Synthesis and characteristics of biodegradable and temperature responsive polymeric micelles based on poly(aspartic acid)-g-poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide)

Temperature responsive polymeric micelles can release drug at controlled rate and minimize the side effects, and have been widely used for drug delivery system. In this study, biodegradable and temperature responsive micelles comprised of poly(aspartic acid)-g-poly(N-isopropylacryamide-co-N,N-dimethylacrylamide) (PASp-g-poly(NIPAAm-co-DMAAm)) were successfully synthesized by grafting poly(NIPAAm-co-DMAAm) onto poly(succinimide) and followed by aminolysis with ammonia hydroxide. The micelles had free amine group and exhibited a phase transition temperature above normal body temperature, which was suitable for targeting drug delivery. In addition, PASp-g-poly(NIPAAm-co-DMAAm) was stable in phosphate buffer solution at 37 °C, and 25% of micelles could degrade within 3 days. Based on these results, the present study demonstrated that PASp-g-poly(NIPAAm-co-DMAAm) can be used as a drug carrier for targeting treatment.