Contact allergenic activity of Tween 80 before and after air exposure

Tween 80 is an ethoxylated hydrophilic non-ionic surfactant, which is used for the preparation of oil-in-water emulsions in pharmaceutical products, cosmetics, and industrial detergents. Ethoxylated surfactants are polyethers and are thus easily oxidized by atmospheric oxygen to a variety of hydroperoxides, peroxides and carbonyl compounds. The aim was to investigate the formation of oxidation products and the allergenic potential of Tween 80 before and after air exposure. The formation of peroxides and formaldehyde was followed with chemical analyses during air and pure oxygen exposure of water solutions of Tween 80 of technical quality. A complex mixture of compounds was formed when Tween 80 was oxidized. Formaldehyde was detected in amounts that may be eliciting in allergic individuals. Acetaldehyde was identified in Tween 80 before oxygen exposure, whereafter the amount gradually decreased. The contact allergenic activity was determined in experimental sensitization studies in guinea pigs. Non-oxidized as well as oxidized Tween 80 of technical quality showed allergenic activity. The results indicate that allergens are present in Tween 80 before oxidation and that new allergens are formed in the oxidation process. No obvious dose-response relationship was found in the sensitization studies. The possibility that allergenic compounds can be formed during storage and handling of products containing ethoxylated surfactants should be taken into consideration.