cetylpyridinium

Cetylpyridinium, most commonly encountered as cetylpyridinium chloride (CPC), is a quaternary ammonium compound used as an antiseptic and surfactant. The cation consists of a cetyl group (a 16-carbon alkyl chain) attached to a pyridinium ring, with chloride serving as the counterion in the chloride salt.

CPC is widely used in consumer and professional antiseptic products, particularly in oral care. It appears in mouthwashes, lozenges, and some toothpaste formulations, as well as topical antiseptics and certain throat sprays. In mouthwash applications, CPC is typically present at concentrations around 0.05% to 0.1%, where it helps reduce oral microbial load and plaque formation.

Mechanistically, CPC is a cationic surfactant that disrupts microbial cell membranes and proteins, leading to increased permeability and cell death. It shows broad-spectrum activity against many bacteria, especially Gram-positive organisms, and some fungi. It is not considered a sterilant and is less effective against bacterial spores.

Safety and regulation for CPC reflect its widespread use. At approved concentrations, adverse effects are uncommon, but mucosal irritation or allergic reactions can occur in sensitive individuals. Ingesting large amounts can be harmful. Long-term or excessive use should follow product labeling, and users should be aware of potential interactions when CPC is combined with other active ingredients in multi-ingredient formulations, such as fluoride-containing products.

Chemically, CPC is produced by quaternization of a pyridine derivative with a long-chain alkylating agent, followed by formation of the chloride salt used in regulated products.