Development of polysaccharide-based mucoadhesive ophthalmic lubricating vehicles: The effect of different polymers on physicochemical properties and functionality

Abstract

Incorporation of mucoadhesive polymers is one of the first efficient modification of conventional liquid ophthalmic formulations in order to prolong the residence time at ocular surface. The aim of this work was formulation of viscous ophthalmic vehicles/ocular lubricants containing derivative of guar gum, chitosan and cellulose derivatives (hypromellose and hydroxyethylcellulose) alone or in combination. Optimized formulations were developed by choosing appropriate polymer or combination of polymers in suitable concentrations with adequate physicochemical, rheological and mucoadhesive properties. Influence of the addition of simulated tear fluid, steam sterilization and storage on clarity, pH value and rheological properties of different formulations were evaluated. The compounded vehicles were compared with commercially available ocular lubricants containing similar polymers. It was observed that viscosities of commercially available eye drops were above the optimal viscosity range. The mucoadhesive potential of the vehicles, rheological synergism and type of polymer-mucin interaction were determined. Combination of chitosan and guar gum exhibited optimal physicochemical, rheological and mucoadhesive properties and had a potential for the longest retention time in tear film. Considering the simplicity of its preparation and stability (over a period of one-month storage), this vehicle could be used for extemporaneously compounded ocular preparations for specific needs of individual patients.