Thermal stability of sodium hyaluronate in aqueous solution.

Since its identification 60 years ago as a ubiquitous component of the body of mammals, hyaluronic acid has been widely studied, primarily in the fields of medicine and biology. On the other hand, our research has dealt with hyaluronic acid as a chemical intermediate in the synthesis of novel lubricious coatings, and in this connection data were needed on stability of aqueous solutions of the polymer over a range of temperatures from 25-100 degrees C. The investigation reported here provides that information, obtained by exposing samples in sealed ampules in baths at controlled temperatures and determining the resulting change in viscosity of the solutions. Data of this kind have not previously been reported on sodium hyaluronate freed from the proteins and other organics normally associated with the polymer in its natural environment.