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Updated: Jan 4, 2026
Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation
Published on: May 2, 2020
Physicochemical Properties of Hyaluronic Acid-Based Lubricant Eye Drops
Pasquale Aragona1, Peter A Simmons2,3, Hongpeng Wang2
1Department of Biomedical Science, Regional Referral Center for Ocular Surface Diseases, University of Messina, Messina, Italy.
Purpose:
To assess the physicochemical properties of hyaluronic acid (HA)-based artificial tears.
Methods:
The average molecular weight (MW) and polydispersion index (PDI) of HA in 18 commercially available artificial tears were determined by light scattering/high-performance liquid chromatography. Osmolality, pH, viscosity, and sodium concentration were determined using an osmometer, pH meter, rheometer, and inductively coupled plasma mass spectrometer, respectively.
Results:
The MW of HA varied considerably between formulations. The PDI was >2.0 in two formulations (2.28 and 4.94), suggesting the presence of a copolymer and/or HA size variability. Three formulations exhibited viscosity exceeding the blur threshold at different shear rates. Viscosity at low shear rates was generally highest in formulations containing high-MW HA. Correlations were found between observed viscosity and a predictive/calculated value, except for four copolymer-containing formulations, and osmolality (range, 154-335 mOsm/kg) and sodium concentration (range, 22-183 mM), with two exceptions. Compared with organic osmolytes, adding sodium decreased viscosity, particularly at lower shear rates.
Conclusions:
In the context of the literature, our findings suggest that for most patients with dry eye disease, the ideal HA-based artificial tear should include high-MW HA with a low PDI and exhibit enhanced viscosity at low shear rate (without exceeding the blur threshold). The inclusion of synergistic copolymers and a low sodium concentration may increase viscosity, but whether any of these physicochemical properties or correlations can predict clinical efficacy will require further investigation.
Translational Relevance:
Understanding the properties of HA-based artificial tears will support the development of unique formulations that target specific ocular surface conditions.
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