In vitro metabolic profile of mexedrone, a mephedrone analog, studied by high‐ and low‐resolution mass spectrometry

Abstract

Mexedrone is a synthetic cathinone structurally related to mephedrone, which belongs to the class of N-alkyl cathinone derivatives, whose metabolic profile has not been fully clarified yet. This study considers the in vitro phase I metabolism of mexedrone, to pre-select the most appropriate marker(s) of intake. Mexedrone was incubated in the presence of either human liver microsomes or single recombinant CYP450 isoforms. The metabolic profile was outlined by ultra-high-performance liquid chromatography coupled to both high-and low-resolution mass spectrometry.In detail, the phase I metabolic profile of mexedrone was initially defined by a timeof-flight analyzer, while the chemical structures of the detected metabolites and the potential presence of minor metabolites were subsequently studied by tandem mass spectrometry, using a triple quadrupole analyzer. The main phase I metabolic reactions were hydroxylation and N-and O-dealkylation. The CYP450 isoforms most involved were CYP2C19, responsible for the formation of both hydroxylated and dealkylated metabolites, followed by CYP2D6 and CYP1A2, involved in the hydroxylation reactions only. Finally, a significant fraction of mexedrone unchanged was also detected. Based on this evidence, the most appropriate markers of intake are mexedrone unchanged and the hydroxylated metabolites.

Annual banned‐substance review—Analytical approaches in human sports drug testing 2021/2022–

“…Chromatographic separation was accommodated by a C‐18 analytical column (2.1 × 100 mm, 1.7 μm particle size), and mass spectrometric analyses concerning routine doping control assay validations were conducted on a QqQ‐based MS, enabling an LOD of 5 ng/ml. Similarly, the metabolic profile of mexedrone (Figure 1, 10 ) was studied by Camuto et al, and in accordance with the fact that both compounds ( N ‐ethyl‐heptedrone and mexedrone) are related cathinone derivatives, hydroxylations and dealkylation reactions were identified as main metabolic pathways 82 . The analytical conditions were slightly modified with C‐18 analytical columns featuring dimensions of 2.1 × 10 mm (1.8 μm particle size) and 2.1 × 150 mm (2.7 μm particle size), depending on the use of LC–Q/TOF–MS and LC–QqQ–MS analyses, respectively, and the intact substance as well as the hydroxylated or N ‐dealkylated species were suggested as viable target analytes for routine doping controls.…”

“…Chromatographic separation was accommodated by a C-18 analytical column (2.1 Â 100 mm, 1.7 μm particle size), and mass spectrometric analyses concerning routine doping control assay validations were conducted on a QqQ-based MS, enabling an LOD of 5 ng/ml. Similarly, the metabolic profile of mexedrone (Figure1, 10) was studied by Camuto et al, and in accordance with the fact that both compounds (N-ethyl-heptedrone and mexedrone) are related cathinone derivatives, hydroxylations and dealkylation reactions were identified as main metabolic pathways 82. The analytical conditions were slightly modified with C-18 analytical columns featuring dimensions of 2.1 Â 10 mm (1.8 μm particle size) and 2.1 Â 150 mm (2.7 μm particle size), depending on the use of LC-Q/TOF-MS and LC-QqQ-MS analyses, respectively, and the intact substance as well as the hydroxylated or N-dealkylated species were suggested as viable target analytes for routine doping controls.In contrast to these xenobiotic stimulants, means to detect the prohibited use of synthetic phenylethylamine has necessitated the consideration of diagnostic metabolite ratios as discussed by Krombholz et al83 In addition to a formerly identified metabolite referred toas 2-(2-hydroxyphenyl)acetamide sulfate, the utility of an additional TC, namely, phenylacetylglutamine, was reported to strengthen the discrimination of urinary metabolite profiles resulting from naturally produced phenylethylamine and the oral administration of a synthetic product.…”

Epigenetic Studies for Evaluation of NPS Toxicity: Focus on Synthetic Cannabinoids and Cathinones

“…In vitro and in vivo studies concerning NPSs were widely present in the literature [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. In particular, Lenzi and colleagues have demonstrated the mutagenic capability of synthetic cathinone and cannabinoids [ 39 , 40 ], underlying their potential toxicity.…”