Development and In-vitro Evaluation of Dexamethasone Enriched Nanoemulsion for Ophthalmic Indication

Background: Dexamethasone (DEX) is a glucocorticosteroid used in the treatment of steroid-responsive inflammatory conditions of the eye. The currently marketed formulations pose several issues, like poor drug residence time, resulting in frequent administration of the formulation, making them less effective. Objective: The present study aims to provide comprehensive data encompassing the designing, optimization, development, and characterization of DEX nanoemulsion (DEX NE) for treating inflammatory conditions of the anterior segment of the eye by employing the Quality by Design (QbD) approach. Methods: A Plackett-Burman Design (PBD) was employed to screen seven independent variables, such as oil concentration, surfactant concentration, polymer concentration, homogenization speed and time, microfluidization pressure and cycles, and their influence on critical quality attributes (CQAs), such as globule size, zeta potential, and viscosity, was evaluated. Furthermore, the Box- Behnken Design (BBD) was employed for optimization, and design space was generated to obtain the optimized DEX NE. Results: The experimental results after DEX NE characterization reveal a globule size of 181 ± 90 nm with a zeta potential of -21.03 ± 1.68 mV and a viscosity of 19.99 cp. Furthermore, the drug release study of simulated tear fluid demonstrated prolonged and steady release for up to 48 hr. Cytotoxicity assay of DEX NE exhibited good cell viability. Conclusion: All these findings pave the way for a better understanding of developing a robust, safe, and non-toxic formulation for ocular drug delivery.