Development of mucoadhesive poly(lactide-co-glycolide) nanoparticles for ocular application.

Pilocarpine loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by solvent evaporation method and coated with various mucoadhesive polymers, in particular chitosan, sodium alginate and poloxamers. The size of chitosan-coated nanoparticles was larger than the size of all the other particles obtained. Their surface charge was changed from negative (-22.8 mV) to positive (+61.0 mV). The interaction between mucin and chitosan-coated nanoparticles took place up to six hours according to turbidimetric study. The positive charge of chitosan-coated nanoparticles decreased significantly six hours after incubation in mucin dispersion, which was attributed to their electrostatic interaction. The coating with chitosan could be considered useful approach aiming to prolong nanoparticle residence time after local ocular application.