URINARY METABOLITES OF DL-NORGESTREL IN WOMEN

Abstract

ABSTRACT Urines obtained from women administered the totally synthetic progestational steroid, 14C-dl-norgestrel, were fractionated on DEAE-Sephadex A-25. This anion exchanger separated unchanged norgestrel and ether extractable metabolites (6.5–10.2 % of the urinary radioactivity) as well as neutral, non-extractable metabolites (4.0–12.3 % of the urinary radioactivity) from anionic conjugates of norgestrel and its metabolites (75.8–88.8 % of the urinary radioactivity). The latter, in turn, were separated into seven fractions. One fraction, after solvolysis, was found to contain only the major metabolite, 16β-hydroxynorgestrel as sulphate(s) (approximately 30 % of the urinary activity). The remaining conjugated fractions as well as the free fraction were analyzed, and at least 23 metabolites were detected. Among them were biotransformation products resulting from hydroxylation at the 16α, 16β, 1β, 2α and 6ε position, D-homoannulation and ring-A reduction (3α,5β-tetrahydronorgestrel and its 3β, 5β and 3α, 5α isomers and a 16-hydroxylated tetrahydronorgestrel). Structures of the major metabolites were confirmed by mass spectrometry.