Abstract
Purpose:
Hydroxypropyl Guar (HPG) in the presence of demulcents propylene glycol and polyethylene glycol has been shown to provide cellular protection from desiccation. This work describes pre-clinical data to show the benefits of a dual polymer system comprised of Hydroxypropyl Guar and Hyaluronic acid (HA) in providing prolonged protection, retention of effect and recovery from damage in human corneal epithelial (HCE) cell models.
Methods:
The ability of the dual polymer solution to protect human corneal epithelial cells from desiccation was tested in a temperature/humidity controlled environment. Cells were incubated with test solutions for 30 minutes and then desiccated for 0 or 30 minutes at 37°C, 45% relative humidity. To assess retention of cellular protection, cells were washed between test compound exposure and desiccation multiple times. A cell proliferation assay was used to determine % protection compared to controls. HCE cells were exposed to triton-X-100 for 30 minutes following initial exposure with test formulations to produce damage. Ability of the test formulations to provide barrier protection and promote cellular recovery was examined using sodium fluorescein permeability (NaF) and trans-epithelial electrical resistance (TEER) assays.
Results:
The dual polymer combination demonstrated significantly greater hydration protection (54%) and substantivity (50%) than HPG (37% and 30%) and HA (15% and 10%) alone (p<0.05). There was a statistically significant reduction in % fluorescence (p<0.05) when the HCE cells were allowed to recover from damage after treatment with the combination system (69%) relative to HPG (93%) and HA (83%) alone. The lower % fluorescence value is indicative of improved barrier protection, cellular recovery and regeneration.
Conclusions:
The combination of HPG/HA with the active demulcents provides an effective lubricant formulation that shows prolonged hydration protection and recovery in response to external stress environments in an in-vitro HCE cell model. These data provide supporting evidence for the dual polymer solution in potentially promoting desiccation protection and retention on the ocular surface.
Keywords: 486 cornea: tears/tear film/dry eye