UK researchers develop effective new xerostomia solution

According to a 2018 systematic review, xerostomia affects roughly 22% of the global population and can lead to severe complications. The physical, emotional and social impacts of xerostomia on patients have previously been reported by Dental Tribune International. The global rise in xerostomia cases in recent years is attributed to increased polypharmacy and use of cancer-related radiation therapies and a growing incidence of chronic, neurodegenerative and autoimmune diseases like Sjögren’s syndrome, coupled with the significant growth of the global ageing population.

Although a broad range of saliva substitutes are available, they do not relieve xerostomia for a sufficient period of time. Prof. Anwesha Sarkar, who led the development of the saliva substitute and is chair in colloids and surfaces at the School of Food Science and Nutrition at the university, commented in a press release: “The problem with many of the existing commercial products is they are only effective for short periods because they do not bind to the surface of the mouth, with people having to frequently reapply the substance, sometimes while they are talking or as they eat. That affects people’s quality of life.”

The newly developed saliva substitute, a microgel-reinforced hydrogel-based lubricant, was evaluated against eight existing commercial products, including well-known brands such as Biotène from GSK, Glandosane from Fresenius Kabi, Saliveze from Wyvern Medical, and Oralieve. The experiments were conducted on an artificial tongue-like surface.

The study found that the saliva substitute provided significantly enhanced boundary lubrication, being 41%–99% more effective against liquids and viscous substances compared with current products. This result is primarily due to its adsorption properties, which enable it to bind more effectively to oral surfaces. In contrast to the 23%–58% desorption rate observed with commercial alternatives, the novel saliva substitute demonstrated a notably lower desorption rate of 7%. In addition, the research team observed that the dairy formulation showed slightly better performance than its vegan counterpart.

Lead author Dr Olivia Pabois, a postdoctoral research fellow at the university, said: “The test results provide a robust proof of concept that our material is likely to be more effective under real-world conditions and could offer relief up to five times longer than the existing products that are available.”

She added: “The results of the benchmarking show favourable results in three key areas. Our microgel provides high moisturisation, it binds strongly with the surfaces of the mouth and is an effective lubricant, making it more comfortable for people to eat and talk.”

The first formulation of the new solution is based on a dairy protein and the vegan version based on a potato protein. The substances used in the production of the saliva substitute are non-toxic and non-caloric.

Study limitations

While the study measured lubricity under conditions relevant to oral use, it did not assess the long-term hydration efficiency of the newly developed lubricant compared with competitive samples. Additionally, it has to be taken into consideration that the temperature of ingested products could potentially affect the lubrication properties of the saliva substitute.

Future applications

The study authors aim to transform the novel saliva substitute into commercially available products, intending to enhance the lives of individuals suffering from challenging dry mouth conditions. This extensive benchmarking study thus sets the stage for the use of these microgel-based aqueous lubricant formulations as an innovative approach to treating xerostomia.

The study, titled “Benchmarking of a microgel-reinforced hydrogel-based aqueous lubricant against commercial saliva substitutes”, was published online on 20 November 2023 in Scientific Reports.

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