Tetrasodium Etidronate is a chemical compound.

Decomposition of the name and function of the components

• Tetrasodium - Indicates the presence of four sodium ions. These ions are vital for the compound's water solubility.
• Etidronate - Derived from etidronic acid, a phosphonic acid. Etidronic acid is the backbone of the compound, responsible for its chelating ability.

Description and function of the raw materials used in production

• Etidronic acid - A phosphonic acid used as a base for producing Tetrasodium Etidronate. It has a strong ability to bind metal ions.
• Sodium hydroxide - Reacts with etidronic acid to form the tetrasodium salt, thereby enhancing the compound's solubility.

Summary of the industrial synthesis process step by step

• Base-acid reaction - Etidronic acid is reacted with an appropriate amount of sodium hydroxide in water. This reaction yields Tetrasodium Etidronate and water.
• Crystallization - After the reaction, the solution is cooled to allow for Tetrasodium Etidronate crystals to form.
• Filtration - The formed crystals are then separated from the solution through a filtration process.
• Drying - The crystals are then dried to remove residual moisture, producing a pure Tetrasodium Etidronate powder.

It appears in the form of a white powder.

What it is for and where

Cosmetics

It is a restricted ingredient as III/53  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:

(1-Hydroxyethylidene)diphosphonic acid and its salts

Chelating agent. It has the function of preventing unstable reactions and improving the bioavailability of chemical components within a product, and removes calcium and magnesium cations that can cause cloudiness in clear liquids.

Emulsion stabiliser. Emulsions are thermodynamically unstable. Emulsion stabilisers improve the formation and stability of single and double emulsions. as well as their shelf-life. It should be noted that in the structure-function relationship, the molar mass of the ingredient used plays an important role.

Viscosity control agent. It controls and adapts, Increasing or decreasing, viscosity to the required level for optimal chemical and physical stability of the product and dosage in gels, suspensions, emulsions, solutions. 

Safety

Tetrasodium Etidronate is considered an allergen and, in particular, a moderate eye irritant (1).

Skin and Eye Irritation: While generally considered safe in cosmetic formulations, at high concentrations, it can cause skin or eye irritation.

Ingestion: Accidental ingestion in large amounts can be harmful, and in such cases, it is advisable to seek medical attention immediately.

Environment: From an environmental perspective, there is some concern about tetrasodium etidronate being released into wastewater as it might negatively affect aquatic life.

Long-term Use: There aren't concrete evidences suggesting negative effects from its long-term use in personal care products, but it's always good practice to use products as directed and monitor for any adverse reactions.

Commercial applications

Cosmetic and Personal Care Products: It's commonly used in products such as soaps, shampoos, cleansers, and many other items to prevent deterioration and maintain product clarity and stability.

Soaps: Helps prevent soap scum and mineral deposits from forming on the skin.

Properties

Chelating Agent: Binds to metal ions, preventing them from reacting with other ingredients and causing issues like rancidity or texture changes.

Preservative: Assists in enhancing the shelf life of products by preventing unwanted reactions.

Stabilizer: Keeps the product's consistency and appearance intact.

• Molecular Formula   C₂H₄Na₄O₇P₂
• Molecular Weight   293.96 g/mol
• CAS   3794-83-0 
• EC number   223-267-7
• UNII   CZZ9T1T1X4
• DTXSID7029663
• Nikkaji    J87.541D

Chemical safety

References_____________________________________________________________________

(1) Acid, E. (2016). Safety Assessment of Etidronic Acid and Its Simple Salts as Used in Cosmetics.

Liou YL, Boyd A, Hylwa SA. What Is Tetrasodium Etidronate and How Is It Related to Formaldehyde? Dermatitis. 2018 Sep/Oct;29(5):289-290. doi: 10.1097/DER.0000000000000408. PMID: 30234615.