title: Influence of post-emulsification drying processes on the microencapsulation of human serum albumin.
abstract: In the present work, methods used to microencapsulate Human Serum Albumin (HSA) in a biodegradable polymer were compared for their effects on the physicochemical characteristics of HSA-loaded microparticles and on the release and integrity of encapsulated HSA. The polymer used was poly(D,L-lactide-co-glycolide) (75:25) (PLGA) (Boehringer Ingelheim, Resomer RG 752, MW 20,900). Microparticles were formulated by (i) w/o/w emulsification and freeze-drying (EFD) or (ii) w/o/w emulsification and spray-drying (ESD). Particle morphology and size were evaluated by scanning electron microscopy and by laser diffraction analysis. Loading, encapsulation efficiency and protein release were determined using a commercial protein assay kit. Protein integrity was evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Particles produced by emulsification/spray-drying exhibited greater diversity in shape than those produced by emulsification/freeze-drying. Additionally, protein loading values were significantly higher for particles produced by emulsification/spray-drying rather than particles produced by emulsification/freeze-drying. The structural integrity of encapsulated protein was confirmed for particles produced by both processes. The fraction of HSA released was similar for both formulations. The emulsification/spray-drying technique described appears to be a rapid and efficient method for the preparation of PLGA microparticles loaded with a model protein.
authors.affiliation: The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK. majella.lane@ulsop.ac.uk
authors.forename: Majella E
authors.initials: ME
authors.lastname: Lane
authors.forename: Fiona S
authors.initials: FS
authors.lastname: Brennan
authors.forename: Owen I
authors.initials: OI
authors.lastname: Corrigan
mesh_terms: D002152:Calorimetry, Differential Scanning; D003890:Desiccation / Q000379:methods; D004337:Drug Carriers; D004339:Drug Compounding / Q000379:methods*; D004355:Drug Stability; D004655:Emulsions; D005612:Freeze Drying; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D011108:Polymers; D012709:Serum Albumin; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid