title: Physicochemical characterization and release mechanism of a novel prednisone biodegradable microsphere formulation.
abstract: The aim of this work was the characterization of a new formulation of prednisone long-term controlled release biodegradable microspheres. Poly(DL-lactide-co-glycolide) (PLGA) polymers were used for MS preparation. A S/O/W solvent evaporation method was employed for prednisone entrapment. The system was characterized by using UV spectrophotometry, particle sizing, scanning electron microscopy, differential scanning calorimetry, X rays diffractometry, and microRaman spectroscopy. The release mechanism was studied by fitting Weibull, Peppas, Higuchi, and zero order kinetic models. The microspheres (MS) showed a good encapsulation efficiency and morphology, a suitable size and long-term release profile. Burst release was seen to depend on crystalline prednisone distributing close to the MS surface, and no particular prednisone-polymer interaction occurred. Weibull and Peppas were the best fitting models. Prednisone was released from PLGA MS following a Fickian diffusion and case II transport for higher molecular weight (MW) polymers, and a more complex mechanism involving solubilization, diffusion, and erosion, for low MW PLGA. Fully characterized PLGA MS may represent a good tool for a long-term delivery of prednisone in low-dose regimen treatments.
authors.affiliation: Department of Chemistry and Technology of Drugs, Via del Liceo 1, 06123 Perugia, Italy. eureka@unipg.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Giovagnoli
authors.forename: Paolo
authors.initials: P
authors.lastname: Blasi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ricci
authors.forename: Aurelie
authors.initials: A
authors.lastname: Schoubben
authors.forename: Luana
authors.initials: L
authors.lastname: Perioli
authors.forename: Carlo
authors.initials: C
authors.lastname: Rossi
mesh_terms: D000465:Algorithms; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical; D002627:Chemistry, Physical; D004339:Drug Compounding; D005079:Excipients; D019344:Lactic Acid; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D008956:Models, Chemical; D010316:Particle Size; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D011241:Prednisone / Q000008:administration & dosage* / Q000737:chemistry*; D012995:Solubility; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
chemical_list: D000893:Anti-Inflammatory Agents; D005079:Excipients; D011108:Polymers; D012997:Solvents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011241:Prednisone