Synonyms: 1H-Benzimidazolium,2-[3-[1,3-dihydro-1-methyl-3-(4-sulfobutyl)-5-(trifluoromethyl)-2H-benzimidazol-2-ylidene]-1-propenyl]-1-methyl-3-(4-sulfobutyl)-5-(trifluoromethyl)-,hydroxide, inner salt, sodium salt; 1H-Benzimidazolium,2-[3-[1,3-dihydro-1-methyl-3-(4-sulfobutyl)-5-(trifluoromethyl)-2H-benzimidazol-2-ylidene]-1-propenyl]-1-methyl-3-(4-sulfobutyl)-5-(trifluoromethyl)-,inner salt, sodium salt (9CI)