Solvent‑Free Bioerodible Ophthalmic Inserts for Mangiferin Delivery: Physicochemical Characterization and In Vivo...

Ophthalmic topical dosage forms are often limited by their low bioavailability, primarily due to rapid precorneal clearance. Prolonging the precorneal residence time enables sufficient drug absorption and facilitates the desired pharmacological effects. In this study, mangiferin-loaded ophthalmic inserts were successfully formulated using hydroxypropyl methylcellulose acetate succinate (HPMC AS) as a matrix-forming agent via the hot-melt extrusion technique. The prepared inserts were systematically characterized with respect to morphology, drug-polymer interaction, drug polymorphism, drug content, surface pH, and drug release. A correlation between independent factors and drug release in vitro was established, enabling the customization of drug release profiles. The in vivo study exhibited that the formulation was well tolerant to the rabbit eyes and remained in the lower conjunctival cul-de-sac for over 12 h. Furthermore, the concentration of mangiferin in the lacrimal fluid remained relatively consistent for up to 12 h, thereby allowing sustained exposure of the cornea-conjunctiva surface-the target site of action-to drug therapeutic levels. These findings suggest that the developed ophthalmic inserts offer a promising strategy for the ocular delivery of mangiferin in the treatment of herpes keratitis.