Benzalkonium chloride (BZK, BKC, BAK, BAC), also known as alkyldimethylbenzylammonium chloride (ADBAC) and by the trade name Zephiran, is a type of cationic surfactant. It is an organic salt classified as a quaternary ammonium compound.
Benzalkonium chloride also possesses surfactant properties, dissolving the lipid phase of the tear film and increasing drug penetration, making it a useful excipient, but at the risk of causing damage to the surface of the eye.
Benzalkonium chloride is a mainstay of phase-transfer catalysis, an important technology in the synthesis of organic compounds, including drugs.
Especially for its antimicrobial activity, benzalkonium chloride is an active ingredient in many consumer products:
Benzalkonium chloride is also used in many non-consumer processes and products, including as an active ingredient in surgical disinfection. A comprehensive list of uses includes industrial applications.An advantage of benzalkonium chloride, not shared by ethanol-based antiseptics or hydrogen peroxide antiseptic, is that it does not cause a burning sensation when applied to broken skin. However, prolonged or repeated skin contact may cause dermatitis.