Synthesis of 5,6,6-[2H3]Finasteride and Quantitative Determination of Finasteride in Human Plasma at Picogram Level by an Isotope-Dilution Mass Spectrometric Method

This 1995 paper describes a sensitive and accurate method for determining finasteride levels in human plasma using gas chromatography-mass spectrometry and a deuterated internal standard. The method was applied to the determination of the pharmacokinetic profile of finasteride in five male volunteers treated with a single oral 5-mg dose of the drug, and the results were in good agreement with previous studies. The method is suitable for routine determination of finasteride at picogram levels.