Objective: To prepare mPEG-PCL copolymer and polymersomes

then investigate in vitro release of INS-mPEG114-PCL152 polymersomes. Method: mPEG-PCL block copolymer was synthesized by ring-opening polymerization method

chemical structure of these polymers were characterized by FT-IR and 1H-NMR.Polymersomes were prepared by film hydration method

particle size and apparent morphology were examined by dynamic light scattering and transmission electron microscope

respectively;critical aggregation concentration(CAC) was detected by fluorescence techniques with pyrene as a probe.Encapsulation efficiency

drug loading and in vitro release characteristic of INS-mPEG114-PCL152 polymersomes were determined by Bradford method. Result: Average particle sizes of blank polymersomes were about 200 nm

CAC were all low value.These prepared INS-mPEG114-PCL152 with 20% drug-copolymer ratio had maximize utilizaiton ratio

average encapsulation efficiency (62.80±2.14)% as well as drug loading (11.10±0.34)%.In vitro cumulative release of INS-mPEG114-PCL152 polymersomes in 48 h was about 55.05%

with relatively significant burst release at initial 2 h about 19.28%. Conclusion: These polymersomes have uniform particle size with a great anti-dilution capability.INS-mPEG114-PCL152 polymersomes show a significant burst release at initial stage and then a good sustained-release property with dissociation of surface model drug.