Title: Exemestane
CAS Registry Number: 107868-30-4
CAS Name: 6-Methyleneandrosta-1,4-diene-3,17-dione
Manufacturers' Codes: FCE-24304
Trademarks: Aromasin (Pharmacia & Upjohn)
Molecular Formula: C20H24O2
Molecular Weight: 296.40
Percent Composition: C 81.04%, H 8.16%, O 10.80%
Literature References: Irreversible aromatase inhibitor. Prepn: E. Di Salle et al., DE 3622841; F. Buzzetti et al., US 4808616 (1987, 1989 both to Farmitalia Carlo Erba). Pharmacology: D. Giudici et al., J. Steroid Biochem. 30, 391 (1988). HPLC determn in plasma: M. Breda et al., J. Chromatogr. 620, 225 (1993). Clinical pharmacology: T. R. J. Evans et al., Cancer Res. 52, 5933 (1992). Review of clinical experience in primary and secondary therapy for breast cancer: J. M. Dixon, Expert Rev. Anticancer Ther. 2, 267-275 (2002). Clinical trial in sequential therapy following tamoxifen in breast cancer: R. C. Coombes et al., N. Engl. J. Med. 350, 1081 (2004).
Properties: White to slightly yellow crystalline powder. mp 188-191°. uv max: 247 nm (e 13750). Freely sol in DMF; sol in methanol. Practically insol in water.
Melting point: White to slightly yellow crystalline powder. mp 188-191°
Absorption maximum: uv max: 247 nm (e 13750)
Therap-Cat: Antineoplastic (hormonal).
Keywords: Antineoplastic (Hormonal); Aromatase Inhibitors; Aromatase Inhibitors.
Exendins Exifone Exiproben Exisulind Exosurf?

Systematic (IUPAC) name
Clinical data
Trade names Aromasin
AHFS/Drugs.com monograph
MedlinePlus a607006
Pregnancy cat. D
Legal status Rx only
Routes Oral
Pharmacokinetic data
Bioavailability ~60%
Protein binding 90%
Half-life 27 hours
CAS number 107868-30-4 YesY
ATC code L02BG06
PubChem CID 60198
DrugBank DB00990
ChemSpider 54278 YesY
KEGG D00963 YesY
Chemical data
Formula C20H24O2 
Mol. mass 296.403 g/mol
 YesY (what is this?)  (verify)

Exemestane (trade name Aromasin) is a drug used to treat breast cancer. It is a member of the class of drugs known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs), and are called ER-positive. They may also be called estrogen-responsive, hormonally-responsive, or hormone-receptor-positive. Aromatase is an enzyme that synthesizes estrogen. Aromatase inhibitors block the synthesis of estrogen. This lowers the estrogen level, and slows the growth of cancers.