A validated liquid chromatographic–tandem mass spectroscopy method for the quantification of abiraterone acetate and abiraterone in human plasma

A sensitive and selective LC–MS/MS method has been developed and validated for the quantification of abiraterone acetate and its metabolite, abiraterone (an androgen biosynthesis inhibitor) in human plasma. Analytes were extracted by SPE with cation mixed-mode polymer cartridges. Chromatography was performed on a Luna C5 5 μm, 50 mm × 2.1 mm i.d. column, using a mobile phase of 2% propan-2-ol in acetonitrile and 10 mM ammonium acetate. The assay was linear from 5 to 500 nM (r2 = 0.998). The intra- and inter-day coefficients of variation were <13.9% for both analytes. This method will be applied to a clinical trial investigating the pharmacokinetics of abiraterone acetate and abiraterone in patients with prostate cancer.