Synthetic cathinones belong to the most often seized new psychoactive substances on an international level. This study investigated the toxicometabolomics, particularly the in vitro metabolism of 2-(methylamino)-1-(4-methylphenyl)-1-pentanone (4-MPD) and 2-(ethylamino)-1-(4-methylphenyl)-1-pentanone (4-MEAP) in pooled human liver microsomes (pHLM) using untargeted metabolomics techniques. Incubations were performed with the substrates in concentrations ranging from 0, 12.5, and 25 µM. Analysis was done by means of high-performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC-HRMS/MS) in full scan only and the obtained data was evaluated using XCMS Online and MetaboAnalyst. Significant features were putatively identified using a separate parallel reaction monitoring method. Statistical analysis was performed using Kruskal-Wallis test for prefiltering significant features and subsequent hierarchical clustering, as well as principal component analysis (PCA). Hierarchical clustering or PCA showed a distinct clustering of all concentrations with most of the features z-scores rising with the concentration of the investigated substances. Identification of significant features left many of them unidentified but revealed metabolites of both 4-MPD and 4-MEAP. Both substances formed carboxylic acids, were hydroxylated at the alkyl chain, and formed metabolites after combined hydroxylation and reduction of the cathinone oxo group. 4-MPD additionally formed a dihydroxy metabolite and a hydroxylamine. 4-MEAP was additionally found reduced at the cathinone oxo group, N-dealkylated, and formed an oxo metabolite. These findings are the first to describe the metabolic pathways of 4-MPD and to extend our knowledge about the metabolism of 4-MEAP. Findings, particularly the MS data of the metabolites, are essential for setting up metabolite-based toxicological (urine) screening procedures.

中文翻译：

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基于液相色谱-高分辨质谱的人肝微粒体中合成Cathinones 4-MPD和4-MEAP的体外毒物代谢组学

在国际上，合成的卡西酮属于最常被缉获的新型精神活性物质。这项研究调查了毒性代谢组学，特别是2-（甲基氨基）-1-（4-甲基苯基）-1-戊酮（4-MPD）和2-（乙基氨基）-1-（4-甲基苯基）-1的体外代谢使用非靶向代谢组学技术测定合并的人肝微粒体（pHLM）中的β-戊酮（4-MEAP）。用浓度为0、12.5和25 µM的底物进行孵育。仅通过全扫描结合高效液相色谱和高分辨率质谱（HPLC-HRMS / MS）进行分析，并使用XCMS Online和MetaboAnalyst评估获得的数据。使用单独的平行反应监测方法推定了重要特征。使用Kruskal-Wallis检验进行统计分析，以对重要特征进行预过滤和随后的层次聚类，以及主成分分析（PCA）。层次聚类或PCA显示具有所有特征的所有浓度的明显聚类z分数随所研究物质的浓度而增加。重大特征的鉴定使许多人无法鉴定，但揭示了4-MPD和4-MEAP的代谢产物。两种物质均形成羧酸，在烷基链上被羟基化，并在结合羟基化和Cathinone羰基还原后形成代谢物。4-MPD还形成了二羟基代谢产物和羟胺。4- MEAP被加发现在卡西酮氧代基团，降低Ñ-脱烷基，并形成氧代代谢产物。这些发现是第一个描述4-MPD代谢途径并扩展我们对4-MEAP代谢知识的研究。研究结果，特别是代谢物的MS数据，对于建立基于代谢物的毒理学（尿液）筛查程序至关重要。