One of the main challenges posed by the emergence of new psychoactive substances is their identification in human biological samples. Trying to detect the parent drug could lead to false-negative results when the delay between consumption and sampling has been too long. The identification of their metabolites could then improve their detection window in biological matrices. Oxidative metabolism by cytochromes P450 and glucuronidation are two major detoxification pathways in humans. In order to characterize possible CYP- and UGT-dependent metabolites of the 2-(4-bromo-2,5-dimethoxy-phenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25B-NBOMe), a synthetic psychoactive drug, analyses of human liver microsome (HLM) incubates were performed using an ultra-high performance liquid chromatography system coupled with a quadrupole-time of flight mass spectrometry detector (UHPLC-Q-TOF/MS). On-line analyses were performed using a Waters OASIS HLB column (30 x 2.1 mm, 20 µm) for the automatic sample loading and a Waters ACQUITY HSS C18 column (150 x 2 mm, 1.8 µm) for the chromatographic separation. Twenty-one metabolites, consisting of 12 CYP-derived and 9 UGT-derived metabolites, were identified. O-Desmethyl metabolites were the most abundant compounds after the phase I process, which appears to be in accordance with data from previously published NBOMe-intoxication case reports. Although other important metabolic transformations, such as sulfation, acetylation, methylation or glutathione conjugation, were not studied and artefactual metabolites might have been produced during the HLM incubation process, the record of all the metabolite MS spectra in our library should enable us to characterize relevant metabolites of 25B-NBOMe and allow us to detect 25B-MBOMe users.

The use of new psychoactive substances (NPS) has rapidly increased over the last decade. In the last 4 years, producers increasingly appear to be targeting non-controlled synthetic opioids, involving fentanyl derivatives such as ocfentanil (OcF). Identification of metabolites is of major importance in the context of NPS use, as it could improve the detection window in biological matrices in clinical and forensic intoxication cases. Hence, this work aims to report a fatality involving OcF documented by the identification of metabolites. A 30-year-old woman was found dead at home: an unidentified powder was found near her body and some injection sites were found at the autopsy. Toxicological analyses allowed to determine the presence of OcF in the powder, blood (3.7/3.9 μg/L, peripheral/cardiac) and in other post-mortem samples. The most relevant potential CYP- and UGT-dependent metabolites of OcF were investigated in vitro using human liver microsome incubation and liquid chromatography coupled with high resolution mass spectrometry, and subsequently confirmed in post-mortem samples. Four OcF metabolites were produced in vitro (a mono-hydroxylated OcF, O-desmethylOcF, a hydroxylated desmethylOcF and a glucuronidated form of the O-desmethylOcF), and all except the glucuronide were observed in blood and bile post-mortem samples. Considering the relative intensity of the chromatographic peak areas, O-desmethylOcF can be suggested to be an abundant metabolite of OcF. Nevertheless, the relevance of O-desmethylOcF as being a complementary analytical target of OcF for OcF use detection needs further in vivo confirmation, especially through analysis of urines from users.

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This report deals with the design, the synthesis and the pharmacological evaluation of pyroglutamide-based P2RX7 antagonists. A dozen were shown to possess improved properties, among which inhibition of YO-PRO-1/TO-PRO-3 uptake and IL1β release upon BzATP activation of the receptor and dampening signs of DSS-induced colitis on mice, in comparison with reference antagonist GSK1370319A. Docking study and biological evaluation of synthesized compounds has highlighted new SAR, and low toxicity profiles of pyroglutamides herein described are clues for the finding of a usable h-P2RX7 antagonist drug. Such a drug would raise the hope for a cure to many P2RX7-dependant pathologies, including inflammatory, neurological and immune diseases.