Design, Development and Process Validation of Antibiotic-Loaded Ocular Inserts

Abstract

The present study aimed to formulate and evaluate Levofloxacin-loaded ocular inserts for sustained ocular drug delivery using the solvent casting method. Conventional ophthalmic formulations, such as eye drops, exhibit poor bioavailability due to rapid precorneal elimination and drainage from the ocular cavity, resulting in reduced therapeutic efficacy and the need for frequent administration. To overcome these limitations, ocular inserts were developed using gelatin, chitosan, and HPMC K4M as film-forming polymers, with PEG 400 as a plasticizer and benzalkonium chloride as a preservative. Preformulation studies, including melting point determination, Fourier Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC), were performed to assess drug purity and compatibility with the selected excipients. The prepared ocular inserts were evaluated for physical appearance, thickness, weight variation, folding endurance, tensile strength, drug content uniformity, and in-vitro drug diffusion. All formulations exhibited satisfactory physicochemical characteristics, acceptable mechanical strength, and uniform drug distribution.  In-vitro diffusion studies demonstrated sustained drug release for up to 10 hours. Among all formulations, F3 exhibited an optimal drug release profile along with satisfactory mechanical properties and stability. Drug release kinetic analysis indicated that the release profile predominantly followed zero-order kinetics and the Korsmeyer–Peppas model, suggesting a non-Fickian diffusion mechanism. Stability studies further confirmed that the optimized formulation remained stable without significant changes in physical appearance or drug content.  The results suggest that Levofloxacin-loaded ocular inserts may serve as a promising sustained-release ocular drug delivery system by improving precorneal residence time, potentially enhancing ocular bioavailability, and improving patient compliance compared with conventional ophthalmic dosage forms.