PEG/PBT microspheres

PEG/PBT copolymers are also very good matrix materials for the release of growth factors in tissue engineering. Proteins have been delivered from PEG/PBT microspheres with preservation of protein delivery of complete activity. In the case of protein delivery from PLGA and poly(ortho ester) microspheres, the protein activity was significantly reduced. " ... 

Protein-containing PEG/PBT microspheres were prepared according to the well-known double-emulsion method (52,53). In contrast to what is often observed for hydrophobic polymers like PLGA, dense poly(ether ester) microspheres were obtained. This outcome was explained by the amphiphilic character of the polymers, which created very stable emulsions. The latter is considered a prerequisite for the formation of non-porous microspheres. A drawback of applying the w/o/w emulsion technique for the production of protein-... 

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