Abstract: The scavening action to hydroxyl free radical of benzisoselenazolones and diselenides has been studied by fluorometry. The hydroxyl free radicals were produced via Fenton reaction. The method used provides a sensitive, simple and accurate measurement of the scavening action to hydroxyl free radical for synthetic drugs of highly biological activity.

Key words: fluorometry, hydroxyl free radical, Fenton reaction, benzisoselenazolone, diselenide