Amphiphilic Multi-Arm Block Copolymer Based on Hyperbranched Polyester, Poly(L-lactide) and Poly(ethylene glycol) as a Drug Delivery Carrier

A novel type of biodegradable/biocompatible amphiphilic hyperbranched copolymer (H40-PLA-b-MPEG) was synthesized. Its micellar properties were studied by DLS, fluorescence spectroscopy and TEM. The drug release profile showed that the H40-PLA-b-MPEG micelles provide an initial burst release, followed by a sustained release of the entrapped hydrophobic model drug over a period of 4 to 58 h. The copolymer degraded hydrolytically within 6 weeks under physiological conditions. The MTT assay showed no obvious cytotoxicity against a human endothelial cell line at a concentration range of 0-400 mu g.mL(-l). These results indicate that the H40-PLA-b-MPEG micelles have great potential as hydrophobic drug delivery carriers.