Synthesis of novel pH-sensitive chitosan graft copolymers and micellar solubilization of paclitaxel

Herein, highly pH-sensitive graft copolymers, N-octyl-N-(2-carboxylbenzoyl) chitosan derivatives, were synthesized and characterized by FTIR, 1H NMR, 13C NMR, differential scanning calorimetry and X-ray diffraction spectrometry. The polymers can form micelles solublizing paclitaxel, with critical micellar concentrations ranged from 0.07 to 0.32 mg/ml, drug-loading rate ranged from 30.7% to 65.3% and entrapment efficiency ranged from 44.2% to 61.4%. Additionally, the result shows that the micelles display highly sensitivity to mildly acidic pH while reasonably stable at physiologic pH, which might pave the way for building pharmaceutical nanocarriers specifically releasing cargo at certain pathological sites of body.