4887 17a-Estradiol 17a-estradiol is found in the estrogen patch. The estrogen patch is a delivery system for estradiol used as hormone replacement therapy to treat the symptoms of menopause, such as hot flashes and vaginal dryness, and to prevent osteoporosis. Originally marketed as Vivelle (Novartis), it was discontinued in 2003 and reintroduced in a smaller form as Vivelle-Dot. Although the estrogen is given transdermally rather than in the standard oral tablets, the estrogen patch carries similar risks and benefits as more conventional forms of estrogen-only hormone replacement therapy. 57-91-0 68570 C18H24O2 White powder. 216 - 219 °C 0.0039 mg/mL No indication of carcinogenicity to humans (not listed by IARC). 2014-09-11T05:18:22Z 2026-04-05T15:31:20Z C02537 17160 true [H][C@@]12CC[C@@H](O)[C@@]1(C)CC[C@]1([H])C3=C(CC[C@@]21[H])C=C(O)C=C3 C18H24O2 InChI=1S/C18H24O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h3,5,10,14-17,19-20H,2,4,6-9H2,1H3/t14-,15-,16+,17-,18+/m1/s1 VOXZDWNPVJITMN-SFFUCWETSA-N 272.382 272.177630012 Endogenous Solid HMDB00429 CHEMBL286452 61840 Gardi, Rinaldo; Pedrali, Cesare; Ercoli, Alberto. 3-Cyclopentyl ethers of 16,17-oxygenated estrogens. New synthesis of 17a-estradiol. Gazzetta Chimica Italiana (1963), 93(8-9), 1028-43. CHEM003788 DTXSID8022377 NS00075580 40.46 79.90469999999999 31.927942457761795 0 2 2 10.327060716263132 -0.8839974156894889 0 4 3.57 -4.11 2.13e-02 g/l