A study of in vitro metabolism and cytotoxicity of mephedrone and methoxetamine in human and pig liver models using GC/MS and LC/MS analyses

Alshamaileh, Majed, Hussain, Issam, Baron, Mark, Croxton, Ruth, Vetter, Marleen and Gonzalez-Rodriguez, Jose (2020) A study of in vitro metabolism and cytotoxicity of mephedrone and methoxetamine in human and pig liver models using GC/MS and LC/MS analyses. Open Chemistry, 18 (1). pp. 1507-1522. ISSN 2391-5420

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In the current study, the metabolism of two novel psychoactive substances (NPSs), mephedrone and methoxetamine (MXE), was studied in vitro in pig liver microsomes to determine potential metabolites by liquid chromatography-mass spectrometry (LC-MS). Later, in vitro studies were performed using HepaRG™ cells to determine the human metabolites of these drugs using gas chromatography-mass spectrometry (GC-MS). The aim of the study was to detect metabolites from the metabolic mixture in the human cell lines using GC-MS, since this is a more readily available technique within forensic laboratories. Microsomes were prepared through a conventional ultracentrifugation method and incubated under optimized conditions with the drugs for 3 h. Subsequently, the samples were investigated using LC-MS. A similar methodology was then applied in the HepaRG™ cells, and the GC-MS conditions were optimized using N,O-bis(trimethylsilyl)trifluoroacetamide as a derivatization agent. The analysis showed two molecules from a successful in vitro metabolism, namely, hydroxytoly-mephedrone and nor-dihydro mephedrone. For MXE, two metabolites are presented produced by the O-demethylation and reduction of the ketone moiety to the corresponding alcohol, respectively. Using the human HepaRG™ cells, only nor-dihydro mephedrone could be identified by GC-MS. Since hydroxytoly-mephedrone and the MXE metabolites are more polar, it is suggested that GC-MS even with derivatization may not be suitable. In addition, cytotoxicity was studied utilizing HepaRG™ cell lines. The drugs show cytotoxic effects causing in vitro cell death, within the specified range of EC50 0.3211 mM (79 μg/mL) and 0.6297 mM (111 μg/mL) for mephedrone and MXE, respectively. These drugs were able to cause 73-84% cell death.

Item Type: Article
Additional Information: Funding Information: The authors appreciate the financial support to the main author by Mutah University (Jordan) for the current research work as a part of a funded PhD scholarship.
Uncontrolled Keywords: cytotoxicity, EC50, in vitro metabolism, mass spectrometry, mephedrone, methoxetamine
Subjects: F100 Chemistry
F200 Materials Science
Department: Faculties > Health and Life Sciences > Applied Sciences
Depositing User: Rachel Branson
Date Deposited: 12 May 2022 15:29
Last Modified: 12 May 2022 15:30
URI: http://nrl.northumbria.ac.uk/id/eprint/49114

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