pH-responsive polymeric micelles based on poly(ethyleneglycol)-b-poly(2-(diisopropylamino) ethyl methacrylate) block copolymer for enhanced intracellular release of anticancer drugs.

We present a pH-responsive poly(ethyleneglycol)-b-poly(2-(diisopropylamino) ethyl methacrylate) block copolymer (MPEG-PPDA) that can self-assemble into micelles at very low critical micelle concentration. The formed micelles exhibit superior stability in physiological environment and pH-triggered transforming capability between self-assembly and disassembly. Moreover, the resulting micelles can load hydrophobic anticancer drug molecules such as doxorubicin in the core of micelles. The pH-triggered drug release kinetics matches the classical hydrazone bond model. The blank micelles demonstrate minimal cytotoxicity while the drug-loaded micelles exhibit significantly improved anticancer efficacy. These results indicate that this MPEG-PPDA block copolymer could be utilized as a universal pH-responsive delivery system for controlled release of hydrophobic anticancer drug in chemotherapy.