Abstract
Purpose: :
Polymers used in lubricant eye drops display particular physico-chemical properties which can translate to improved performance. Hydroxypropyl Guar (HPG) in the presence of the demulcents propylene glycol and polyethylene glycol has been shown to provide lubrication. This work summarizes the interaction of a dual polymer system (DPS) comprised of Hydroxypropyl Guar (HPG) with corneal epithelial cells.
Methods: :
Biological performance was measured as the ability of lubricant solution to protect immortalized human corneal epithelial cells from desiccation stress. Cells were incubated with test solutions or media for 30 minutes and then desiccated for 0 or 30min at 37°C; 45% humidity. To assess retention of cellular protection, cells were washed between test compound exposure and desiccation. A MTS assay was used to determine % protection compared to control. Fluorescently tagged polymers were used to determine the relative binding of the polymers to the cell surface after 30min incubation followed by rinsing. Remaining fluorescence was measured in a fluorometer and % total fluorescence was calculated.
Results: :
The DPS combination demonstrates significantly greater desiccation protection (52%) and retention (93%) than HPG alone. Fluorescent tagging of the polymers demonstrates an increase in the amount of each polymer bound to the surface when in combination, for example 12% HPG in DPS vs 8.6% HPG alone.
Conclusions: :
A novel DPS lubricant solution containing the demulcents PG and PEG showed improved cell desiccation protection and increased retention to the surface of corneal epithelial cells. These data indicate the DPS should provide long lasting lubrication and surface protection in the eye.
Keywords: cornea: tears/tear film/dry eye