title: Encapsulation, stabilization, and release of BSA-FITC from polyanhydride microspheres.
abstract: In order to determine the efficacy of using polyanhydrides as a carrier for therapeutic proteins, the model protein bovine serum albumin labeled with fluorescein isothiocyanate (BSA-FITC) was encapsulated in microspheres of poly sebacic anhydride (poly(SA)), and random copolymers of poly(SA) and poly(1,6-bis-p-carboxyphenoxy)hexane (poly(CPH)). The microspheres were fabricated via the double emulsion (water/oil/water) technique and were characterized using scanning electron microscopy, gel permeation chromatography, confocal microscopy, and a Coulter counter. The effect of protein loading, protein distribution, and change in polymer composition was examined in an in vitro release study. The secondary structure of the encapsulated BSA-FITC was determined with Fourier transform infrared spectroscopy. The primary structure of the released protein was analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis. Poly(SA) and 20:80 (CPH:SA) microspheres were found to conserve the primary structure of the released protein and the secondary structure of the encapsulated protein, and showed a sustained delivery for approximately 15 and 30 days, respectively. As the CPH content in the copolymer increased, the secondary structure of FITC-BSA was not conserved, as indicated by the steep decrease in the alpha-helix content.
authors.affiliation: Department of Chemical Engineering, Iowa State University, 2035 Sweeney Hall, Ames, IA 50011, USA.
authors.forename: Amy S
authors.initials: AS
authors.lastname: Determan
authors.forename: Brian G
authors.initials: BG
authors.lastname: Trewyn
authors.forename: Victor S-Y
authors.initials: VS
authors.lastname: Lin
authors.forename: Marit
authors.initials: M
authors.lastname: Nilsen-Hamilton
authors.forename: Balaji
authors.initials: B
authors.lastname: Narasimhan
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D016650:Fluorescein-5-isothiocyanate / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000737:chemistry; D008863:Microspheres; D049388:Polyanhydrides / Q000008:administration & dosage*; D012710:Serum Albumin, Bovine / Q000008:administration & dosage* / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D049388:Polyanhydrides; C039217:fluorescein isothiocyanate bovine serum albumin; D012710:Serum Albumin, Bovine; D016650:Fluorescein-5-isothiocyanate