Metabolic Profile of Four Selected Cathinones in Microsome Incubations: Identification of Phase I and II Metabolites by Liquid Chromatography High Resolution Mass Spectrometry

Abstract

Consumption of synthetic cathinones, the second largest class of new psychoactive substances (NPS) reported worldwide, represents a serious public health risk. One of the biggest challenges created by the rapid spread of NPS on the illegal drug market is the discovery of selective biomarkers for their detection in biological matrices, which is only possible through the study of their metabolic profile. The synthetic cathinones 4′-methyl-N,N-dimethylcathinone (4-MDMC), 4′-methyl-N,N-diethylcathinone (4-MDEC), 4′-chloro-α-pyrrolidinovalerophenone (4Cl-PVP), and 4′-chloroethylcathinone (4-CEC) are NPS recently seized in Europe, and, with the exception of 4-CEC, no metabolism study was reported for these cathinones. With the ultimate goal of overcoming this gap, these cathinones were incubated in vitro in human and rat liver microsomes in the presence of Phase I and II (glucuronidation) co-factors, using α-pyrrolidinovalerophenone (α-PVP) as positive control. The metabolite identification was performed by liquid chromatography coupled to tandem high resolution mass spectrometry (LC-HRMS/MS). This allowed the identification of multiple Phase I and glucuronide metabolites of the selected cathinones. Additionally, a new glucuronide conjugate, derived from the recreational drug α-PVP, was herein identified for the first time. Importantly, we have demonstrated that 4-MDMC and 4-MDEC can act as prodrugs of the controlled substances 4-MMC and 4-MEC, respectively. The metabolites herein identified are expected to play an important role not only by acting as potential selective biomarkers of the intake of the synthetic cathinones selected for this study but also to understand their potential adverse effects and link these causative agents to toxicities, thereby helping in the treatment of non-fatal intoxications.

Tryptophanol-Derived Oxazolopyrrolidone Lactams as Potential Anticancer Agents against Gastric Adenocarcinoma

“…The evaluation of the metabolic stability of compound 7s was conducted in human liver microsomes (GIBCO TM , 20 donors) by a previously reported procedure [35]. Specifically, for a total incubation volume of 1 mL, in 100 mM phosphate buffer at pH 7.4, 7s (10 μM), human liver microsomes (0.8 mg protein/mL), NADPH (1 mM), and NADPH regeneration system (10 μL, Vivid® Regeneration System, 100×) were used.…”

Quantitative determination and metabolic profiling of synthetic cathinone eutylone in vitro and in urine samples by liquid chromatography tandem quadrupole time‐of‐flight mass spectrometry

“…Eutylone and five metabolites that were identified in the incubation sample are reported in Figure 1. Besides confirming the exact mass of the precursor ions of eutylone and its identified metabolites, the full MS/MS spectrum at 20 eV CE and based on the secondary mass fragments of other cathinones, [29][30][31] the possible structure of each fragment ion are reported in Figure 2. Moreover, the fragmentation pathways and corresponding Product Ion types are listed in Table 2.…”

Enantioselectivity of Pentedrone and Methylone on Metabolic Profiling in 2D and 3D Human Hepatocyte-like Cells

“…The large availability of HLM, their easy use, and the fact that they are one of the best-characterized in vitro systems for drug biotransformation research contribute to the popularity of this in vitro model [ 37 ]. HLM incubations have been quite successfully used for the generation of metabolites for synthetic cathinones [ 15 , 38 , 39 , 40 ]. Thus, the identification and enantioselective formation of methylone and pentedrone metabolites were initially studied in ultra-pool HLM by incubating individually each enantiomer.…”