7α-thiomethylspironolactone 7α-thiomethylspironolactone 7α-thiomethylspironolactone (7α-tms; developmental code name sc-26519) is a steroidal antimineralocorticoid and antiandrogen of the spirolactone group and the major active metabolite of spironolactone. other important metabolites of spironolactone include 7α-thiospironolactone (7α-ts; sc-24813), 6β-hydroxy-7α-thiomethylspironolactone (6β-oh-7α-tms), and canrenone (sc-9376). 7α-thiomethylspironolactoneclinical dataother names7α-tms; sc-26519; 17α-hydroxy-7α-(methylthio)-3-oxopregn-4-ene-21-carboxylic acid γ-lactonedrug classantimineralocorticoididentifiers iupac name (7r,8r,9s,10r,13s,14s,17r)-10,13-dimethyl-7-methylsulfanylspirophenanthrene-17,5'-oxolane]-2',3-dione cas number38753-77-4pubchem cid162325chemspider142539unii0yu66jy4wlchemblchembl3544705comptox dashboard (epa)dtxsid80959567 chemical and physical dataformulac23h32o3smolar mass388.57 g·mol−13d model (jsmol)interactive image smiles c12ccc(=o)c=c1c(32cc4(3cc45ccc(=o)o5)c)sc inchi inchi=1s/c23h32o3s/c1-21-8-4-15(24)12-14(21)13-18(27-3)20-16(21)5-9-22(2)17(20)6-10-23(22)11-7-19(25)26-23/h12,16-18,20h,4-11,13h2,1-3h3/t16-,17-,18+,20+,21-,22-,23+/m0/s1key:fwrdlpqbeokire-rjkhxgposa-n spironolactone is a prodrug with a short terminal half-life of 1.4 hours. the active metabolites of spironolactone have extended terminal half-lives of 13.8 hours for 7α-tms, 15.0 hours for 6β-oh-7α-tms, and 16.5 hours for canrenone, and accordingly, these metabolites are responsible for the therapeutic effects of the drug. 7α-ts and 7α-tms have been found to possess approximately equivalent affinity for the rat ventral prostate androgen receptor (ar) relative to that of spironolactone. the affinity of 7α-ts, 7α-tms, and spironolactone for the rat prostate ar is about 3.0 to 8.5% of that of dihydrotestosterone (dht). pharmacokinetics of 100 mg/day spironolactone and its metabolites compoundcmax (day 1)cmax (day 15)auc (day 15)t1/2 spironolactone72 ng/ml (173 nmol/l)80 ng/ml (192 nmol/l)231 ng•hour/ml (555 nmol•hour/l)1.4 hours canrenone155 ng/ml (455 nmol/l)181 ng/ml (532 nmol/l)2,173 ng•hour/ml (6,382 nmol•hour/l)16.5 hours 7α-tms359 ng/ml (924 nmol/l)391 ng/ml (1,006 nmol/l)2,804 ng•hour/ml (7,216 nmol•hour/l)13.8 hours 6β-oh-7α-tms101 ng/ml (250 nmol/l)125 ng/ml (309 nmol/l)1,727 ng•hour/ml (4,269 nmol•hour/l)15.0 hours sources: see template. 7α-tms has been found to account for around 80% of the potassium-sparing effect of spironolactone, whereas canrenone accounts for the remaining approximate 10 to 25% of the potassium-sparing effect of the drug.