Postmortem distribution of α-pyrrolidinovalerophenone and its metabolite in body fluids and solid tissues in a fatal poisoning case measured by LC–MS–MS with the standard addition method

Postmortem findings of organ damage in novel psychoactive substances users: A comprehensive review

INTRODUCTION

Despite the rising number of NPS-related deaths, comprehensive data on their prevalence, identification, and associated organ damage remain scarce.

MATERIALS AND METHODS

A literature search was conducted. Predefined inclusion and exclusion criteria were applied, resulting in the identification of 197 articles.

RESULTS

We identified 446 cases of NPS-related deaths, involving a total of 176 different substances. Synthetic opioids were the most prevalent class (34 %), followed by synthetic cannabinoids (22 %) and cathinones (21 %). Co-ingestion of NPS with other substances occurred in 77 % of cases. Macroscopic findings varied across organs, with congestion and edema most observed in the brain (23 %) and lung (56 %), respectively.

DISCUSSION

The existing literature lacks comprehensive descriptions of organs subjected to autopsy and histological examination in NPS-positive subjects. Despite this limitation, our findings underscore the prominence of lung pathology. Moreover, the prevalence of normal organs in cases of acute intoxication is a significant observation. We advocate for future research to provide more detailed insights to enhance our understanding of the multifaceted landscape of NPS-related deaths.

Quantification of mycolic acids in different mycobacterial species by standard addition method through liquid chromatography mass spectrometry

Mycobacteria possess unique and robust lipid profile responsible for their pathogenesis and drug resistance. Mycolic acid (MA) represents an attractive diagnostic biomarker being absent in humans, inert and known to modulate host-pathogen interaction. Accurate measurement of MA is significant to design efficient therapeutics. Despite considerable advances in Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) based approaches, quantification of mycobacterial lipids including MA is still challenging mainly because of ion suppression effects due to complex matrix and non-availability of suitable internal standards for MA. The current study demonstrates the use of standard addition method (SAM) to circumvent this problem and provides a reliable and exhaustive analytical method to quantify mycobacterial MA based on reversed-phase ultra-high-performance liquid chromatography- mass spectrometry data acquisition. In this method, multiple reaction monitoring (MRM) has been applied, wherein 16 MRM channels or transitions have been chosen for quantification of alpha-, methoxy- and keto-MAs with C-24 and C-26 hydrocarbon chains that are actually best suited for TB diagnostics. We found that the overall methodological limit of detection and limit of quantification were in the range 0.05-0.71 ng/µl and 0.16-2.16 ng/µl. Taken together, SAM quantitative technique could serve as promising alternative for relative concentration determination of MA to aid medical research.

In vitro, in vivo metabolism and quantification of the novel synthetic opioid N-piperidinyl etonitazene (etonitazepipne)

OBJECTIVES

N-piperidinyl etonitazene (etonitazepipne) is a newly synthesized opioid related to the 2-benzylbenzimidazole analog class. Etonitazepipne has been formally notified and placed under intensive monitoring in Europe in January 2022. Nitazenes have high affinity at µ-opioid receptor (MOR). Etonitazepipne, specifically shows a EC50 of 2.49 nM, suggesting about 50 times higher potency combined with higher efficacy compared to morphine. Antinociceptive potency l ('hot plate test' with rats) was 192-fold greater than that of morphine.

METHODS

Here we report on a post-mortem case involving etonitazepipne and its quantification using a standard addition method (SAM) through liquid chromatography tandem mass spectrometry (LC-MS/MS). In addition, characterization and identification of phase I human metabolites using in vitro assay based on pooled human liver microsomes (pHLM) was performed along with the analysis of authentic urine samples by means of high-performance liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS).

RESULTS

The concentration of etonitazepipne in post-mortem blood and urine was 8.3 and 11 ng/mL, respectively. SAM was validated by assessing the following parameters: intraday and interday repeatability, matrix effect and recovery rate in post-mortem blood. A total of 20 and 14 metabolites were identified after pHLM incubation and urine analysis, respectively. Most pronounced in vitro and in vivo transformations were O-deethylation, hydroxylation, ketone reduction, and combinations thereof.

CONCLUSIONS

Considering small traces of the parent drug often found in real cases, the identification of metabolic biomarkers is crucial to identify exposure to this drug. O-deethylated, oxidated metabolites, and combination thereof are proposed as urinary biomarkers along with the parent compound.

Identification and quantification of diphenhydramine, haloperidol, and its metabolite, reduced haloperidol in a saponified brain specimen that was immersed in the sea water for more than 10 years

In forensic toxicology, blood and urine specimens are commonly used for detecting and quantifying drugs and their metabolites. When the cadaver is so damaged or decomposed such that the specimens mentioned above cannot be collected, it is necessary to perform drug analysis using alternative specimens such as hair, nails, oral fluids and meconium. Adipocere is resistant to further degradation; it is thus possible to be used as an alternative specimen to analyze drugs and their metabolites. Some researchers indeed have reported drug concentrations in saponified samples that were collected years after decedents' deaths. In this study, we subjected saponified brain, which remained under sea for over 10 years after death, to forensic toxicological analysis using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Using product ion scan analysis, we confirmed the presence of diphenhydramine, haloperidol, and reduced haloperidol, a metabolite of haloperidol. In addition, drugs and metabolite quantification were performed using the standard addition method. Correlation coefficients of the calibration curves were over 0.98. Analyte concentrations in the saponified brain were as follows: diphenhydramine was 1.84 ng/g, haloperidol was 1.30 ng/g, and reduced haloperidol was 3.02 ng/g. Our results suggest that it can be possible to quantify not only parent drugs but also their metabolites in saponified brain. These findings indicate that saponified tissues could be applied as alternative specimens for forensic toxicology, and could be useful as supporting information for victim identification.

A Review on Spike and Recovery Method in Analytical Method Development and Validation

In multidisciplinary science, Analytical approaches based on spike and recovery (SAR) play a substantial role in analytical testing. The spike and recovery method is an important technique for analyzing and accessing the accuracy of analytical methods. The goal of this review seeks to provide clarity on the role of SAR methods in the forensic science discipline. Recent literature has been searched from numerous databases like Google, Web of Sciences, Scopus, PubMed, Google Scholar, and SciFinder. Websites like Science Direct are critically explored to gather scientific reports related to SAR utility. This review discusses the applications and current role of the SAR methods in Forensic Toxicology. It is suggested as one of the major parameters in the validation of the analytical method. SAR methodology is extremely important for the identification and quantitation of analytes in the sample matrix. Moreover, the extension of SAR methods to any scientific discipline is equally important for quality assurance. All relevant processes like method development and its optimization, quality control, and assurance rely on SAR-based studies. However, the method requires better apprehension and needs to be utilized using standard guidelines.

Overview, consequences, and strategies for overcoming matrix effects in LC-MS analysis: a critical review

The high-performance liquid chromatography-mass spectrometry (LC-MS) technique is widely applied to routine analysis in many matrices. Despite the enormous application of LC/MS, this technique is subjected to drawbacks called matrix effects (MEs) that could lead to ion suppression or ion enhancement. This phenomenon can exert a deleterious impact on the ionization efficacy of an analyte and subsequently on the important method performance parameters. LC-MS susceptibility to MEs is the main challenge of this technique in the analysis of complex matrices such as biological and food samples. Nowadays, the assessment, estimation, and overcoming of the MEs before developing a method is mandatory in any analysis. Two main approaches including the post-column infusion and post-extraction spike are proposed to determine the degree of MEs. Different strategies can be adopted to reduce or eliminate MEs depending on the complexity of the matrix. This could be done by improving extraction and clean-up methods, changing the type of ionization employed, optimization of liquid chromatography conditions, and using corrective calibration methods. This review article will provide an overview of the MEs as the Achilles heel of the LC-MS technique, the causes of ME occurrence, their consequences, and systemic approaches towards overcoming MEs during LC-MS-based multi-analyte procedures.

Detection of 4-FMC, 4-MeO-α-PVP, 4-F-α-PVP, and PV8 in blood in a forensic case using liquid chromatography-electrospray ionization linear ion trap mass spectrometry

We present a case of fatal poisoning by 4-F-methcathinone (4-FMC; also called flephedrone), 4-methoxy-α-pyrrolidinopentiophenone (4-MeO-α-PVP), 4-fluoro-α-pyrrolidinopentiophenone (4-F-α-PVP), and α-pyrrolidinohepatanophenone (PV8). In this study, we compared the mass spectra of 4-FMC, 4-MeO-α-PVP, 4-F-α-PVP, PV8, and α-pyrrolidinohexanophenone between LC-ESI-LIT-MS and GC-EI-MS analyses. Subsequently, we applied LC-ESI-LIT-MS for detection and quantification analyses of 4-FMC, 4-MeO-α-PVP, 4-F-α-PVP, and PV8 in human authentic whole blood samples. More specific mass spectra for the target compounds were obtained with the LC-ESI-LIT-MS qualitative analyses than with the GC-EI-MS analyses, indicating that LC-ESI-LIT-MS was more suitable for the qualitative analysis of cathinones. The LC-ESI-LIT-MS validation data showed moderately good linearity and reproducibility for the compounds in the quantitative analyses at the range of 1-500 ng/mL. The detection limits of four cathinones ranged from 0.1 to 1 ng/mL. The concentrations of 4-FMC, 4-MeO-α-PVP, 4-F-α-PVP, and PV8 in heart whole blood samples were 365, 449, 145, and 218 ng/mL, respectively. Those of the 4 cathinones in femoral vein whole blood samples were 397, 383, 127, and 167 ng/mL, respectively. We can then assume that the cause of death was acute poisoning by a combination of 4-FMC, 4-MeO-α-PVP, 4-F-α-PVP, and PV8. In this article, we present a detailed LC-ESI-LIT-MS procedure for detection and quantification analyses of 4-FMC, 4-MeO-α-PVP, 4-F-α-PVP, and PV8 in authentic human whole blood samples.

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.

The standard addition method and its validation in forensic toxicology

Purpose

In the quantitative forensic toxicological analyses using instruments, major methods to be employed are conventional matrix-matched calibration method (MMCM). However, nowadays, the needs for using the standard addition methods (SAM) are increasing. In spite of this situation, there are no reports of the guidelines for the validations of SAM. In this review, the principle, how to perform it, advantages, disadvantages, reported application data, and the details of validation procedures for the SAM are described.

Methods

Various databases such as SciFinder, Google and Google Scholar were utilized to collect relevant reports referring to the SAM. The long experiences of our research group on the SAM were also included in this review.

Results

Although the experimental procedures for the SAM are much more laborious than those of the MMCM, the SAM is essential to quantify target xenobiotic(s) in special matrices such as human solid tissues or biles, which remarkably interfere with the usual quantitative analyses. The validation methods for the SAM have been also proposed for the cases in the absence of the blank matrices.

Conclusions

To our knowledge, this is the first presentation of detailed SAM procedure and its validation, which will facilitate the use of the SAM in forensic toxicology. Especially for its validation, new simple methods have been proposed.

Flakka: New Dangerous Synthetic Cathinone on the Drug Scene

New psychoactive substances are being used as drugs and appear to be quite popular nowadays. Thanks to their specific properties, these drugs create inimitable experiences for intoxicated people. Synthetic cathinones are the most common compounds in these new drugs. Among them, α-pyrrolidopentadione (α-PVP), or “Flakka” (street name), is one of the most famous cathinone-designed drugs. Similar to other synthetic cathinone drugs, α-PVP can effectively inhibit norepinephrine and dopamine transmitters. The adverse reactions of α-PVP mainly include mania, tachycardia, and hallucinations. An increasing number of people are being admitted to emergency wards due to the consequences of their use. This work mainly summarizes the history, synthesis, pharmacology, toxicology, structure–activity relationship, metabolism, clinical process and health risks, poisoning and death, forensic toxicology, and legal status of α-PVP. We hope this review will help bring more attention to the exploration of this substance in order to raise awareness of its negative impacts on humans.

Postmortem distribution/redistribution of buformin in body fluids and solid tissues in an autopsy case using liquid chromatography-tandem mass spectrometry with QuEChERS extraction method

An autopsy for a suicidal case of a male in his 40s, who had died of poisoning due to ingestion of a large amount of buformin, was performed at our department. Buformin is biganide class agent used for patients of diabetes mellitus, which can occasionally cause severe lactic acidosis. The autopsy was performed about 10 days after his death, and the direct cause of his death was judged as asphyxia due to the aspiration of stomach contents into the airway. The nine body fluids and eight solid tissues specimens were dealt with for investigating postmortem distribution/redistribution of buformin in a whole body; femoral vein blood, right and left heart blood, pericardial fluid, urine, bile, stomach contents, small intestine contents, cerebrospinal fluid, the brain, lung, heart muscle, liver, spleen, kidney and skeletal muscle were examined. For extracting buformin from specimens, a modified QuEChERS method including dispersive solid-phase extraction was employed, followed by the analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS). Buformin in various kinds of human matrices were quantified by the standard addition method in this study, which can overcome the matrix effects and recovery rates without use of blank human matrices. All concentrations of buformin in specimens examined in this case were extremely higher than those of previously reported poisoning cases. The concentrations of buformin in left and right heart blood and femoral vein blood specimens of this case were 399, 216 and 261μg/mL, respectively; although the direct cause of his death was judged as asphyxia due to occlusion of airway with stomach contents, the vomiting was thought to be provoked by buformin poisoning. In this study, marked differences of buformin concentrations between brain tissue and cerebral spiral fluids, and other specimens were observed, which suggested that its distribution was influenced also by blood-brain-barrier. Although a number of buformin poisoning cases were published so far, they gave sporadic data on its concentrations and/or distribution in some limited human specimens. This study is the first to describe detailed distribution/redistribution of buformin in a whole human body quantified by using LC-MS/MS.

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.

Time- and temperature-dependent postmortem concentration changes of the (synthetic) cannabinoids JWH-210, RCS-4, as well as ∆9-tetrahydrocannabinol following pulmonary administration to pigs

In forensic toxicology, interpretation of postmortem (PM) drug concentrations might be complicated due to the lack of data concerning drug stability or PM redistribution (PMR). Regarding synthetic cannabinoids (SC), only sparse data are available, which derived from single case reports without any knowledge of dose and time of consumption. Thus, a controlled pig toxicokinetic study allowing for examination of PMR of SC was performed. Twelve pigs received a pulmonary dose of 200 µg/kg BW each of 4-ethylnaphthalene-1-yl-(1-pentylindole-3-yl)methanone (JWH-210), 2-(4-methoxyphenyl)-1-(1-pentyl-indole-3-yl)methanone (RCS-4), and Δ9-tetrahydrocannabinol via an ultrasonic nebulizer. Eight hours after, the pigs were put to death with T61 and specimens of relevant tissues and body fluids were collected. Subsequently, the animals were stored at room temperature (n = 6) or 4 °C (n = 6) and further samples were collected after 24, 48, and 72 h each. Concentrations were determined following enzymatic cleavage and solid-phase extraction by liquid-chromatography tandem mass spectrometry applying the standard addition approach. High concentrations of the parent compounds were observed in lung, liver, kidney and bile fluid/duodenum content as well as brain. HO-RCS-4 was the most prevalent metabolite detected in PM specimens. In general, changes of PM concentrations were found in every tissue and body fluid depending on the PM interval as well as storage temperature.

Hazard Characterization of Synthetic Cathinones Using Viability, Monoamine Reuptake, and Neuronal Activity Assays

Synthetic cathinones are the second largest class of new psychoactive substances (NPS) on the drug market. Despite the large number of different cathinones and their abundant use, hazard characterization is mainly limited to their potential to inhibit monoamine transporters. To expand the current hazard characterization, we first investigated the acute effects of several synthetic cathinones [4-methylethcathinone (4-MEC), 3-methylmethcathinone (3-MMC), 4-MMC, methylone, pentedrone, α-pyrrolidinovalerophenone (α-PVP), and 3,4-methylenedioxypyrovalerone (MDPV)] on human dopamine, norepinephrine, and serotonin reuptake transporters (hDAT, hNET, and hSERT), which were stably transfected in human embryonic kidney (HEK) 293 cells. Next, we examined effects on spontaneous neuronal activity in rat primary cortical cultures grown on microelectrode arrays (MEAs) as an integrated endpoint for neurotoxicity. Changes in neuronal activity were assessed after acute (30 min) and prolonged (4.5 h) exposure. Moreover, we investigated whether neuronal activity recovered after washout of the exposure (24 h after the start of the 5 h exposure). Low micromolar concentrations of synthetic cathinones inhibited monoamine uptake via hDAT and hNET, while higher cathinone concentrations were needed to inhibit uptake via hSERT. Comparable high concentrations were needed to inhibit spontaneous neuronal activity during acute (30 min) and prolonged (4.5 h) exposure. Notably, while the inhibition of neuronal activity was reversible at low concentrations, only partial recovery was seen following high, but non-cytotoxic, concentrations of synthetic cathinones. Synthetic cathinones with either a pyrrolidine moiety or long alkyl-tail carbon chain more potently inhibit monoamine uptake via hDAT and neuronal activity. Monoamine uptake via hNET was most potently inhibited by synthetic cathinones with a pyrrolidine moiety. The combination of integrated measurements (MEA recordings of neuronal activity) with single target assays (monoamine reuptake transporter inhibition) indicates inhibition of hDAT and hNET as the primary mode of action of these synthetic cathinones. Changes in neuronal activity, indicative for additional mechanisms, were observed at higher concentrations.

Simultaneous Quantification of the New Psychoactive Substances 3-FMC, 3-FPM, 4-CEC, and 4-BMC in Human Blood using GC-MS

A gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of 3-fluoromethcathinone (3-FMC), (±)-3-fluorophenmetrazine (3-FPM), 4-chloroethcathinone (4-CEC) and 4-Bromomethcathinone (4-BMC) in human blood with (±)-methcathinone-D3 as internal standard has been developed and validated. Whole blood samples were treated with 10% trichloroacetic acid for protein precipitation before solid phase extraction. The method was selective, the calibration curves showed linearity for all substances with R2 ranging from 0.991 to 0.998 in the range 5-1.000 ng/mL. Analysis of blank samples showed no-sign of carryover. Precision and accuracy were acceptable with values less than 20% (RSD) and ± 20% (Bias). The limit of quantification (LOQ) for all substances was 5ng/mL. Intra-day and inter-day precision were 2.111.7% and 1.3 -10.2% respectively and accuracy biases were between -10.6-19.6% % (intra-day) and 11-12.1% (inter-day). The extraction efficiencies were 85.4, 82.8, 79.1 and 74.9% for 3-FMC, 3-FPM, 4-CEC and 4-BMC respectively.

A robust and reliable simultaneous quantification method using gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS-SIM) is reported.

Death cases involving certain new psychoactive substances: A review of the literature

In the last decades, more and more new psychoactive substances (NPS) were introduced on the drug market which were sold as "legal" alternatives for classic drugs and misused medications. Due to an increased number of available substances and a growing utilization by users of common drugs but also by inexperienced users because of the supposed "legal" status, also undesired adverse effects of these NPS, at worst leading to death, became apparent. This review summarizes fatalities previously described in scientific literature which were attributed to the use of NPS or such cases, in which intake of NPS was proven or even assumed to contribute to death. This summary includes an overview of substances involved (particularly synthetic cannabinoids ("spice"), novel opioids and synthetic cathinones ("bath salts")) as well as of postmortem concentrations determined in various biological matrices. The compiled data assist forensic toxicologists with the interpretation of death cases involving NPS.

DARK Classics in Chemical Neuroscience: α-Pyrrolidinovalerophenone ("Flakka")

Flakka (alpha-pyrrolidinovalerophenone, α-PVP) is a new psychoactive substance, chemically close to cathinone, the primary psychoactive alkaloid of khat ( Catha edulis). Like other synthetic cathinones, α-PVP is a potent inhibitor of the dopamine and norepinephrine transporters. Its robust clinical effects include hallucinations, arousal, aggression/violence, and euphoria. In animal models, α-PVP evokes hyperlocomotion and aberrant/stereotypic behaviors. Here, we discuss the history, synthesis, pharmacological mechanisms, metabolism, abuse potential, and societal impact of α-PVP. Today, α-PVP is a tightly controlled substance, currently banned in the United States and other countries worldwide. However, the growing abuse and complex central nervous system (CNS) effects of α-PVP remain poorly understood, necessitating further pharmacological and pharmacogenetic studies of this drug. Its interesting pharmacological profile (co-inhibition of dopamine and norepinephrine, but not serotonin, transporters) also calls for further studies of α-PVP in animal models, to dissect serotonergic from other monoaminergic mechanisms of action of drugs of abuse. Finally, screening α-PVP and related compounds in vivo may foster discovery of new CNS drugs, including developing novel CNS drugs and identifying their molecular targets.

Toxicokinetics of the Synthetic Cathinone α-Pyrrolidinohexanophenone

Synthetic cathinones inhibit monoamine transporters, such as serotonin, norepinephrine, and dopamine transporters, and act on the central nervous system via increasing synaptic concentrations of monoamines. These compounds, which are highly addictive and potentially poisonous, are new psychoactive substances. In this study, we investigated the toxicokinetics of the synthetic cathinone, α-pyrrolidinohexanophenone (α-PHP), and assessed the relationship between the toxicokinetics and the long-term clinical symptoms induced by α-PHP in a male patient. The patient (39 years old) suddenly started uttering inarticulate words and demonstrating incomprehensible behavior in his house, and was brought to the emergency department of Iwate Medical University hospital. He presented with psychotic symptoms, such as hallucinations and delusion; however, his vital signs were normal. The hallucinations and delusion improved by the third day of hospitalization. Toxicological analysis was performed using liquid chromatography-tandem mass spectrometry with QuEChERS extraction. α-PHP was detected in his serum at a concentration of 175 ng/mL on his arrival at the hospital. His serum concentrations of α-PHP were serially determined and their natural logarithms were plotted against time after arrival. Although serum concentrations at early time points were lacking, the obtained curve was consistent with a two-compartment model and indicated a serum elimination half-life of 37 h. The long-lasting psychotic symptoms induced by synthetic cathinones appear to be correlated with their toxicokinetic characteristics, such as their long half-lives. Finally, interpreting the toxicokinetics of synthetic cathinones may provide useful information for the toxicological assessment of new psychoactive substances for forensic and clinical purposes.

Postmortem distribution of mepirapim and acetyl fentanyl in biological fluid and solid tissue specimens measured by the standard addition method

Purpose

Mepirapim is a new synthetic cannabinoid. We previously reported that the concentrations of unchanged mepirapim in whole blood and urine were much higher than those of other synthetic cannabinoids. To determine the postmortem distribution of mepirapim and acetyl fentanyl in the deceased individual, we established a standard addition method for detailed analysis by liquid chromatography–mass spectrometry (LC–MS) for quantification of these drugs.

Methods

The LC–MS method was fully validated for linearity, extraction recovery, matrix effect and repeatability.

Results

Good linearities, extraction recoveries, matrix effects and repeatabilities were shown for both target compounds in all specimens. The concentrations of mepirapim and acetyl fentanyl in three body fluid specimens and 12 solid tissue specimens were measured. For mepirapim, the highest concentrations were found in the liver and kidney, and the concentrations in the blood and urine specimens were one order of magnitude lower than the high concentrations in the solid tissues except the psoas major muscle. For acetyl fentanyl, the highest concentrations were found in the myocardium, spleen and kidney, and the concentrations in the body fluid specimens were also one order of magnitude lower than the highest concentrations in the solid tissues. There were concentration differences of mepirapim and acetyl fentanyl among the regions of the brain.

Conclusions

The concentration of unchanged mepirapim in urine was much higher than those of other synthetic cannabinoids; the higher dosage, urinary excretion, metabolisms and/or pharmacokinetics of mepirapim may be quite different from those of other synthetic cannabinoids.

Fatal case of poisoning with a new cathinone derivative: α-propylaminopentiophenone (N-PP)

PURPOSE

Similar to synthetic cannabinoids, synthetic cathinone derivatives are the most popular compounds among novel psychoactive substances. Along with a growing number of new cathinones, the number of consumers wishing to enrich their experience with these compounds is also growing, and the same can be said about the growing numbers of poisonings. The reason for overdosing is a lack of consumer awareness regarding composition of the product, with which they experiment, and even more, regarding concentration of psychoactive substances contained in the taken product. In this paper, we report a case of the purposeful intake of a high dose of powder containing a novel cathinone derivative, α-propylaminopentiophenone, which resulted in the deadly poisoning of a woman.

METHODS

Aiming to identify this psychoactive substance causing the fatality, the postmortem specimens collected from the autopsy was analyzed by means of high-performance liquid chromatography coupled with mass spectrometry, and the analysis of a powder material found with the victim was additionally analyzed by means of gas chromatography with mass spectrometric detection.

RESULTS

In the course of analysis performed on the specimens originating from autopsy (blood, eyeball fluid, liver, kidney and brain), high concentrations of α-propylaminopentiophenone were established, which was responsible for the death of a young woman. The same psychoactive compound was also identified in the powder material.

CONCLUSIONS

To the best of the authors' knowledge, this is the first case reported in the literature on fatal poisoning with α-propyloaminopentiophenone.

High-throughput determination of valproate in human samples by modified QuEChERS extraction and GC-MS/MS

A new high-throughput method was developed for analysis of valproate in human plasma samples by QuEChERS extraction and gas chromatography-tandem mass spectrometry (GC-MS/MS). Plasma samples (0.2 ml) spiked with valproate and secobarbital-d₅ (internal standard) were diluted with 1.3 ml of distilled water. Acetonitrile (1 ml) was added followed by 0.4 g MgSO₄ and 0.1 g NaOAC. After a centrifugation step (2000 g for 10 min), 1 ml of the supernatant was transferred to a dispersive-solid phase extraction (dSPE) tube containing 150 mg MgSO₄ and 50 mg C₁₈. This mixture was vortexed and centrifuged at 3000 g for 5 min, and then the upper layer was evaporated to dryness under a stream of nitrogen. The residue was dissolved in 40 μl ethyl acetate, and a 1-μl aliquot was injected into the GC-MS/MS. The GC separation of the compounds was achieved on a fused-silica capillary column Rxi-5Sil MS (30 m × 0.25 mm i.d.; 0.25-µm film thickness) and detected by MS/MS operating in electron ionization ion source mode. The regression equations showed excellent linearity (r > 0.9997) from 50 to 5000 ng/ml for plasma, with limit of detection of 10 ng/ml. The extraction efficiency of valproate for plasma ranged between 71.2%-103.5%. The coefficient of variation was <18.5%. The method was successfully applied to actual analyses of an autopsy case. This method can be useful for simple and reliable measurements of valproate in clinical and toxicological analyses; it can be integrated in screening and simultaneous determination methods for multiple drugs and poisons in the further studies.

Fatal Poisonings Associated with New Psychoactive Substances

This chapter describes how new psychoactive substances (NPS) have been involved in fatal intoxications from 2010 and onwards. It summarizes the circumstances, antemortem symptoms, and adverse effects that have led to death after ingestion of one or more NPS and tabulates concentrations, and postmortem findings from these intoxications.Consumption of NPS exerts health problems and unknown risks for the users. Data on toxicity of many NPS are scarce or nonexistent and long-term toxicity and risks are still largely unknown. In addition, purity and composition of products containing NPS are often inconsistent or not known, which places users at high risk as evidenced by hospital emergency admissions and deaths.The most serious threat to drug users are the synthetic opioids that with strong central nervous depressant effects have caused numerous accidental deaths spread over the entire globe. The synthetic cannabinoids seem to be the most unpredictable with no clear toxidrome and unknown or poorly understood mechanisms of toxicity, but with adverse effects pointing toward the cardiovascular system. The toxidromes commonly encountered after ingestion of cathinones and phenethylamines are of sympathomimetic and hallucinogenic character, which includes risk of developing a serotonin syndrome, excited delirium, and life-threatening cardiovascular effects. In comparison to their conventional "parent" drug, i.e., heroin, cannabis, and amphetamine, most NPS appear to exhibit more severe adverse effects. The deaths attributed to NPS have dramatically increased in the last years. In our opinion, this is because of the shift from synthetic cannabinoids and cathinones to the even more toxic and dangerously potent fentanyl analogues.

Effect fingerprinting of new psychoactive substances (NPS): What can we learn from in vitro data?

The use of new psychoactive substances (NPS) is increasing and currently >600 NPS have been reported. However, limited information on neuropharmacological and toxicological effects of NPS is available, hampering risk characterization. We reviewed the literature on the in vitro neuronal modes of action to obtain effect fingerprints of different classes of illicit drugs and NPS. The most frequently reported NPS were selected for review: cathinones (MDPV, α-PVP, mephedrone, 4-MEC, pentedrone, methylone), cannabinoids (JWH-018), (hallucinogenic) phenethylamines (4-fluoroamphetamine, benzofurans (5-APB, 6-APB), 2C-B, NBOMes (25B-NBOMe, 25C-NBOMe, 25I-NBOMe)), arylcyclohexylamines (methoxetamine) and piperazine derivatives (mCPP, TFMPP, BZP). Our effect fingerprints highlight the main modes of action for the different NPS studied, including inhibition and/or reversal of monoamine reuptake transporters (cathinones and non-hallucinogenic phenethylamines), activation of 5-HT₂receptors (hallucinogenic phenethylamines and piperazines), activation of cannabinoid receptors (cannabinoids) and inhibition of NDMA receptors (arylcyclohexylamines). Importantly, we identified additional targets by relating reported effect concentrations to the estimated human brain concentrations during recreational use. These additional targets include dopamine receptors, α- and β-adrenergic receptors, GABA_Areceptors and acetylcholine receptors, which may all contribute to the observed clinical symptoms following exposure. Additional data is needed as the number of NPS continues to increase. Also, the effect fingerprints we have obtained are still incomplete and suffer from a large variation in the reported effects and effect sizes. Dedicated in vitro screening batteries will aid in complementing specific effect fingerprints of NPS. These fingerprints can be implemented in the risk assessments of NPS that are necessary for eventual control measures to reduce Public Health risks.

Measuring inhibition of monoamine reuptake transporters by new psychoactive substances (NPS) in real-time using a high-throughput, fluorescence-based assay

The prevalence and use of new psychoactive substances (NPS) is increasing and currently over 600 NPS exist. Many illicit drugs and NPS increase brain monoamine levels by inhibition and/or reversal of monoamine reuptake transporters (DAT, NET and SERT). This is often investigated using labor-intensive, radiometric endpoint measurements. We investigated the applicability of a novel and innovative assay that is based on a fluorescent monoamine mimicking substrate. DAT, NET or SERT-expressing human embryonic kidney (HEK293) cells were exposed to common drugs (cocaine, dl-amphetamine or MDMA), NPS (4-fluoroamphetamine, PMMA, α-PVP, 5-APB, 2C-B, 25B-NBOMe, 25I-NBOMe or methoxetamine) or the antidepressant fluoxetine. We demonstrate that this fluorescent microplate reader-based assay detects inhibition of different transporters by various drugs and discriminates between drugs. Most IC₅₀ values were in line with previous results from radiometric assays and within estimated human brain concentrations. However, phenethylamines showed higher IC₅₀ values on hSERT, possibly due to experimental differences. Compared to radiometric assays, this high-throughput fluorescent assay is uncomplicated, can measure at physiological conditions, requires no specific facilities and allows for kinetic measurements, enabling detection of transient effects. This assay is therefore a good alternative for radiometric assays to investigate effects of illicit drugs and NPS on monoamine reuptake transporters.

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.

Clinical characteristics of α-pyrrolidinovalerophenone (α-PVP) poisoning

CONTEXT

α-Pyrrolidinovalerophenone (α-PVP) is a synthetic cathinone that has been abused in recent years. The clinical presentation of acute α-PVP poisoning has not been well characterized.

OBJECTIVE

To elucidate the clinical features of acute α-PVP poisoning.

MATERIALS AND METHODS

This retrospective case series included eight subjects that visited our hospital emergency department (ED) between March 2012 and November 2014 and had analytically confirmed blood α-PVP levels. Data related to subject demographics, clinical history, laboratory findings, blood drug levels, and outcome were collected.

RESULTS

The median age of the eight study subjects was 27 (range; 21-63) years, and six were male. Drug preparations had been administered by rectal insertion (three subjects) or inhalation (five subjects). The time between drug exposure and presentation at the ED was 8.5 (1-24) h and blood α-PVP concentrations ranged from 1.0 to 52.5 ng/ml. Although psychiatric and neurological findings were reported before arrival at the ED in 5/8 and 7/8 subjects, respectively, these were only observed in 1/8 and 2/8 subjects, respectively, at the ED. Symptoms of high body temperature (3/8), tachycardia (5/8), hypertension (3/8), acid-base balance disorder (5/8), coagulopathy (4/6), blood creatinine phosphokinase >190 U/l (6/8), and a blood lactate level > 1.7 mmol/l (5/7) were observed. All subjects survived and were discharged.

CONCLUSIONS

This retrospective case series showed that after acute exposure to α-PVP, transient neuropsychiatric findings were accompanied by more persistent sympathomimetic physical findings, disorders of acid-base balance and blood coagulation, high blood creatinine phosphokinase, and hyperlactacidemia.

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.