Time-course profile of urinary excretion of intravenously administered α-pyrrolidinovalerophenone and α-pyrrolidinobutiophenone in a human

An updated review on synthetic cathinones

Cathinone, the main psychoactive compound found in the plant Catha edulis Forsk. (khat), is a β-keto analogue of amphetamine, sharing not only the phenethylamine structure, but also the amphetamine-like stimulant effects. Synthetic cathinones are derivatives of the naturally occurring cathinone that largely entered the recreational drug market at the end of 2000s. The former "legal status", impressive marketing strategies and their commercial availability, either in the so-called "smartshops" or via the Internet, prompted their large spread, contributing to their increasing popularity in the following years. As their popularity increased, the risks posed for public health became clear, with several reports of intoxications and deaths involving these substances appearing both in the social media and scientific literature. The regulatory measures introduced thereafter to halt these trending drugs of abuse have proved to be of low impact, as a continuous emergence of new non-controlled derivatives keep appearing to replace those prohibited. Users resort to synthetic cathinones due to their psychostimulant properties but are often unaware of the dangers they may incur when using these substances. Therefore, studies aimed at unveiling the pharmacological and toxicological properties of these substances are imperative, as they will provide increased expertise to the clinicians that face this problem on a daily basis. The present work provides a comprehensive review on history and legal status, chemistry, pharmacokinetics, pharmacodynamics, adverse effects and lethality in humans, as well as on the current knowledge of the neurotoxic mechanisms of synthetic cathinones.

Tentative identification of the phase I and II metabolites of two synthetic cathinones, MDPHP and α-PBP, in human urine

Cathinone derivatives are one of the more prominent groups of new psychoactive substances in terms of the number of forensic case reports and the variety of chemical structures available. These substances often sold as "bath salts" are classified as psychostimulants. Using liquid chromatography-high resolution mass spectrometry, the metabolites of two pyrrolidine cathinone derivatives, α-PBP and the less common MDPHP, were tentatively identified in urine samples collected from patients admitted to hospital following drug intoxications. The major metabolic pathways for α-PBP and MDPHP were similar to those of their more common analogs (α-PVP and MDPV). Metabolites arising from hydroxylation, reduction of the carbonyl group to an alcohol, oxidation to form a lactam and subsequent ring-opening, and a combination of these processes were identified. In addition, biotransformations of the benzodioxole moiety in MDPHP included demethylenation with subsequent methylation and carboxylation of the butyl group. The majority of the hydroxylated metabolites of α-PBP and MDPHP were found to be glucuronidated. Both α-PBP and MDPHP undergo extensive metabolism and the chromatographic peak areas of the metabolites were found to be comparable to or exceeded those of the parent substances. Metabolites resulting from demethylenation and subsequent methylation (MDPHP), reduction of carbonyl group (α-PBP), and oxidation to form a lactam combined with ring-opening (α-PBP and MDPHP) were found to be the most useful target analytes for the confirmation of ingestion.

The synthetic cathinone α-pyrrolidinovalerophenone (α-PVP): pharmacokinetic and pharmacodynamic clinical and forensic aspects

New psychoactive substances (NPS), often referred as 'legal highs' or 'designer drugs', are derivatives and analogs of existing psychoactive drugs that are introduced in the recreational market to circumvent existing legislation on drugs of abuse. This work aims to review the state-of-the-art regarding chemical, molecular pharmacology, and in vitro and in vivo data on toxicokinetics of the potent synthetic cathinone α-pyrrolidinovalerophenone (α-PVP or flakka or zombie drug). Chemical, pharmacological, toxicological, and clinical effects of α-PVP were searched in PubMed (U.S. National Library of Medicine) and governmental websites without limitation of the period. α-PVP is a wide spread and easy to get special type of synthetic cathinone with seemingly powerful cocaine-like stimulant effects, high brain penetration, high liability for abuse and with increased risk of adverse effects such as tachycardia, agitation, hypertension, hallucinations, delirium, mydriasis, self-injury, aggressive behavior, and suicidal ideations. α-PVP undergoes extensive metabolism via different pathways and the α-PVP itself or its metabolites β-hydroxy-α-PVP and α-PVP lactam represent the main targets for toxicological analysis in urine. There is a limited knowledge regarding the short- and long-term effects of α-PVP and metabolites, and pharmacogenetic influence, hence further clinical and forensic toxicological studies are required. Moreover, since α-PVP cannot be detected with classic routine analysis procedures, statements on the frequency of their consumption cannot be made.

Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens

Urine drug testing is frequently used in clinical, employment, educational, and legal settings and misinterpretation of test results can result in significant adverse consequences for the individual who is being tested. Advances in drug testing technology combined with a rise in the number of novel misused substances present challenges to clinicians to appropriately interpret urine drug test results. Authors searched PubMed and Google Scholar to identify published literature written in English between 1946 and 2016, using urine drug test, screen, false-positive, false-negative, abuse, and individual drugs of abuse as key words. Cited references were also used to identify the relevant literature. In this report, we review technical information related to detection methods of urine drug tests that are commonly used and provide an overview of false-positive/false-negative data for commonly misused substances in the following categories: cannabinoids, central nervous system (CNS) depressants, CNS stimulants, hallucinogens, designer drugs, and herbal drugs of abuse. We also present brief discussions of alcohol and tricyclic antidepressants as related to urine drug tests, for completeness. The goal of this review was to provide a useful tool for clinicians when interpreting urine drug test results and making appropriate clinical decisions on the basis of the information presented.

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.

First metabolic profile of PV8, a novel synthetic cathinone, in human hepatocytes and urine by high-resolution mass spectrometry

Novel psychoactive substances (NPS) are ever changing on the drug market, making it difficult for toxicology laboratory methods to stay current with so many new drugs. Recently, PV8, a synthetic pyrrolidinophenone, was detected in seized products in Japan (2013), The Netherlands (2014), and Germany (2014). There are no controlled PV8 administration studies, and no pharmacodynamic and pharmacokinetic data. The objective was to determine PV8's metabolic stability in human liver microsome (HLM) incubation and its metabolism following human hepatocyte incubation and high-resolution mass spectrometry (HRMS) with a Thermo Scientific Q-Exactive. Data were acquired with a full-scan data-dependent mass spectrometry method. Scans were thoroughly data mined with different data processing algorithms and analyzed in WebMetaBase. PV8 exhibited a relatively short 28.8 min half-life, with an intrinsic 24.2 μL/min/mg microsomal clearance. This compound is predicted to be an intermediate clearance drug with an estimated human 22.7 mL/min/kg hepatic clearance. Metabolic pathways identified in vitro included: hydroxylation, ketone reduction, carboxylation, N-dealkylation, iminium formation, dehydrogenation, N-oxidation, and carbonylation. The top three in vitro metabolic pathways were di-hydroxylation > ketone reduction > γ-lactam formation. Authentic urine specimen analyses revealed the top three metabolic pathways were aliphatic hydroxylation > ketone reduction + aliphatic hydroxylation > aliphatic carboxylation, although the most prominent peak was parent PV8. These data provide useful urinary metabolite targets (aliphatic hydroxylation, aliphatic hydroxylation + ketone reduction, aliphatic carboxylation, and di-hydroxylation) for forensic and clinical testing, and focus reference standard companies' synthetic efforts to provide commercially available standards needed for PV8 biological specimen testing. Graphical Abstract Top four PV8 metabolites identified in vitro. Biotransformations highlighted in blue. Markush structures presented when exact location of biotransformation is unknown.

Spin column extraction as a new sample preparation method in bioanalysis

Sample preparation is important in obtaining accurate data for qualification and quantification in bioanalysis. We have recently focused on monolithic silica for high-throughput analysis. These extraction processes - using monolithic silica packed in spin column - such as sample loading, washing and elution, are executed by centrifugation. There are several possibilities such as on-column derivatization for the determination of amines or carboxylic acids in the sample. The spin column extraction reduces the sample preparation time required for determination of drugs and other chemicals in biological materials and increases productivity in bioanalysis. We expect spin column extraction to become the mainstream method of sample processing in the future.

4-Methoxy-α-PVP: in silico prediction, metabolic stability, and metabolite identification by human hepatocyte incubation and high-resolution mass spectrometry

Novel psychoactive substances are continuously developed to circumvent legislative and regulatory efforts. A new synthetic cathinone, 4-methoxy-α-PVP, was identified for the first time in illegal products; however, the metabolism of this compound is not known. Complete metabolic profiles are needed for these novel psychoactive substances to enable identification of their intake and to link adverse effects to the causative agent. This study assessed 4-methoxy-α-PVP metabolic stability with human liver microsomes (HLMs) and identified its metabolites after HLM and hepatocyte incubations followed by high-resolution mass spectrometry (HRMS). A Thermo QExactive high-resolution mass spectrometer (HRMS) was used with full scan data-dependent mass spectrometry, with (1) and without (2) an inclusion list of predicted metabolite, and with full scan and all-ion fragmentation (3) to identify potential unexpected metabolites. In silico predictions were performed and compared to in vitro results. Scans were thoroughly mined with different data processing algorithms using WebMetabase (Molecular Discovery). 4-Methoxy-α-PVP exhibited a long half-life of 79.7 min in HLM, with an intrinsic clearance of 8.7 µL min⁻¹ mg⁻¹. In addition, this compound is predicted to be a low-clearance drug with an estimated human hepatic clearance of 8.2 mL min⁻¹ kg⁻¹. Eleven 4-methoxy-α-PVP metabolites were identified, generated by O-demethylation, hydroxylation, oxidation, ketone reduction, N-dealkylation, and glucuronidation. The most dominant metabolite in HLM and human hepatocyte samples was 4-hydroxy-α-PVP, also predicted as the #1 in silico metabolite, and is suggested to be a suitable analytical target in addition to the parent compound.

Postmortem distribution of MAB-CHMINACA in body fluids and solid tissues of a human cadaver

During the latter part of 2014, we experienced an autopsy case in which 5-fluoro-ADB, one of the most dangerous synthetic cannabinoids, was identified and quantitated in solid tissues and in three herbal blend products [Forensic Toxicol (2015) 33:112-121]. At that time, although we suspected that there may be some drug(s) other than 5-fluoro-ADB in the herbal products, all trials to find it/them were unsuccessful. Subsequently, we carefully re-examined the presence of other synthetic cannabinoid(s) in the above herbal blend products using accurate mass spectrometry and found two new compounds, 5-fluoro-ADB-PINACA and MAB-CHMINACA (Forensic Toxicol. doi: 10.1007/s 11419-015-0264-y). In the present communication, we report the distribution of MAB-CHMINACA in body fluids and solid tissue specimens collected from the same deceased individual (kept frozen at -80 °C) as described above for demonstration of 5-fluoro-ADB. Unexpectedly, unchanged MAB-CHMINACA could be identified and quantitated in whole blood and in pericardial fluid specimens, but it was below the detection limit (0.1 ng/ml) in the urine specimen. A higher concentration of MAB-CHMINACA could be found in all of the nine solid tissues; the highest concentration of MAB-CHMINACA was found in the liver (156 ng/g), followed by the kidney, pancreas and so on. The compounds were detected in all nine solid tissues; their levels were generally higher than those in the whole blood and pericardial fluid. Contrary to expectations, the concentration of MAB-CHMINACA in the adipose tissue was relatively low. Our results show that the victim smoked one of the three herbal blend products containing both MAB-CHMINACA and 5-fluoro-ADB, resulting in the coexistence of both compounds. It should be concluded that 5-fluoro-ADB and MAB-CHMINACA synergically exerted their toxicities, leading to death after a short interval. The differences in the distribution of 5-fluoro-ADB and MAB-CHMINACA among the cadaver specimens were also discussed in view of the structures of both compounds. To our knowledge, this is the first report to demonstrate MAB-CHMINACA in biological/human specimens.

Comprehensive review of the detection methods for synthetic cannabinoids and cathinones

A number of N-alkyl indole or indazole-3-carbonyl analogs, with modified chemical structures, are distributed throughout the world as synthetic cannabinoids. Like synthetic cannabinoids, cathinone analogs are also abused and cause serious problems worldwide. Acute deaths caused by overdoses of these drugs have been reported. Various analytical methods that can cope with the rapid changes in chemical structures are required for routine analysis and screening of these drugs in seized and biological materials for forensic and clinical purposes. Although many chromatographic methods to analyze each drug have been published, there are only a few articles summarizing these analytical methods. This review presents the various colorimetric detections, immunochemical assays, gas chromatographic-mass spectrometric methods, and liquid chromatographic-mass spectrometric methods proposed for the analysis of synthetic cannabinoids and cathinones.