title: Ethyl acetate as a dispersing solvent in the production of poly(DL-lactide-co-glycolide) microspheres: effect of process parameters and polymer type.
abstract: This study deals with the production of poly(DL-lactide-co-glycolide) (PLGA) microspheres using ethyl acetate as a dispersing solvent, a partially water soluble and less toxic solvent, by using emulsification and solvent diffusion/ evaporation techniques. PLGA 50 : 50 was used, having molecular weights, 12000 and 34000 with the end group capped (RG502, 503) and uncapped (RG502H, 503H) biodegradable polymers. The microspheres were loaded with nifedipine (NFD) as a model drug. Solvent removal from the embryonic microspheres was manipulated by adopting different techniques. These methods have shown a significant effect on the physicochemical and release characteristics of the microspheres. Rapid removal of the solvent resulted in microspheres with a loose matrix and large size. Use of higher molecular weight polymers increased the size of the microspheres as well as delayed release of the drug. The uncapped polymer has given a higher rate of diffusion when compared to the capped polymers. Thermal analyses showed a uniform molecular distribution of the drug in the polymer matrix. The mechanism of drug release from the PLGA microspheres followed the Fickian diffusion.
authors.affiliation: Department of Chemistry, Polymer Research Group, Karnatak University, Dharwad, India.
authors.forename: K S
authors.initials: KS
authors.lastname: Soppimath
authors.forename: T M
authors.initials: TM
authors.lastname: Aminabhavi
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000465:Algorithms; D004055:Differential Thermal Analysis; D004058:Diffusion; D019344:Lactic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D012997:Solvents
chemical_list: D000085:Acetates; D011108:Polymers; D012997:Solvents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C007650:ethyl acetate