Monograph: |
Oxyquinoline is a heterocyclic phenol amine and Oxyquinoline Sulfate is its salt. In hair products containing hydrogen peroxide, these ingredients function as chelators. Binding trace levels of metals that may be present helps stabilize the hydrogen peroxide.
Oxyquinoline was metabolized and excreted in the urine as glucuronides. These ingredients exhibited little acute or subchronic toxicity. A 100 mg dose of Oxyquinoline was only slightly irritating to the eye. Oxyquinoline and Oxyquinoline Sulfate were genotoxic in certain Salmonella typhimirium strains with metabolic activation and in a lymphoma assay. No genotoxicity was found in a fruit fly sex-linked recessive lethal test, bone marrow micronucleus test, a bone marrow and hepatocyte micronucleus test, unscheduled DNA synthesis in hepatocytes, and chromosome aberrations and sister-chromatid exchanges in hepatocytes. Oxyquinoline was non-carcinogenic in several feeding studies, and newly available studies including one with the human c-Ha-ras gene, demonstrated that Oxyquinoline was not carcinogenic. In clinical tests, Oxyquinoline was neither an irritant nor a sensitizer when tested at 1% in petrolatum. The available data demonstrated that Oxyquinoline and Oxyquinoline Sulfate as stabilizers for hydrogen peroxide in rinse-off hair care products were safe in the present practices of use. The CIR Expert Panel requested additional information on UV absorption and phototoxicity data to assess the safety for leave-on cosmetics and personal care products.
Health Canada permits the use of Oxyquinoline and Oxyquinoline Sulfate (8-Hydroxyquinoline and its sulfate salt) as stabilizers for hydrogen peroxide in rinse-off and leave-on hair care products at concentrations equal to or less than 0.3% and 0.03%, respectively.
Oxyquinoline and Oxyquinoline Sulfate are listed as Hydroxy-8-quinoline and its sulfate in the Cosmetics Directive of the European Union (see Annex III) and may be used as stabilizers for hydrogen peroxide in rinse-off and non-rinse-off hair care products at a maximum concentration of 0.3% and 0.03%, respectively. As indicated in Annex II, these ingredients may not be used in any other manner in cosmetics and personal care products in the European Union.
Hydroxyquinoline sulfate and potassium hydroxyquinoline sulfate have antibacterial, antifungal, and deodorant properties, and have been used similarly in the topical treatment of skin, oropharyngeal, and vaginal disorders. Potassium hydroxyquinoline sulfate is often used with benzoyl peroxide. Derivatives of hydroxyquinoline including the salicylate, benzoate, borate, hydrofluoride, iodochloride, silicofluoride, and sodium hydroxyquinoline sulfate have been used similarly.
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