Preparation And Characterization Of Doxorubicin-Loaded PELA Triblock Copolymer Microcapsules

The triblock Copolymers poly(lactic acid)-poly(ethylene glucol)-poly(lactic acid)(PELA) were synthesized by ring-opening bulk polymerization of D,L-lactide initiated with poly(ethylene glycol).The structure of PELA Copolymers were characterized by IR. The water adsorption and degradation properties of the Copolymers were studied. It was found that the water adsorption capacity of the copolymer films increased with the increase of the molecular weight and contents of PEG segment in copolymer. The degradation time of copolymer in phosphate buffer solution (pH 7.4) at 37℃was extended with the decreased content of PEGDoxorubicin (DOX) -loaded microcapsules were prepared by a double emulsion technique and characterized by Zetasizer, SEM and CLSM. The SEM image shows that the microcapsules with a size of ca. 900nm have a smooth and spherical surface. The CLSM images directly verified that DOX was encapsulated into microcapsules. The entrapment ratio of DOX in the capsules amounts to 35.7%. The effects of preparation conditions on the microcapsule size and DOX encapsulation efficiency were also investigated.In vitro studies indicated that release of DOX from microcapsules could last over 10 days and ionic intensity, pH, the properties of microcapsules influenced the release of DOX from microcapsules.