estradiol acetylsalicylate estradiol acetylsalicylate estradiol acetylsalicylate, or estradiol 3-acetylsalicylate, is a synthetic estrogen and estrogen ester – specifically, the c3 acetylsalicylic acid (aspirin) ester of estradiol – which was described in the late 1980s and was never marketed. in dogs, the oral bioavailability of estradiol acetylsalicylate was found to be 17-fold higher than that of unmodified estradiol. however, a subsequent study found that the oral bioavailability of estradiol and estradiol acetylsalicylate did not differ significantly in rats (4.3% and 4.2%, respectively), suggestive of a major species difference. estradiol acetylsalicylateclinical dataother namesestradiol 3-acetylsalicylate; acetylsalicylate estradiolroutes ofadministrationby mouthdrug classestrogen; estrogen esteridentifiers iupac name phenanthren-3-yl] 2-acetyloxybenzoate cas number111111-98-9 ypubchem cid183168chemspider159276uniij9b90asj1ychemical and physical dataformulac27h30o5molar mass434.532 g·mol−13d model (jsmol)interactive image smiles cc(=o)oc1=cc=cc=c1c(=o)oc2=cc3=c(c=c2)4cc5((4cc3)cc5o)c inchi inchi=1s/c27h30o5/c1-16(28)31-24-6-4-3-5-22(24)26(30)32-18-8-10-19-17(15-18)7-9-21-20(19)13-14-27(2)23(21)11-12-25(27)29/h3-6,8,10,15,20-21,23,25,29h,7,9,11-14h2,1-2h3/t20-,21-,23+,25+,27+/m1/s1key:knjutxjfanovgr-hxvsazqxsa-n