Functional Category

Antimicrobial preservative; antiseptic; disinfectant; solubilizing agent; wetting agent.

Applications in Pharmaceutical Formulation or Technology

Benzalkonium chloride is a quaternary ammonium compound used in pharmaceutical formulations as an antimicrobial preservative in applications similar to other cationic surfactants, such as cetrimide. In ophthalmic preparations, benzalkonium chloride is one of the most widely used preservatives, at a concentration of 0.01–0.02% w/v. Often it is used in combination with other preservatives or excipients, particularly 0.1% w/v disodium edetate, to enhance its antimicrobial activity against strains of Pseudomonas. In nasal, and otic formulations a concentration of 0.002–0.02% w/v is used, sometimes in combination with 0.002–0.005% w/v thimerosal. Benzalkonium chloride 0.01% w/v is also employed as a preservative in small-volume parenteral products. Benzalkonium chloride was also shown to enhance the topical penetration of lorazepam. Benzalkonium chloride is additionally used as a preservative in cosmetics.

Description

Benzalkonium chloride occurs as a white or yellowish-white amorphous powder, a thick gel, or gelatinous flakes. It is

hygroscopic, soapy to the touch, and has a mild aromatic odor and very bitter taste.