Amphiphilic Block-Graft Copolymers Poly(ethylene glycol)-b-(polycarbonates-g-palmitate) Prepared via the Combination of Ring-Opening Polymerization and Click Chemistry

Amphiphilic block-graft copolymers mPEG-b-P(DTC-ADTC-g-Pal) were synthesized by ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and 2,2-bis(azidomethyl) trimethylene carbonate (ADTC) with poly(ethylene glycol) monomethyl ether (mPEG) as an initiator, followed by the click reaction of propargyl palmitate and the pendant azido groups on the polymer chains. Stable micelle solutions of the amphiphilic block-graft copolymers could be prepared by adding water to a THF solution of the polymer followed by the removal of the organic solvent by dialysis. Dynamic light scattering measurements showed that the micelles had a narrow size distribution. Trans-mission electron microscopy images displayed that the micelles were in spherical shape. The grafted structure could enhance the interaction of polymer chains with drug molecules and improve the drug-loading capacity and entrapment efficiency. Further, the amphiphilic block-graft copolymers mPEG-b-P(DTC-ADTC-g-Pal) were low cytotoxic and had more sustained drug release behavior. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: 2687-2696, 2012