Optimization and characterization of lipid based nano emulsion of prednisolone acetate for ophthalmic drug delivery

Prednisolone acetate is a topical anti-inflammatory agent used in the treatment of steroid responsive inflammation of palpeberal and bulber conjunctiva, cornea and anterior segments of the globe. The aim of the present work is to optimize and characterize lipid based nano emulsion of a poorly water-soluble drug, Prednisolone acetate. Lipid based nanoemulsion was prepared using micro fluidization process. Solubility studies were carried out to identify suitable oil and surfactant. A three level three factor Box-Behenken design was used to optimize lipid based nano emulsion. Prepared formulation was characterized for drug content, pH, globule size, zeta potential, polydispersity index, osmolality and in vitro drug release study by dialysis method using bottle apparatus. Eye irritation study was carried out by Hen's egg chorioallantoic Membrane test. Stability study of the prepared formulation was performed as per ICH guidelines. Prepared nanoemulsion is transparent with a blue tinge. Optimized batch of lipid based nanoemulsion showed average globule size of 110nm with a poly dispersity index less than 0.11. The results of in vitro drug release study suggest more than 90% drug release over a period of 12h. Developed formulation was found to be non-irritant and stable when stored at 40°C and can be used for ophthalmic delivery.