inocoterone acetate inocoterone acetate inocoterone acetate (usan) (developmental code names ru-38882, ru-882) is a steroid-like nonsteroidal antiandrogen (nsaa) that was developed for topical administration to treat acne but was never marketed. it is the acetate ester of inocoterone, which is less potent in comparison. inocoterone acetate is actually not a silent antagonist of the androgen receptor but rather a weak partial agonist, similarly to steroidal antiandrogens like cyproterone acetate. inocoterone acetateclinical dataother namesru-38882; ru-882; 2,5-seco-a-dinorestr-9-en-17β-ol-5-one 17β-acetatedrug classnonsteroidal antiandrogenidentifiers iupac name naphthalen-3-yl] acetate cas number83646-86-0pubchem cid6917958chemspider5293176uniionu02d116skeggd04538chemblchembl2107564comptox dashboard (epa)dtxsid401003615 chemical and physical dataformulac18h26o3molar mass290.403 g·mol−13d model (jsmol)interactive image smiles ccc1=c2cc3((2ccc1=o)cc3oc(=o)c)c inchi inchi=1s/c18h26o3/c1-4-12-13-9-10-18(3)15(14(13)5-7-16(12)20)6-8-17(18)21-11(2)19/h14-15,17h,4-10h2,1-3h3/t14-,15+,17+,18+/m1/s1key:jdluqdytlspfgs-fzclsbeqsa-n inocoterone acetate was investigated for the treatment of acne but showed only modest (albeit statistically significant) efficacy in clinical trials. a reduction of 26% of lesions was observed in males treated with the drug after 16 weeks (~3.7 months). however, this is notably far less than that achieved with other agents such as benzoyl peroxide or antibiotics, which produce 50–75% reductions within 2 months. similar poor results with the topical route have disappointingly been found for other antiandrogens such as cyproterone acetate and spironolactone. similarly to rosterolone, inocoterone acetate has no systemic antiandrogenic activity when applied systemically.