Synthesis of Amphiphilic Comb-Shape Copolymers Via Ring-Opening Polymerization of a Macromonomer

Amphiphilic comb-shape copolymers PCL-co-P(MTC-mPEG(16)) (where PCL, MTC, and mPEG refer to poly(epsilon-caprolactone), 2-methyltrimethylene carbonate, and methoxy poly(ethylene glycol), respectively) are synthesized by ring-opening polymerization of epsilon-caprolactone and cyclic carbonate-terminated PEG macromonomer (MTC-mPEG(16)) with benzyl alcohol as an initiator and Sn(Oct)(2) as a catalyst. Amphiphilic copolymers PCL-co-P(MTC-mPEG(16)) can form micelles in aqueous solution by self-assembly. The diameters of PCL-co-P(MTC-mPEG(16)) micelles characterized by dynamic light scattering area few dozens of nanometers with a narrow size distribution and the morphology of the micelles observed through transmission electron microscopy are nanosized spheres. The in vitro drug release of comb-shape copolymer PCL-co-P(MTC-mPEG(16)) micelles is more stable and sustained than that of linear block copolymers mPEG-b-PCL.