title: Protein encapsulation within poly(ethylene glycol)-coated nanospheres. II. Controlled release properties.
abstract: The development of injectable nanoparticulate "stealth" carriers for protein delivery is a major challenge. The aim of this work was to investigate the possibility of achieving the controlled release of a model protein, human serum albumin (HSA), from poly(ethylene glycol) (PEG)-coated biodegradable nanospheres (mean diameter of about 200 nm) prepared from amphiphilic diblock PEG-poly(lactic acid) (PLA) copolymers. HSA was efficiently incorporated into the nanospheres, reaching loadings as high as 9% (w/w). Results of the in vitro release studies showed that it is possible to control the HSA release by choosing the appropriate nanosphere size, loading, and composition. These results also revealed that, following their release, HSA molecules readsorbed onto the nanospheres surfaces when they were not protected by a PEG coating. We were surprised to observe that in spite of the water uptake of the PLA-PEG nanospheres [11-29% (w/w)], the copolymer did not significantly degrade after a 15-day incubation period. Therefore, we concluded that during this time HSA release from PLA-PEG nanospheres followed a diffusion mechanism where bulk erosion and surface desorption were negligible.
authors.affiliation: Laboratoire de Chimie Physique Macromoléculaire UMR CNRS-INPL 7568, Groupe ENSIC, BP 451, 54001 Nancy Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Quellec
authors.forename: R
authors.initials: R
authors.lastname: Gref
authors.forename: E
authors.initials: E
authors.lastname: Dellacherie
authors.forename: F
authors.initials: F
authors.lastname: Sommer
authors.forename: M D
authors.initials: MD
authors.lastname: Tran
authors.forename: M J
authors.initials: MJ
authors.lastname: Alonso
mesh_terms: D001673:Biodegradation, Environmental; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004355:Drug Stability; D006801:Humans; D007700:Kinetics; D008863:Microspheres; D011092:Polyethylene Glycols / Q000493:pharmacokinetics; D012709:Serum Albumin; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D012709:Serum Albumin; D011092:Polyethylene Glycols