Preclinical Evaluation of a New Hydroxypropyl-Guar Phospholipid Nanoemulsion-Based Artificial Tear Formulation in Models of Corneal Epithelium.

PURPOSE: To evaluate the effect of hydroxypropyl-guar anionic phospholipid nanoemulsion (HP-guar nanoemulsion), a new artificial tear formulation for treatment of dry eye disease (DED), in corneal epithelium models. METHODS: Cultured human corneal epithelial cells were used to assess (1) hydration protection and hydration retention protection against desiccation, and (2) cell recovery after benzalkonium chloride (BAC) damage. Corneal epithelium permeability was measured by 5,6-carboxyfluorescein (CF) uptake in intact rabbit eyes. Lubricity was determined using simulated blinking in bovine pericardium-pericardium tribological experiments; elastic filament strength was measured using an extensional rheometer. Comparator arms included vehicle/control and the microemulsion [Systane® Balance (SYSB)]. RESULTS: Cell hydration protection was 39.5%, 7.1%, and -0.1%, and surface hydration retention was 32.6%, 11.0%, and -1.2% with HP-guar nanoemulsion, SYSB, and vehicle, respectively, after desiccation. After 48 h, cell recovery from BAC exposure (relative fluorescence units ± SD) was faster with HP-guar nanoemulsion treatment (2.66 ± 0.2) than SYSB (2.76 ± 0.2) and vehicle (3.11 ± 0.4). The CF permeability (ng CF/g) decreased in rabbit cornea treated with HP-guar nanoemulsion (9.6 ± 2.3) than those with SYSB (13.12 ± 2.8) or BAC-exposed cornea (22.6 ± 5.1). HP-guar nanoemulsion demonstrated greater lubricity and polymer filament break-up time than SYSB and vehicle. In all assessments, HP-guar nanoemulsion showed significant improvement versus vehicle/control (P < 0.05); outcomes were better with HP-guar nanoemulsion versus microemulsion. CONCLUSIONS: The HP-guar nanoemulsion promotes greater moisture retention, protection, improved cell barrier function, and increased elastic filament strength in corneal epithelium models. The potential clinical benefits of HP-guar nanoemulsion needs to be evaluated in patients with DED, in future studies.