102676-31-3

IC50: 6.4 nM (aromatase)

Fadrozole hydrochloride is a potent, selective and nonsteroidal inhibitor of aromatase with an IC ₅₀ of 6.4 nM. In hamster ovarian slices, Fadrozole hydrochloride inhibits the production of estrogen with an IC ₅₀ of 0.03 μM. The production of progesterone is inhibited with an IC ₅₀ of 120 μM. Synthesis of other cytochrome P-450 dependent steroids can be suppressed to various degrees with higher doses of Fadrozole hydrochloride.

Fadrozole hydrochloride is able to inhibit the aromatase-mediated uterine hypertrophy in immature female rats with an ED ₅₀ of 0.03 mg/kg when given orally. In the same model, aminoglutethimide elicits the same effect with an ED ₅₀ of 30 mg/kg when given orally. Fadrozole hydrochloride prevents the development of both benign and malignant spontaneus mammary neoplasns in female Sprague-Dawley rats. It also slows the spontaneous development of ptuitary pars distalis adenomas in female rats, and reduces the incidence of spontaneous hepatocellular tumours in male and female rats. Administration of Fadrozole hydrochloride in male and female mice accompanies with a 70% reduction in parasite burden. This protective effect is associated in male mice with a recovery of the specific cellular immune response. Interleukin-6 (IL-6) serum levels, and its production by splenocytes, is augmented by 80%, together with a 10-fold increase in its expression in testes of infected male mice. Fadrozole hydrochloride treatment returns these levels to baseline values.