Controlled release of insulin from PLGA nanoparticles embedded within PVA hydrogels

A simple and versatile delivery platform for peptide and protein based on physically cross-linked poly (vinyl alcohol) (PVA) hydrogels containing insulin-loaded poly (lactic-co-glycolic acid) ( PLGA) nanoparticles was successfully fabricated. The particle morphology and size were characterized by SEM and laser light scattering method, respectively. Results showed that these particles had a mean diameter of 615 nm with a narrow size distribution and homogeneous particle production. The protein encapsulation efficiency was 72.6%. When insulin-loaded PLGA nanoparticles were administered intraperitoneally as a single dose (20 U/kg) to streptozotocin-induced diabetic mouse, blood glucose levels of these mice decreased and it could be sustained at such levels over 24 h. In vitro release further indicated that entrapment of the nanoparticles into the PVA hydrogels causes a reduction in both the release rate and the total amount of insulin released, which suggesting that PLGA nanoparticles entrapped into the PVA hydrogels showed more suitable controlled release kinetics for protein delivery.