title: Influence of morphology and drug distribution on the release process of FITC-dextran-loaded microspheres prepared with different types of PLGA.
abstract: The aim of the present work was to understand the collaborative roles and the comprehensive effects of polymer nature, morphology, drug distribution and release behaviour for PLGA microspheres prepared by the double emulsion method. The morphology and drug distribution of the FITC-dextran-loaded microspheres were investigated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), respectively. The results show that the morphology and release profiles depend on the polymer nature. For the capped PLGA RG502, the porosity, pore size and drug distribution had no pronounced influence on the release profile beyond the initial release. No significant changes in size and morphology were found and there was negligible water uptake during the release process. PEG addition as a pore maker indicated a possible way to modify the release rate at the second release stage. However, in the case of the uncapped PLGA RG503H, release profiles were dependent upon changes in porosity, pore size and drug loading. Increases in porosity, internal pore size and loading resulted in a continuous release profile. Previous studies have shown the importance of different process parameters on morphology and drug release, but in this work it is clear that polymer nature is a determining factor.
authors: Department of Pharmaceutics and Biopharmacy, Phillips-University of Marburg, Germany.
authors: Cuifang
authors: C
authors: Cai
authors: Shirui
authors: S
authors: Mao
authors: Oliver
authors: O
authors: Germershaus
authors: Andreas
authors: A
authors: Schaper
authors: Erik
authors: E
authors: Rytting
authors: Dawei
authors: D
authors: Chen
authors: Thomas
authors: T
authors: Kissel
mesh_terms: D003911:Dextrans / Q000008:administration & dosage*; D004655:Emulsions / Q000737:chemistry; D016650:Fluorescein-5-isothiocyanate / Q000008:administration & dosage / Q000031:analogs & derivatives*; D019344:Lactic Acid / Q000737:chemistry*; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity
chemical_list: D003911:Dextrans; D004655:Emulsions; C015219:fluorescein isothiocyanate dextran; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D016650:Fluorescein-5-isothiocyanate