10,13-Dimethyl-1,6,7,8,9,10,11,12,13,14,15,16-dodecahydro-3'H-spi ro[cyclopenta[a]phenanthrene-17,2'-furan]-3,5'(2H,4'H)-dione

SC-5233 is a steroidal antimineralocorticoid of the spirolactone group that was developed by G. D. Searle & Company in the 1950s but was never marketed. It was the first antagonist of the mineralocorticoid receptor to have been identified and tested in humans. The drug was found to have poor oral bioavailability and potency, but it nonetheless produced a mild diuretic effect in patients with congestive heart failure. SC-8109, the 19-nor (19-demethyl) analogue, was developed and found to have improved oral bioavailability and potency, but still had relatively low potency. Spironolactone (SC-9420; Aldactone) followed and had both good oral bioavailability and potency, and was the first antimineralocorticoid to be marketed.