RESUMO
PURPOSE: To characterize formulations of nanostructured lipid carriers (NLCs) as an artificial tear film and evaluate their efficacy in protecting the ocular surface epithelial cells from desiccating stress in vivo. METHODS: The physicochemical properties of NLCs, produced with components similar to the tear film such as phosphatidylcholine and squalene, were determined. In vitro cytotoxicity of NLCs was evaluated by a short-time exposure test in porcine corneal epithelial cells using a methyl thiazol diphenyl-tetrazolium bromide assay. The residence time of NLCs in rabbit eyes and the efficacy of NLCs eye drops in protecting the rabbit corneal epithelium from desiccating stress were assessed. RESULTS: Nanosized NLCs with a mean size of â¼39 ± 5 nm and a zeta potential of -30 mV could be produced and formulated into eye drop with a pH of 6.90 ± 0.01, osmolarity of 273 ± 1 mOsm/L, and surface tension of 39 ± 1 mN/m (for air interface). Eye drop formulations of NLCs were nontoxic to porcine corneal epithelial cells. NLCs drops showed higher ocular surface retention and formed a stable corneal film compared with a saline solution. Moreover, NLCs eye drops showed greater efficacy in protecting the corneal surface against desiccating stress compared with a polymer-based commercial artificial tear. CONCLUSIONS: NLCs eye drops are biocompatible in rabbit eyes and show potential as a tear replacement vehicle for the treatment of dry eye disease.
