Indigo carmine or indigotindisulfonate sodium

This classification denotes a dye with the molecular formula C16H8N2O8S2.2Na, a preparation that US FDA recognizes as an active ingredient or moiety under Unique Ingredient Identifier D3741U8K7L, chemically known as 2-(1,3-dihydro-3-oxo-5-sulfo-2h-indol-2-ylidene)-2,3-dihydro-3-oxo-1h-indole-5-sulfonic acid, disodium salt but more generally known as acid blue 74, which bears US NIH Compound Identifier 5282429. European Medicines Agency schedules Indigo carmine in its eXtended EudraVigilance Medicinal Product Dictionary or XEVMPD under Index SUB12518MIG World Health Organization schedules acid blue 74 in its Anatomical Therapeutic Chemical (ATC) Classification. Indigotindisulfonate sodium bears US NLM identifiers UMLS ID C0021219 and NCI Concept Code C83799. SMILES: S(=O)(=O)(O)C1CC2C(N/C(=C3/NC4C(C3=O)CC(S(=O)(=O)O)CC4)C2=O)CC1.[NA].[NA].