Uric acid, a water soluble antioxidant, is able to react with micelle incorporated diphenylpicrylhydracyl radicals. This indicates that uric acid can react at the lipid/water interface. The rate of the process follows the order cationic micelles >buffer/etanol > neutral micelles anionic micelles These results can be explained in terms of the compartmentalization of the reactants in different environments and the effect of electrostatic interactions in modulating the access of the urate anion to the micellar interface. Experiments aimed to determine if urate is able to react with alpha-tocopheroxyl radicals regenerating a-tocopherol were uncesessful, indicating that urate is not able to delay vitamin E consumption in the presence of lipid - soluble free radicals