While both theophylline and potassium persulfate have similar water solubilities, the persulfate is an energetic oxidizing agent and tends to release gas on contact with water andwith organic copolymer.EXAMPLE 7A commercial herbicide material (metasulfuron methyl, available from the Du Pont Company) was compounded according to the technique of Example 1 as follows:metasulfuron methyl--70 partsCrys