Development and Evaluation of Prednisolone Acetate-Loaded Nanostructured Lipid Carriers Integrated into pH-Triggered <i>In Situ</i> Gels for Ocular Drug Delivery

This study aimed to enhance the therapeutic efficacy of prednisolone by developing a nanostructured lipid carrier (NLC) system for topical ocular administration and addressing the limitations of current topical therapy. Drug-loaded NLCs (prednisolone acetate [PSA1]-PSA13) were formulated using high-pressure homogenization techniques, optimized with a central composite design, and evaluated for various pharmaceutical properties. An optimization study indicates that the lipid ratio and surfactant concentration influence particle size, entrapment efficiency (EE), and drug release. The optimized NLC formulation (PSA3) was integrated into a pH-triggered <i>in situ</i> gel system and assessed for drug permeation, ocular irritation, and stability. The optimized drug-loaded NLC formulations (PSA3) exhibited a nano size of 96.80 ± 0.51 nm, achieving an EE of 84.51 ± 1.31% and a drug release rate of 95.76 ± 1.23%. The drug permeation through the goat cornea was significantly higher in the <i>in situ</i> gel (PSAG4) compared with the control (marketed PSA eye drop). Additionally, the eye irritation data indicated good ocular tolerance, while stability studies confirmed that the developed formulation remained stable at room temperature. In conclusion, the developed NLC-based <i>in situ</i> gel appears to be a promising approach to enhancing the efficacy of prednisolone in topical therapy for the successful treatment of ocular inflammation.