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 µg · mL−1. These results indicate that the H40‐PLA‐b‐MPEG micelles have great potential as hydrophobic drug delivery carriers.
