Sodium croscarmellose is an internally

cross-linked In chemistry and biology, a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural ...

sodium

carboxymethylcellulose Carboxymethyl cellulose (CMC) or cellulose gum is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used in its sodiu ...

for use as a superdisintegrant in pharmaceutical formulations. E468 is the

E number E numbers, short for Europe numbers, are codes for substances used as food additives, including those found naturally in many foods, such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

of crosslinked sodium carboxymethyl cellulose, used in food as an

emulsifier An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althou ...

Background

The cross-linking reduces water

solubility In chemistry, solubility is the ability of a chemical substance, substance, the solute, to form a solution (chemistry), solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form su ...

while still allowing the material to swell (like a

sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

) and absorb many times its weight in water. As a result, it provides superior drug dissolution and disintegration characteristics, thus improving formulas′ subsequent

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

by bringing the active ingredients into better contact with bodily fluids. Sodium croscarmellose also resolves formulators′ concerns over long-term functional stability, reduced effectiveness at high tablet hardness levels, and similar problems associated with other products developed to enhance drug dissolution. It is a very commonly used pharmaceutical additive approved by the

U.S. Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

. Its purpose in most tablets – including dietary supplements – is to assist the tablet in disintegrating in the gastrointestinal tract promptly. If a tablet disintegrating agent is not included, the tablet could disintegrate too slowly, in the wrong part of the intestine or not at all, thereby reducing the efficacy and

of the active ingredients. Croscarmellose is made by first soaking crude

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

, and then reacting the cellulose with sodium monochloroacetate to form sodium

. Excess sodium monochloroacetate slowly hydrolyzes to

glycolic acid Glycolic acid (or hydroxyacetic acid; chemical formula ) is a colorless, odorless and hygroscopic crystal, crystalline solid, highly solubility, soluble in water. It is used in various skin care, skin-care products. Glycolic acid is widespread in ...

and the glycolic acid catalyzes the cross-linkage to form sodium croscarmellose. Chemically, it is the sodium salt of a cross-linked, partly O-(carboxymethylated) cellulose. Sodium croscarmellose was first used as a

stabilizer Stabilizer, stabiliser, stabilisation or stabilization may refer to: Chemistry and food processing * Stabilizer (chemistry), a substance added to prevent unwanted change in state of another substance ** Polymer stabilizers are stabilizers used ...

in horse supplements.{{Citation needed, date=February 2009

References

Excipients Organic sodium salts Cellulose E-number additives