Biotin EP Impurity A

Chemical Name: D-Biotin Dimer Acid ; 5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]-2-[[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]propyl]pentanoic acid,