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.^{[1][2][3][4][5][6]} It was developed in China in the late 1970s and early to mid 1980s for use as a hormonal contraceptive.^{[1][2][3][4][5][6]} 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.^[1][2] 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."^[1] 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.^[2]

Cymegesolate

Clinical data
Other names	Cypionyl 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-cypionate
Routes of administration	By mouth[1][2]
Drug class	Progestin; Progestogen; Progestogen ester
Identifiers
IUPAC name [(3S,8R,9S,10R,13S,14S,17R)-17-Acetyl-17-acetyloxy-6,10,13-trimethyl-1,2,3,8,9,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-3-yl] 3-cyclopentylpropanoate
CAS Number	72648-88-5 Y
PubChem CID	126290
ChemSpider	112247
UNII	4D9TFH8PLX
CompTox Dashboard (EPA)	DTXSID70993490
Chemical and physical data
Formula	C32H46O5
Molar mass	510.715 g·mol−1
3D model (JSmol)	Interactive image
SMILES CC1=C[C@@H]2[C@H](CC[C@]3([C@H]2CC[C@@]3(C(=O)C)OC(=O)C)C)[C@@]4(C1=C[C@H](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/s1 Key:WAHQVRCNDCHDIB-QZYSPNBYSA-N

Chemistry

See also: Progestogen ester and List of progestogen esters

Cymegesolate, also known as megestrol acetate 3β-cypionate, as well as 17α-acetoxy-6-dehydro-6-methylprogesterone 3β-cyclopentylpropionate or 17α-acetoxy-6-methylpregna-4,6-diene-3,20-dione 3β-cyclopentylpropionate, is a synthetic pregnane steroid and a derivative of progesterone and 17α-hydroxyprogesterone.^[1][2] It is the C3β cypionate (cyclopentylpropionate) ester of megestrol acetate.^[1][2] A closely related medication is acetomepregenol (mepregenol diacetate; also known as megestrol 3β,17α-diacetate), which, in contrast, has been marketed.^{[7][8][9][10]}