Nilestriol

Nilestriol
Clinical data
Trade names	Wei Ni An
Other names	Nylestriol; LY-49825; Ethinylestriol cyclopentyl ether; EE3CPE; 17α-Ethynylestriol 3-cyclopentyl ether
Routes of; administration	By mouth
Drug class	Estrogen; Estrogen ether
Identifiers
	IUPAC name (8R,9S,13S,14S,16R,17R)-3-cyclopentyloxy-17-ethynyl-13-methyl-7,8,9,11,12,14,15,16-octahydro-6H-cyclopenta[a]phenanthrene-16,17-diol;
CAS Number	39791-20-3;
PubChem CID	38346;
ChemSpider	35146;
UNII	7JA3B3IALU;
KEGG	D05212;
ChEMBL	ChEMBL2104468;
CompTox Dashboard (EPA)	DTXSID601043308 ;
Chemical and physical data
Formula	C25H32O3
Molar mass	380.528 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES C[C@]12CC[C@H]3[C@H]([C@@H]1C[C@H]([C@]2(C#C)O)O)CCC4=C3C=CC(=C4)OC5CCCC5;
	InChI InChI=1S/C25H32O3/c1-3-25(27)23(26)15-22-21-10-8-16-14-18(28-17-6-4-5-7-17)9-11-19(16)20(21)12-13-24(22,25)2/h1,9,11,14,17,20-23,26-27H,4-8,10,12-13,15H2,2H3/t20-,21-,22+,23-,24+,25+/m1/s1; Key:CHZJRGNDJLJLAW-RIQJQHKOSA-N;

Nilestriol (INNTooltip International Nonproprietary Name) (brand name Wei Ni An; developmental code name LY-49825), also known as nylestriol (USANTooltip United States Adopted Name, BANTooltip British Approved Name), is a synthetic estrogen which was patented in 1971^[1] and is marketed in China.^[2]^[3] It is the 3-cyclopentyl ether of ethinylestriol, and is also known as ethinylestriol cyclopentyl ether (EE3CPE).^[4] Nilestriol is a prodrug of ethinylestriol, and is a more potent estrogen in comparison.^[4] It is described as a slowly-metabolized, long-acting estrogen and derivative of estriol.^[5]^[6] Nilestriol was assessed in combination with levonorgestrel for the potential treatment of postmenopausal osteoporosis, but this formulation ultimately was not marketed.^[7]