CMC-Na, Carmellose Sodium, Cellulose Gum, E466: The Names of Sodium CMC Explained
CMC-Na, Na-CMC, carmellose sodium, carboxymethylcellulose sodium, cellulose gum, E466 and INS 466 are one substance, CAS 9004-32-4. Which name is used where, the look-alikes that are different products, and what to write on an order.
Written byZhou Zhi · Head of Quality Control
Technical reviewGuo Jianping · Head of Technology
Published · Updated · 6 min read
CMC-Na, Na-CMC, sodium CMC, carmellose sodium, carboxymethylcellulose sodium, cellulose gum, E466 and INS 466 are all names for one substance: the sodium salt of carboxymethyl cellulose, CAS 9004-32-4. The name changes with the industry and its rulebook, not with the chemistry. Food labels say cellulose gum or E466, the European and Japanese pharmacopoeias say carmellose sodium, the United States Pharmacopeia says carboxymethylcellulose sodium, cosmetic ingredient lists say Cellulose Gum, and chemical buyers write CMC or CMC-Na. What does differ from one product to the next is the grade: its degree of substitution (DS), viscosity and purity.
One substance, many names
| Name | Where you will see it | Notes |
|---|---|---|
| Sodium carboxymethyl cellulose | Safety data sheets, specifications and customs documents | Also written carboxymethylcellulose sodium or sodium carboxymethylcellulose |
| CMC | Everyday trade name in every industry | Strictly the name of the family; in trade it means the sodium salt |
| CMC-Na, Na-CMC, NaCMC, sodium CMC | Technical data sheets, scientific papers and laboratory catalogues | “Na” is the chemical symbol for sodium |
| Cellulose gum | Food ingredient lists and cosmetic ingredient lists (INCI name: Cellulose Gum) | The usual label name in the United States |
| E466 | Food labels in the European Union | Official EU name: sodium carboxy methyl cellulose, cellulose gum |
| INS 466 | Codex Alimentarius and the countries that follow its numbering | The same number as the E number |
| Carmellose sodium | European, British and Japanese pharmacopoeias; medicine leaflets | In Spanish carmelosa sódica, in Portuguese carmelose sódica |
| Carboxymethylcellulose sodium | United States Pharmacopeia–National Formulary (USP–NF) | The same substance as carmellose sodium |
| CAS 9004-32-4 | Safety data sheets, chemical inventories and catalogues | CAS 9000-11-7 is the free acid, carboxymethyl cellulose |
| HS 3912.31 | Customs declarations | Heading text: carboxymethylcellulose and its salts |
Why one chemical has so many names
Sodium CMC is used in more industries than most chemicals, and each industry has its own naming system. Food law numbers additives. Pharmacopoeias give every ingredient a nonproprietary name. Cosmetic law uses INCI names, customs uses HS codes, and chemical inventories use CAS numbers. None of these systems was designed to match the others, so the same white powder ends up with a different name on a yoghurt label, a tablet leaflet, a toothpaste tube and a shipping document.
CMC-Na and Na-CMC: what the “Na” means
Na is the chemical symbol for sodium, from the Latin natrium. Carboxymethyl cellulose in its free-acid form does not dissolve in water. During manufacture it is neutralised with sodium hydroxide, and the result is the water-soluble sodium salt that is actually sold. CMC-Na, Na-CMC, NaCMC and sodium CMC are four ways of writing that salt, and “CMC” on a commercial specification means the same thing. The abbreviation CMC-Na is most common in laboratory catalogues, pharmacy textbooks and research papers.
Carmellose sodium: the pharmacopoeia name
Carmellose is a contraction of carboxymethyl cellulose that is used as a nonproprietary name for medicines. The European, British and Japanese pharmacopoeias title their monograph “carmellose sodium”, while the United States Pharmacopeia–National Formulary titles it “carboxymethylcellulose sodium”. In medicines it serves as a tablet binder, as a suspending and thickening agent in liquids, and as the lubricant in many artificial-tear eye drops.
Pharmaceutical use requires a grade that is made and released to the relevant pharmacopoeia monograph under pharmaceutical good manufacturing practice. Sentai does not supply pharmaceutical grades; its refined grades serve food, toothpaste, battery and industrial uses.
Cellulose gum, E466 and INS 466: the food names
On food labels, sodium CMC appears as cellulose gum, as sodium carboxymethyl cellulose or by its additive number: E466 in the European Union and INS 466 in the Codex Alimentarius system. In the United States, sodium carboxymethylcellulose is listed as generally recognised as safe (GRAS) under 21 CFR 182.1745. It thickens and stabilises ice cream, acidified milk drinks, sauces, baked goods and beverages. In toothpaste and cosmetics, the ingredient list uses the INCI name Cellulose Gum.
Food grades are refined grades. Sentai's food-grade CMC is specified at a purity of ≥ 99.5 %, and its toothpaste grades at ≥ 98 %.
Names that look similar but are different products
| Name | What it is | Same as sodium CMC? |
|---|---|---|
| Croscarmellose sodium (E468) | Cross-linked sodium CMC that swells in water but does not dissolve; used to make tablets break apart | No |
| Carmellose calcium | The calcium salt of carboxymethyl cellulose; it swells in water and is also a tablet disintegrant | No |
| Carmellose (carboxymethyl cellulose, free acid) | The acid form, CAS 9000-11-7; it does not dissolve in water | No |
| Enzymatically hydrolysed CMC (E469) | Sodium CMC cut into shorter chains by enzymes; a separate food additive | No |
| Polyanionic cellulose (PAC) | A sodium CMC with a higher and more uniform DS, made for drilling fluids | Same chemistry, sold as a separate product |
| Sodium carboxymethyl starch (CMS) | Made from starch instead of cellulose; in medicines it is called sodium starch glycolate | No |
| Microcrystalline cellulose (MCC, E460) | Purified cellulose that has not been etherified; it does not dissolve in water | No |
| HPMC, HEC and MC | Nonionic cellulose ethers with different properties | No |
Other meanings of the abbreviation CMC
Outside the cellulose industry, CMC also stands for critical micelle concentration in surfactant science, ceramic matrix composite in materials engineering, and chemistry, manufacturing and controls in drug registration. If a document does not mention cellulose, viscosity or thickening, it is probably about one of these.
What to write on an enquiry or purchase order
- The chemical name and CAS number: sodium carboxymethyl cellulose, CAS 9004-32-4.
- The application or grade type: food, toothpaste, battery, detergent, paper, ceramic, drilling or mining.
- Viscosity with its test conditions: concentration (1 % or 2 %), temperature and viscometer.
- Degree of substitution (DS) and purity on a dry basis.
- Particle form: powder, granular or instant.
- The regulation or standard the product must meet in your market, for example the E466 purity criteria for food use.
- HS code 3912.31 for the customs declaration; check the national tariff line and duty rate of the importing country.
FAQ
Is CMC-Na the same as CMC?+
Yes. CMC-Na, also written Na-CMC, is sodium carboxymethyl cellulose, and that sodium salt is what is sold as CMC. The free-acid form does not dissolve in water and is not traded as a thickener.
Is carmellose sodium the same as carboxymethylcellulose sodium?+
Yes. Carmellose sodium is the name in the European, British and Japanese pharmacopoeias, and carboxymethylcellulose sodium is the name in the United States Pharmacopeia. Both describe the sodium salt of carboxymethyl cellulose, CAS 9004-32-4.
Is cellulose gum the same as E466?+
Yes. E466 is the European Union's food additive number for sodium carboxymethyl cellulose, and cellulose gum is part of its official name there. The Codex Alimentarius uses the same number as INS 466.
What is the difference between carmellose sodium and croscarmellose sodium?+
Carmellose sodium dissolves in water and thickens it. Croscarmellose sodium is the same polymer cross-linked so that it swells without dissolving, which is why it is used to make tablets break apart. As a food additive it has its own number, E468.
What are the CAS number and HS code of CMC-Na?+
CAS 9004-32-4 and HS 3912.31 (carboxymethylcellulose and its salts). National tariff schedules add further digits, so check the schedule of the importing country.
What is the difference between carboxymethylcellulose sodium and the base form?+
The base form is carboxymethyl cellulose in its free-acid form (CAS 9000-11-7), which does not dissolve in water. Carboxymethylcellulose sodium (CAS 9004-32-4) is its sodium salt: during manufacture the acid groups are neutralised with sodium hydroxide, which makes the polymer water-soluble. The sodium salt is the product sold as CMC, CMC-Na or cellulose gum; the free acid is not traded as a thickener.
What are the differences between sodium carboxymethylcellulose and other forms of CMC?+
Sodium CMC dissolves in hot and cold water and thickens. Croscarmellose sodium (E468) is cross-linked and carmellose calcium is the calcium salt; both swell without dissolving and are used to make tablets break apart. The free acid does not dissolve in water. Enzymatically hydrolysed CMC (E469) has shorter chains and is a separate food additive, and polyanionic cellulose (PAC) is a sodium CMC with a higher, more uniform DS made for drilling fluids.
What does CMC stand for?+
In the chemical trade, carboxymethyl cellulose. The same letters also stand for critical micelle concentration, ceramic matrix composite, and chemistry, manufacturing and controls, so check the context.
Sources
Zhou Zhi · 周智
Head of Quality Control
- 15 years in CMC quality control and R&D
Technical review: Guo Jianping · Head of Technology
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