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Cetylpyridinium chloride (CPC) is a cationic quaternary ammonium compound used in some types of mouthwashes, toothpastes, lozenges, 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. Cetylpyridinium chloride may cause brown stains between the teeth and on the surface of teeth. However, these stains can be easily removed by a dental hygienist during a routine check-up.
Contents
Synonyms
Cetylpyridinium chloride is present in commercial products such 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.
Chemistry
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 soluble in water but insoluble in acetone, acetic acid, or ethanol. It has a pyridine-like odor. It is combustible. Concentrated solutions are destructive to mucous membranes. Its critical micelle concentration (CMC) is 0.00012M, and is strongly dependent on the salt concentration of the solution.
In some products, the bromide salt, cetylpyridinium bromide, is used instead. Its properties are virtually identical.
Toxicology and pharmacology
With intravenous infusion as the delivery mechanism, the LD50 of cetylpyridinium chloride has been measured at 30 mg/kg in rats and 36 mg/kg in rabbits. Conversely, with oral administration LD50 levels are higher, having been measured at 200 mg/kg in rats, 400 mg/kg in rabbits, and 108 mg/kg in mice.
Use in over-the-counter drugs
OTC products containing cetylpyridinium chloride include oral wash, oral rinse, as well as ingestable products (e.g. CPC lozenges). In addition, cough syrups containing CPC are also available as OTC medications.
The FDA monograph on oral antiseptic drug products reviewed the data regarding CPC and concluded the following: "The agency believes that the information contained in its adverse reaction files, 30 years of safe marketing of an OTC mouthwash containing cetylpyridinium chloride (NDA 14- 598), and the safety data evaluated by the Oral Cavity Panel are sufficient to conclude that 0.025 to 0.1 percent cetylpyridinium chloride is safe as an OTC oral antiseptic when labeled for short-term use (not to exceed 7 days)."
In addition, the National Library of Medicine Toxicology Data Network (TOXNET) reviewed the range of toxicity of CPC, and stated that, "Significant toxicity is rare after exposure to low concentration products that are typically available in the home."
The fatal dose in humans ingesting cationic detergents has been estimated to be 1 to 3 g. Therefore, a person using a typical oral ingestible product that provides 0.25 mg CPC per dose will need to take 4000 doses at one time before they would be in the estimated fatal dose range.
A review of clinical studies on cetylpyridinium chloride found that mouthwashes containing CPC "provide a small but significant additional benefit when compared with toothbrushing only or toothbrushing followed by a placebo rinse" in reducing plaque and gingivitis-inflammation. In combination with chlorhexidine and zinc lactate, CPC has been found to be effective in treating halitosis.