Biomedical Chromatography 2013-11-01

Determination of 3-α-hydroxytibolone in human plasma by LC-MS/MS: application for a pharmacokinetic study after administration of a tibolone formulation.

Fabiana Fernandes de Santana e Silva Cardoso, Isabela Costa César, Iram Moreira Mundim, Leonardo de Souza Teixeira, Enikson Pontes da Silva, Ricardo Rodrigues Bonfim, Sandro Antônio Gomes, Denys Pires Ferreira, Aderimar Rogério Batista Lopes, Helifas Duarte Pascoal, Weidson Carlo de Souza, Gerson Antônio Pianetti

Index: Biomed. Chromatogr. 27(11) , 1457-62, (2013)

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Abstract

A new method was developed for the quantitation of 3-α-hydroxy tibolone, in human plasma, after oral administration of a tablet formulation containing tibolone (2.5 mg). 3-α-Hydroxy tibolone was extracted by a liquid-liquid procedure, using cyproterone acetate as internal standard and chlorobutane as extraction solvent. After extraction, samples were submitted to a derivatization step with p-toluenesulfonyl isocyanate. A mobile phase consisting of acetonitrile and water (72:28 v/v) was used and chromatographic separation was achieved using Agilent XDB C18 column (100 × 4.6 mm i.d.; 5 µm particle size), at 40°C. Mass spectrometric detection was performed using atmospheric pressure chemical ionization in negative mode for 3-α-hydroxy tibolone and in positive mode for cyproterone acetate. The fragmentation transitions were m/z 510.2 → m/z 170.1 and m/z 417.0 → m/z 357.1 for 3-α-hydroxy tibolone and cyproterone acetate, respectively. Calibration curves were constructed over the range 100-30,000 pg/mL and the method was shown to be specific, precise and accurate, with a mean recovery rate of 94.2% for 3-α-hydroxy tibolone. No matrix effect or carry-over was detected in the samples. The validated method was applied in a pharmacokinetic study with a tibolone formulation in healthy female volunteers.Copyright © 2013 John Wiley & Sons, Ltd.