title: Preparation of biodegradable microparticles using solution-enhanced dispersion by supercritical fluids (SEDS).
abstract: OBJECTIVE
  We have evaluated a new process, involving solution-enhanced dispersion by supercritical fluids (SEDS), for the production of polymeric microparticles.
  
  
  METHODS
  The biodegradable polymers, Poly (DL-lactide-co-glycolide): copolymer composition 50:50 (DL-PLG), Poly (L-lactide) (L-PLA), Poly (DL-lactide) (DL-PLA) and Polycaprolactone (PCL), were used for preparation of microparticles using SEDS. Solutions of the polymers in organic solvents were dispersed and sprayed with supercritical CO2. Extraction of the organic solvents resulted in the formation of solid microparticles. The amounts of highly toxic solvents such as dichloromethane (MC) were reduced in the process.
  
  
  RESULTS
  Microparticles were obtained from all polymers. The mean particle size and shape varied with the polymer used. The morphology of the particles was strongly affected by the choice of polymer solvent. Discrete spherical microparticles of DL-PLG were produced with a mean volumetric diameter of 130 microm. The microparticles of the L-PLA were almost spherical, and their size increased from 0.5 to 5 microm as the density of supercritical CO2 decreased. PCL formed microparticles with diameters of 30-210 microm and showed a strong tendency to form films at high pressure.
  
  
  CONCLUSIONS
  The SEDS process appears a promising method for production of microparticles from biodegradable polymers without the use of toxic solvents.
authors.affiliation: Uppsala University, BMC, Department of Pharmaceutics, Sweden. raouf.ghaderi@galenik.uu.se
authors.forename: R
authors.initials: R
authors.lastname: Ghaderi
authors.forename: P
authors.initials: P
authors.lastname: Artursson
authors.forename: J
authors.initials: J
authors.lastname: Carlfors
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D001673:Biodegradation, Environmental; D002152:Calorimetry, Differential Scanning; D002627:Chemistry, Physical / Q000295:instrumentation* / Q000379:methods*; D005898:Glass; D019344:Lactic Acid / Q000737:chemistry; D008422:Materials Testing / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D011312:Pressure; D013696:Temperature; D014783:Viscosity
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; C016240:polycaprolactone; D011100:Polyglycolic Acid; D019344:Lactic Acid