Sodium Carboxymethylcellulose (CAS 9000-11-7)

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 as its sodium salt, sodium carboxymethyl cellulose. It used to be marketed under the name Tylose, a registered trademark of SE Tylose.

CMC is used in food under the E number E466 or E469 (when it is enzymatically hydrolyzed) as a viscosity modifier or thickener, and to stabilize emulsions in various products including ice cream. It is also a constituent of many non-food products, such as toothpaste, laxatives, diet pills, water-based paints, detergents, textile sizing, reusable heat packs, and various paper products. It is used primarily because it has high viscosity, is nontoxic, and is generally considered to be hypoallergenic as the major source fiber is either softwood pulp or cotton linter. CMC is used extensively in gluten free and reduced fat food products. In laundry detergents, it is used as a soil suspension polymer designed to deposit onto cotton and other cellulosic fabrics, creating a negatively charged barrier to soils in the wash solution. In ophthalmology, CMC is used as a lubricant in artificial tears to treat dry eyes. Extensive treatment may be required to treat severe dry eye syndrome or Meibomian gland dysfunction (MGD).

CMC is also used as a thickening agent, for example, in the oil-drilling industry as an ingredient of drilling mud, where it acts as a viscosity modifier and water retention agent. Sodium CMC(Na CMC) for example, is used as a negative control agent for alopecia in rabbits.

Knitted fabric made of cellulose (e.g. cotton or viscose rayon) may be converted into CMC and used in various medical applications.