Characterization of the metabolite of AdipoRon in rat and human liver microsomes by ultra-high-performance liquid chromatography combined with Q-Exactive Orbitrap tandem mass spectrometry.

AdipoRon is an orally active adiponectin receptor agonist. The aim of this study was to characterize the metabolites of AdipoRon in rat and human liver microsomes using ultra-high performance liquid chromatography combined with Q-Exactive Orbitrap tandem mass spectrometry (UPLC-Q-Exactive-Orbitrap-MS) together with data processing techniques including extracted ion chromatograms and a mass defect filter. AdipoRon (10 µm) was incubated with liver microsomes in the presence of NADPH and this resulted in a total of 11 metabolites being detected. The identities of these metabolites were characterized by comparing their accurate masses and fragment ions as well as their retention times with those of AdipoRon using MetWorks software. Metabolites M1-M3, M6, and M8-M11 were identified for the first time. Metabolite M4, the major metabolite both in rat and human liver microsomes, was further confirmed using the reference standard. Our results revealed that the metabolic pathways of AdipoRon in liver microsomes were N-dealkylation (M2), hydroxylation (M, M5-M9), carbonyl reduction (M4) and the formation of amide (M10 and M11). Our results provide valuable information about the in vitro metabolism of AdipoRon, which would be helpful for us to understand the mechanism of the elimination of AdipoRon and, in turn, its effectiveness and toxicity.