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(ɛ-caprolactone) Grafted Poly(ethylene glycol) Based Poly(ß-amino ester) (PEGAE-g-PCL) are described here. The successful synthesis of the graft copolymer was confirmed by 1H 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.