title: In vitro degradation of polyanhydride/polyester core-shell double-wall microspheres.
abstract: Double-wall microspheres (DWMS), comprising distinct polymer core and shell phases, are useful and interesting for controlled-release drug delivery. In particular, the presence of a surface-eroding polymer core may be expected to limit water penetration and, therefore, delay degradation of the core phase and drug release. In this study, solid microspheres and DWMS were fabricated using a surface-eroding polymer (poly[1,6-bis(p-carboxyphenoxy)hexane]; PCPH) and a bulk-eroding polymer (poly(D,L-lactide-co-glycolide); PLG). Erosion of the particles was observed by optical and electron microscopy, while polymer degradation was followed by gel permeation chromatography, during incubation in buffer at 37 degrees C. Degradation and erosion were very different depending on which polymer formed the particle shell. Nevertheless, the relatively thin (approximately 5 microm) PCPH shells could not prevent water penetration, and the PLG cores completely eroded by 6 weeks of incubation.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Illinois, Box C-3, 600 S. Mathews Ave., Urbana, IL 61801, USA.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Pollauf
authors.forename: Cory
authors.initials: C
authors.lastname: Berkland
authors.forename: Kyekyoon Kevin
authors.initials: KK
authors.lastname: Kim
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Pack
mesh_terms: D002850:Chromatography, Gel; D004339:Drug Compounding; D004355:Drug Stability; D005079:Excipients; D006586:Hexanes / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008863:Microspheres; D008970:Molecular Weight; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: C120991:1,6-bis(carboxyphenoxy)hexane; D005079:Excipients; D006586:Hexanes; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid