Preparation and characterization of agarose hydrogel nanoparticles for protein and peptide drug delivery

The purpose of this work was to develop and characterize a protein and peptide injectable drug delivery system in agarose hydrogel nanoparticles. The nanoparticles were prepared by using a new emulsion-converted-to-suspension in situ method. This is an emulsifier-free method that has advantages for protein and peptide drug encapsulations. Ovalbumin, used as a model protein drug, was successfully encapsulated into nearly spherical agarose hydrogel nanoparticles under mild conditions. The nanoparticles possessed a log-normal size distribution with an average size of 504 nm. They imbibed a large amount of water (66.85% to 84.33%) and the water content was a function of temperature; the water content increased with increase in temperature. Release studies of the ovalbumin from the agarose hydrogel nanoparticles revealed a diffusion-controlled release mechanism with a temperature dependence; the ovalbumin release rate was higher at 37 degrees C than that at room temperature. The great biocompatibility of agarose hydrogel, plus the mild conditions for drug encapsulation, make the agarose hydrogel nanoparticles a potential system for protein and peptide drug delivery.