A HPLC-fluorescence method for the quantification of abiraterone in plasma from patients with metastatic castration-resistant prostate cancer

Abiraterone acetate is an oral prodrug of abiraterone, a selective inhibitor of CYP17, used for patients with metastatic castration-resistant prostate cancer (mCRPC). To date, a single liquid chromatographic-tandem mass spectroscopy method has been reported to assay abiraterone concentration in plasma from mCRPC patients. The aim of this study was to develop a simple and sensitive high performance liquid chromatographic (HPLC) method with fluorescence detection for quantification of abiraterone in plasma from mCRPC patients. After protein precipitation with acetonitrile and a liquid-liquid extraction with diethyl ether, abiraterone, and hydroxy-itraconazole (internal standard) were separated on a C8 Xterre (R) MS column using a mobile phase of acetonitrile and glycine buffer 88.4mM (pH 9.0) (60:40, v/v). Samples were eluted isocratically at a flow rate of 0.9 ml/min throughout an 11-min run. Fluorescence wavelengths' excitation and emission were 255 and 373 nm, respectively. The calibration was linear in the range 1.75-50 ng/ml. Inter- and intraday imprecision were less than 3.5 and 7%, respectively. This method is simple, sensitive, and selective. This analytical method was successfully applied to determine the steady-state plasma exposure to abiraterone in mCRPC patients. This method can be used in routine clinical practice to monitor plasma abiraterone concentrations in mCRPC patients. (C) 2015 Elsevier B.V. All rights reserved.