Pharmacokinetic studies of testosterone propionate using gas chromatography/mass spectrometry/selected ion monitoring.

A sensitive and accurate method for the quantitative estimation of testosterone propionate in human plasma was developed using gas chromatography/mass spectrometry/selected ion monitoring. The method employing stable isotopically labelled testosterone propionate as tracer was employed to follow the time course of plasma testosterone propionate and its active metabolite testosterone in normal men. Intramuscularly administered (19,19,19-2H3)testosterone propionate was readily transferred from the injection site to systemic circulation. Plasma (19,19,19-2H3)testosterone levels were maintained above the physiological testosterone level for 48 h, while plasma levels of endogenous testosterone changed little.