cymegesolate cymegesolate cymegesolate (developmental code name progestin no. 1), also known as cypionyl megestrol acetate or as megestrol acetate 3β-cypionate, is a progestin medication which was never marketed. it was developed in china in the late 1970s and early to mid 1980s for use as a hormonal contraceptive. the medication was formulated at a dose of 50–100 mg in combination with a "trace" dose of 0.25–0.5 mg quinestrol as a long-lasting, once-a-month combined oral contraceptive pill. this combination has been studied in 1,213 women across a total of 9,651 menstrual cycles, with contraceptive effectiveness of over 99.13% and "very few side effects." at the high dose (100 mg / 0.5 mg), it showed an anovulation rate of only about 60%, and instead mediated its contraceptive effects via a marked anti-implantation effect. cymegesolateclinical dataother namescypionyl megestrol acetate; megestrol acetate 3β-cypionate; megestrol acetate 3β-cyclopentylpropionate; progestin no. 1; progestin i; progestagen i; 17α-acetoxy-6-dehydro-6-methylprogesterone 3β-cypionate; 17α-acetoxy-6-methylpregna-4,6-diene-3,20-dione 3β-cypionateroutes ofadministrationby mouthdrug classprogestin; progestogen; progestogen esteridentifiers iupac name phenanthren-3-yl] 3-cyclopentylpropanoate cas number72648-88-5 ypubchem cid126290chemspider112247unii4d9tfh8plxcomptox dashboard (epa)dtxsid70993490 chemical and physical dataformulac32h46o5molar mass510.715 g·mol−13d model (jsmol)interactive image smiles cc1=c2(cc3(2cc3(c(=o)c)oc(=o)c)c)4(c1=c(cc4)oc(=o)ccc5cccc5)c inchi inchi=1s/c32h46o5/c1-20-18-25-26(13-16-31(5)27(25)14-17-32(31,21(2)33)37-22(3)34)30(4)15-12-24(19-28(20)30)36-29(35)11-10-23-8-6-7-9-23/h18-19,23-27h,6-17h2,1-5h3/t24-,25+,26-,27-,30+,31-,32-/m0/s1key:wahqvrcndchdib-qzyspnbysa-n chemistry