title: Development of PEG-PLA/PLGA microparticles for pulmonary drug delivery prepared by a novel emulsification technique assisted with amphiphilic block copolymers.
abstract: We developed a novel "spray dry-based" method for preparing surface-modified particle via "block copolymer-assisted" emulsification/evaporation for pulmonary drug delivery. The method included three steps: (1) o/w emulsion containing both hydrophobic polymers and amphiphilic block copolymers was obtained by emulsification of water and a polymer-containing organic solvent, (2) the o/w emulsion was misted with a nebulizer, and (3) the emulsion mists were dried by a heater. In this way, the hydrophobic polymers and the hydrophobic part of the amphiphilic block copolymers gradually tangled during the evaporation of organic solvents from the o/w emulsion. Consequently, the hydrophilic polymer chain was introduced on the particle surface. The particle surface can be easily modified although there are no reactive groups in the hydrophobic polymer molecules. We successfully obtained dry PEG-PLA/PLGA microparticles by controlling the weight ratio of the block copolymer and the hydrophobic polymer. The introduction of PEG to the particle surface involves an increase in the Zeta potential of the particles. Interestingly, the "dimpled" microparticles having a diameter of approximately 2 μm were obtained. The "dimpled" microparticles can serve as drug carriers for pulmonary drug delivery, because the particles have a large surface area. We expect that this novel surface-modification technique will enable efficient fabrication of particles in drug delivery systems.
authors.affiliation: Department of Organic and Polymer Materials Chemistry, Faculty of Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Takami
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Murakami
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004339:Drug Compounding / Q000379:methods*; D016503:Drug Delivery Systems / Q000379:methods*; D045703:Emulsifying Agents / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry; D019344:Lactic Acid / Q000032:analysis / Q000138:chemical synthesis*; D008171:Lung Diseases / Q000188:drug therapy; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011092:Polyethylene Glycols / Q000032:analysis / Q000138:chemical synthesis*; D011100:Polyglycolic Acid / Q000032:analysis / Q000138:chemical synthesis*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D045703:Emulsifying Agents; D004655:Emulsions; D012997:Solvents; C542623:monomethoxypolyethyleneglycol-polylactide block copolymer; D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols