Organ distribution of 4-MEC, MDPV, methoxetamine and α-PVP: comparison of QuEChERS and SPE

Fatal cases involving new psychoactive substances and trends in analytical techniques

New psychoactive substances (NPS) are an emerging public health issue and deaths are commonly associated with polydrug abuse. Moreover, the number of new substances available is constantly increasing, causing intoxications in low doses, characteristics that impose to toxicology and forensic laboratories to keep routine methods up to date, with high detectability and constantly acquiring new analytical standards. Likewise, NPS metabolites and respective elimination pathways are usually unknown, making it difficult the detection and confirmation of the drug involved in the fatal case in an analytical routine. A literature search was performed on PubMed, Scopus and Web of Science databases for papers related to chromatographic analyses from fatal cases related to NPS use published from 2016 to 2021. A total of 96 papers were retrieved and reviewed in this study. Opioids, synthetic cathinones, phenethylamines/amphetamines and cannabinoids were the NPS classes most found in the fatal cases. In many cases, multiple compounds were detected in the biological samples, including prescription and other illegal drugs. Liquid chromatography-tandem mass spectrometry, an alternative to overcome the gas chromatography-mass spectrometry limitations for some compounds, was the analytical technique most used in the studies, and high resolution mass spectrometry was often applied to NPS metabolite investigation and structural characterization and identification of unknown compounds. Toxicological screening and quantitation methods need to be continuously updated to include new substances that are emerging on the drug market that can be fatal at very low doses.

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.

Recent bionalytical methods for the determination of new psychoactive substances in biological specimens

One of the problems associated with the consumption of new psychoactive substances is that in most scenarios of acute toxicity the possibility of quick clinical action may be impaired because many screening methods are not responsive to them, and laboratories are not able to keep pace with the appearance of new substances. For these reasons, developing and validating new analytical methods is mandatory in order to efficiently face those problems, allowing laboratories to be one step ahead. The goal of this work is to perform a critical review regarding bionalytical methods that can be used for the determination of new psychoactive substances (phenylethylamines, cathinones, synthetic cannabinoids, opioids, benzodiazepines, etc), particularly concerning sample preparation techniques and associated analytical methods.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.

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.

Organ distribution of diclazepam, pyrazolam and 3-fluorophenmetrazine

The organ distribution of 3-fluorophenmetrazine (3-FPM), pyrazolam, diclazepam as well as its main metabolites delorazepam, lormetazepam and lorazepam, was investigated. A solid phase extraction (SPE) and a QuEChERS (acronym for quick, easy, cheap, effective, rugged and safe) - approach were used for the extraction of the analytes from human tissues, body fluids and stomach contents. The detection was performed on a liquid chromatography-tandem mass spectrometry system (LCMS/MS). The analytes of interest were detected in all body fluids and tissues. Results showed femoral blood concentrations of 10 μg/L for 3-FPM, 28 μg/L for pyrazolam, 1 μg/L for diclazepam, 100 μg/L for delorazepam, 6 μg/L for lormetazepam, and 22 μg/L for lorazepam. Tissues (muscle, kidney and liver) and bile exhibited higher concentrations of the mentioned analytes than in blood. Additional positive findings in femoral blood were for 2-fluoroamphetamine (2-FA, approx. 89 μg/L), 2-flourometamphetamine (2-FMA, hint), methiopropamine (approx. 2.2 μg/L), amphetamine (approx. 21 μg/L) and caffeine (positive). Delorazepam showed the highest ratio of heart (C) and femoral blood (P) concentration (C/P ratio = 2.5), supported by the concentrations detected in psoas muscle (430 μg/kg) and stomach content (approx. 210 μg/L, absolute 84 μg). The C/P ratio indicates that delorazepam displays susceptibility for post-mortem redistribution (PMR), supported by the findings in muscle tissue. 3-FPM, pyrazolam, diclazepam, lorazepam and lormetazepam did apparently not exhibit any PMR. The cause of death, in conjunction with autopsy findings was concluded as a positional asphyxia promoted by poly-drug intoxication by arising from designer benzodiazepines and the presence of synthetic stimulants.

[A Forensic Autopsy Case in which Sulpiride and Estazolam Were Detected in an Adipoceratous Cadaver by LC-MS/MS]

We had a forensic autopsy case in which drugs were detected in a cadaver that had been stored in a cold and wet condition for 5 years. The skin of the cadaver was hard, and the color was partly whitish or dark brown. Though the cadaver had transformed into adipocere in the wet and cold condition, QuEChERS extraction and LC-MS/MS revealed the presence of sulpiride and estazolam in the femoral muscle and bone marrow. The concentrations of sulpiride and estazolam in the femoral muscle were 10.6 ng/g and 39.9 ng/g, respectively. The result of a drug screening test led not only to the cause of death but also to the personal identification of the cadaver. The individual had a history of drug taking, which had been stored in his medical records at the hospital for a long time. The fact of taking sulpiride and estazolam at the same time was characteristic, and it was useful in identifying the cadaver in this case. The progress in analytical technology has made possible the detection of particle drugs from old or adipoceratous cadavers, but there have been no reports of particle drugs being detected in a cadaver that had been dead for 5 years and had transformed to adipocere, as in our present case. The analytical results by LC-MS/MS were certainly important for the diagnosis of the cause of death, and, moreover, they were useful for the purpose of personal identification.

Post-mortem distribution of the synthetic cannabinoid MDMB-CHMICA and its metabolites in a case of combined drug intoxication

This case report centres on the post-mortem distribution of the synthetic cannabinoid MDMB-CHMICA and its metabolites in the case of a 27-year-old man found dead after falling from the 24th floor of a high-rise building. Toxicological analysis of post-mortem samples confirmed, besides consumption of the synthetic cannabinoids MDMB-CHMICA (1.7 ng/mL femoral blood) and EG-018, the abuse of THC (9.3 ng/mL femoral blood), amphetamine (1050 ng/mL femoral blood), MDMA (275 ng/mL femoral blood), and cocaine. Regarding EG-018 and cocaine, only traces were detected in heart blood as well as in the brain (EG-018) and urine (cocaine), respectively, which is why no quantification was conducted in the femoral blood sample. It was concluded from femoral blood analysis that, at the time of death, the man was under the influence of the synthetic cannabinoid MDMB-CHMICA, THC, amphetamine and MDMA. Comprehensive screenings of all post-mortem specimens were conducted to elucidate the post-mortem distribution of MDMB-CHMICA and its metabolites. The MDMB-CHMICA concentrations ranged between 0.01 ng/mL (urine) and 5.5 ng/g (brain). Comparably low concentrations were detected in cardiac and femoral blood (2.1 ng/mL and 1.7 ng/mL, respectively) as well as in the psoas major muscle (1.2 ng/g). Higher concentrations were found in the lung (2.6 ng/g), liver (2.6 ng/g), and kidney (3.8 ng/g). Gastric content yielded a MDMB-CHMICA concentration of 2.4 ng/g (1.1 μg absolute). Screening for MDMB-CHMICA metabolites resulted in the detection of mainly monohydroxylated metabolites in the blood, kidney, and liver specimens. Results indicated that monohydroxylated metabolites of MDMB-CHMICA are appropriate target analytes for detecting MDMB-CHMICA intake.