title: Factors affecting the loading efficiency of water-soluble drugs in PLGA microspheres.
abstract: Poly(lactide-co-glycolide), PLGA, microspheres containing blue dextran as a hydrophilic model drug were prepared by a solvent evaporation method from w/o/w emulsions using a micro homogenizer. Effects of surfactant concentration in oil phase, stirring time period and stirring rate in the preparation procedure of primary emulsion (w/o) upon drug-loading efficiency were evaluated. Stirring rate during preparation of primary emulsion and surfactant concentration in oil phase affected drug-loading efficiency and the particle size of primary emulsion. Microspheres having the higher drug-loading efficiency were obtained when size differences between the primary emulsions and the secondary ones were large. That is, when the diameter of the primary emulsion is much smaller than that of the secondary emulsion, PLGA microspheres with high-loading efficiency of blue dextran were obtained.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Ito
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fujimori
authors.forename: Kimiko
authors.initials: K
authors.lastname: Makino
mesh_terms: D003911:Dextrans / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods*; D019344:Lactic Acid / Q000737:chemistry*; D008863:Microspheres; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D003911:Dextrans; D011108:Polymers; D013501:Surface-Active Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C017080:blue dextran