RESUMO
The aim of the present study was to load docetaxel (DCT) and Fe3O4 magnetic nanoparticles (MNPs) in polymeric micelles to concentrate them by an external magnetic field in target tissues. Oleic acid (OA) coated MNPs were prepared by hydrothermal method. The micelles were characterized for their zeta potential, particle size, drug loading and release efficacy. Fe loading efficacy was determined by atomic absorption. The magnetic micelles were characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy and vibrating sample magnetometer (VSM). The cytotoxicity of the micelles was studied by MTT assay on L929 fibroblast cells and also on two breast cancer cell lines of MCF-7 and MDA-MB-231. The optimum formulation showed 70% drug loading efficiency, zeta potential of -2.58 mV, particle size of 144.3 nm and drug release efficiency within 24 h of 68.9% at pH 5.5. Fe was loaded in these nanomicelles 290 µg/100 ml. TGA results confirmed the coating of MNPs with OA and polymeric micelles. The VSM analysis confirmed superparamagnetic property of the micelles. DCT loaded in micelles showed significantly more cytotoxicity compared to free drug on MCF-7 and MDA-MB-231 cells, but blank magnetic micelles had no significant cytotoxicity on normal fibroblast cells.