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Journal of Steroid Biochemistry and Molecular Biology


Abiraterone acetate (AA), the prodrug of abiraterone, is FDA-approved for the treatment of castration-resistant prostate cancer. Abiraterone is metabolized in patients to a more potent analogue, D4A. However, we have recently reported that this analogue is further metabolized to additional metabolites in patients treated with AA. Here, we present a liquid chromatography-tandem mass spectrometry method developed to resolve and detect abiraterone and its seven metabolites in human serum using an AB Sciex Qtrap 5500 mass analyzer coupled with a Shimadzu Nexera UPLC station. Analytes and the internal standard (abiraterone-d4) were extracted from human serum using the liquid–liquid extraction procedure. The analytes were separated using a Zorbax Eclipse Plus C18 150 × 2.1 mm, 3.5 μm column at 40 °C and an isocratic mobile phase 35% A (0.1% formic acid in water), 65% B (0.1% formic acid in methanol:acetonitrile; 60:40). Electrospray ionization in positive mode was applied with multiple reaction monitoring in a total run time of 13 min. Abiraterone detection was linear in the range 2–400 ng/mL and all metabolites from 0.1–20 ng/mL. The method was validated following US FDA guidelines for bioanalytical method validation, and all the metabolite results were within the acceptance limits. Despite the similarity in structure and mass transition between the metabolites, the validated method separated all the metabolites, including diastereomers, to allow accurate identification and quantitation of each compound.


This work has been supported in part by funding from a Howard Hughes Medical Institute Physician-Scientist Early Career Award (to N.S.), a Prostate Cancer Foundation Challenge Award (to N.S.), an American Cancer Society Research Scholar Award (12-038-01-CCE; to N.S.), grants from the National Cancer Institute (R01CA168899, R01CA172382, and R01CA190289; to N.S.), a grant from the US Army Medical Research and Materiel Command (PC121382 to Z.L.), a Prostate Cancer Foundation Young Investigator Award to Z.L.