title: Reversible protein precipitation to ensure stability during encapsulation within PLGA microspheres.
abstract: Proteins were precipitated to ensure their stability upon subsequent encapsulation within PLGA microspheres. Spherical, nanosized protein particles were formed by the addition of a salt (sodium chloride) and a water-miscible organic solvent (glycofurol) to protein solutions. Various process parameters were modified to optimize the precipitation efficiency of four model proteins: lysozyme, alpha-chymotrypsin, peroxidase and beta-galactosidase. As monitored by enzymatic activity measurement of the rehydrated particles, conditions to obtain more than 95% of reversible precipitates were defined for each protein. The study of the structure of the rehydrated particles by absorbance spectroscopy, fluorescence spectroscopy and circular dichroism showed an absence of structural-perturbation after precipitation. Protein particles were then microencapsulated within PLGA microspheres using s/o/w technique. The average encapsulation yield was around 80% and no loss of protein activity occurred after the encapsulation step. Additionally, a lysozyme in vitro release study showed that all of the released lysozyme was biologically active. This method of protein precipitation is appropriate for the encapsulation in PLGA microspheres of various proteins without inactivation.
authors.affiliation: INSERM U646, Angers, France.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Giteau
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Venier-Julienne
authors.forename: Stéphane
authors.initials: S
authors.lastname: Marchal
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Courthaudon
authors.forename: Michèle
authors.initials: M
authors.lastname: Sergent
authors.forename: Claudia
authors.initials: C
authors.lastname: Montero-Menei
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Verdier
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Benoit
mesh_terms: D000818:Animals; D011232:Chemical Precipitation; D002626:Chemistry, Pharmaceutical; D002918:Chymotrypsin / Q000737:chemistry; D004337:Drug Carriers; D004339:Drug Compounding; D004795:Enzyme Stability; D004798:Enzymes / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D019344:Lactic Acid / Q000737:chemistry*; D008863:Microspheres; D009113:Muramidase / Q000737:chemistry; D009821:Oils / Q000737:chemistry; D009195:Peroxidase / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011487:Protein Conformation; D012965:Sodium Chloride / Q000737:chemistry; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*; D014867:Water / Q000737:chemistry; D001616:beta-Galactosidase / Q000737:chemistry
chemical_list: D004337:Drug Carriers; D004798:Enzymes; D009821:Oils; D012997:Solvents; D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D009195:Peroxidase; D009113:Muramidase; D001616:beta-Galactosidase; D002918:Chymotrypsin; C117608:alpha-chymotrypsin; C018557:glycofurol