GC–MS analysis of the designer drug α-pyrrolidinovalerophenone and its metabolites in urine and blood in an acute poisoning case

Toxicological Investigation of a Case Series Involving the Synthetic Cathinone α-Pyrrolidinohexiophenone (α-PHP) and Identification of Phase I and II Metabolites in Human Urine

α-Pyrrolidinohexiophenone (α-PHP) is a derivative of the class of α-pyrrolidinophenones, a subgroup of synthetic cathinones. These substances are the second most abused drugs of new psychoactive substances. Here, we report the toxicological investigation of a series of 29 authentic forensic and clinical cases with analytically confirmed intake of α-PHP including two cases of drug testing in newborns using meconium. The age range of subjects where serum samples were available was 23-51 years (median 39.5), and 90% were male. Serum α-PHP concentrations, determined by a validated LC-MS-MS method, showed a high variability ranging from 1 to 83 ng/mL (mean, 40 ng/mL; median, 36 ng/mL). Comprehensive toxicological analysis revealed co-consumption of other psychotropic drugs in almost all cases with frequent occurrence of opiates (60%), benzodiazepines (35%), cannabinoids (30%), and cocaine (20%). Hence, forensic and clinical symptoms like aggressive behavior, sweating, delayed physical response, and impaired balance could not be explained by the abuse of α-PHP alone but rather by poly-intoxications. Liquid chromatography-quadrupole time-of-flight mass spectrometry and gas chromatography-mass spectrometry were used to investigate the metabolism of α-PHP in vivo using authentic human urine samples. Altogether, 11 phase I metabolites and 5 phase II glucuronides could be identified by this approach. Apart from the parent drug, most abundant findings in urine were the metabolites dihydroxy-pyrrolidinyl-α-PHP and dihydro-α-PHP and, to a lesser extent, 2'-oxo-dihydro-α-PHP and 2'-oxo-α-PHP. Monitoring of these metabolites along with the parent drug in forensic and clinical toxicology could unambiguously prove the abuse of the novel designer drug α-PHP.

Behavioral patterns of people who use synthetic psychostimulants: Results of a qualitative study in St. Petersburg, Russia

BACKGROUND

Russia, like many other places, is currently experiencing a proliferation of new psychoactive substances, many of which are psychostimulants. In St. Petersburg, these appear to be mostly congeners of cathinone. We sought to obtain qualitative data to better understand the impact on the health and behaviors of people who use drugs (PWUD) by recruiting individuals who reported recent use of psychostimulants.

METHODS

In-depth qualitative data on current drug use and its effects were collected through thirty interviews (n=30) and two focus groups (n=10: five male, five female). The interviews and focus groups also provided data on the social contexts of drug use including sexual behaviors and associated medical issues. Secondary data about online drug purchases were obtained from a source that accesses and analyzes darknet purchases. Qualitative data were initially coded using a priori codes developed on the basis of the interview guide, and then data were coded again inductively based on emergent findings from the data. Thematic analysis was carried out using OpenCode 4.0 qualitative data analysis software.

RESULTS

Thematic analysis of the interviews and focus groups identified distinct differences in behavior patterns between older, more experienced PWUD and a "new generation" of PWUD. Routes of initiation of drug use and sexual behaviors associated with drug use differed, but both groups reported high levels of unsafe injection and sexual behaviors. In interpreting the texts and purchasing data, we have attempted to anticipate how the drug use patterns can influence HIV transmission.

CONCLUSIONS

The emergence of a new class of psychostimulant drugs presents new threats to the health of drug users and new opportunities to intervene to reduce those risks. The information obtained may assist HIV/AIDS prevention specialists and drug user support groups in their efforts to decrease unsafe drug use and sexual behaviors.

Ethanol pre-exposure differentially impacts the rewarding and aversive effects of α-pyrrolidinopentiophenone (α-PVP): Implications for drug use and abuse

RATIONALE

Exposure to a drug can subsequently impact its own reactivity as well as that of other drugs. Given that users of synthetic cathinones, i.e., "bath salts", typically have extensive and varied drug histories, an understanding of the effects of drug history on the behavioral and physiological consequences of synthetic cathiones may be important to their abuse liability.

OBJECTIVES

The goal of the current work was to assess the effects of an ethanol pre-exposure on the rewarding and aversive effects of α-PVP.

METHODS

Adult male Sprague Dawley rats were exposed to ethanol prior to combined conditioned taste avoidance/conditioned place preference training in which rats were injected with 1.5, 3 or 5 mg/kg of racemic α-PVP or vehicle. Following a 7-day washout period, rats were then tested for thermoregulatory effects of α-PVP using subcutaneous probes to measure body temperature changes over the course of 8 h. This was followed 10 days later by assessments for α-PVP-induced locomotor activity and stereotypies over a 1-h session.

RESULTS

α-PVP induced significant dose- and trial-dependent taste avoidance that was significantly attenuated by ethanol history and dose- and time-dependent increases in locomotor activity that were significantly increased by ethanol. α-PVP also induced place preferences and dose- and time-dependent increases in body temperature, but these measures were unaffected by ethanol history.

CONCLUSIONS

α-PVP's aversive effects (as measured by taste avoidance) were attenuated, while its rewarding effects (as indexed by place preference conditioning) were unaffected, by ethanol pre-exposure. Such a pattern may indicate increased α-PVP abuse liability, as changes in the balance of aversion and reward may impact overall drug effects and likelihood of drug intake. Future self-administration studies will be necessary to explore this possibility.

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.

Electrochemical Fingerprints of Illicit Drugs on Graphene and Multi-Walled Carbon Nanotubes

Illicit drugs use and abuse remains an increasing challenge for worldwide authorities and, therefore, it is important to have accurate methods to detect them in seized samples, biological fluids and wastewaters. They are recently classified as the latest group of emerging pollutants as their consumption increased tremendously in recent years. Nanomaterials have gained much attention over the last decade in the development of sensors for a myriad of applications. The applicability of these nanomaterials, functionalized or not, significantly increases and it is therefore highly suitable for use in the detection of illicit drugs. We have assessed the suitability of various nanoplatforms, such as graphene (GPH), multi-walled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs) and platinum nanoparticles (PtNPs) for the electrochemical detection of illicit drugs. GPH and MWCNTs were chosen as the most suitable platforms and cocaine, 3,4-methylendioxymethamfetamine (MDMA), 3-methylmethcathinone (MMC) and α-pyrrolidinovalerophenone (PVP) were tested. Due to the hydrophobicity of the nanomaterials-based platforms which led to low signals, two strategies were followed namely, pretreatment of the electrodes in sulfuric acid by cyclic voltammetry and addition of Tween 20 to the detection buffer. Both strategies led to an increase in the oxidation signal of illicit drugs. Binary mixtures of illicit drugs with common adulterants found in street samples were also investigated. The proposed strategies allowed the sensitive detection of illicit drugs in the presence of most adulterants. The suitability of the proposed sensors for the detection of illicit drugs in spiked wastewaters was finally assessed.

Analysis for Alpha-Pyrrolidinovalerophenone and Its 2-Oxo-PVP Metabolite in Plasma by Liquid Chromatography-Tandem Mass Spectrometry

Alpha-pyrrolidinovalerophenone (alpha-PVP), a novel psychoactive substance, has widespread recreational use. This with interest in its pharmacological effects creates a need for methods that measure alpha-PVP concentrations. We therefore developed a LC-MS/MS method that can quantitate alpha-PVP and 2-oxo-PVP in rat plasma using a 0.1-mL sample volume. Addition of internal standards (2.5 ng/mL alpha-PVP-d8/2-oxo-PVP-d6) was followed by liquid-liquid extraction with 1-chlorobutane:acetonitrile (4:1), evaporation and reconstitution with 0.1% formic acid. Extracts were analyzed by LC-MS/MS using an Agilent 1100 HPLC and a Thermo Scientific TSQ Quantum Access MS/MS, with a YMC ODS-AQ, 50 mm × 2 mm, 3 μm column. The mobile phase was 0.1% formic acid:acetonitrile gradient at a 0.2-mL/minute flow rate with positive ion electrospray. SRM was used for the analysis with transitions: alpha-PVP, 232 → 91; alpha-PVP-d8, 240 → 91; 2-oxo-PVP, 246 → 91; 2-oxo-PVP-d6, 252 → 91. Alpha-PVP and 2-oxo-PVP eluted at 6.4 and 8.9 min. Calibrators range from 0.25 to 500 ng/mL. Accuracy and precision evaluated quality control samples prepared at 0.75, 10 and 400 ng/mL. The intra-assay evaluation also included the 0.25-ng/mL LOQs prepared in six different blank plasma sources. The intra-assay accuracy ranged from 88.9 to 117.8% of the target, and the intra-assay precision ranged from 0.9 to 16.0%. The inter-assay accuracy ranged from 98.7 to 110.7% of the target, and the inter-assay precision ranged from 4.5 to 12.0%. Extraction recovery was at least 52% for alpha-PVP and 67% for 2-oxo-PVP. Ionization recoveries were at least 64% for alpha-PVP and 82% for 2-oxo-PVP. These losses did not adversely affect assay performance. Alpha-PVP and 2-oxo-PVP controls were stable at room temperature for up to 24 h and frozen for at least 36 days. Alpha-PVP and 2-oxo-PVP were also stable in processed samples (extracts) stored at room temperature for at least 24 days. The procedure was used to analyze rat plasma samples from a pharmacokinetic study.

Eutylone Intoxications-An Emerging Synthetic Stimulant in Forensic Investigations

Synthetic stimulants are the largest class of novel psychoactive substances identified each year by forensic laboratories internationally. While hundreds of these drugs appear in drug powders, only a few proliferate in use among forensically relevant populations and eventually emerge in postmortem and clinical investigations. Beta-keto-methylenedioxyamphetamines (i.e., novel psychoactive substances with names ending in "ylone") are currently the most popular subclass of synthetic stimulants. Leading up to its federal scheduling in 2018, N-ethyl pentylone was the most encountered synthetic stimulant. The popularity of N-ethyl pentylone declined once it was scheduled, but it was quickly replaced by eutylone (bk-EBDB), a structurally related analog from the same family. In cases encountered between January 2019 and April 2020, eutylone was quantitatively confirmed in 83 forensic investigations, including postmortem cases and driving under the influence of drugs cases. Matrix types included blood, urine and tissue. Eutylone was identified in cases submitted from 13 states, demonstrating proliferation around the United States; Florida accounted for 60% of the positive cases. The mean concentration of eutylone in postmortem blood was 1,020 ng/mL (standard deviation = ±2,242 ng/mL; median = 110 ng/mL, range = 1.2-11,000 ng/mL, n = 67). The mean concentration of eutylone in blood from driving under the influence of drugs cases was 942 ng/mL (standard deviation = ±1,407 ng/mL; median = 140 ng/mL, range = 17-3,600 ng/mL, n = 7). This report includes cause and manner of death data for 22 postmortem cases. Further analysis of authentic human specimens revealed the presence of three eutylone metabolites, including one unique biomarker and one metabolite in common with butylone. Laboratories should be aware that eutylone may be present in cases of suspected Ecstasy, "Molly" and/or methylenedioxymethamphetamine use, causing or contributing to impairment or death.

Pyrrolidinyl Synthetic Cathinones α-PHP and 4F-α-PVP Metabolite Profiling Using Human Hepatocyte Incubations

For more than ten years, new synthetic cathinones (SCs) mimicking the effects of controlled cocaine-like stimulants have flooded the illegal drug market, causing numerous intoxications and fatalities. There are often no data on the pharmacokinetics of these substances when they first emerge onto the market. However, the detection of SC metabolites is often critical in order to prove consumption in clinical and forensic settings. In this research, the metabolite profile of two pyrrolidinyl SCs, α-pyrrolidinohexaphenone (α-PHP) and 4''-fluoro-α-pyrrolidinovalerophenone (4F-α-PVP), were characterized to identify optimal intake markers. Experiments were conducted using pooled human hepatocyte incubations followed by liquid chromatography-high-resolution tandem mass spectrometry and data-mining software. We suggest α-PHP dihydroxy-pyrrolidinyl, α-PHP hexanol, α-PHP 2'-keto-pyrrolidinyl-hexanol, and α-PHP 2'-keto-pyrrolidinyl as markers of α-PHP use, and 4F-α-PVP dihydroxy-pyrrolidinyl, 4F-α-PVP hexanol, 4F-α-PVP 2'-keto-pyrrolidinyl-hexanol, and 4F-α-PVP 2'-keto-pyrrolidinyl as markers of 4F-α-PVP use. These results represent the first data available on 4F-α-PVP metabolism. The metabolic fate of α-PHP was previously studied using human liver microsomes and urine samples from α-PHP users. We identified an additional major metabolite (α-PHP dihydroxy-pyrrolidinyl) that might be crucial for documenting exposure to α-PHP. Further experiments with suitable analytical standards, which are yet to be synthesized, and authentic specimens should be conducted to confirm these results.

Intoxication cases associated with the novel designer drug 3',4'-methylenedioxy-α-pyrrolidinohexanophenone and studies on its human metabolism using high-resolution mass spectrometry

Among the increasing number of new psychoactive substances, 3',4'-methylenedioxy-α-pyrrolidinohexanophenone (MDPHP) belongs to the group of synthetic cathinones, which are the derivatives of the naturally occurring compound cathinone, the main psychoactive ingredient in the khat plant. Currently, only limited data are available for MDPHP, and no information is available on its human metabolism. We describe the toxicological investigation of nine cases associated with the use of MDPHP during the period February-June 2019. Serum MDPHP concentrations showed a high variability ranging from 3.3 to 140 ng/mL (mean 30.3 ng/mL and median 16 ng/mL). Intoxication symptoms of the described cases could not be explained by the abuse of MDPHP alone because in all cases the co-consumption of other psychotropic drugs with frequent occurrence of opiates and benzodiazepines could be verified. Therefore, the patients showed different clinical symptoms, including aggressive behaviour, delayed physical response, loss of consciousness and coma. Liquid chromatography-high-resolution mass spectrometry was successfully used to investigate the human in vivo metabolism of MDPHP using authentic human urine samples. The metabolism data for MDPHP were further substantiated by the analysis of human urine using gas chromatography-mass spectrometry (GC-MS, a widely used systematic toxicological analysis method appropriate for the toxicological detection of MDPHP intake), which revealed the presence of seven phase I metabolites and three phase II metabolites as glucuronides. GC-MS spectral data for MDPHP and metabolites are provided. The identified metabolite pattern corroborates the principal metabolic pathways of α-pyrrolidinophenones in humans.

Determination of synthetic cathinone α-pyrrolidinovalero-phenone and its metabolite in urine using solid-phase extraction and gas chromatography-mass spectrometry

RATIONALE

The presence of α-pyrrolidinovalerophenone (α-PVP) and its metabolites in urine is evidence of the administration of α-PVP. A toxicological challenge is that the metabolites of α-PVP exhibit amphoteric properties, which make them unsuitable for detection using gas chromatography-mass spectrometry (GC/MS). In the study reported, proper derivatization and sample extraction were essential for improving the sensitivity for GC/MS analysis.

METHODS

An automated solid-phase extraction (SPE) method has been developed and optimized. The derivatization efficiency was tested using longer reaction time and the addition of polar pyridine into a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane. Method validation, including linearity, limit of detection, precision, accuracy, and recovery, was evaluated using automatic SPE and GC/MS.

RESULTS

The results suggested that adding pyridine to BSTFA (1:1, v/v) significantly improved derivatization efficiency and precision. After optimization, the linear range was from 25 to 1000 ng mL^-1 with R²  > 0.9950. The limit of detection was 5 ng mL^-1 for α-PVP and 25 ng mL^-1 for OH-α-PVP. The recovery for SPE was over 88%. The inter-day and intra-day precisions were less than 15%. A forensic sample has been found containing α-PVP (67.3 ng mL^-1 ) and OH-α-PVP (560.2 ng mL^-1 ).

CONCLUSIONS

This study is the first to validate an auto-SPE-GC/MS method for the quantification and qualification of α-PVP and OH-α-PVP in urine. We have successfully improved the derivatization efficiency and developed a sensitive and semi-automatic approach. This approach is desirable for the detection of synthetic cathinone at trace levels in biological samples.

HPLC-MS/MS combined with membrane-protected molecularly imprinted polymer micro-solid-phase extraction for synthetic cathinones monitoring in urine

Synthetic cathinones are a type of drug belonging to group of new psychoactive substances (NPSs). The illicit market for these substances is characterized by the continuous introduction to the market of new analogs to evade legislation and to avoid detection. New screening and confirmation assays are therefore needed, mainly in forensic/clinical samples. In the current development, a porous membrane-protected, micro-solid-phase extraction (μ-SPE) has been developed for the assessment of several cathinones in urine. The μ-SPE device consisted of a cone-shaped polypropylene (PP) porous membrane containing the adsorbent (molecularly imprinted polymers, MIPs, synthesized for the first time for this class of drugs). MIPs were prepared using ethylone and 3-methylmethcathinone (3-MMC) as templates, ethylene glycol dimethacrylate (EGDMA) as a functional monomer, divinylbenzene (DVB) as a cross-linker, and 2,2´-azobisisobutyronitrile (AIBN) as an initiator. The prepared ethylone-based MIP and 3-MMC-based MIP have been fully characterized and evaluated as new selective adsorbents for μ-SPE. Cathinones separation/determination was performed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Optimum loading conditions (pH 5.0, loading for 4.0 minutes under orbital-horizontal shaking at 200 rpm) and elution conditions [2.0 mL of 75:20:5 heptane/2-propanol/ammonium hydroxide and ultrasounds assistance (37 kHz, 325 W) for 4.0 minutes] were found for ethylone-based MIP. Validation (intra-day and inter-day precision and analytical recovery) showed RSD values lower than 9 and 10% for intra-day and inter-day precision, and within the 88%-101% range for intra-day and inter-day analytical recovery.

Simultaneous Determination of Amphetamine-Related New Psychoactive Substances in Urine by Gas Chromatography–Mass Spectrometry†

Despite the efforts to prevent the spread of new psychoactive substances (NPS) such as synthetic amphetamine derivatives, it is apparent that newer types of NPS are still emerging on the market in recent years. Due to high potential for their abuse, reliable analytical methods are required to determine these substances in biological samples. The objective of this study was to develop and validate the gas chromatography–mass spectrometric (GC–MS) method for the simultaneous determination of 13 amphetamine-related NPS (amphetamine; AP, 4-fluoroamphetamine; 4FA, methamphamine; MA, 4-fluoromethamphetamine; 4FMA, 4-chloroamphetamine; 4CA, para-methoxyamphetamine; PMA, 4-chloromethamphetamine; 4CMA, 6-(2-aminopropyl)benzofuran; 6APB, 4-methylenedioxyamphetamine; MDA, para-methoxymethamphetamine; PMMA, 6-(2-methylaminopropyl)benzofuran; 6MAPB, 3,4-methylenedioxymethamphetamine; MDMA, 5,6-methylenedioxy-2-aminoindane; MDAI) in urine. The analytes were extracted at pH 7.4 by liquid–liquid extraction prior to their trifluoroacetyl derivatives and then analyzed by GC–MS. The validation parameters included selectivity, linearity, lower limits of quantification (LLOQ), intra and interday precision and accuracy, recovery and stability. The linear ranges were 2–100 ng/mL for AP, 4FA, 4FMA, 4CA, PMA, 6APB, MDA, and MDAI, 2–250 ng/mL for 4CMA, PMMA, and 6MAPB and 25–1,000 ng/mL for MA and MDMA, with acceptable coefficients of determination (r2 > 0.9963). The intra and interday precision were within 11.9 and 12.5%, while the intra and interday accuracies ranged from −10.6% to 13.0% and −11.0% to 6.8% for the nominal concentration at all studied levels, respectively. The LLOQs for each analyte were 2.0–25 ng/mL. The recoveries ranged from 69.3% to 96.4%. The short- and long-term variations of the analytes in urine were lower than 8.5 and 12.7%, indicating that the analytes are stable at least for 16 h at room temperature and for 7 days at 4°C, respectively. The applicability of the method was examined by analyzing urine samples from drug abusers and was determined to be effective for detecting multiple drug use.

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.

Spray-inlet microwave plasma torch ionization tandem mass spectrometry for the direct detection of drug samples in liquid solutions

RATIONALE

Drug abuse or dependence results in a series of social problems, including crime and traffic accidents. Spray-inlet microwave plasma torch tandem mass spectrometry (MPT-MS/MS) was developed and used for the direct detection of such drugs in liquid solutions.

METHODS

Drug sample solutions were directly sprayed into the flame of an MPT by a sampling pump and the ions produced by Penning ionization and ion-molecule reactions were guided into a quadrupole time-of-flight (QTOF) tandem mass spectrometer for mass analysis. The MPT was operated at 40 W and 2.45 GHz in a 700 mL/min argon flow both for the inner and middle plasma.

RESULTS

Intact quasi-molecular and molecular ions of various drugs were successfully characterized by spray-inlet MPT-MS/MS. The analysis of one sample was finished within 30 s. Furthermore, the method exhibited excellent efficiency, precision and sensitivity, and the limits of detection and limits of quantification of the samples in methanol were in the range of 5.25-60.0 and 17.5-200 ng g^-1 , respectively. Excellent linearities with coefficients of determination (R² ) of 0.9627-0.9980 were verified in the range 0.05-50 μg g^-1 . Four different beverages purchased locally were also analyzed with spray-inlet MPT-MS/MS, and caffeine was directly determined in two of the beverages. By adding six standard drug samples to sport drinks (each drug was 1 μg g^-1 ) and Chinese spirit (each drug was 0.1 μg g^-1 ), all the drugs except for caffeine were detected successfully.

CONCLUSIONS

This study indicates that spay-inlet MPT-MS/MS is an effective method for direct and rapid identification of drug solutions, and it has substantial potential for fast and sensitive drug residue detection.

MDPV and α-PVP use in humans: The twisted sisters

The new psychoactive substances phenomenon continues to represent a considerable public health challenge. Synthetic cathinones are β-keto amphetamine analogues, also known as legal highs, research chemicals, bath salts. These drugs have surfaced as a popular alternative to other illicit drugs of abuse, such as cocaine, MDMA, and methamphetamine, due to their potent psychostimulant and empathogenic effects. Pyrovalerone cathinones (a-pyrrolidinophenones) form a distinct group of designer cathinones, such as MDPV. After being listed as an illegal product, "second generation" compounds such as α-PVP, sharing a very similar chemical structure with MDPV, were developed. Clinical effects of these compounds are individual, dose- and route of administration-dependent. Both of them have been involved in an increased number of, not only acute intoxications but also fatalities over the past few years, raising concerns in the medical field. In this paper, we will review the available data regarding the use and effects of MDPV and α-PVP in humans in order to highlight their impact on public health. Health actors and general population need to be clearly informed of potential risks and consequences of these 2 novel psychoactive substances spread and use. The literature search conducted led to the identification of potentially 83 relevant articles. All articles were screened from their abstracts to determine their relevance in the framework of the current review. This article is part of the Special Issue entitled 'Designer Drugs and Legal Highs.'

The Novel Psychoactive Substances in the UK Project: empirical and conceptual review work to produce research recommendations

Background

Although illegal drug use has largely been declining in the UK over the past decade, this period has witnessed the emergence of a range of novel psychoactive substances (NPS) (‘legal highs’). These are new, mostly synthetic, substances that mimic the effects of existing drugs). Despite there being many causes for concern in relation to NPS, there has been little prior study of the burden associated with their use in public health terms. Clarity is lacking on research priorities in this rapidly developing literature.

Objectives

To inform the development of public health intervention research on NPS by reviewing existing data on their use, associated problems and potential responses to such problems.

Design

A scoping review and narrative synthesis of selected bodies of evidence was undertaken to summarise and evaluate what is known about NPS use and the related harms of, and responses to, such use. Relevant literature was identified from electronic databases (covering January 2006 to June 2016 inclusive), Google (Google Inc., Mountain View, CA, USA), relevant websites and online drug forums and by contacting experts. Articles were included if they were primary studies, secondary studies involving the analysis and interpretation of primary research or discussion papers. A conceptual framework postulating an evidence-informed public health approach to NPS use in the UK was developed through a pragmatic literature review, the iterative development of concepts and finalisation in light of the results from the empirical review work. The process also involved feedback from various stakeholders. Research recommendations were developed from both strands of work.

Results

A total of 995 articles were included in the scoping review, the majority of which related to individual-level health-related adverse effects attributable to NPS use. The prevalence of lifetime NPS use varied widely between (e.g. with higher prevalence in young males) and within population subgroups. The most commonly reported adverse effects were psychiatric/other neurological, cardiovascular, renal and gastrointestinal manifestations, and there is limited evidence available on responses. In these and other respects, available evidence is at an early stage of development. Initial evidence challenges the view that NPS should be treated differently from other illicit drugs. The conceptual framework indicated that much of the evidence that would be useful to inform public health responses does not yet exist. We propose a systems-based prevention approach that develops existing responses, is multilevel and life course informed in character, and emphasises commonalities between NPS and other legal and illegal drug use. We make 20 recommendations for research, including nine key recommendations.

Limitations

Scoping reviews do not interrogate evidence in depth, and the disjunction between the scoping review and the conceptual framework findings is worthy of careful attention.

Conclusions

Key research recommendations build on those that have previously been made and offer more evidence-based justification and detail, as previous recommendations have not yet been acted on. The case for decision-making on commissioning new research based on these recommendations is both strong and urgent.

Future work

The validity of recommendations generated through this project could be enhanced via further work with research commissioners, policy-makers, researchers and the public.

Study registration

The systematic review element of this study is registered as PROSPERO CRD42016026415.

Funding

The National Institute for Health Research Public Health Research programme.

Toxicity evaluation of α-pyrrolidinovalerophenone (α-PVP): results from intoxication cases within the STRIDA project

CONTEXT

An increasing number of new psychoactive substances (NPS) of different chemical classes have become available through marketing and sale over the Internet. This report from the Swedish STRIDA project presents the prevalence, laboratory results, and clinical features in a series of intoxications involving the stimulant NPS α-pyrrolidinovalerophenone (α-PVP), a potent dopamine re-uptake inhibitor, over a 4-year period.

STUDY DESIGN

Observational case series of consecutive patients with admitted or suspected intake of NPS presenting to hospitals in Sweden from 2012 to 2015.

PATIENTS AND METHODS

In the STRIDA project, blood and urine samples are collected from intoxicated patients with admitted or suspected intake of NPS or unknown drugs presenting to hospitals over the country. Analysis of NPS is performed by mass spectrometry multicomponent methods. Clinical data are collected when caregivers consult the Swedish Poisons Information Centre (PIC), and retrieved from medical records. The severity of poisoning is graded retrospectively using the Poisoning Severity Score (PSS). The inclusion criteria for this study included absence of other stimulants than α-PVP.

RESULTS

During the 4-year study period, 23 intoxications were originally coded as "α-PVP related" out of a total 3743 NPS-related inquiries (0.6%) at the PIC. The present study covered 42 analytically confirmed cases in which α-PVP was the only stimulant detected. The age range of patients was 20-58 (median 32) years, of which 79% were males. The α-PVP concentration in serum was 4.0-606 (median 64; n = 42) ng/mL and 2.0-41,294 (median 1782; n = 25) ng/mL in urine. There was no statistically significant association between the serum α-PVP concentration and urinary α-PVP/creatinine ratio in 25 cases, where both sets of data were available. In 14/42 (33%) cases, α-PVP was the only psychoactive substance identified. In the remaining cases, additional substances comprised opioids, benzodiazepines, and ethanol. The main clinical manifestations were tachycardia (80%), agitation (70%), hypertension (33%), hallucinations (20%), and delirium (18%). Classification of poisoning severity yielded 25 (60%) moderate (PSS 2), 7 (17%) severe (PSS 3), and 2 fatal cases (PSS 4).

CONCLUSIONS

In analytically confirmed α-PVP intoxication cases involving no other stimulant drugs, the urine and serum concentrations showed high variability. The clinical features were consistent with a severe sympathomimetic toxidrome. The results further demonstrated that α-PVP prevailed as a drug of abuse after being classified as a narcotic substance, and despite a high incidence of severe poisonings and fatalities. However, the low prevalence of α-PVP cases registered at the PIC suggested that many were unaware of the actual substance they had taken.

Toxicological investigation of forensic cases related to the designer drug 3,4-methylenedioxypyrovalerone (MDPV): Detection, quantification and studies on human metabolism by GC-MS

3,4-methylenedioxypyrovalerone (MDPV) is a synthetic cathinone belonging to the class of α-pyrrolidinophenones that become increasingly popular as a designer psychostimulant. Here, we report a comprehensive collection of MDPV exposure with quantitative serum level confirmation in Germany. During the years 2014-2016, we could proof consumption of MDPV in 23 cases where urine and blood samples were submitted to our laboratory by the police of Lower Saxony. Most of the samples underwent systematic toxicological analysis by gas chromatography-mass spectrometry (GC-MS), where MDPV could be detected in urine and/or serum samples. The determined concentrations of MDPV in serum showed a high variability, ranging from traces (<10ng/mL) up to 576ng/mL with a mean concentration of 118ng/mL and median of 47ng/mL. The majority of MDPV users were men (87%) and the age ranged from 23 to 49 years (mean 35.9, median 37 years). For most of the analytically confirmed MDPV cases we could prove co-consumption of other psychotropic drugs with frequent occurrence of opiates and cannabinoids in 22% of the cases, followed by benzodiazepines and cocaine in 17%. Analysis of urine samples by GC-MS disclosed the presence of MDPV and its metabolites 2'-oxo-MDPV, demethylenyl-MDPV, demethylenyl-methyl-MDPV, demethylenyl-oxo-MDPV, demethylenyl-methyl-oxo-MDPV and demethylenyl-methyl-N,N-bisdealkyl-MDPV. The metabolite pattern substantiates previous suggestions for principle metabolic pathways of MDPV in humans.

Identification of the Metabolic Enzyme Involved Morusin Metabolism and Characterization of Its Metabolites by Ultraperformance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (UPLC/Q-TOF-MS/MS)

Morusin, the important active component of a traditional Chinese medicine, Morus alba L., has been shown to exhibit many vital pharmacological activities. In this study, six recombinant CYP450 supersomes and liver microsomes were used to perform metabolic studies. Chemical inhibition studies and screening assays with recombinant human cytochrome P450s were also used to characterize the CYP450 isoforms involved in morusin metabolism. The morusin metabolites identified varied greatly among different species. Eight metabolites of morusin were detected in the liver microsomes from pigs (PLMs), rats (RLMs), and monkeys (MLMs) by LC-MS/MS and six metabolites were detected in the liver microsomes from humans (HLMs), rabbits (RAMs), and dogs (DLMs). Four metabolites (M₁, M₂, M₅, and M₇) were found in all species and hydroxylation was the major metabolic transformation. CYP1A2, CYP2C9, CYP2D6, CYP2E1, CYP3A4, and CYP2C19 contributed differently to the metabolism of morusin. Compared to other CYP450 isoforms, CYP3A4 played the most significant role in the metabolism of morusin in human liver microsomes. These results are significant to better understand the metabolic behaviors of morusin among various species.

Neurobiology of 3,4-methylenedioxypyrovalerone (MDPV) and α-pyrrolidinovalerophenone (α-PVP)

Synthetic cathinones are analogs of cathinone or β-ketoamphetamine - the major psychostimulant component of the shrub Catha edulis or khat. Cathinone analogs - though not termed as such - have been known for >100 years, but confusing chemical nomenclature often made the topic difficult to appreciate. In addition, many of the early analogs were prepared as synthetic precursors for the development of various other agents, and relatively few were pharmacologically evaluated. Cathinone is a close structural relative of amphetamine. Today, certain cathinone derivatives, synthetic cathinones, are known to produce central stimulant actions and represent a "new" class of drugs of abuse. Depending upon the nature of their terminal amine, α substituent, and aryl substituents, they seem to produce their effects via release or reuptake of various neurotansmitters including dopamine norepinephreine and/or serotonin. Two of the newest and most prominent members of the class are MDPV and its parent α-PVP ("flakka"). Both have been encountered on their own and in what might be constituents of what has been termed by a variety of names including psychoactive "bath salts". Here, we describe the nomenclature of synthetic cathinones, the mechanism(s) of action of MDPV and α-PVP, and their structure-activity relationships. In order to assist in forensic studies, and to identify novel substances requiring future pharmacological evaluation, the metabolism of these agents is also described. Finally, the preclinical behavioral actions of these two agents in a variety of behavioral assays, including rodent locomotor assays, self-administration studies, intracranial self-stimulation, conditioned place preference, and drug discrimination, is summarized. The results of these studies with MDPV and α-PVP are consistent with their acting as potent cocaine-like central stimulants with abuse liability.