Metabolism of the synthetic cannabinoid PX-2 in human liver microsomes

This study was performed to determine the metabolic profile of a new illicit drug, PX-2, in human liver microsomes. Q Exactive™ HF Quadrupole-Orbitrap LC-MS (LC-QE-HF-Orbitrap-MS) was employed to determine the metabolic sites and pathways of phase Ⅰ and phase II metabolism. PX-2 was added to a microsomal incubation model to simulate human hepatic metabolism. The results showed that a total of 18 phase Ⅰ metabolites and 3 glucuronidated phase II metabolites were generated, with the main metabolic pathways of phase Ⅰ metabolism including amide hydrolysis, fluoropentyl oxidative defluorination, benzyl hydroxylation, and carbazole ring hydroxylation. Based on the type and sites of metabolism, phase Ⅰ metabolites M1.1 (amide hydrolysis), M4.1 (carbazole cyclic hydroxylation), and M3.1 (oxidative defluorinative hydroxylation) are proposed to be potential poisoning markers. The results of this study provide a basis for identification of related drugs and establishment of testing methods in biological samples.