8 Final Report on the Safety Assessment of Triethanolamine, Diethanolamine, and Monoethanolamine

Abstract

Triethanolamine (TEA), Diethanolamine (DEA), and Monoethanolamine (MEA) are amino alcohols used in cosmetic formulations as emulsifiers, thickeners, wetting agents, detergents, and alkalizing agents. The nitrosation of the etha-nolamines may result in the formation of N-nitrosodiethanolamine (NDELA) which is carcinogenic in laboratory animals. In single-dose oral toxicity for rats, TEA was practically nontoxic to slightly toxic, and DEA and MEA were slightly toxic. Long-term oral ingestion of the ethanolamines by rats and guinea pigs produced lesions limited mainly to the liver and kidney. Long-term cutaneous applications to animals of the ethanolamines also produced evidence of hepatic and renal damage. TEA and DEA showed little potential for rabbit skin irritation in acute and subchronic skin irritation tests. MEA was corrosive to rabbit skin at a 30% concentration in a single semioccluded patch application and at a >10% concentration in 10 open applications over a period of 14 days. The ethanolamines were nonmutagenic in the Ames test and TEA is also nonmutagenic to Bacillus subtilis. TEA did not cause DNA-damage inducible repair in an unscheduled DNA synthesis test. TEA had no carcinogenic or cocarcinogenic activity when dermally applied to mice for 18 months. Clinical skin testing of TEA and cosmetic products containing TEA and DEA showed mild skin irritation in concentrations above 5%. There was very little skin sensitization. There was no phototoxicity or photosensitization reactions with products containing up to 20.04% TEA. A formulation containing 11.47% MEA and a formulation containing 1.6% DEA and 5.9% MEA were irritating to human skin in patch tests. The Panel concludes that TEA, DEA, and MEA are safe for use in cosmetic formulations designed for discontinuous, brief use followed by thorough rinsing from the surface of the skin. In products intended for prolonged contact with the skin, the concentration of ethanolamines should not exceed 5%. MEA should be used only in rinse-off products. TEA and DEA should not be used in products containing N-nitrosating agents.