Chemical Component Summary

NameEthinyl estradiol
FormulaC20 H24 O2
Molecular Weight296.40
Isomeric SMILESC[C@]12CC[C@H]3[C@@H](CCc4cc(O)ccc34)[C@@H]1CC[C@@]2(O)C#C

Chemical Details

Formal Charge0
Atom Count46
Chiral Atom Count5
Chiral AtomsCAR, CAS, CAT, CAU, CAV
Bond Count49
Aromatic Bond Count6
Leaving Atomsn/a

Drug Info: DrugBank

DrugBank IDDB00977 Different stereochemistry
NameEthinyl Estradiol
DescriptionA semisynthetic alkylated estradiol with a 17-alpha-ethinyl substitution. It has high estrogenic potency when administered orally and is often used as the estrogenic component in oral contraceptives [PubChem]. Ethinyl estradiol is marketed mostly as a combination oral contraceptive under several brand names such as Alesse, Tri-Cyclen, Triphasil, and Yasmin. The FDA label includes a black box warning that states that combination oral contraceptives should not be used in women over 35 years old who smoke due to the increased risk of serious cardiovascular side effects.
  • 17 alpha-Ethinylestradiol
  • 17 alpha-Ethynylestradiol
  • 17 alpha-Ethynyloestradiol
  • 17-ethinyl-3,17-estradiol
  • 17-ethinyl-3,17-oestradiol
Brand Names
  • Afirmelle
  • Alesse 21
  • Alesse 28
  • Altavera
  • Alyacen 1/35
Affected OrganismHumans and other mammals
IndicationFor treatment of moderate to severe vasomotor symptoms associated with the menopause, female hypogonadism, prostatic carcinoma-palliative therapy of advanced disease, breast cancer, as an oral contraceptive, and as emergency contraceptive.
PharmacologyEthinyl estradiol is a synthetic derivative of the natural estrogen estradiol. It is one of two estrogens currently used in oral contraceptive pills. The other, mestranol, is converted to ethinyl estradiol before it is biologically active. Ethinyl estradiol and norethindrone are used together as an oral contraceptive agent.
Mechanism of actionEstrogens diffuse into their target cells and interact with a protein receptor. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. This cascade is initiated by initially binding to the estrogen receptors. The combination of an estrogen with a progestin suppresses the hypothalamic-pituitary system, decreasing the secretion of gonadotropin-releasing hormone (GnRH).
Route of administration
  • Oral
  • Transdermal
  • Vaginal
  • BSEP/ABCB11 Inhibitors
  • Chemical Actions and Uses
  • Cytochrome P-450 CYP2C8 Inhibitors
  • Cytochrome P-450 CYP3A4 Substrates
  • Estradiol Congeners
  • G03AA03
  • G03AA04
  • G03AA08
  • G03AA10
  • G03AB07
CAS number57-63-6
Drug Info/Drug Targets: DrugBank 3.0: a comprehensive resource for 'omics' research on drugs. Knox C, Law V, Jewison T, Liu P, Ly S, Frolkis A, Pon A, Banco K, Mak C, Neveu V, Djoumbou Y, Eisner R, Guo AC, Wishart DS. Nucleic Acids Res. 2011 Jan; 39 (Database issue):D1035-41. | PMID:21059682