Allergenicity of epoxy resins in the guinea pig.

The sensitizing capacity of epoxy resins of diglycidylether-Bisphenol A type was investigated using the "guinea pig maximization test". One isolated resin had a molecular weight (MW) of 340, which is the lowest among this type of epoxy resin. The other resins were mixtures with different MWs. Their distribution is not known, but only their average MW. The low molecular weight resin sensitized all of the animals and can be classified as an extreme allergen. The sensitizing capacity decreased in inverse proportion to the increase in the average MW of the resin mixtures. The cross-testing also indicated that the resin mixtures with higher average MW contained enough of the low MW resin (MW 340) to render this resin a sensitizer. Bisphenol A did not sensitize the animals at all but epichlorhydrin sensitized 60%. It is evident that in order to formulate hypoallergenic epoxy resins it will be necessary to achieve sensitization of animals with isolated resins of varying molecular weight.