The identification of some human metabolites of norgestrel a new progestational agent.

Administration of norgestrel I (racemic 13β-ethyl-17 α -ethynyl-17β-hydroxygon-4-en-3-one) to humans has been shown by mass spectrometry and other analytical techniques to yield a range of metabolites. The major metabolite has been identified as optically pure 13β-ethyl-17 α -ethynyl-5β-gonan-3 α ,17β-diol VIIIc, corresponding in absolute configuration to the natural steroid hormones. Other metabolites have been shown to correspond in structure to the unaltered drug, 13β-ethyl-l7 α -ethynyl-5β-gonan-3β,17β-diol VIIId, and to two different mono-hydroxylated derivatives of I (which are probably not the 2,4,6 or 10-substituted derivatives), but no information is available as to their state of optical resolution. The 13β-ethyl group labels metabolites of I without resort to 14 C-containing compounds when mass spectrometry is used as an analytical technique.