Formulation development and characterization of flucinolone acetonide nanoemulsion for ocular drug delivery system

Background: The purpose of this study is to enhance and demonstrate the effectiveness of the corticosteroid drug fluocinolone acetonide in the form of an ophthalmic nanoemulsion. This formulation is designed to improve targeted delivery and ocular penetration, making it suitable for the treatment of conditions such as age-related macular degeneration, diabetic macular edema, and posterior uveitis. Methodology: To formulate the nanoemulsion, we used polysorbate 20 and a castor oil derivative known as HCO-40. The continuous emulsification method was employed to prepare the formulation. Initial batches were tested for key properties, including pH, osmolality, drug content, globule size, and zeta potential. A factorial design approach was applied, in which polysorbate 20 and the castor oil derivative (Cremophor RH 40) were considered independent variables. The nanoemulsion was further evaluated for ocular irritancy using cell line analysis, in vitro scleral permeability, and the Hen’s Egg Chorioallantoic Membrane (HET-CAM) test. Results and Discussion: The optimized batch of the nanoemulsion showed a penetration rate exceeding 80% and a small globule size of 19–20 nm. In vitro tests using human retinal pigment epithelial (ARPE-19) cells and the HET-CAM test indicated that the formulated nanoemulsion is non-toxic and non-irritating to the eye, confirming its cytocompatibility. Conclusion: The developed optimized nanoemulsion formulation of flucinolone acetonide provides improved targeting, non-invasive administration & enhanced patient compliance when used as a topical eye drop for treating ocular diseases such as age-related macular degeneration and posterior uveitis.