Anastrozole

Anastrozole is a potent, highly selective aromatase inhibitor, which inhibits human placental aromatase with an IC₅₀ of 15 nM. IC50 & Target:IC50: 15 nM (human aromatase)^[1] In Vitro:Anastrozole is a comparatively simple, achiral benzyltriazole derivative, that inhibits human placental aromatase with an IC₅₀ of 15 nM. In the same assay it is 200 times as potent as aminoglutethimide (AG), twice as potent as 4-OHA and one third as potent as Fadrozole^[1]. In Vivo:Groups of eight immature (22-day-old) female rats are given androstenedione (AD) (30 mg/kg) in arachis oil s.c. daily for 3 days with or without various doses of Anastrozole p.o. on day 4 the uteri are dissected, blotted and weighed. An oral dose of 0.1 mg/kg of Anastrozole given on day 2 or day 3 of the cycle completely blocked ovulation. At the same daily dosage (0.1 mg/kg), Anastrozole completely extinguished the uterotrophic activity of exogenous AD in immature rats. In male pigtailed monkeys, twice-daily oral treatment with 0.1 mg/kg and above of Anastrozole reduced circulating oestradiol concentrations by 50-60%^[1].