Olmesartan Medoxomil Impurity: (5-Methyl-2-oxo-1,3-dioxol-4-yl)methyl 4-(1-methoxy-1-methylethyl)-2-propyl-1-[[2?-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-imidazole-5-carboxylate.