Final Report on the Safety Assessment of Di-t-Butylhydroquinone

Abstract

Di-t-Butylhydroquinone is an antioxidant that may be used in cosmetic products; currently, however, there are no reported uses. Di-t-Butylhydroquinone is approved for use as an indirect food additive. Very little data relevant to assessing the safety of Di-t-Butylhydroquinone in cosmetics are available. In a study in which rats were exposed to 2% Di-t-Butylhy-droquinone in their feed, all died within 2 weeks. Other studies reported results that vary as a function of the base feed used. In a chronic study, rats fed up to 0.2% Di-t-Butylhydroquinone did not exhibit a significant response. Exposure of male Syrian hamsters to 1% Di-t-Butylhydroquinone in the feed resulted in inflammation, hyperkeratosis, hyperplasia, and papillomas in the non-squamous stomach. Animal tests show that Di-t-Butylhydroquinone as low as 10% can cause erythema, but not sensitization. Di-t-Butylhydroquinone does not appear to cause depigmentation. However, additional safety data are needed. Information is needed on the concentration of its use in cosmetics, the presence of impurities, UV absorption, 28-day dermal toxicity, skin penetration, dermal irritation and sensitization, and genotoxicity, (two different assays, one in a mammalian system). Additionally, if there is UV absorption, photosensitization data are needed; if there is significant skin absorption, reproductive and developmental toxicity data may be needed; and if there is positive mutagenicity, a dermal carcinogenicity assay is needed. In the absence of these data, it was concluded that the available data are not sufficient to support the safety of Di-t-Butylhydroquinone in cosmetic products.