Sodium Hyaluronate (HA) is a naturally occurring high molecular weight linear polysaccharidefound in many parts of the human body including connective tissues, the extracellular matrix of tears and the vitreous body inside the eye. HA has attracted great interest and attention from ophthalmic surgical and eye care companies due to its unique properties including viscosity, water retention, wound healing, and anti-inflammatory effects.

It is well known that biologically inactive high-molecular weight (HMW) HA plays an important role in maintaining tissue integrity and homeostasis in the extracellular matrix. HMW HA has been utilized therapeutically as a mean of decreasing inflammation and tissue destruction. However, low-molecular-weight LMW HA can activate epithelial cells, endothelial cells, macrophages, and fibroblasts to secrete chemokines, cytokines and degenerative enzymesto enhance inflammation.

Currently HA is getting more popularly used in multi-purpose solution. It is, therefore, important to characterize the molecular weights of HA in these products so that theireffects can be better predicted.

The concentration and molecular weights of HA in 5 commercially available HA containing MPSwere examined. The HA concentrations ranged from 0.003% - 0.08% and the weight-average molecular weights (Mw) rangedalso widely from 185KDa to 1.92MDa. The HA present in the Biotrue MPS solution has a concentration of 0.01% and is measured to have the highest molecular weight (1.92MDa).

The major objective of adding HA in MPS is to improve the surface wettability of the lens and enhanced lens hydration. Another study was conducted to investigate the adsorption and release of HA after soaking seven types of hydrogel and silicone hydrogel lenses in Biotrue MPS for overnight. Fluorescein was tagged to the HA in the test solution and the rate of adsorption and release was evaluated using fluorescence spectroscopy. The release profile was monitored by dripping a saline solution over the lenses at the rate of tear film secretions. The results showed that the rate of HA release was found to extend for at least 20 hours for all lens types investigated. The adsorption and release of HA to and from various lens types can be explained by the hydrogen bonding potential between the known lens surface chemistry and the polysaccharide (HA).