The prediction of drug-drug interactions mediated by the induction or inhibition of cytochrome P450 enzymes is of great relevance in the development of new drugs. Due to the fact that HepaRG, a new human cell line derived from a hepatocellular carcinoma, is being considered a promising model to evaluate the in vitro metabolism of drugs, it was herein used for investigating metabolic-based drug-drug interactions mediated by metabolic induction. In this study, rifampicin and phenytoin were used as probe inducers and amiodarone (AM) as a model drug. HepaRG cells were firstly seeded in the supplemented Williams' E, and then differentiated in the same culture medium, supplemented with 2% dimethyl sulfoxide for 2 weeks. For metabolic induction studies AM was incubated during 12h in HepaRG cells which were pre-incubated with phenytoin or rifampicin for 72 h. The concentrations of AM and its main metabolite, mono-N-desethylamiodarone, were quantified by HPLC-DAD. This study evidenced that rifampicin and phenytoin are powerful inducers of the metabolism of AM, including at therapeutic drug concentrations. These experimental findings demonstrated, for the first time, the applicability of HepaRG cells as a useful in vitro model for the prediction of metabolic-based drug-drug interactions, namely those mediated by metabolic induction. Thus, this model could potentially be a worthy alternative to the primary human hepatocytes.

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