Development and Validation of LC-MS/MS Method for the Quantification of Chiral Separated R-Bicalutamide in Human Plasma

A simple, rapid, specific and precise liquid chromatography—tandem mass spectrophotometric (LC-MS/MS) method was developed and validated for the quantification of chiral separated R-bicalutamide from S-bicalutamide, in human plasma. Topiramate (TPM) was used as internal standard, added to plasma sample prior to extraction using t-butyl methyl ether (TBME). Chromatographic separation was achieved on CHIRALPAK AD-RH column (150 mm × 4.6 mm, 5 μm) with acteonitrile: 0.1% formic acid Buffer (50:50 v/v) as an isocratic mobile phase with a flow rate of 1.0 mL·min. Quantitation was performed by transition of 429.0 → 255.0 (m/z) for R-bicalutamide and 338.1 → 77.8 (m/z) for topiramate. The lower limit of quantitation was 20 ng·mL with a 100 μL plasma sample. The concentrations of eight working standards showed linearity between 20 to 3200 ng·mL (r ≥ 0.9990). Chromatographic separation was achieved within 6 min, compared to the 15 min of previous methods. The average extraction recoveries of 3 quality control concentrations were 98.56% for R-bicalutamide and 92.42% for topiramate. The coefficient of variation was ≤15% for intraand inter-batch assays. Therefore a rapid, specific and sensitive LC-MS/MS method for the quantification of R-bicalutamide in human plasma was developed and validated can be used in the bioequivalence study of this drug.