Sodium Hyaluronate is a chemical compound, polysaccharide, sodium salt of hyaluronic acid. Hyaluronic acid is a natural substance produced by the human body and found in connective tissues such as skin and cartilage, in connective, epithelial and neural cells. It can be extracted from animals.

The name describes the structure of the molecule:

• Sodium indicates the presence of sodium ions (Na+) in the compound.
• Hyaluronate is the salt form of hyaluronic acid, a polysaccharide naturally present in the body that plays a crucial role in maintaining hydration and facilitating healing.

The synthesis process takes place in different stages:

• Fermentation. Sodium hyaluronate is produced through a fermentation process using specific strains of bacteria. These bacteria are able to produce hyaluronic acid.
• Recovery. Hyaluronic acid is recovered from the fermentation broth.
• Purification. The recovered hyaluronic acid undergoes a series of purification steps to remove impurities.
• Conversion to sodium salt. The purified hyaluronic acid is converted into its sodium salt form, sodium hyaluronate, through a neutralisation process.

It takes the form of a white powder. Stable, incompatible with strong oxidising agents.

What it is used for and where

Medical

Used in medicine as a protector in cases of injury to internal organs. It can alleviate inflammation of synovial tissue, strengthen the function of lubrication and viscosity of joint fluid, protect joint cartilage. It can improve intestinal function and protect the gastric mucosa.

It is an antioxidant that plays an important role in immunological processes, cell motility and wound healing (1).

Cosmetics

Wetting agent, moisturising, can reduce wrinkles by reinforcing nutrients in the skin or added through creams or lotions. Used in toothpastes as a protective agent.

Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis.  The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.

Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Used in toothpastes as a protective agent.

Safety

The EFSA Panel for the Review of Cosmetic Ingredients considers Sodium Hyaluronate to be a safe ingredient (2).

Sodium Hyaluronate studies

Typical commercial product characteristics Sodium Hyaluronate

• Molecular Formula     C₂₈H₄₄N₂NaO23⁺
• Molecular Weight   799.641 g/mol
• Exact Mass   799.22300
• CAS   9067-32-7
• EC Number:618-620-0
• UNII    YSE9PPT4TH
• DSSTox Substance ID  
• IUPAC  sodium;(2S,3S,4S,5R,6R)-6-[(2S,3R,4R,5S,6R)-3-acetamido-2-[(2S,3S,4R,5R,6R)-6-[(2R,3R,4R,5S,6R)-3-acetamido-2,5-dihydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-2-carboxy-4,5-dihydroxyoxan-3-yl]oxy-5-hydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-3,4,5-trihydroxyoxane-2-carboxylic acid
• InChI=1S/C28H44N2O23.Na/c1-5(33)29-9-18(11(35)7(3-31)47-25(9)46)49-28-17(41)15(39)20(22(53-28)24(44)45)51-26-10(30-6(2)34)19(12(36)8(4-32)48-26)50-27-16(40)13(37)14(38)21(52-27)23(42)43;/h7-22,25-28,31-32,35-41,46H,3-4H2,1-2H3,(H,29,33)(H,30,34)(H,42,43)(H,44,45);/q;+1/t7-,8-,9-,10-,11-,12-,13+,14+,15-,16-,17-,18-,19-,20+,21+,22+,25-,26+,27-,28-;/m1./s1 
• InChl Key   YWIVKILSMZOHHF-QJZPQSOGSA-N   
• SMILES   CC(=O)NC1C(C(C(OC1O)CO)O)OC2C(C(C(C(O2)C(=O)O)OC3C(C(C(C(O3)CO)O)OC4C(C(C(C(O4)C(=O)O)O)O)O)NC(=O)C)O)O.[Na+]
• MDL number  MFCD01773053
• PubChem Substance ID    24895688
• NACRES NA.25 
• RTECS   MT7250000

Synonyms

• Hyaluronate Sodium
• Hyalurone sodium
• Healon
• Hyaluronic acid, sodium salt
• Synacid
• Hyaluronic acid sodium
• Hyalgan
• Equron
• Nrd101
• Monovisc
• Hyaluronsan
• Nidelon
• Hyaluronan
• Orthovisc
• Suvenyl
• Ostenil
• Hyasol
• Provisc
• Hyladerm Khionat
• Sinovial
• (2S,3S,4R,5R,6R)-6-(((2R,3R,4R,5S,6R)-3-acetamido-2,5-dihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-4-yl)oxy)-3-(((2S,3R,4R,5S,6R)-3-acetamido-4-(((2R,3R,4S,5S,6S)-6-carboxy-3,4,5-tri
• Supartz

References_____________________________________________________________________

(1) Pechová V, Gajdziok J. Possibilities of using sodium hyaluronate in pharmaceutical and medical fields. Ceska Slov Farm. 2017 Summer;66(4):154-159. 

Abstract. Sodium hyaluronate represents a contemporary biomaterial with broad use in different pharmaceutical and medical fields. It is a physiological glycosaminoglycan, which occurs primarily in the extracellular matrix, synovial fluid, cartilage, epidermis and vitreous body. It plays a critical role as a signalling molecule in immunological processes, cell motility and wound healing, and it possesses antioxidant activity. It is used in many fields of medicine if supplementation of hyaluronan is needed or in the cases of preventive and therapeutic interventions. Thanks to its moisturizing, regenerative and protective effects it is used in cosmetics as well.

(2) Becker LC, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW; Cosmetic Ingredient Review Expert Panel; Andersen FA. Final report of the safety assessment of hyaluronic acid, potassium hyaluronate, and sodium hyaluronate. Int J Toxicol. 2009 Jul-Aug;28(4 Suppl):5-67. doi: 10.1177/1091581809337738. 

Abstract. Hyaluronic acid, sodium hyaluronate, and potassium hyaluronate function in cosmetics as skin conditioning agents at concentrations up to 2%. Hyaluronic acid, primarily obtained from bacterial fermentation and rooster combs, does penetrate to the dermis. Hyaluronic acid was not toxic in a wide range of acute animal toxicity studies, over several species and with different exposure routes. Hyaluronic acid was not immunogenic, nor was it a sensitizer in animal studies. Hyaluronic acid was not a reproductive or developmental toxicant. Hyaluronic acid was not genotoxic. Hyaluronic acid likely does not play a causal role in cancer metastasis; rather, increased expression of hyaluronic acid genes may be a consequence of metastatic growth. Widespread clinical use of hyaluronic acid, primarily by injection, has been free of significant adverse reactions. Hyaluronic acid and its sodium and potassium salts are considered safe for use in cosmetics as described in the safety assessment.