Synthesis and characterization of an amphiphilic graft polymer and its potential as a pH-sensitive drug carrier

The synthesis and properties of a new pH-sensitive polymer Poly(epsilon-caprolactone) Grafted Poly(ethylene glycol) Based Poly(beta-amino ester) (PEGAE-g-PCL) are described here. The successful synthesis of the graft copolymer was confirmed by H-1 NMR. The self-assemble behavior of the amphiphilic polymer was investigated using pyrene as a probe. Dynamic light scattering (DLS) showed that the polymeric micelles had a size of 60 nm at physiological pH and were responsive to pH. A spherical morphology was observed for the micelles using transmission electron microscopy (TEM). Zeta-potential measurement at different pH showed that the micelles were neutral at pH 7.4 and positively charged at lower pH. Doxorubicin (DOX) was used as a model drug and loaded in the micelles. The drug loaded micelles showed a slow and pH-dependant drug release behavior. The remaining hydroxyl groups on the main chain made it possible the further conjugation of imaging agents or targeting groups. (C) 2011 Elsevier Ltd. All rights reserved.