title: Resorbable polymeric microspheres for drug delivery--production and simultaneous surface modification using PEO-PPO surfactants.
abstract: Poly(oxyethylene)-poly(oxypropylene) (PEO-PPO) co-polymers have been used as surfactants to produce resorbable poly(DL-lactide co-glycolide) (PLG) microspheres in the 500 nm-1 micron size range by an emulsification/solvent evaporation technique based on acetone-dichloromethane mixtures. The high polydispersity of microspheres could be reduced by using low PLG concentrations of 1% (w/v). Surface analysis by static secondary ion mass spectroscopy revealed the presence of PEO-PPO at the microsphere surface after cleaning by centrifuging and resuspension in water, and after further cleaning by dialysis. Physical entrapment of PEO-PPO chains in the particle surface is indicated due to rapid collapse of the solvent swollen PLG network as acetone is extracted from the suspended droplets. Opportunities are presented for simultaneous manufacture and surface modification of microspheres.
authors.affiliation: Department of Pharmaceutical Sciences, University of Nottingham, University Park, UK.
authors.forename: A G
authors.initials: AG
authors.lastname: Coombes
authors.forename: P D
authors.initials: PD
authors.lastname: Scholes
authors.forename: M C
authors.initials: MC
authors.lastname: Davies
authors.forename: L
authors.initials: L
authors.lastname: Illum
authors.forename: S S
authors.initials: SS
authors.lastname: Davis
mesh_terms: D002626:Chemistry, Pharmaceutical; D004337:Drug Carriers; D005079:Excipients / Q000737:chemistry; D005427:Flocculation; D019344:Lactic Acid; D008863:Microspheres; D010316:Particle Size; D011060:Poloxalene; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D018629:Spectrometry, Mass, Secondary Ion; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D005079:Excipients; D011108:Polymers; D013501:Surface-Active Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011060:Poloxalene