Isolation and identification of a sulfur-containing metabolite of spironolactone from human urine

In the urine of normal subjects who were given an oral dose of 500 mg spironolactone (3-(3-oxo-7alpha-acetylthio-17beta-hydroxy-4-androsten-17alpha-yl)-propionic acid gamma-lactone; Aldactone) together with 100uCi H-20, 21 spironolactone, a so far unknown major metabolite has been detected by thin layer chromatography. The metabolite then could be isolated by means of counter-current-distribution. According to masspectral and magnetic resonance data, the metabolite has been assigned the structure of 3-(3-oxo-7alpha-methyl sulfonyl-6beta, 17beta-dihydroxy-4-androsten-17alpha-yl)-propionic acid gamma-lactone. By oxidation of the corresponding methylsulfinyl compound - another already known metabolite of spironolactone - with m-chloroperbenzoic acid, a compound has been isolated which proved to be identical with the new metabolite according to TLC, MS and NMR.