An LC-MS/MS method for the simultaneous determination of goserelin and testosterone in rat plasma for pharmacokinetic and pharmacodynamic studies.

Shu Zhang, Jiangbin Han, Guangyi Leng, Xin Di, Chunjie Sha, Xuemei Zhang, Youxin Li, Wanhui Liu

Index: J. Chromatogr. B. Analyt. Technol. Biomed. Life Sci. 965 , 183-9, (2014)

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Abstract

A liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed, using testosterone-d3 as a surrogate analyte, for the simultaneous quantification of goserelin and testosterone in rat plasma. According to this method, the pharmacokinetic and pharmacodynamic data were obtained from a single plasma sample aliquot. The method involved the addition of alarelin as an internal standard (IS) for goserelin and testosterone-(13)C3 for testosterone or testosterone-d3. The conditions for the separation of these two compounds were achieved on a ZORBAX Eclipse Plus C18 column (Agilent, 2.1 × 50 mm, 1.8 μm, Stockport, UK) in a single chromatographic run at a flow rate of 400 μL/min. In order to minimize interferences of complex matrix, the extraction of plasma consisted of a protein precipitation step using methanol, followed by purification using an Oasis(®) HLB solid-phase extraction column. The method was validated in the concentration range of 0.01-30.0 ng/mL for goserelin and 0.05-30.0 ng/mL for testosterone-d3, respectively. The within- and between-run precisions were 1.7-9.2% and 2.1-6.9%, respectively. The within- and between-run accuracies were -1.8 to 5.3% and -4.9 to 4.0%, respectively. This accurate and highly specific assay provides a useful method to evaluate the pharmacokinetics and pharmacodynamics of goserelin in rats.Copyright © 2014 Elsevier B.V. All rights reserved.