Tumor necrosis factor alpha blocking peptide loaded PEG-PLGA nanoparticles: preparation and in vitro evaluation

Nanoparticles prepared from polyethyleneglycol-modified poly(d,l-lactide-co-glycolide) (PEG-PLGA-NPs) are being extensively investigated as drug carriers due to their controlled release, biodegradable and biocompatibility. The purpose of this study was to evaluate the in vitro characteristics of PEG-PLGA-NPs loading tumor necrosis factor alpha blocking peptide (TNF-BP). PEG-PLGA copolymer was synthesized by ring-opening polymerization of d,l-lactide, glycolide and methoxypolyethyleneglycol (mPEG) (Mw = 5000). Blank PEG-PLGA-NPs, with particle size within the range of 79.7 to 126.1 nm and zeta potential within the range of -12.91 to -24.55 mV, were prepared by the modified-spontaneous emulsification solvent diffusion (modified-SESD) method. PEG-PLGA-NPs uptake by murine peritoneal macrophages (MPM) was lower than that of PLGA-NPs. TNF-BP was loaded on the blank nanoparticles by electrostatic interactions, and TNF-BP loading capacity of PEG-PLGA-NPs was found to be dependent on the characteristics of blank nanoparticles, peptide concentration and incubation medium. In vitro release experiments showed the peptide release rate affected by the drug loading and ionic strength, and approximately 60.2% of TNF-BP released from nanoparticles still possessed bioactivity. These experimental results indicate that PEG-PLGA-NPs could be used to develop as drug carriers for TNF-BP.