title: Preparation and in vitro and in vivo characterization of composite microcapsules for cell encapsulation.
abstract: Cell encapsulation technology raises great hopes in medicine and biotechnology. Transplantation of encapsulated pancreatic islets represents a promising approach to the final cure of type 1 diabetes mellitus. Unfortunately, long-term graft survival and functional competence remain only partially fulfilled. Failure was often ascribed to the lack of biocompatibility generating inflammatory response, limited immunobarrier competence, hypoxia, and low beta-cell replication. In the present work, ketoprofen loaded biodegradable microspheres, embedded into alginate/poly-L-ornithine/alginate microcapsules, were prepared in order to release ketoprofen at early stages after implantation. Morphology, size, in vitro release behaviour, and in vivo biocompatibility were assessed. The effect of some preparation parameters was also evaluated. Polymeric microspheres were spherical and smooth, two populations of about 5 and 20 microm of mean diameter characterized the particle size distribution. A high burst effect was observed for all preparations during in vitro release studies. Ketoprofen, plasticizing the polymeric matrix, could be responsible of this release behaviour. Alginate/poly-L-ornithine/alginate microcapsules were not modified upon ketoprofen loaded microspheres encapsulation and an optimal dispersion was obtained. Composite system showed good biocompatibility when a high molecular weight polymer was employed. Therefore a potentially suitable composite system for cell encapsulation was obtained. This system may be successfully used to release NSAIDs and other active molecules capable to improve cell system functional performance and life-span.
authors.affiliation: Department of Chemistry and Technology of Drugs, School of Pharmacy, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy. kaolino@unipg.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Blasi
authors.forename: Stefano
authors.initials: S
authors.lastname: Giovagnoli
authors.forename: Aurélie
authors.initials: A
authors.lastname: Schoubben
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ricci
authors.forename: Carlo
authors.initials: C
authors.lastname: Rossi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Luca
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Basta
authors.forename: Riccardo
authors.initials: R
authors.lastname: Calafiore
mesh_terms: D001672:Biocompatible Materials; D002214:Capsules; D004055:Differential Thermal Analysis; D004339:Drug Compounding; D019344:Lactic Acid; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D012997:Solvents
chemical_list: D001672:Biocompatible Materials; D002214:Capsules; D011108:Polymers; D012997:Solvents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid