Hyaluronic acid is a straight chain acid mucopolysaccharide isolated from bovine vitreous with the connection between ascetyl glucosamine and glucose aldehydic acid disaccharide unit made by the United States Meyer in 1934.HA exists in human and animal skin, serum, tissue interstitial fluid, with a unique skin moisturizing, nutrition, anti-aging, stability, emulsification, anti-bacterial anti-inflammatory and promote wound healing and drug delivery and other special functions, is in Japan chemical, pharmaceutical, chemical and biological areas such as health food and extremely versatile, excellent functional biochemicals.

Earlier, as many animal tissues and organs HA as raw materials in the system, a complex production process, low output and high cost, and therefore prices are too expensive, so its application is limited to medical and biochemical glutathione fields. HA prepared with microbial fermentation technology is developing rapidly, increasing production, and its scope of application of gradually in Japan, health food and other areas will be expanded. 1980s, HA on its excellent moisturizing, nutrition, skin and other special performance by the international cosmetics industry attention. Since then, the HA as a series of special features cosmetic raw materials have come out, clearly showing that HA functions as a new cosmetic raw materials strong development momentum.

The basic chemical structure of HA is a D-N-acetyl-D-glucosamine and glucuronic acid as structural unit, and a 1,4-glycosidic bond alternating links into a straight chain polymer acid mucopolysaccharide compounds 3'6 J, as a white powder, no special smell, relative molecular mass is generally 0.8 × lo6 ~ 2.0 × lo6, rotation: a 74o (25 , 0.025% water). It can be slow but eventually completely soluble in water to form a sticky, slightly milky white or colorless solution, insoluble in organic solvents. HA strong compatibility, compatibility is good, almost any water can be added to the cosmetic matrix. Typically, cosmetic grade HA products glucuronic acid mass fraction /> 42%, protein mass fraction 0.1%, loss on drying 10%, 0.1% aqueous solution of pH 6.0 ~ 7.5, burning Residue on ignition <20%. In the cosmetics production process, common to HA, sodium or potassium salt. HA sodium salt as a white fibrous or powdery, with a weak aroma that can slow the formation of slightly soluble in water, white or colorless high viscous liquid, it can be dissolved in sodium chloride solution, practically insoluble in organic solvents. HA sodium salt mass fraction is usually not less than 98%, loss on drying 10%, 0.2% aqueous solution of pH 5.5 ~ 7.5 Residue on ignition <20%, dynamic viscosity of 8 Pa s (30 ).

Preparation of HA solution, the HA should first loose, thrown into the water slowly, stirring a little, and then swelling to fully carry out intermittent stirring to dissolve. Also be the first with the volume fraction of 75% ethanol to HA soaked, and then slowly add water, intermittent agitation to increase its dissolution rate, can be used after waving to make ethanol. The water should be soft water or deionized water, so as not to affect the clarity of solution. Production of cosmetics, the substrate temperature should be reduced to below 60 , and then adding HA solution in order to avoid the formation of clots or degradation of HA. In addition, the HA should be low-temperature solid, dry and dark storage. HA solution is best prepared before use, and once used up, such as long-term storage, should be added to the amount of preservatives to prevent deterioration

HA becoming a cosmetics material with unique function and widely application, has attracted widespread attention outside the cosmetics industry. With HA as the functional components, the new special cosmetic has become the mainstream products of the international chemical industry. It has very broad application prospects. Research and development of new cosmetics are also changing, highly competitive market, natural cosmetics, environmentally friendly additives has become the main research directions. Thus, with the rapid development of science and technology, the natural trend of people advocating full use of HA resources, research and development of new, high-grade HA series of functional cosmetics, to meet the growing demand of consumers, improve people's health, is a great need. Its potential economic and social benefits are also obvious.Source:http://www.cosprm.com