Gas chromatographic mass spectrometric characterization of dromostanolone metabolites in human urine

Abstract

The metabolism of dromostanolone (2 alpha-methyl-5 alpha-androstan-17 beta-ol-3-one) was studied in three adult volunteers after oral dose of 20 mg. Solvent extracts of urine obtained after enzyme hydrolysis were derivatized with MSTFA/TMCS and MSTFA/TMIS. The structures of intact drug and its metabolites were determined by gas chromatography/mass spectrometry (GC/MS) in electron impact (EI) mode. The major metabolite (2 alpha-methyl-5 alpha-androstan-3 alpha-ol-17-one), its 3 beta-epimer, parent compound, and several hydroxylated metabolites including intact drug were detected by comparing total ion chromatograms of control urine with that of the administered sample. Two epimers of 2 alpha-methyl-5 alpha-androstan-3,17 beta-diol were detected using selected ion monitoring. The maximum excretion of dromostanolone and 2 alpha-methyl-5 alpha-androstan-3 alpha-ol-17-one was reached in 6.2-15 hr. The half-life of intact dromostanolone was 5.3 hr. About 3.0% of the administered amount was found to be excreted within 95 hr as unchanged form.