Synonyms: 5-amino-3-[[4-[5-[(8-amino-1-hydroxy-3,6-disulpho-2-naphthyl)azo]-1H-benzimidazol-2-yl]phenyl]azo]-4-hydroxynaphthalene-2,7-disulphonic acid, sodium salt;2,7-Naphthalenedisulfonic acid, 5-amino-3-[[4-[5-[(8-amino- 1-hydroxy-3,6-disulfo-2-naphthalenyl)azo]-1H-benzimidazol -2-yl]phenyl]azo]-4-hydroxy-, sodium salt