Chemical Name: 4,4'-(1H-1,2,4-Triazol-1-ylmethanediyl)dibenzonitrile
Molecular Formula: C17H11N5
Molecular Weight: 285.30 g/mol
Structure: It features a triazole ring connected to two benzyl cyanide groups.
Physical Properties
Appearance: Letrozole is a white to off-white powder.
Solubility: It is soluble in DMSO and other organic solvents.
Stability: Store at -20°C for long-term storage (up to 3 years in powder form) or at 4°C for shorter durations (up to 2 years). In solvent, store at -80°C for up to 6 months or at -20°C for up to 1 month.
Biological Activity
Mechanism of Action: Letrozole selectively inhibits the activity of aromatase, an enzyme responsible for the conversion of androgens to estrogens. This leads to a reduction in estrogen levels.
IC50 Value: The IC50 value for Letrozole is 11.5 nM, indicating its potent inhibitory effect on aromatase.
In Vitro Studies: Letrozole has been shown to significantly inhibit the growth of MCF-7 epithelial breast cancer cells in a dose- and time-dependent manner. It also inhibits the stimulatory effects of testosterone on MCF-7 cell proliferation and suppresses the levels of secreted metalloproteinases (MMP-2 and MMP-9) in these cells.
In Vivo Studies: Letrozole exhibits anti-tumor effects in rats, with complete regression of mammary tumors observed at certain dosage levels.
