1,3-Dimethylol-5,5-dimethylhydantoin
MAK-Begründung, Nachtrag
Andrea Hartwig1 (Vorsitz der Ständigen Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Deutsche Forschungsgemeinschaft)MAK Commission2
1 Institut für Angewandte Biowissenschaften, Abteilung Lebensmittelchemie und Toxikologie, Karlsruher Institut für Technologie (KIT), Adenauerring 20a, Geb. 50.41, 76131 Karlsruhe, Deutschland
2 Ständige Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Deutschland
Abstract
The German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) has re-evaluated 1,3-dimethylol-5,5-dimethylhydantoin [6440-58-0] with regard to its carcinogenicity and germ cell mutagenicity classification, its ability to be absorbed through the skin, its sensitization potential and whether an occupational exposure limit value (maximum concentration at the workplace, MAK value) can be derived. Relevant studies were identified from a literature search. The substance is a formaldehyde releaser and is expected to undergo hydrolysis in aqueous solution. For this reason, the observed effects are attributed to the hydrolysis products formaldehyde and 5,5-dimethylhydantoin. There are no studies available that investigated the carcinogenicity, toxicity and genotoxicity of 1,3-dimethylol-5,5-dimethylhydantoin in the upper respiratory tract or nose, which are the likely target organs. The substance has genotoxic potential in vitro, presumably due to the release of formaldehyde. Formaldehyde was classified in Carcinogen Category 4 because it induces tumours in nasal tissue at concentrations that exceed its detoxification capacity. As a formaldehyde releaser, the substance could likewise be classified in Carcinogen Category 4. However, because it is not possible to derive a MAK value for 1,3-dimethylol-5,5-dimethylhydantoin, the substance has been assigned to Carcinogen Category 2 and given the footnote “Prerequisite for Category 4 in principle fulfilled, but insufficient data available for the establishment of a MAK or BAT value”. As there are no data for the systemic bioavailability of 1,3-dimethylol-5,5-dimethylhydantoin and the formaldehyde released by hydrolysis in tissues, there is no experimental evidence that the formaldehyde reaches the germ cells. Therefore, 1,3-dimethylol-5,5-dimethylhydantoin has been classified in Category 3 B for germ cell mutagens. 1,3-Dimethylol-5,5-dimethylhydantoin has skin sensitizing potential and the substance has therefore been designated with “Sh“. Skin contact is not expected to contribute significantly to systemic toxicity.
