Characterization of Biocompatible Gellan Gum Fractions for Prolonged Retention in Ocular Drug Delivery Systems

ABSTRACT Gellan gum (GG) emerges as a promising candidate for developing polymeric carriers with extended retention on the ocular surface, aiming to enhance the efficacy of topical ocular drug delivery systems. This study undertakes the purification of commercial GG through fractional dissolution and ultrasonic treatment, producing fractions characterized by 1 H, 13 C NMR, FTIR spectroscopy and thermogravimetric analysis. The intrinsic viscosity of GG samples was measured in a 0.025 M tetramethylammonium chloride solution and their molecular weights were calculated via the Mark‐Kuhn‐Houwink equation. Methodological choices regarding synthetic procedures, solvents and reagents were guided by considerations of biocompatibility, aligning with the end goal of drug delivery applications. The study further explores the mucoadhesive potential of GG fractions with varying molecular weights for ocular drug delivery, utilizing an in vitro flow‐through technique with fluorescent detection on freshly excised bovine corneal mucosa surfaces. The findings under‐score the viability of GG formulations in enhancing ocular drug retention and pave the way for future applications in topical ocular therapeutics.