Quadrosilan

Quadrosilan
Clinical data
Trade names	Cisobitan
Other names	Quadrosilane; KABI-1774; 2,6-cisdiphenylhexa-; methylcyclotetrasiloxane
Drug class	Nonsteroidal estrogen
Identifiers
	IUPAC name 2,2,4,6,6,8-hexamethyl-4,8-diphenyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane;
CAS Number	4657-20-9 ;
PubChem CID	20774;
ChemSpider	19557;
UNII	MM48TFA73C;
CompTox Dashboard (EPA)	DTXSID3063546 ;
Chemical and physical data
Formula	C18H28O4Si4
Molar mass	420.758 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES C[Si]1(O[Si](O[Si](O[Si](O1)(C)C2=CC=CC=C2)(C)C)(C)C3=CC=CC=C3)C;
	InChI InChI=1S/C18H28O4Si4/c1-23(2)19-25(5,17-13-9-7-10-14-17)21-24(3,4)22-26(6,20-23)18-15-11-8-12-16-18/h7-16H,1-6H3; Key:ZTQZMPQJXABFNC-UHFFFAOYSA-N;

Quadrosilan (INNTooltip International Nonproprietary Name, BANTooltip British Approved Name) (brand name Cisobitan; former developmental code name KABI-1774) is a synthetic nonsteroidal estrogen that was developed in the 1970s and that is or has been used as an antigonadotropic agent in the treatment of prostate cancer.^[1]^[2]^[3]^[4] It is an organosilicon compound, and is also known as 2,6-cisdiphenylhexamethylcyclotetrasiloxane.^[3]^[5] Quadrosilan has estrogenic activity equivalent to that of estradiol,^[6] and can produce feminization and gynecomastia as side effects in male patients.^[7]^[8]