Nanoparticle-loaded hydrogels as a pathway for enzyme-triggered drug release in ophthalmic applications.

The aim of this study was to develop nanoparticle loaded hydrogel based contact lenses that could be used for ocular drug delivery. Two potential contact lens platforms for controlled ophthalmic drug delivery were developed by incorporating chitosan-poly (acrylic acid) nanoparticles into polyvinyl alcohol (PVA) hydrogels and in-situ gelled nanoparticles and cellulose nanocrystals (CNC) in PVA lenses. The nanoparticles were shown to disintegrate in a physiological 0.2 mM concentration of lysozyme resulting from the hydrolysis of the chitosan chains by lysozyme. An extended release over a 28-h period was demonstrated once the nanoparticles had been integrated into the composite lenses, with nanoparticle-CNC PVA lenses showing even greater potential for extended release. The platform shows great promise in developing enzyme-triggered ocular drug delivery systems.