Biological Effects of Letrozole-Loaded Lipid Nanocapsules on MCF-7 Cell Line

Aromatase inhibitors such as letrozole inhibit the synthesis of estrogens and help in the treatment of estrogen-dependent breast cancer. Using letrozole-loaded lipid nanocapsules (LNCs) as site directed drugs may help in the treatment of these tumors. LNCs were prepared by triglycerides، lecithin and polyethylene glycol in water phase inversion method. Prepared LNCs had particle size of less than 100 nm and were characterized with their particle size، zeta potential، and polydispersity index by Malvern Zeta-Sizer. LNCs were tested against MCF-7 cells (human breast adenocarcinoma cell line). They were compared with free letrozole in terms of cytotoxicity using 3- (4،5-dimethylthiazol-2-yl) -2،5-diphenyltetrazolium bromide (MTT) assay. S17O20L1. 5W3. 5، with particle size of 100 ± 3. 4 nm، zeta potential of -3. 6 ± 0. 4، polydispersity of 0. 283 ± 0. 08، and loading efficiency of 96. 6 ± 1. 5، was the optimum formulation. Cytotoxicity of the prepared LNCs was 80% of that of free letrozole. This effect was concentration-dependent، i. e. cell survivals in stock solutions of 50 µg/ml، 10 µg/ml، and 5 µg/ml were 20%، 40%، and 60 %، respectively. LNCS can be used as a selective formulation against cancer cells. Their cytotoxic effect is comparable to free letrozole.