... of solution Clear Clear Related Substance Ethyl 4-hydroxy-2-methyl-2H-1, 2-benzothiazine-3carboxylate 1, -dioxide ≤ 0. ... ylamine ≤ 0.1% 0.0007% 4-hydroxy-2-methyl-N- (5-methyl-1, 3-thiazol-2-yl)-2H-1, 2-benzothiazine ... 1,1-dioxide ≤ 0.05% No trace Methyl 4-hydroxy-2-methyl-2H-1, 2-benzothiazine-3-carboxylate 1,1 ... dioxide ≤ 0.1% No trace 4-hydroxy-2-methyl-N-methyl-N- (5-methyl-1, 3-thiazol-2-yl)-2H-1, 2 ...