title: Critical solvent properties affecting the particle formation process and characteristics of celecoxib-loaded plga microparticles via spray-drying.
abstract: OBJECTIVE
  It is imperative to understand the particle formation mechanisms when designing advanced nano/microparticulate drug delivery systems. We investigated how the solvent power and volatility influence the texture and surface chemistry of celecoxib-loaded poly (lactic-co-glycolic acid) (PLGA) microparticles prepared by spray-drying.
  
  
  METHODS
  Binary mixtures of acetone and methanol at different molar ratios were applied to dissolve celecoxib and PLGA prior to spray-drying. The resulting microparticles were characterized with respect to morphology, texture, surface chemistry, solid state properties and drug release profile. The evaporation profiles of the feed solutions were investigated using thermogravimetric analysis (TGA).
  
  
  RESULTS
  Spherical PLGA microparticles were obtained, irrespectively of the solvent composition. The particle size and surface chemistry were highly dependent on the solvent power of the feed solution. An obvious burst release was observed for the microparticles prepared by the feed solutions with the highest amount of poor solvent for PLGA. TGA analysis revealed distinct drying kinetics for the binary mixtures.
  
  
  CONCLUSIONS
  The particle formation process is mainly governed by the PLGA precipitation rate, which is solvent-dependent, and the migration rate of celecoxib molecules during drying. The texture and surface chemistry of the spray-dried PLGA microparticles can therefore be tailored by adjusting the solvent composition.
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark.
authors.forename: Feng
authors.initials: F
authors.lastname: Wan
authors.forename: Adam
authors.initials: A
authors.lastname: Bohr
authors.forename: Morten Jonas
authors.initials: MJ
authors.lastname: Maltesen
authors.forename: Simon
authors.initials: S
authors.lastname: Bjerregaard
authors.forename: Camilla
authors.initials: C
authors.lastname: Foged
authors.forename: Jukka
authors.initials: J
authors.lastname: Rantanen
authors.forename: Mingshi
authors.initials: M
authors.lastname: Yang
mesh_terms: D000068579:Celecoxib; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage*; D003890:Desiccation; D004337:Drug Carriers / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry*; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011720:Pyrazoles / Q000008:administration & dosage*; D012997:Solvents / Q000737:chemistry; D013449:Sulfonamides / Q000008:administration & dosage*; D013499:Surface Properties
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D004337:Drug Carriers; D011720:Pyrazoles; D012997:Solvents; D013449:Sulfonamides; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D000068579:Celecoxib