Development and validation of analytical method for the determination of radotinib in human plasma using liquid chromatography-tandem mass spectrometry

This study describes the development of an analytical method to determine radotinib levels in human plasma using high performance liquid chromatography (HPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS) for pharmacokinetic application. Plasma samples were sequentially processed by liquid-liquid extraction using methyl tert-butyl ether, evaporation, and reconstitution. Analytes were separated and analyzed using HPLC-MS/MS in selected reaction monitoring mode, monitoring the specific transitions of m/z 531 to 290 for radotinib and m/z 409 to 238 for amlodipine (internal standard). The HPLC-MS/MS analytical method was validated with respect to selectivity, linearity, sensitivity, accuracy, precision, recovery, and stability. Calibration curves were linear over a concentration range 5–3,000 ng/mL with correlation coefficients (r) > 0.998. The lower limit of quantification for radotinib in plasma was 5 ng/mL. The accuracy and precision of the analytical method were acceptable within 15% at all quality control levels. This method was suitable to determine radotinib levels in human plasma because of its simplicity, selectivity, precision, and accuracy.