Toxicity experiments with rabbits h

Toxicity experiments with rabbits have shown benzalkoniumchloride to be harmful to the eye in concentrations higher than thatnormally used as a preservative. However, the human eye appears tobe less affected than the rabbit eye and many ophthalmic productshave been formulated with benzalkonium chloride 0.01% w/v asthe preservative.Benzalkonium chloride is not suitable for use as a preservative insolutions used for storing and washing hydrophilic soft contactlenses, as the benzalkonium chloride can bind to the lenses and maylater produce ocular toxicity when the lenses are worn.(18) Solutionsstronger than 0.03% w/v concentration entering the eye requireprompt medical attention.Local irritation of the throat, esophagus, stomach, and intestinecan occur following contact with strong solutions (>0.1% w/v).The fatal oral dose of benzalkonium chloride in humans is estimatedto be 1–3 g. Adverse effects following oral ingestion includevomiting, collapse, and coma. Toxic doses lead to paralysis of therespiratory muscles, dyspnea, and cyanosis.