Bioavailability Test of TestoTM Tablets (Methyltestosterone, 25 mg) in Male Healthy Volunteers by a Gas-chromatography/Mass Selective Detector

Abstract

A simple and specific method for determination of methyltestosterone (MT) has been established by a gas chromatography/mass selective detector and applied in plasma of healthy male volunteers received a single oral dose of 50 mg MT (TestoTM tablets, 25 mg) for bioavailability test. This method involves using liquid-liquid extraction of the sample with diethyl ether and derivatization with MSTFA. MT showed good resolution in this condition. The detection limit of quantitation was 5 ng/ml. A good linearity (r > 0.996) was obtained at the range of 5-250 ng/ml of MT. Intra-day precision and accuracy were 2.76-12.56% and 0.39-8.01%, and inter-day precision and accuracy were 2.29-17.69% and 0.42-7.99%, respectively. The established method was applied on bioavailability test of MT in human volunteers. The value of AUC0 to last was 264.5 ±？123.9 ngáhr/ml and that of AUC0 to inf was determined to be 275.2 ± 126.5 ngáhr/ml. The values of Cmax and Tmax were 95.9 ±？67.1 ng/ml and 1.13 ±？0.79 hr, respectively. The mean elimination half-life (t1/2) was 4.4 ± 0.9 hr. This analytical method is suitable and useful for the pharmacokinetics and bioequivalence studies of MT.