Micelle-Based Ocular Inserts for Sustained Delivery and Improved Corneal Permeation of Rebamipide in Dry Eye Disease

Background: Rebamipide (REB) is a poorly water-soluble drug with limited ocular bioavailability, necessitating advanced delivery strategies for sustained therapy in dry eye disease. Methods: In the present study, micelle-assisted ocular inserts were developed using non-ionic surfactants to enhance REB solubilization, drug loading, and controlled ocular delivery. The intrinsic solubility of REB in simulated tear fluid (STF, pH 7.4) was evaluated and compared with micellar systems. The formulations were characterized for particle size, polydispersity index, and zeta potential. Ocular inserts were fabricated via UV photopolymerization and evaluated for physicochemical properties, drug content, in vitro drug release, ex vivo permeation, cytocompatibility using SIRC cells, and histopathological analysis. Results: REB exhibited low intrinsic solubility in STF (26.05 ± 1.00 µg/mL), which was significantly enhanced in micellar systems, particularly with Solutol HS 15 (306.71 ± 1.10 µg/mL) and Tween 80 (263.18 ± 1.19 µg/mL). All micellar formulations formed stable nanosized micelles (7.5-15.1 nm) with low polydispersity (PDI < 0.35) and near-neutral zeta potential (-0.08 to -2.81 mV). The prepared ocular inserts showed uniform thickness, weight, and physiological surface pH. Micelle-assisted inserts demonstrated significantly higher drug content (87.40 ± 3.25 to 99.19 ± 2.44 µg/insert) compared to plain REB inserts (21.41 ± 2.28 µg/insert). In- vitro studies revealed sustained drug release over 24 h (92.25 ± 1.64 to 100.50 ± 1.10%), whereas plain inserts showed burst release. Ex vivo permeation studies indicated enhanced drug permeation (up to 77.30 ± 0.34 µg) and improved flux (1.38-8.52 µg/cm²·h) compared to plain REB. Cytocompatibility studies confirmed >90% SIRC cell viability, and histopathological analysis showed no structural damage to corneal tissue. Conclusions: Micelle-assisted ocular inserts, particularly those formulated with Solutol HS 15 and Tween 80, provide a promising platform for sustained, safe, and effective ocular delivery of Rebamipide in the management of dry eye disease.