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| The amphiphilic block copolymer polystyrene-b-poly(N,N-diethylacrylamide-co-N,N-dimethyl-acrylamide) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of N,N-diethylacrylamide (DEA) and N,N-dimethylacrylamide (DMA) using polystyrene as macro-RAFT agent. Polymeric micelles were prepared by dialysis of the block copolymer solution in THF against aqueous media. The polymeric micelles PM73 based on block copolymer P73, which was prepared with molar ratio DEA/DMA/PSt CTA/AIBN = 700:300:10:1, exhibited a lower critical solution temperature (39.2°C) in aqueous solution which was a little higher than the human body temperature. Polymeric micelles PM73 showed a unimodal size distribution with an average diameter of 24.2±0.5 nm. The micelles were thermodynamically stable in aqueous media above the critical micelle concentration (1 mg/l). The anti-inflammation drug, prednisone acetate, was incorporated into PM73 as the model drug. The loading capacity was found to be around 8 wt%, and the drug-loaded micelles showed similar size distribution patterns (monodisperse with an average diameter of 32.1±0.5 nm) and morphology (spherical) to the empty micelles. The drug-loaded micelles showed remarkable thermoresponsive drug release behavior, in response to the micellar structural change. These results suggest that the nano-size polymeric micelles might be useful as drug carriers to achieve the site-specific delivery of drugs. |
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| Keywords:PSt-b-P(DEA-co-DMA)； RAFT；Polymeric micelle；Thermo-sensibility; Drug delivery system |
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