PEG-chitosan-coated iron oxide nanoparticles with high saturated magnetization as carriers of 10-hydroxycamptothecin: Preparation, characterization and cytotoxicity studies

A magnetic nano-sized carrier for 10-hydroxycamptothecin (HCPT) was prepared by using Fe3O4 nanoparticles as cores and chitosan (CS) as a polymeric shell by a novel reverse ultrasonic emulsification method. Poly(ethylene glycol) (PEG) chains were then coupled onto the magnetic particles (CS-Fe3O4) to improve their biocompatibility (PEG-CS-Fe3O4). HCPT was loaded onto PEG-CS-Fe3O4 by a subtle precipitation method. Under optimum conditions, the CS-Fe3O4 was close to spherical in shape with an average size of 174 nm and a high saturated magnetization. After coupling PEG chains, the unspecific adsorption of bovine serum albumin (BSA) on PEG-CS-Fe3O4 decreased significantly. The drug loading content and loading efficiency were 9.8–11.8% and 49–59% for magnetic composite nanoparticles, respectively. HCPT-loaded magnetic composite nanoparticles showed sustained release profiles up to 48 h, and the cumulative release amount of HCPT from nanoparticles at 45 °C increased significantly compared to that at 37 °C. Cytotoxicity assay suggests that CS-Fe3O4 does not exhibit noteworthy cytotoxicity against HepG2 cells, but the antitumor activities of HCPT-loaded magnetic composite nanoparticles against HepG2 cells increased significantly in comparison with that of pristine HCPT powder. These results reveal the promising potential of PEG-CS-Fe3O4 as a stable magnetic targeting drug carrier in cancer therapy.