In vivo studies of octreotide-modified N-octyl-O, N-carboxymethyl chitosan micelles loaded with doxorubicin for tumor-targeted delivery.

Octreotide (OCT) was recently found to have a high binding affinity for the somatostatin receptor expressed on tumor cells. In this study, OCT-polyethylene glycol-stearic acid (OCT-Phe-PEG-A) was used as a targeting molecule for N-octyl-O, N-carboxymethyl chitosan (OCC) micelles loaded with doxorubicin (DOX). For in vivo fluorescence imaging, the fluorescent probe Cyanine 7 (Cy7) was successfully loaded into OCC micelles with or without OCT modification (Cy7-OCC, Cy7-OCC-OCT), and their physicochemical properties were compared with DOX-loaded micelles (DOX-OCC and DOX-OCC-OCT). All micelles were less than 120 nm with spherical shape and zeta potential of around -30 mV. Enhanced tumor-targeting capacity of OCC-OCT micelles was observed in BALB/c nude mice bearing MCF-7 cancer xenografts as compared with the OCC micelles. Moreover, pharmacodynamic studies demonstrated that DOX-OCC-OCT presented a strongest inhibition of tumor growth and lowest systemic toxicity compared with the DOX solution and DOX-OCC micelles. All the results indicated that OCC-OCT micelles might be a promising tumor-targeting carrier for cancer therapy.