Octreotide-modified N-octyl-O, N-carboxymethyl chitosan micelles as potential carriers for targeted antitumor drug delivery.

Octreotide (OCT) was recently found to have high binding affinity to the positive tumor cells of somatostatin receptors (SSTRs). In this study, octreotide-Phe-polyethylene glycol-stearic acid was first successfully synthesized and used as a targeting molecule for N-octyl-O, N-carboxymethyl chitosan (OCC). Doxorubicin (DOX) was loaded into OCT-modified OCC micelles (DOX-OCC-OCT). The drug-loaded micelles obtained exhibited spherical shape, small particle sizes, and negative zeta potentials. The cytotoxicity of DOX-OCC-OCT micelles against MCF-7 cells (SSTRs expressing) was found to significantly increase with the increased amount of OCT modification, whereas no significant difference was observed against WI-38 cells (no SSTRs expressing). Results of flow cytometry, fluorescence microscopy, and confocal laser scanning microscopy confirmed that DOX-OCC-OCT micelles could remarkably increase the uptake of DOX in MCF-7 cells. All the results indicated that OCC-OCT micelles may be a promising intracellular targeting carrier for efficient delivery of antitumor drugs into tumor cells.