Atorvastatin-loaded lipid nanoparticles: antitumor activity studies on MCF-7 breast cancer cells

Atorvastatin is a synthetic statin commonly used in the treatment of hypercholesterolemia. Apart from this, statins appear to have pleiotropic effects, including modulation of cell growth, apoptosis. Through modulation of these pathways, statins have the potential to influence a wide range of disease processes, including cancer. However, poor aqueous solubility (0.1 mg/mL) and poor oral bioavailability has limited therapeutic application of atorvastatin. Present work is an attempt to improve tumor targeting of atorvastatin by incorporating in nanostructured lipid carriers (NLCs) and studying its anticancer activity on MCF-7 cell lines. NLCs of atorvastatin were formulated by high-speed homogenization followed by probe sonication method. The optimized batch of NLCs had a mean size of 130.02 +/- 3.1 nm and entrapment efficiency of 90.42 +/- 3.7%. The in vitro drug release study by dialysis method indicated that drug entrapped in the NLCs remains entrapped at acidic pH as well as in phosphate buffer of pH 7.4 for a prolonged period of time as compared to plain drug. In vitro cytotoxicity studies on MCF-7 (mammary adenocarcinoma human cell lines) cell lines showed that concentration of drug required for total growth inhibition (TGI) and 50% growth inhibition (GI50) of MCF-7 cells was found to be 27.4 mu g/mL and <10 mu g/mL respectively, in case of atorvastatin-NLCs which is less than that required in case of plain atorvastatin and almost similar to that of adriamycin. All these findings reinforce the fact that atorvastatin loaded NLCs are promising novel delivery system for treating breast cancer.