Keywords: meloxicam impurity, ethyl 4-hydroxy-2-methyl-2H-1, 2-benzothiazine-3-carboxylate 1, 1-dioxide, (Z) - N-methyl meloxicam, N - [(2Z) - 3, 5-dimethylthiazol-2 (3H) - ylidene] - 4-hydroxy-2-methyl-2H-1, 2-benzothiazine-3-carboxamide 1, 1-dioxide