Identification of Optimal Urinary Biomarkers of Synthetic Cannabinoids BZO-HEXOXIZID, BZO-POXIZID, 5F-BZO-POXIZID, and BZO-CHMOXIZID for Illicit Abuse Monitoring

Identification of phase-I and phase-II metabolites and the metabolic pathway of the novel synthetic cannabinoid 5F-EDMB-PICA in vitro

5F-EDMB-PICA is a newly emerged synthetic cannabinoid which has been characterized in relevant literature in recent years. Although phase-I metabolites of 5F-EDMB-PICA have been partly reported, the phase-II metabolism of this synthetic cannabinoid has not been studied yet. In this study, we established a phase-I and phase-II metabolism model in vitro by using pooled human liver microsomes, NADPH regeneration system, and UGT incubation system, with 1 mg/ml 5F-EDMB-PICA added and incubated at 37 °C for 60 min. The metabolites were analyzed by Q Exactive™ Hybrid Quadrupole-Orbitrap™ Mass Spectrometer, via which we discovered and identified 14 phase-I metabolites and 4 phase-II metabolites of 5F-EDMB-PICA, involving pathways such as ester hydrolysis, dehydrogenation, hydrolytic defluorination, hydroxylation, dihydroxylation, glucuronidation, and combinations of the pathways mentioned above. We recommend considering the monohydroxylation metabolites (M9, M10) with higher content and intact ester and 5-fluoropentyl structures as potential biomarkers of 5F-EDMB-PICA.

Five cases of unintentional exposure to BZO-4en-POXIZID among nightclub attendees in New York City

A new class of synthetic cannabinoids called OXIZIDs has emerged in recent years. This class consists of compounds with oxindole cores and hydrazide/hydrazone linker moieties and has often been described as being designed to circumvent a Chinese class-wide ban that was effective as of 1 July 2021. However, through hair testing of nightclub attendees in New York City-a high-risk population for recreational drug use-we have evidence suggesting exposures to an OXIZID called BZO-4en-POXIZID (4en-pentyl MDA-19) prior to the effective ban. Through analysis of 6 cm segmented hair samples from attendees collected in 2021, we detected five cases of exposure. Specifically, we detected a cluster of three cases based on hair samples collected on 20 June 2021, and then two additional cases from samples collected on 16 July 2021. Four of these hair samples were long enough to analyze two 6 cm hair segments (representing approximately two 6-month timeframes) and three of four of these cases tested positive for repeated exposure (for an estimated exposure over 6 months prior to hair collection). All cases included young adult females reporting past-year cannabis use but all tested negative for tetrahydrocannabinol exposure. Three cases also reported past-year use of cocaine, ecstasy, and/or ketamine, and four cases tested positive for exposure to cocaine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), methamphetamine and/or eutylone. These subjects were exposed to BZO-4en-POXIZID-likely as an adulterant in other drugs, and these cases are among the first documented cases which occurred approximately half a year before the Chinese legislative ban.

The metabolic profile of the synthetic cannabinoid receptor agonist ADB-HEXINACA using human hepatocytes, LC-QTOF-MS and synthesized reference standards

Synthetic cannabinoid receptor agonists (SCRAs) remain a major public health concern, with their use implicated in intoxications and drug-related deaths worldwide. Increasing our systematic understanding of SCRA metabolism supports clinical and forensic toxicology casework, facilitating the timely identification of analytical targets for toxicological screening procedures and confirmatory analysis. This is particularly important as new SCRAs continue to emerge on the illicit drug market. In this work, the metabolism of ADB-HEXINACA (ADB-HINACA, N-[1-amino-3,3-dimethyl-1-oxobutan-2-yl]-1-hexyl-1H-indazole-3-carboxamide), which has increased in prevalence in the United Kingdom and other jurisdictions, was investigated using in vitro techniques. The (S)-enantiomer of ADB-HEXINACA was incubated with pooled human hepatocytes over 3 hours to identify unique and abundant metabolites using liquid chromatography-quadrupole time-of-flight mass spectrometry. In total, 16 metabolites were identified, resulting from mono-hydroxylation, di-hydroxylation, ketone formation (mono-hydroxylation then dehydrogenation), carboxylic acid formation, terminal amide hydrolysis, dihydrodiol formation, glucuronidation and combinations thereof. The majority of metabolism took place on the hexyl tail, forming ketone and mono-hydroxylated products. The major metabolite was the 5-oxo-hexyl product (M9), while the most significant mono-hydroxylation product was the 4-hydroxy-hexyl product (M8), both of which were confirmed by comparison to in-house synthesized reference standards. The 5-hydroxy-hexyl (M6) and 6-hydroxy-hexyl (M7) metabolites were not chromatographically resolved, and the 5-hydroxy-hexyl product was the second largest mono-hydroxylated metabolite. The structures of the terminal amide hydrolysis products without (M16, third largest metabolite) and with the 5-positioned ketone (M13) were also confirmed by comparison to synthesized reference standards, along with the 4-oxo-hexyl metabolite (M11). The 5-oxo-hexyl and 4-hydroxy-hexyl metabolites are suggested as biomarkers for ADB-HEXINACA consumption.

Study of the Metabolic Profiles of "Indazole-3-Carboxamide" and "Isatin Acyl Hydrazone" (OXIZID) Synthetic Cannabinoids in a Human Liver Microsome Model Using UHPLC-QE Orbitrap MS

Unregulated core structures, "isatin acyl hydrazones" (OXIZIDs), have quietly appeared on the market since China legislated to ban seven general core scaffolds of synthetic cannabinoids (SCs). The fast evolution of SCs presents clinical and forensic toxicologists with challenges. Due to extensive metabolism, the parent compounds are barely detectable in urine. Therefore, studies on the metabolism of SCs are essential to facilitate their detection in biological matrices. The aim of the present study was to elucidate the metabolism of two cores, "indazole-3-carboxamide" (e.g., ADB-BUTINACA) and "isatin acyl hydrazone" (e.g., BZO-HEXOXIZID). The in vitro phase I and phase II metabolism of these six SCs was investigated by incubating 10 mg/mL pooled human liver microsomes with co-substrates for 3 h at 37 °C, and then analyzing the reaction mixture using ultrahigh-performance liquid chromatography-quadrupole/electrostatic field orbitrap mass spectrometry. In total, 9 to 34 metabolites were detected for each SC, and the major biotransformations were hydroxylation, dihydrodiol formation (MDMB-4en-PINACA and BZO-4en-POXIZID), oxidative defluorination (5-fluoro BZO-POXIZID), hydrogenation, hydrolysis, dehydrogenation, oxidate transformation to ketone and carboxylate, N-dealkylation, and glucuronidation. Comparing our results with previous studies, the parent drugs and SC metabolites formed via hydrogenation, carboxylation, ketone formation, and oxidative defluorination were identified as suitable biomarkers.

Advances in urinary biomarker research of synthetic cannabinoids

New psychoactive substances (NPS) are chemical compounds designed to mimic the action of existing illicit recreational drugs. Synthetic cannabinoids (SCs) are a subclass of NPS which bind to the cannabinoid receptors, CB1 and CB2, and mimic the action of cannabis. SCs have dominated recent NPS seizure reports worldwide. While urine is the most common matrix for drug-of-abuse testing, SCs undergo extensive Phase I and Phase II metabolism, resulting in almost undetectable parent compounds in urine samples. Therefore, the major urinary metabolites of SCs are usually investigated as surrogate biomarkers to identify their consumption. Since seized urine samples after consuming novel SCs may be unavailable in a timely manner, human hepatocytes, human liver microsomes and human transporter overexpressed cell lines are physiologically-relevant in vitro systems for performing metabolite identification, metabolic stability, reaction phenotyping and transporter experiments to establish the disposition of SC and its metabolites. Coupling these in vitro experiments with in vivo verification using limited authentic urine samples, such a two-pronged approach has proven to be effective in establishing urinary metabolites as biomarkers for rapidly emerging SCs.