Effects of Cytochrome P450 enzymes and drug-drug interaction on donafenib metabolism: in vivo, in vitro and in silico.

This study systematically elucidated the metabolic characteristics of the hepatocellular carcinoma (HCC) therapeutic drug donafenib and its drug-drug interaction (DDI) with the antiviral agent arbidol. In vitro phenotyping assays using chemical inhibitors and recombinant CYP enzymes identified CYP3A4 as the primary enzyme catalyzing donafenib N-oxide formation. This was further confirmed by in vivo pharmacokinetic experiments in Cyp3a1/2 knockout rats, where AUC, AUC and t of donafenib were increased compared with wild-type rats. Additionally, the study was the first to report the effects of 8 CYP3A4 variants (CYP3A4.39-.46) on donafenib metabolism. Among these, 7 variants (except CYP3A4.42) had reduced metabolic catalytic activity compared to wild-type CYP3A4.1, and the intrinsic clearance (CL) was 8.60%-97.89% of that of CYP3A4.1. Subsequently, the potential mechanism of enzymatic activity changes was investigated through molecular docking. Finally, the study found that arbidol significantly inhibited donafenib metabolism, where the half-maximum inhibitory concentration (IC) value of arbidol was 3.16 ± 0.09 μM in rat liver microsome (RLM) and 36.38 ± 1.23 μM in human liver microsome (HLM), respectively. Animal studies have shown that the pharmacokinetics of donafenib were significantly altered following co-administration of arbidol in Sprague-Dawley rats. The results indicated that the AUC, AUC and C of donafenib were increased by 1.19-, 1.05- and 0.54-fold, respectively. Moreover, T was prolonged by 68.42%, while CL/F was decreased by 53.85%. These results provided critical references for clinical dosage adjustment, facilitating personalized treatment and reducing the risk of adverse reactions.