title: Preparation and characterization of poly(lactic acid)-poly(ethylene glycol)-poly(lactic acid) (PLA-PEG-PLA) microspheres for controlled release of paclitaxel.
abstract: Microspheres of a new kind of copolymer, poly(lactic acid)-poly(ethylene glycol)-poly(lactic acid) (PLA-PEG-PLA), are proposed in the present work for clinical administration of an antineoplastic drug paclitaxel with hypothesis that incorporation of a hydrophilic PEG segment within the hydrophobic PLA might facilitate the paclitaxel release. Paclitaxel-loaded PLA-PEG-PLA microspheres of various compositions were prepared by the solvent extraction/evaporation method. Characterization of the microspheres was then followed to examine the particle size and size distribution, the drug encapsulation efficiency, the colloidal stability, the surface chemistry, the surface and internal morphology, the drug physical state and its in vitro release behavior. The effects of polymer types, solvents and drug loading were investigated. It was found that in the microspheres the PEG segment was homogeneously distributed and caused porosity. Significantly faster release from PLA-PEG-PLA microspheres resulted in comparison with the PLGA counterpart. Incorporation of water-soluble solvent acetone in the organic solvent phase further increased the porosity of the PLA-PEG-PLA microspheres and facilitated the drug release. A total of 49.6% sustained release of paclitaxel within 1 month was achieved. Potentially, the presence of PEG on the surface of PLA-PEG-PLA microspheres could improve their biocompatibility. PLA-PEG-PLA microspheres could thus be promising for the clinical administration of highly hydrophobic antineoplastic drugs such as paclitaxel.
authors.affiliation: Department of Chemical and Environmental Engineering, Faculty of Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
authors.forename: Gang
authors.initials: G
authors.lastname: Ruan
authors.forename: Si-Shen
authors.initials: SS
authors.lastname: Feng
mesh_terms: D020341:Absorbable Implants; D000327:Adsorption; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D003692:Delayed-Action Preparations / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D016503:Drug Delivery Systems / Q000295:instrumentation / Q000379:methods; D007773:Lactates / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D008422:Materials Testing; D008863:Microspheres; D008968:Molecular Conformation; D009038:Motion; D017239:Paclitaxel / Q000008:administration & dosage* / Q000737:chemistry*; D014677:Pharmaceutical Vehicles / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D011506:Proteins / Q000008:administration & dosage / Q000737:chemistry; D013499:Surface Properties
chemical_list: D020099:Coated Materials, Biocompatible; D003692:Delayed-Action Preparations; D007773:Lactates; D014677:Pharmaceutical Vehicles; D011506:Proteins; C088513:poly(lactic acid-ethylene glycol); D011092:Polyethylene Glycols; D017239:Paclitaxel