride and a tetra-phospho-nate cavitand

A new supra-molecular complex (I) between the tetra-phospho-nate cavitand Tiiii[C3H7,CH3,C6H5] [systematic name: 2,8,14,20-tetra-propyl-5,11,17,23-tetra-methyl-6,10:12,16:18,22:24,4-tetra-kis-(phenyl-phospho-nato-O,O')resorcin[4]arene] and mephedrone hydro-choride {C11H16NO+·Cl-; systematic name: meth-yl[1-(4-methyl-phen-yl)-1-oxopropan-2-yl]aza-nium chloride} has been obtained and characterized both in solution and in the solid state. The complex of general formula (C11H16NO)@Tiiii[C3H7,CH3,C6H5]Cl·CH3OH or C11H16NO+·Cl-·C68H68O12P4·CH3OH, crystallizes in the monoclinic space group P21/c with one lattice methanol mol-ecule per cavitand, disordered over two positions with occupancy factors of 0.665 (6) and 0.335 (6). The mephedrone guest inter-acts with the P=O groups at the upper rim of the cavitand through two charge-assisted N-H⋯O hydrogen bonds, while the methyl group directly bound to the amino moiety is stabilized inside the π basic cavity via cation⋯π inter-actions. The chloride counter-anion is located between the alkyl legs of the cavitand, forming C-H⋯Cl inter-actions with the aromatic and methyl-enic H atoms of the lower rim. The chloride anion is also responsible for the formation of a supra-molecular chain along the b-axis direction through C-H⋯Cl inter-actions involving the phenyl substituent of one phospho-nate group. C-H⋯O and C-H⋯π inter-actions between the guest and adjacent cavitands contribute to the formation of the crystal structure.

A validated workflow for drug detection in oral fluid by non-targeted liquid chromatography-tandem mass spectrometry

Oral fluid is recognized as an important specimen for drug testing. Common applications are monitoring in substance abuse treatment programs, therapeutic drug monitoring, pain management, workplace drug testing, clinical toxicology, and driving under the influence of drugs (DRUID). In this study, we demonstrate that non-targeted LC-MS/MS with subsequent compound identification by tandem mass spectral library search is a valuable tool for comprehensive detection and confirmation of drugs in oral fluid samples. The workflow developed involves solid-phase extraction and chromatographic separation on reversed phase materials. Mass spectrometric detection is accomplished on a quadrupole-quadrupole-time-of-flight instrument operated with data-dependent acquisition control. The workflow was optimized for 500 μl of neat oral fluid collected with the Greiner Bio-One saliva collection system. The fitness of the developed method was tested and proven by analyzing blank and spiked samples as well as 59 authentic patient samples. We could demonstrate that compounds with logP values in the range 0.5-5.5 are efficiently detected at low nanograms per milliliter concentrations. The true positive and true negative rates of automated library search were equal or close to 100%. The beauty of the non-targeted LC-MS/MS approach is the ability to detect compounds hardly included in routinely applied targeted assays, and this was demonstrated by detecting the synthetic opioid U-47700 in two patient samples. Graphical abstract ᅟ.

Collaboration of the Joint Research Centre and European Customs Laboratories for the Identification of New Psychoactive Substances

BACKGROUND

The emergence of psychoactive designer drugs has significantly increased over the last few years. Customs officials are responsible for the control of products entering the European Union (EU) market. This control applies to chemicals in general, pharmaceutical products and medicines. Numerous products imported from non-EU countries, often declared as 'bath salts' or 'fertilizers', contain new psychoactive substance (NPS).

REVIEW

These are not necessarily controlled under international law, but may be subject to monitoring in agreement with EU legislation. This situation imposes substantial challenges, for example, for the maintenance of spectral libraries used for their detection by designated laboratories. The chemical identification of new substances, with the use of powerful instrumentation, and the time needed for detailed analysis and interpretation of the results, demands considerable commitment. The EU Joint Research Centre endeavors to provide scientific support to EU Customs laboratories to facilitate rapid identification and characterisation of seized samples. In addition to analysing known NPS, several new chemical entities have also been identified. Frequently, these belong to NPS classes already notified to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) by the European Early- Warning System (EWS).

CONCLUSION

The aim of this paper is to discuss the implementation of workflow mechanisms that are in place in order to facilitate the monitoring, communication and management of analytical data. The rapid dissemination of this information between control authorities strives to help protect EU citizens against the health risks posed by harmful substances.

Estimating heroin abuse in major Chinese cities through wastewater-based epidemiology

Heroin consumption in major cities across China was estimated for the first time via wastewater-based epidemiology. Influent and effluent wastewater samples were collected from 49 wastewater treatment plants (WWTPs) in 24 major cities that cover all the geographic regions of the country. Concentrations of morphine, 6-acetylmorphine, and codeine were measured. Near complete removal of morphine by wastewater treatment processes was observed, whereas removal rates of codeine were slightly lower. Morphine loads were much higher than codeine loads at most WWTPs in China, a trend opposite to that in many European countries. In addition, morphine and codeine loads were strongly correlated at most WWTPs, indicating morphine and codeine in wastewater were predominantly from the same source, street heroin. At WWTPs in Guangzhou and Shenzhen, codeine loads were considerably higher than morphine loads, consistent with previous reports of codeine abuse (e.g., as cough syrup) among middle and high school students in Guangdong province. Heroin consumption was derived based on morphine loads and taking into account therapeutic use of morphine and codeine, as well as contribution of codeine and acetylcodeine in street heroin. Highest heroin consumption was observed in northwestern and southwestern China. The average heroin consumption of the sampled cities was 64.6±78.7mg/1000inh/d. The nation-wide average heroin consumption was much lower than that of methamphetamine, consistent with seizure data and numbers of registered heroin and methamphetamine users in China.

Challenges in Laboratory Detection of Unusual Substance Abuse: Issues with Magic Mushroom, Peyote Cactus, Khat, and Solvent Abuse

Drug abuse is a worldwide problem. Although commonly abused drugs can be identified during routine urine drug testing, less commonly abused drugs may escape detection. These less commonly abused drugs not only include some designer drugs such as synthetic cannabinoid but also include abuse of psychedelic magic mushroom (active ingredients: psilocybin and psilocin), peyote cactus (active ingredient: mescaline), and khat plants (active ingredient: cathinone). Moreover, solvent and glue abuse is gaining popularity among teenagers and young adults which may even cause fatality. Amphetamine/methamphetamine immunoassay has a low cross-reactivity with psilocin. Cathinone, if present in the urine, can be detected by amphetamine/methamphetamine immunoassay due to cross-reactivity of cathinone with assay antibody. Currently there is one commercially available immunoassay which is capable of detecting synthetic cathinone known as bath salts as well as mescaline. However, gas chromatography combined with mass spectrometry as well as liquid chromatography combined with tandem mass spectrometry (LC/MS/MS)-based method is available for confirmation of the active ingredients present in magic mushroom, peyote cactus, and khat plant. Such chromatography-based methods also offer more sensitivity and specificity compared to an immunoassay.

Clinical Pharmacology of the Synthetic Cathinone Mephedrone

4-Methyl-N-methylcathinone (mephedrone) is a popular new psychoactive substance (NPS) that is structurally related to the parent compound cathinone, the β-keto analogue of amphetamine. Mephedrone appeared on the street drug market as a substitute for 3,4-methylenedioxy-N-methylamphetamine (MDMA, ecstasy) and was subsequently banned due to the potential health risks associated with its use. Nevertheless, mephedrone continues to be widely consumed among specific populations, with unique patterns of misuse. To date, most information about the biological effects of mephedrone comes from user experiences, epidemiological data, clinical cases, toxicological findings, and animal studies, whilst there are very few data regarding its human pharmacodynamics and pharmacokinetics. This chapter reviews the available published data on patterns of mephedrone use, its acute and chronic effects, and its pharmacokinetic properties. More human research is needed to elucidate the safety, toxicity, and addiction potential of mephedrone and related NPS.

Synthetic cathinone pharmacokinetics, analytical methods, and toxicological findings from human performance and postmortem cases

Synthetic cathinones are commonly abused novel psychoactive substances (NPS). We present a comprehensive systematic review addressing in vitro and in vivo synthetic cathinone pharmacokinetics, analytical methods for detection and quantification in biological matrices, and toxicological findings from human performance and postmortem toxicology cases. Few preclinical administration studies examined synthetic cathinone pharmacokinetic profiles (absorption, distribution, metabolism, and excretion), and only one investigated metabolite pharmacokinetics. Synthetic cathinone metabolic profiling studies, primarily with human liver microsomes, elucidated metabolite structures and identified suitable biomarkers to extend detection windows beyond those provided by parent compounds. Generally, cathinone derivatives underwent ketone reduction, carbonylation of the pyrrolidine ring, and oxidative reactions, with phase II metabolites also detected. Reliable analytical methods are necessary for cathinone identification in biological matrices to document intake and link adverse events to specific compounds and concentrations. NPS analytical methods are constrained in their ability to detect new emerging synthetic cathinones due to limited commercially available reference standards and continuous development of new analogs. Immunoassay screening methods are especially affected, but also gas-chromatography and liquid-chromatography mass spectrometry confirmation methods. Non-targeted high-resolution-mass spectrometry screening methods are advantageous, as they allow for retrospective data analysis and easier addition of new synthetic cathinones to existing methods. Lack of controlled administration studies in humans complicate interpretation of synthetic cathinones in biological matrices, as dosing information is typically unknown. Furthermore, antemortem and postmortem concentrations often overlap and the presence of other psychoactive substances are typically found in combination with cathinones derivatives, further confounding result interpretation.

Oral fluid drug analysis in the age of new psychoactive substances

Oral fluid has become an important matrix for drugs of abuse analysis. These days the applicability is challenged by the fact that an increasing number of new psychoactive drugs are coming on the market. Synthetic cannabinoids and synthetic cathinones have been the main drug classes, but the diversity is increasing and other drugs like piperazines, phenethylamines, tryptamines, designer opioids and designer benzodiazepines are becoming more prevalent. Many of the substances are very potent, and low doses ingested will lead to low concentrations in biological media, including oral fluid. This review will highlight the phenomenon of new psychoactive substances and review methods for oral fluid drug testing analysis using on-site tests, immunoassays and chromatographic methods.

Systematic analytical characterization of new psychoactive substances: A case study

New psychoactive substances (NPS) are synthesized compounds that are not usually covered by European and/or international laws. With a slight alteration in the chemical structure of existing illegal substances registered in the European Union (EU), these NPS circumvent existing controls and are thus referred to as "legal highs". They are becoming increasingly available and can easily be purchased through both the internet and other means (smart shops). Thus, it is essential that the identification of NPS keeps up with this rapidly evolving market. In this case study, the Belgian Customs authorities apprehended a parcel, originating from China, containing two samples, declared as being "white pigments". For routine identification, the Belgian Customs Laboratory first analysed both samples by gas-chromatography mass-spectrometry and Fourier-Transform Infrared spectroscopy. The information obtained by these techniques is essential and can give an indication of the chemical structure of an unknown substance but not the complete identification of its structure. To bridge this gap, scientific and technical support is ensured by the Joint Research Centre (JRC) to the European Commission Directorate General for Taxation and Customs Unions (DG TAXUD) and the Customs Laboratory European Network (CLEN) through an Administrative Arrangement for fast recognition of NPS and identification of unknown chemicals. The samples were sent to the JRC for a complete characterization using advanced techniques and chemoinformatic tools. The aim of this study was also to encourage the development of a science-based policy driven approach on NPS. These samples were fully characterized and identified as 5F-AMB and PX-3 using (1)H and (13)C nuclear magnetic resonance (NMR), high-resolution tandem mass-spectrometry (HR-MS/MS) and Raman spectroscopy. A chemoinformatic platform was used to manage, unify analytical data from multiple techniques and instruments, and combine it with chemical and structural information.

Thermal Degradation of Synthetic Cathinones: Implications for Forensic Toxicology

The synthetic cathinones represent an important class of designer drugs. The widespread attention and publicity associated with these psychostimulants have resulted in numerous legislative actions at state and federal levels throughout the USA. These amphetamine-like compounds are characterized by a β-keto functional group. Although the synthetic cathinones share many properties of their phenethylamine counterparts, the presence of the ketone moiety is responsible for a number of unique and distinct differences in terms of their chemical characteristics and properties. Thermal degradation of methcathinone was first reported several decades ago but has received limited attention. In this study, we identified in situ thermal degradation products for 18 cathinones during gas chromatography-mass spectrometry (GC-MS) analysis. Oxidative degradation arises from the loss of two hydrogens, yielding a characteristic 2 Da mass shift. Degradation products were characterized by prominent iminium base peaks with mass-to-charge ratios 2 Da lower than the parent drug, and in the case of the pyrrolidine-containing cathinones, prominent molecular ions arising from the 2,3-enamine. Chromatographic and mass spectroscopic data are described for 4-ethylmethcathinone, 4-methylethcathinone, buphedrone, butylone, ethcathinone, ethylone, flephedrone, 3,4-methylenedioxy-α-pyrrolidinobutiophenone, 3,4-methylenedioxypyrovalerone, mephedrone, methcathinone, methedrone, methylone, 4-methyl-α-pyrrolidinobutiophenone, naphyrone, pentedrone, pentylone and pyrovalerone. Degradation was minimized by lowering injection temperatures, residence time in the inlet and eliminating active sites during chromatographic analysis. Chromatographic and mass spectral data for the cathinone degradation products are presented and discussed within the context of forensic toxicological analysis, selection of appropriate instrumental methods and implications for the interpretation of results.