Cetylpyridinium chloride

Description

Cetylpyridinium is a quaternary ammonium with broad-spectrum antiseptic activities. It is active against S. mutans, S. sanguis, E. coli, Oxford Staphylococcus, and C. albicans in media (MICs = 1.25-62.5 μg/ml) and against Oxford Staphylococcus in pooled human saliva (MICs = 7.8-15.6 μg/ml). Cetylpyridinium slows plaque formation for at least 21 days compared to a deionized water control in a rat incisor plaque model when applied topically at concentrations ranging from 0.025 to 2%. Formulations containing cetylpyridinium have been used as antiseptic agents in the treatment of gingivitis and as antimicrobial agents in raw food processing.

Description

Cetylpyridinium chloride (CPC) is a quaternary ammonium salt antiseptic that is used in many over-the-counter personal-care products: mouthwashes, toothpastes, lozenges, and breath and nasal sprays, to name a few. It is also used in topical anti-infective products and as a pharmaceutical preservative.
More formally known as 1-hexadecylpyridinium chloride, CPC first appeared in the chemical literature in the 1930s. An early account1 of its disinfecting properties was written by pharmacist C. Lee Huyck at Xavier University of Louisiana (New Orleans) in 1944.
As shown in the hazard information table, CPC by itself has some dangerous properties; but its concentrations in consumer products have been considered too small to be of concern—until recently. In 2020, Brian K. Shoichet at the University of California, San Francisco; Laszlo Urban at the Novartis Institutes for Biomedical Research (Cambridge, MA); and researchers at other institutions published a study showing that some supposedly inert pharmaceutical additives such as CPC have potential biological activity. But the results do not necessarily mean that the substances are toxic.
Some scientists, however, are a bit more suspicious of “quats”, as quaternary ammonium compounds are called in the industry. In the late 2000s, toxicologist Terry Hrubec at Virginia Tech and the Edward Via College of Osteopathic Medicine (both in Blacksburg, VA) noticed that some control mice embryos in a lab study acquired certain defects from two quat disinfectants, which were thought to be safe. Since then, she and other researchers have found more instances of quat-caused animal defects.
CPC has not been implicated in any of these studies; and no human health effects have been associated with exposure to quat-containing products. But this past March, enough evidence about defects in animals attributed to quats had been accumulated that the California Department of Public Health added these substances to its Biomonitoring California program.
1 Am. J. Pharm. 1944, 116, 50–59.

Chemical properties

Cetylpyridinium chloride (CPC) is a white powder or crystals with a characteristic odor. It is slightly soapy to the touch.

Cetylpyridinium chloride is a quaternary ammonium compound and is the active chemical in some human mouthwashes on the market. It has antiseptic properties and is used in solutions or lozenges for the treatment of minor infections of the mouth and throat. The antimicrobial activity is due to an interaction of basic cetylpyridinium ions with acidic molecules on bacteria, which subsequently inhibits bacterial metabolism by forming weak ionic compounds that interfere with bacterial respiration.

The Uses of Cetylpyridinium chloride

Antibacterial in cough lozenges and syrups; emulsifier.

The Uses of Cetylpyridinium chloride

quaternary ammonium compound used as a preservative in cosmetics and pharmaceuticals; topical anti-infective and disinfectant; used on the surface of latex gloves .

Definition

ChEBI: A pyridinium salt that has N-hexadecylpyridinium as the cation and chloride as the anion. It has antiseptic properties and is used in solutions or lozenges for the treatment of minor infections of the mouth and throat.

Production Methods

Cetylpyridinium chloride is prepared from cetyl chloride by treatment with pyridine.

brand name

Ceepryn (Marion Merrell Dow); Cepacol (Marion Merrell Dow).

Flammability and Explosibility

Non flammable

Pharmaceutical Applications

Cetylpyridinium chloride is a quaternary ammonium cationic surfactant, used in pharmaceutical and cosmetic formulations as an antimicrobial preservative. It is used therapeutically as an antiseptic agent; used alone or in combination with other drugs for oral and throat care; used in nonparenteral formulations licensed in the UK; and used in oral and inhalation preparations at concentrations of 0.02–1.5 mg.
Mouthwashes containing cetylpyridinium chloride have been shown to inhibit plaque formation,(1–3) although efficacy is variable owing to limited published data.

Clinical Use

1-Hexadecylpyridinium chloride is a white powder that isvery soluble in water and alcohol. In this compound, thequaternary nitrogen atom is a member of an aromatic pyridinering.
The cetyl derivative is the most active of a series ofalkylpyridinium compounds. It is used as a general antisepticin concentrations of 1:100 to 1:1,000 for intact skin,1:1,000 for minor lacerations, and 1:2,000 to 1:10,000 forthe irrigation of mucous membranes. Cetylpyridinium chlorideis also available in the form of throat lozenges and amouthwash at a 1:20,000 dilution.

Safety Profile

Poison by ingestion, intraperitoneal, subcutaneous, and intravenous routes. Moderately toxic by skin contact. A skin and eye irritant. When E heated to decomposiuon it emits very toxic fumes of NOx and Cl-.

Safety

Cetylpyridinium chloride is used widely in mouthwashes as a bactericidal antiseptic. It is generally regarded as a relatively nontoxic material when used at a concentration of 0.05% w/v, although minor side effects such as mild burning sensations on the tongue have been reported.
At higher concentrations, cetylpyridinium chloride may damage the mucous membranes in the mouth. It is harmful when ingested or inhaled. It can cause eye irritation, and is irritant to the respiratory system and the skin.
LD₅₀ (rat, IP): 0.006 g/kg
LD₅₀ (rat, IV): 0.03 g/kg
LD₅₀ (rat, oral): 0.2 g/kg
LD₅₀ (rat, SC): 0.25 g/kg
LD₅₀ (mouse, IP): 0.01 g/kg
LD₅₀ (mouse, oral): 0.108 g/kg
LD₅₀ (rabbit, oral): 0.4 g/kg
LD₅₀ (rabbit, IV): 0.036 g/kg

storage

Cetylpyridinium chloride is stable under normal conditions. It should be stored in well-closed containers.

Incompatibilities

Incompatible with strong oxidizing agents and bases. It is also incompatible with methylcellulose.
Magnesium stearate suspensions in cetylpyridinium chloride have been shown to significantly reduce its antimicrobial activity. This is due to the absorption of cetylpyridinium chloride on magnesium stearate. The cetylpyridinium chloride ion also interacts with gelatin, resulting in reduced bioavailability.

Regulatory Status

Included in nonparenteral formulations licensed in the UK. Included in the FDA Inactive Ingredients Database, for use in inhalation and oral preparations. Reported in the EPA TSCA Inventory. It is not approved for use in Japan. Included in the Canadian List of Acceptable Non-medicinal Ingredients.