2-[[5-cyano-2,6-bis[(3-methoxypropyl)amino]-4-methyl-3-pyridyl]azo]-5-[[2-(sulphooxy)ethyl]sulphonyl]benzenesulphonic acid, sodium salt

2-[[5-Cyano-2,6-bis[(3-methoxypropyl)amino]-4-methyl-3-pyridinyl]azo]-5-[[2-(sulfooxy)ethyl]sulfonyl]benzenesulfonic acid/sodium,(1:x) salt