Title: Estradiol
CAS Registry Number: 50-28-2
CAS Name: (17b)-Estra-1,3,5(10)-triene-3,17-diol
Additional Names: b-estradiol; cis-estradiol; 3,17-epidihydroxyestratriene; dihydrofollicular hormone; dihydrofolliculin; dihydroxyestrin; dihydrotheelin
Trademarks: Climara (Berlex); Estrace (Warner-Chilcott); Estraderm (Novartis); Estradot (Novartis); Estring (Pharmacia & Upjohn); Estrofem (Novo Nordisk); Estrogel (Solvay); Evorel (Janssen-Cilag); Menostar (Berlex); Systen (Janssen-Cilag); Vivelle (Novartis); Vivelle-Dot (Novartis); Zumenon (Solvay)
Molecular Formula: C18H24O2
Molecular Weight: 272.38
Percent Composition: C 79.37%, H 8.88%, O 11.75%
Literature References: Potent mammalian estrogenic hormone produced by the ovary. Triggers the production of gonadotropins leading to ovulation. Isoln from follicular fluid of sow ovaries: D. W. MacCorquodale et al., J. Biol. Chem. 115, 435 (1936). Has also been isolated from urine of pregnant women and mares. Prepn from estrone: A. Butenandt, C. Georgens, Z. Physiol. Chem. 248, 129 (1937); F. Hildebrandt et al., US 2096744 (1938 to Schering); from cholesterol: H. H. Inhoffen, G. Zühlsdorff, Ber. 74, 1914 (1941). Total syntheses: U. Eder et al., Ber. 109, 2948 (1976); W. Oppolzer, D. A. Roberts, Helv. Chim. Acta 63, 1703 (1980). Pharmacology: R. W. Lievertz, Am. J. Obstet. Gynecol. 156, 1289 (1987). HPLC determn in plasma and urine: W. Slikker et al., J. Chromatogr. 224, 205 (1981). Pharmacokinetics: W. Kuhnz et al., Arzneim.-Forsch. 43, 966 (1993). Clinical evaluation in osteoporosis: J. W. W. Studd et al., Br. J. Obstet. Gynaecol. 101, 787 (1994). Comprehensive description: E. G. Salole, Anal. Profiles Drug Subs. 15, 283-318 (1986). Physiologic review: H. G. Burger, Int. J. Gynaecol. Obstet. 1989, Suppl. 1, 5-9. Review of clinical safety and efficacy in estrogen replacement therapy: A. Cheang et al., Drug Saf. 9, 365-379 (1993); H. L. Judd, J. Reprod. Med. 39, 343-352 (1994).
Properties: White crystalline powder. Prisms from 80% alc, stable in air, mp 173-179°. [a]D25 +76 to +83° (dioxane). uv max: 225, 280 nm. Precipitated by digitonin. Practically insol in water. Freely sol in alcohol; sol in acetone, dioxane, other organic solvents; solns of fixed alkali hydroxides; sparingly sol in vegetable oils. 1 mg = 10,000 international units.
Melting point: mp 173-179°
Optical Rotation: [a]D25 +76 to +83° (dioxane)
Absorption maximum: uv max: 225, 280 nm
Derivative Type: Hemihydrate
CAS Registry Number: 35380-71-3
Trademarks: Estroclim (Sigma-Tau); Menorest (Novartis); Vagifem (Novo Nordisk)
Molecular Formula: C18H24O2.½H2O
Molecular Weight: 281.39
Percent Composition: C 76.83%, H 8.96%, O 14.21%
Derivative Type: 3-Acetate
CAS Registry Number: 4245-41-4
Trademarks: Femring (Warner-Chilcott); Femtrace (Warner-Chilcott)
Molecular Formula: C20H26O3
Molecular Weight: 314.42
Percent Composition: C 76.40%, H 8.33%, O 15.27%
Derivative Type: 3-Benzoate
CAS Registry Number: 50-50-0
Additional Names: Estradiol benzoate
Trademarks: Agofollin (Biotika); Duralease (Merial); Ovahormon (Teikoku Zoki); Progynon B (Schering AG)
Molecular Formula: C25H28O3
Molecular Weight: 376.49
Percent Composition: C 79.75%, H 7.50%, O 12.75%
Properties: Crystals from alc, mp 191-196°. Stable in air. [a]D25 +58 to +63° (c = 2 in dioxane). Sol in alc, acetone, dioxane; slightly sol in ether, vegetable oils.
Melting point: mp 191-196°
Optical Rotation: [a]D25 +58 to +63° (c = 2 in dioxane)
Derivative Type: 17b-Cyclopentanepropanoate
CAS Registry Number: 313-06-4
Additional Names: Estradiol cypionate; ECP
Molecular Formula: C26H36O3
Molecular Weight: 396.56
Percent Composition: C 78.75%, H 9.15%, O 12.10%
Literature References: Prepn: Ott, US 2611773 (1952 to Upjohn).
Properties: Crystals from benzene + petr ether, mp 151-152°. [a]D25 +45° (chloroform). Sol in ether, methanol, benzene, chloroform, peanut oil, cottonseed oil, corn oil, sesame oil.
Melting point: mp 151-152°
Optical Rotation: [a]D25 +45° (chloroform)
Derivative Type: Dipropionate
CAS Registry Number: 113-38-2
Trademarks: Ovahormon Depot (Teikoku)
Molecular Formula: C24H32O4
Molecular Weight: 384.51
Percent Composition: C 74.97%, H 8.39%, O 16.64%
Literature References: Prepn: K. Miescher, C. Scholz, US 2205627 (1940 to Ciba).
Properties: mp 104-105°.
Melting point: mp 104-105°
Derivative Type: 17-Heptanoate
CAS Registry Number: 4956-37-0
Additional Names: Estradiol enanthate
Manufacturers' Codes: SQ-16150
Molecular Formula: C25H36O3
Molecular Weight: 384.55
Percent Composition: C 78.08%, H 9.44%, O 12.48%
Literature References: Prepn: Gauthier et al., Ann. Pharm. Fr. 16, 757 (1958).
Properties: Crystals from diisopropyl ether, mp 94-96°.
Melting point: mp 94-96°
Derivative Type: 17-Valerate
CAS Registry Number: 979-32-8
Trademarks: Climaval (Novartis); Delestrogen (Monarch); Pelanin Depot (Mochida); Progynon Depot (Schering AG); Progynova (Schering AG)
Molecular Formula: C23H32O3
Molecular Weight: 356.50
Percent Composition: C 77.49%, H 9.05%, O 13.46%
Literature References: Prepn: K. Miescher, C. Scholz, US 2233025 (1941 to Ciba). Comprehensive description: K. Florey, Anal. Profiles Drug Subs. 4, 192-208 (1975).
Properties: Crystals, mp 144-145°.
Melting point: mp 144-145°
CAUTION: These substances are listed as known human carcinogens: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-115.
Therap-Cat: Estrogen.
Therap-Cat-Vet: Estrogen.
Keywords: Estrogen; Steroidal.
Estragole Estramustine Estriol Estrone Etafedrine

Systematic (IUPAC) name
Clinical data
Trade names Climara, Menostar
AHFS/ monograph
Pregnancy cat. X (USA)
Legal status S4 (Au), POM (UK), ℞-only (U.S.)
Routes Oral, transdermal
Pharmacokinetic data
Bioavailability 97–99% is bound
Metabolism Liver
Half-life ~13-17 hours
Excretion Urine, and sweat glands
CAS number 50-28-2 YesY
ATC code G03CA03
PubChem CID 5757
IUPHAR ligand 1012
DrugBank DB00783
ChemSpider 5554 YesY
UNII 4TI98Z838E YesY
KEGG D00105 YesY
ChEBI CHEBI:16469 YesY
Synonyms (8R,9S,13S,14S,17S)-13-methyl-6,7,8,9,11,12,14,15,16,17-decahydrocyclopenta[a]phenanthrene-3,17-diol
Chemical data
Formula C18H24O2 
Mol. mass 272.38 g/mol
 YesY (what is this?)  (verify)

Estradiol (E2 or 17β-estradiol, also oestradiol) is a sex hormone. Estradiol is abbreviated E2 as it has two hydroxyl groups in its molecular structure. Estrone has one (E1) and estriol has three (E3). Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect. Except during the early follicular phase of the menstrual cycle, its serum levels are somewhat higher than that of estrone during the reproductive years of the human female. Thus it is the predominant estrogen during reproductive years both in terms of absolute serum levels as well as in terms of estrogenic activity. During menopause, estrone is the predominant circulating estrogen and during pregnancy estriol is the predominant circulating estrogen in terms of serum levels. Estradiol is also present in males, being produced as an active metabolic product of testosterone. The serum levels of estradiol in males (14 - 55 pg/mL) are roughly comparable to those of postmenopausal women (< 35 pg/mL). Estradiol in vivo is interconvertible with estrone; estradiol to estrone conversion being favored. Estradiol has not only a critical impact on reproductive and sexual functioning, but also affects other organs, including the bones.