The most characteristic impurity of the meloxicam drug substance is an N-methylated derivative, equally formed in the various known manufacturing syntheses of the compound. An N-methylated impurity is listed in the European Pharmacopeia monograph of meloxicam as Impurity C, although no evidence has been published for its structure. An unambiguous structure proof of the N-methylated impurity formed in our manufacturing synthesis is ...
![N-[(2E)-3,5-Dimethyl-1,3-thiazol-2(3H)-ylidene]-4-hydroxy-2-methy l-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide Structure](https://image.chemsrc.com/caspic/266/1145656-36-5.png)
