Metabolomics combined with high-resolution mass spectrometry (HR-MS) and multivariate data analysis has broad applications in the study of xenobiotic metabolism. Although information about xenobiotic metabolism is essential to understand toxic mechanisms, pharmacokinetic parameters and excretion pathways, it is limited to predict all generated metabolites in biological fluids. Here, we revisited sildenafil metabolism in human liver microsomes using a metabolomics approach to achieve a global picture of sildenafil phase 1 metabolism. Finally, 12 phase 1 metabolites were identified in human liver microsomes; M1-M5 were previously known metabolites. The chemical structures of the novel metabolites were elucidated by MS² fragmentation using an HR-MS system as follows: M6, reduced sildenafil; M7, N,N-deethylation and mono-oxidation; M8, demethanamine, N,N-deethylation and mono-hydroxylation; M9, demethanamine and N,N-deethylation; M10 and M11, mono-oxidation in the piperazine ring after N-demethylation; and M12, mono-oxidation. All metabolites, except M1, were formed by CYP3A4 and CYP3A5. In conclusion, we successfully updated the metabolic pathway of sildenafil in human liver, including 7 novel metabolites using metabolomics combined with HR-MS and multivariate data analysis.

代谢组学与高分辨率质谱法（HR-MS）和多变量数据分析的结合在异生物代谢研究中具有广泛的应用。尽管有关异源生物代谢的信息对于理解毒性机制，药代动力学参数和排泄途径必不可少，但它只能预测生物液中所有产生的代谢物。在这里，我们使用代谢组学方法重新研究了人肝微粒体中西地那非的代谢，以了解西地那非1期代谢的全局情况。最终，在人肝微粒体中鉴定出12种1期代谢物。M1-M5是先前已知的代谢产物。使用HR-MS系统通过MS ²断裂来阐明新型代谢物的化学结构，如下所示：M6，还原的昔多芬；M7，N，N-脱乙基和单氧化；M8，脱甲胺，N，N-脱乙基和单羟基化；M9，脱甲胺和N，N-脱乙基；M10和M11，N-去甲基化后哌嗪环中的单氧化；和M12，单氧化。除M1外，所有代谢物均由CYP3A4和CYP3A5形成。总之，我们成功地使用代谢组学结合HR-MS和多变量数据分析，更新了西地那非在人肝中的代谢途径，包括7种新的代谢产物。