Breast cancer (BC) is one of the most commonly diagnosed malignancies in the world. It is responsible for the majority of female mortality. Letrozole (LTZ) is an effective treatment for postmenopausal women whose BC responds positively to hormone receptors, but it has also been reported to have some unpleasant side effects. The inherent limitations of current anticancer drugs require the development of innovative technologies for more effective and safer cancer therapy. To address this problem, in this study, we fabricated unique PLGA nanoparticles loaded with LTZ. Optimized LTZ-PLGA nanoparticles (LTZ-PLGA NP) exhibited a particle size of 53.19 nm, with a polydispersity index (PDI) of 0.387 and a negative zeta potential of -10.9 mV. LTZ-PLGA NP also showed dosedependent cell toxicity against MDA-MB-231 human breast cancer cell lines, with an inhibitory concentration (IC50) of 5.64± 0.346 µg/ml. The hemolytic properties indicate that LTZ-PLGA NPs are compatible with blood components. In general, the newly synthesized LTZ-PLGA NPs were in the nanosize range, had good entrapment efficiency and a slow drug release profile with good inhibitory concentrations against MDA-MB-231.

Breast cancer; letrozole; nanoparticle; MDA-MB-231