Esomeprazole Sodium Impurity Ⅲ:N-Methyl Omeprazole (Mixture of isomers with the methylated nitrogens of imidazole);5-Methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1-methyl-1H-benzimidazole; 6-Methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyrid