Development of nanoparticulate formulations for ocular delivery of prednisolone acetate: preparation and characterization

This study describes the development and characterization of biodegradable prednisolone acetate nanoparticles indicated for ocular use. Nanoparticles were prepared by oil-in-water emulsion/solvent evaporation and nanoprecipitation techniques using poly lactide-co-glycolide (50:50) and poly DL-lactide. A 24 factorial design was applied to optimize the drug formulation. The effect of independent variables such as polymer type, drug-to-polymer ratio, surfactant concentration and method of preparation on entrapment efficiency (EE%), particle size, zeta potential and drug release were investigated. Further studies such as differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscope were carried out on the selected formula. O/W emulsion/solvent evaporation technique was superior to the nanoprecipitation method in terms of EE% . In vitro release study showed extended drug release. DSC and XRD indicated the dispersion of the drug within the nanoparticles. These results demonstrate the feasibility of encapsulating prednisolone acetate inside biodegradable nanoparticles for ocular delivery.