Anastrozole-d₁₂is intended for use as an internal standard for the quantification of anastrozole by GC- or LC-MS. Anastrozole is an aromatase/CYP19A1 inhibitor (IC₅₀= 15 nM for human placental aromatase/CYP19A1).¹It is selective for aromatase/CYP19A1 over the cytochrome P450 (CYP) isoforms CYP1A2, CYP2A6, CYP2C9, CYP2D6, and CYP3A (IC₅₀s = 27-650 μM). Anastrozole (0.1 mg/kg) blocks ovulation in mature female rats and androstenedione-stimulated uterine development in pubertal female rats.²It inhibits peripheral aromatase/CYP19A1 and reduces plasma estradiol concentrations in male pigtailed monkeys when administered at doses greater than 0.1 mg/kg. Anastrozole (0.5 mg/kg) reduces tumor incidence and the number of tumors by 40 and 57%, respectively, as well as increases latency to tumor appearance in a rat model of premenopausal mammary tumorigenesis.³Formulations containing anastrozole have been used in the treatment of breast cancer.

1.Grimm, S.W., and Dyroff, M.C.Inhibition of human drug metabolizing cytochromes P450 by anastrozole, a potent and selective inhibitor of aromataseDrug Metabolism and Disposition25(5)598-602(1997) 2.Plourde, P.V., Dyroff, M.C., and Dukes, M.Arimidex?: A potent and selective fourth-generation aromatase inhibitorBreast Cancer Res. Treat.30(1)103-111(1994) 3.Kubatka, P., Sadlonov?, V., Kajo, K., et al.Chemopreventive effects of anastrozole in a premenopausal breast cancer modelAnticancer Res.28(5A)2819-2823(2008)