Nanoparticles Based on a Hydrophilic Polyester with a Sheddable PEG Coating for Protein Delivery

ABSTRACT Purpose To investigate the effect of polyethylene glycol (PEG) in nanoparticles based on blends of hydroxylated aliphatic polyester, poly(D,L-lactic-co-glycolic-co-hydroxymethyl glycolic acid) (PLGHMGA) and PEG-PLGHMGA block copolymers on their degradation and release behavior. Methods Protein-loaded nanoparticles were prepared with blends of varying ratios of PEG-PLGHMGA (molecular weight of PEG 2,000 and 5,000 Da) and PLGHMGA, by a double emulsion method with or without using poly(vinyl alcohol) (PVA) as surfactant. Bovine serum albumin and lysozyme were used as model proteins. Results PEGylated particles prepared without PVA had a zeta potential ranging from ~ −3 to ~−35 mV and size ranging from ~200 to ~600 nm that were significantly dependent on the content and type of PEG-block copolymer. The encapsulation efficiency of the two proteins however was very low (