Abstract
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated N‐cyclohexylhydroxy‐diazene‐1‐oxide, potassium salt to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available unpublished study reports and publications are described in detail. A gavage study with rats given daily doses of the substance for 3 months yielded a NOAEL of 25 mg/kg body weight and day; effects on the blood and liver and mortality occurred at 50 mg/kg body weight and day. Based on this NOAEL, a MAK value of 10 mg/m3 has been established for the inhalable fraction of N‐cyclohexylhydroxy‐diazene‐1‐oxide, potassium salt. The MAK value was derived from a systemic NOAEL; therefore, N‐cyclohexylhydroxy‐diazene‐1‐oxide, potassium salt is classified in Peak Limitation Category II with a default excursion factor of 2 as sufficient toxicokinetic data are not available. Calculations of dermal absorption based on in vitro studies show that dermal absorption would contribute substantially to the systemic toxicity. Therefore, N‐cyclohexylhydroxy‐diazene‐1‐oxide, potassium salt has been designated with an “H”. N‐Cyclohexylhydroxy‐diazene‐1‐oxide, potassium salt is not genotoxic or carcinogenic and limited data show no sensitizing potential in mice. Because there are no studies on developmental toxicity of N‐cyclohexylhydroxy‐diazene‐1‐oxide, potassium salt, it is assigned to Pregnancy Risk Group D.
Hartwig, A