title: Bioadhesive fluorescent microspheres as visible carriers for local delivery of drugs. I: preparation and characterization of insulin-loaded PCEFB/PLGA microspheres.
abstract: Inherently fluorescent microspheres composed of a fluorescent polyanhydride, poly(p-(carboxyethylformamido) benzoic anhydride) (PCEFB), and poly(lactide-co-glycolide) (PLGA) were prepared using the water-in-oil-in-water (w/o/w) emulsion solvent evaporation technique. The effect of the PCEFB/PLGA feed ratio and composition of the oil phase on insulin entrapment and microsphere diameter was evaluated. It was found that the insulin entrapment efficiency increased with PCEFB content and acetone per cent in the oil phase. Microsphere diameter decreased as acetone was added into the oil phase. The blend of microspheres were further characterized by GPC, IR, fluorometry and SEM. Although slight degradation of PCEFB during the fabrication process was revealed by GPC and IR, PCEFB/PLGA microspheres could still be clearly visualized by either CLSM or fluorescent microscopy, which makes it possible to directly detect the microspheres by fluorometry in vivo without the need of labelling with fluorescent dyes. The surface of PCEFB/PLGA (1:2) microspheres was smooth, while PCEFB/PLGA (2:1) microspheres were observed with rough and uneven surfaces. Sustained release of insulin from the microspheres could be achieved for approximately 4 days.
authors.affiliation: Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: H L
authors.initials: HL
authors.lastname: Jiang
authors.forename: K J
authors.initials: KJ
authors.lastname: Zhu
mesh_terms: D000268:Adhesiveness; D000818:Animals; D001565:Benzoates / Q000737:chemistry*; D002214:Capsules; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007328:Insulin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019344:Lactic Acid; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D051381:Rats
chemical_list: D001565:Benzoates; D002214:Capsules; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005456:Fluorescent Dyes; D007328:Insulin; D011108:Polymers; C469869:poly(p-(carboxyethylformamido) benzoic anhydride); D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid