Development of a New Preservative Free Formulation for the Treatment of Dry Eye Syndrome

Abstract

Purpose: : Dry eye syndrome can be considered a group of diseases related to tear film disorders. Evaporative dry eye is one of the most frequent causes of this condition. The lipid layer plays a major role in avoiding the evaporation of the aqueous components of the ocular surface. Treatments directed to replace a disturbed lipid layer may have therapeutic benefits for dry eye patients. These formulations might contain lipid and aqueous components. Moreover these constituents must present film–forming properties. The aim of this work is to evaluate a new formulation destined to topical administration for dry eye syndrome.

Methods: : A preservative free formulation containing aqueous and lipid constituents was prepared. The lipid components were phosphatidylcholine derivatives and chlolesterol in a ratio of 8:1 and they were suspended in an aqueous solution of trehalose. The final concentration of lipids was 25mg/ml. Size of the lipid droplets and in–vitro properties of the solutions such as, surface tension, osmolarity, and pH were evaluated.

Results: : Formulations including phosphatidylcholine and cholesterol in aqueous solution (25mg/ml) resulted in a surface tension value of 25.5 (± 0.3) mN/m. The final solution was hypotonic with a pH value of 7.04 (± 0.5). The sizes of the lipids vesicles were smaller than 1µm (392nm–478.5nm). Particles higher than 1µm were practically absent in the formulation (<2%).

Conclusions: : The free preservative formulation presents good characteristics to be employed as a tear film substitute.

Keywords: cornea: tears/tear film/dry eye • pharmacology • conjunctiva