The active ingredient in Antabuse, a drug used for the treatment of chronic alcoholism, is tetraethylthiuram disulfide, (296.54 g/mol). The sulfur in a 0.4169-g sample of an Antabuse preparation was oxidized to SO₂, which was absorbed in H₂O₂ to give H₂SO₄. The acid was titrated with 19.25 mL of 0.04216 M base. Calculate the percentage of active ingredient in the preparation.