CAS No.: 107868-30-4

Molecular formula: C20H24O2

Molecular weight: 296.4

Overview: Exemestane is an irreversible steroidal aromatase inhibitor, and its structure is similar to the natural androstenedione. Depriving estrogen by inhibiting aromatase is an effective and optional method for the treatment of hormone dependent breast cancer in postmenopausal women. It is used for the advanced breast cancer of natural or artificial postmenopausal women who have not progressed after tamoxifen treatment.

Function and use: exemestane is a steroid aromatase inactivator, whose structure is similar to androstenedione, the natural substrate of aromatase, and is a pseudosubstrate of aromatase. Because the estrogen of postmenopausal women is mainly produced by the conversion of androgen (produced by adrenal cortex) under the action of aromatase in peripheral tissues, this product inactivates the aromatase by irreversible binding with the active site of aromatase, thus significantly reducing the estrogen level of k in the blood circulation of postmenopausal women. This product has no significant effect on the biosynthesis of adrenocortical hormone. Even if the concentration is 600 times higher than the concentration of inhibiting aromatase, it has no significant effect on other enzymes in the pathway of corticosteroid production. The oral absorption of this product is rapid, and the absorption is affected by food. The oral bioavailability is 42%. The drug absorption rate of postmenopausal women is higher than that of healthy subjects. The peak concentration of the drug in the blood reaches 2 to 4 hours after the patient takes the drug orally. The average peak time is 1.2 hours, which is shorter than that of healthy subjects (2.9 hours). Mainly related to α 1-acid glycoprotein and protein binding, the total protein binding rate is 90%. It is mainly delivered by the liver. The metabolite is inactive 17-hydroexemestane with a half-life of 24 hours. It is mainly excreted through urine or feces, accounting for 42% of the dosage.