Development and Validation of an LC-MS/MS Method for the Simultaneous Determination of Bedaquiline and Rifabutin in Human Plasma.

•An LC–MS/MS method for the simultaneous determination of bedaquiline and rifabutin in human plasma for therapeutic drug monitoring is described.•This isotope dilution mass spectrometry method recovered analytes and their major metabolites with negligible matrix effects.•The methods developed in this study are a template for the simultaneous extraction and analysis of multiple anti-mycobacterial agents.•The method makes possible further studies of the complex drug–drug interactions between bedaquiline and rifabutin.