SEPARATION AND CHARACTERIZATION OF MAJOR OXIDATIVE IMPURITY IN FIMASARTAN DRUG SUBSTANCE

In the stress degradation studies of Fimasartan, one major unknown oxidative degradation impurity was identified by LC-MS. This impurity was separated by preparative HPLC. By spectral data analysis (H NMR, C NMR, DEPT, MS/MS and IR), this impurity is characterized as 2-(1-((2’-(1H-tetrazol-5-yl)-[1,1’-biphenyl]-4-yl)methyl)2-butyl-1,6 –dihydro-4-methyl-6-oxo-pyrimidin-5-yl)-N,N-dimethylacetamide. The details of stress studies, identification, isolation, characterization, formation and mechanism of this impurity are discussed and presented here.