Amended Final Report On the Safety Assessment of Pyrocatechol

Abstract

Pyrocatechol is a phenol used primarily in hair dyes but has one reported use in skin care preparations. When this ingredient was first reviewed it was concluded that Pyrocatechol was safe for use in formulations designed for discontinuous, brief use followed by rinsing from the skin and hair at concentrations of up to 1.0%. This amendment to that report was prepared in order to incorporate the results from several studies, including those reporting immunologic, carcinogenic, and cocarcinogenic effects of Pyrocatechol. In vitro, Pyrocatechol has been shown to affect several immunologic and other properties of murine bone marrow cells, both alone and when combined with hydroquinone. Pyrocatechol, when produced as an hepatic metabolite of benzene, has been reported to concentrate in the bone marrow and to adversely affect hematopoietic precursor cells. These effects are somewhat species specific. In vivo, dermal exposure of mice to Pyrocatechol affects the number and distribution of Langerhans cells at the site of exposure but is not associated with a change in contact sensitivity. Oral exposure of pregnant rats to Pyrocatechol did result in an increase in teratogenic effects. The results of a micromass teratogen test in vitro were also positive. Pyrocatechol was tested in a number of bacterial and mammalian mutagenesis systems. Both negative and positive results were observed. Carcinogenicity studies were conducted in rats and mice. Pyrocatechol was provided in the feed. While adenomatous hyperplasia was noted in both species, adenocarcinomas were seen in male and female rats only. In cocarcinogenesis studies there is a similar pattern of hyperplasia and adenomas of the glandular stomach in the groups exposed to Pyrocatechol alone. When administered with several other carcinogens, Pyrocatechol had a cocarcinogenic effects. Pyrocatechol was not a tumor promoter in dermal studies. Based on these data and the significant potential for skin absorption of Pyrocatechol in leave-on preparations, it was concluded that Pyrocatechol is unsafe for use in leave-on cosmetic formulations. Pyrocatechol used in a rinseoff application such as hair dyes may not present a similar concern if Pyrocatechol is completely and rapidly oxidized. Because no data were available, it was concluded that there are insufficient data to support the safety of this ingredient. The data needed to complete the safety assessment include the extent and rate of oxidation when used in hair dyeing. If not rapidly and completely oxidized, then further chemical characterization of cosmetic grade Pyrocatechol is needed, along with cutaneous absorption data in aqueous and at RYERSON UNIV on June 15, 2015 ijt.sagepub.com Downloaded from

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