Special Report: Reproductive and Developmental Toxicity of Ethylene Glycol and Its Ethers

Abstract

Polymers of Ethylene Glycol are linked via ether linkages with various alcohols or via ester linkages to various fatty acids in many cosmetic ingredients. Ethylene Glycol, when reacted with an alkyl alcohol, forms an ethylene glycol monoalkyl ether. These compounds are metabolized in the human body by alcohol dehydrogenase and aldehyde dehydrogenase to form corresponding acetaldehyde and acetic acid derivatives. Data are presented that show reproductive and developmental toxicity is associated with metabolites of ethylene glycol monoalkyl ethers, but not with the monoalkyl ethers themselves. Further, it is suggested that the toxicity of these metabolites is inversely proportional to the length of the alkyl chain in the original alkyl ether. In the case of the compounds used in cosmetics, most have alcohols or fatty acids linked to polyethylene glycol chains, not a single Ethylene Glycol moiety. Where Ethylene Glycol is linked to a fatty acid by an ester linkage, the resulting compound is chemically different from the monoalkyl ethers. Where Ethylene Glycol is linked to an alcohol via an ether linkage, the alkyl chain is large and complex, suggesting little or no potential toxicity. Overall, it was found that metabolites of ethylene glycol monoalkyl ethers are reproductive and developmental toxins. In general, however, the metabolites of concern are not expected to be formed in cosmetic formulations that contain polymers of ethylene glycol.