Synthesis, characterization and properties of biodegradable polylactic acid-β-cyclodextrin cross-linked copolymer microgels

The novel biodegradable polylactic acid-beta-cyclodextrin (PLA-beta-CD) cross-linked copolymer microgels were prepared by the radical copolymerization of PLA macromonomer and polymerizable beta-CD derivatives. The beta-CD derivatives with various numbers of polymerizable vinyl groups were synthesized from 1-allyloxy-2,3-epoxy propane (also called allylglycidyl ether, AGE) and beta-CD. The chemical structures of polymerizable monomers were determined by NMR. The thermal properties, size, morphology, in vitro degradation and swelling behavior of the microgels were investigated. The results indicated that the microgels were stable under thermal conditions up to 200 C. The microgels were spherical in aqueous solution. The hydrophilicity of the microgels increased with increasing beta-CD contents, while the swelling ratios and degradation rate decreased. The more vinyl groups on beta-CD, the higher cross-linked density, which resulted in a decrease of the swelling ratios and the rate of degradation. Crown Copyright (c) 2008 Published by Elsevier Ltd. All rights reserved.