Cetylpyridinium chloride

Cetylpyridinium chloride (CPC) is a cationic quaternary ammonium compound in some types of mouthwashes, toothpastes, lozenges, throat sprays, anti-snore throat sprays, breath sprays, and nasal sprays. It is an antiseptic that kills bacteria and other microorganisms. It has been shown to be effective in preventing dental plaque and reducing gingivitis. It has also been used as an ingredient in certain pesticides. However, this ingredient has also been shown (according to WebMD, eMedicine, and Amazon.com and Drugstore.com reviews of Crest Pro-Health® rinse product) to cause brown stains between the teeth.

Synonyms
Cetylpyridinium chloride is called or is present in commercial products such as n as 1-palmitylpyridinium chloride, C16-alkylpyridinium chloride, 1-hexadecylpyridinium chloride, acetoquat CPC, aktivex, ammonyx CPC, cecure, ceepryn chloride, cepacol, ceprim, cepacol chloride, cetafilm, cetamium, dobendan, halset, ipanol, medilave, mercocet, merothol, pionin B, pristacin, pyrisept and asept.

Physical and chemical properties
Cetylpyridinium chloride has the molecular formula C21H38NCl and at its pure form is in a solid state at room temperature. It has a melting point of 77 °C when anhydrous or 80–83 °C in its monohydrate form. It is insoluble in acetone, acetic acid, or ethanol. It has a pyridine-like odor. It is combustible. Concentrated solutions are destructive to mucous membranes. It is very toxic when inhaled.

The CAS number for the monohydrate is.

In some products, cetylpyridinium bromide is used instead. Its properties are virtually identical.

Toxicology and Pharmacology
The LD50 in rats is 200 mg/kg.