Abstract
Synthetic cannabinoid receptor agonists (SCRAs) continue to show high prevalence on the new psychoactive substances drug market. Around 2019-2020, new SCRAs bearing a cumyl moiety emerged: Cumyl-CBMEGACLONE and Cumyl-NBMEGACLONE, carrying a cyclobutyl methyl (CBM) and a norbornyl methyl moiety (NBM) attached to the γ-carbolinone core. These were followed by Cumyl-NBMINACA, the indazole carboxamide analog of Cumyl-NBMEGACLONE. The study aimed at evaluating the human phase-I metabolism of these compounds and at identifying suitable urinary markers to prove their consumption. After enzymatic hydrolysis, 14 authentic urine samples (eight for Cumyl-CBMEGACLONE, four for Cumyl-NBMEGACLONE, and two for Cumyl-NBMINACA) were analyzed by liquid chromatography-quadrupole time-of-flight mass spectrometry. Results were compared with in vitro metabolites generated by pooled human liver microsomes incubation. Fifteen human phase-I metabolites were identified for Cumyl-CBMEGACLONE, nine for Cumyl-NBMEGACLONE, and thirteen for Cumyl-NBMINACA. The main in vivo metabolites were built by monohydroxylation, dihydroxylation, or trihydroxylation. The following urinary biomarkers are suggested for detecting the consumption of the investigated SCRAs: products of monohydroxylation at the CBM and at the core for Cumyl-CBMEGACLONE; two products of monohydroxylation at the norbonyl methyl tail for Cumyl-NBMEGACLONE; and metabolites built by dihydroxylation at the NBM substructure and by an additional hydroxylation at the cumyl moiety for Cumyl-NBMINACA.