Unveiling the Physicochemical Properties of Sodium Hyaluronate

Sodium hyaluronate, the sodium salt of hyaluronic acid, is currently the most widely used form in cosmetics, food, and pharmaceuticals. Its popularity is inseparable from its unique physicochemical properties.

In terms of appearance and physical properties, sodium hyaluronate is usually a white or off-white powder, odorless and tasteless, with excellent hygroscopic properties. It is stable in a dry state, but once dissolved in water, it rapidly absorbs water and swells, forming a transparent, viscous solution. This excellent water-retention capacity has earned it the title of "natural moisturizing factor"; theoretically, one gram of sodium hyaluronate can bind hundreds or even thousands of times its own weight in water.

Regarding solubility, sodium hyaluronate is readily soluble in water but insoluble in organic solvents. The solution is neutral or weakly acidic, with a wide pH range, thus making it compatible with various formulation systems. This characteristic allows it to remain stable in skincare products, eye drops, oral liquids, and other products, without easily precipitating or becoming ineffective.

Chemically, sodium hyaluronate is a high-molecular-weight polysaccharide composed of repeatedly linked glucuronic acid and acetylglucosamine. Its molecular weight can be controlled to vary from several thousand to millions of Daltons. Different molecular weights determine different functional properties: higher molecular weights are more suited for surface moisturizing and lubrication, while lower molecular weights are more penetrating, participating in deep moisturizing and repair.

Regarding stability, sodium hyaluronate is relatively sensitive to light and heat, and may degrade under high temperatures, strong acids, or strong alkalis. Therefore, during storage and processing, high temperatures and extreme pH conditions should generally be avoided to ensure its activity and performance.

It is precisely because sodium hyaluronate possesses excellent water retention, solubility, biocompatibility, and a controllable molecular structure that it has become a "star ingredient" in modern biomaterials and functional raw materials, continuously playing an irreplaceable role in multiple industries.