Tumor targetability and antitumor effect of docetaxel-loaded hydrophobically modified glycol chitosan nanoparticles

Hydrophobically modified glycol chitosan (HGC) nanoparticles, a new nano-sized drug carrier, were prepared by introducing a hydrophobic molecule, cholanic acid, to water soluble glycol chitosan. The HGC nanoparticles were easily loaded with the anticancer drug docetaxel (DTX) using a dialysis method, and the resulting docetaxel-loaded HGC (DTX-HGC) nanoparticles formed spontaneously self-assembled aggregates with a mean diameter of 350 nm in aqueous condition. The DTX-HGC nanoparticles were well dispersed and stable for 2 weeks under physiological conditions (pH 7.4 and 37°C) and a sustained drug release profile, in vitro. In addition, the DTX-HGC nanoparticles were reasonably stable in the presence of excess bovine serum albumin, which suggested that the DTX-HGC nanoparticles might also be stable in the blood stream. The DTX-HGC nanoparticles exhibited a distinctive deformability in aqueous conditions, in that they could easily pass through a filter membrane with 200 nm pores despite their mean diameter of 350 nm. We also evaluated the time-dependent excretion profile, in vivo biodistribution, prolonged circulation time, and tumor targeting ability of DTX-HGC nanoparticles by using a non-invasive live animal imaging technology. Finally, under optimal conditions for cancer therapy, the DTX-HGC nanoparticles showed higher antitumor efficacy such as reduced tumor volume and increased survival rate in A549 lung cancer cells-bearing mice and strongly reduced the anticancer drug toxicity compared to that of free DTX in tumor-bearing mice. Together our results showed that the anticancer loaded nano-sized drug carriers are a promising nano-sized drug formulation for cancer therapy.