Purchase this article with an account.
Paramita Sarkar, Zora Marlowe, Amy Walsh, Brian Glass, Tammy Kleiber, Megan Cavet, Karen Harrington, Stephen Davio; A Comparative Evaluation of Lipid-based Formulations for Dry-Eye Therapy using a Corneal Epithelial Cell Desiccation Model and Physicochemical Measurements. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4318.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The inclusion of both aqueous and lipid components in a single formulation to target multiple layers of the tear-film is a new trend in dry eye therapy. This study determined the potential beneficial effects of novel (SG1, SG2 and AG2) and marketed (Systane Balance,SB and Refresh Optive Advanced, ROA) lipid-based OTC products on the tear film and ocular surface using multiple physicochemical and corneal epithelial cell models.
Viscosity was measured on a Brookfield viscometer using a cone and plate attachment. Rheological characterization was done on a TA AR2000 instrument. Surface tension measurements and wettability assessments were done using a Kruss-K 100 tensiometer and captive bubble method with Acuvue Oasys lenses respectively. Destabilization of formulations in simulated tear fluid (STF), release of lipids and their impact on a simulated tear film lipid layer (TFLL) were evaluated using a Lumisizer complemented by lipid layer compressibility studies using a Langmuir trough. Protection of human corneal epithelial cells from desiccation-induced death was evaluated using cells pre-treated with formulation and then subjecting them to desiccation, after which cell viability was measured.
The viscosities of SB and ROA were around 3 cps & 12 cps respectively. Only SB showed shear-thinning property. The three novel formulations had viscosities above 50 cps and were markedly shear-thinning. All formulations had low surface tension and good wettability due to the presence of surfactants. SB and ROA did not appear to destabilize upon STF dilution or release their component lipids to improve the compressibility of the TFLL. SG1, SG2 and AG2 showed destabilization by STF and release of lipid and addition to TFLL. All three also provided protection to cells exposed to desiccating conditions whereas SB & ROA had minimal effect.
Three novel dry eye formulations and two OTC products containing lipid and aqueous components showed marked differences in physicochemical properties and efficacy in an in vitro model for desiccation-induced corneal cell death. Clinical impact of these differences should be evaluated.
This PDF is available to Subscribers Only