Thickening, lubricating and wetting capabilities of sodium hyaluronate in comparison with commercial polysaccharides for applications in artificial saliva

Abstract

Xerostomia is closely associated with food avoidance and malnutrition among elderly populations and has become a burgeoning global concern. Artificial saliva consisting of thickening agents has been developed for xerostomia-relieving. However, current available artificial saliva can only provide a short-term relief. The main goal of this work was to evaluate the thickening, lubricating and wetting abilities of sodium hyaluronate (SH) of different molecular weights in comparison with commonly used thickening agents (xanthan gum and sodium carboxymethyl cellulose) in artificial saliva. In this study, tri-detector array gel permeation chromatography (TDA-GPC) was used to characterize the hydrodynamic parameters of three different SH samples. Their rheological, tribological, moistening as well as sensory properties were carefully assessed in parallel with thickening agents. TDA-GPC analysis showed that SH presented a flexible irregular nematic conformation in dilute solution, and the molecular weight affected the rigidity of SH molecular chains. SH solutions behaved clearly shear-thinning as well as viscoelastic. Lubricating properties and hydrophilicity of SH solutions were found to be prominent. Their wettability was also found to be better than xanthan gum. Moreover, the perceived smoothness of high molecular weight SH was higher than that of thickening agents at concentrations of 0.3% and 0.6%. Overall, this study demonstrated that SH was capable of providing efficient moistening and lubrication and could be an ideal structural component for the applications in high performance artificial saliva.