Ethyl (Z)-3'-(2-(1-(3,4-dimethylphenyl)-3-methyl-5-oxo-1,5-dihydro-4H-pyrazol-4-ylidene)hydrazinyl)-2'-hydroxy-[1,1'-biphenyl]-3-carboxylate (as per USP); (Z)-Ethyl 3`-(2-(1-(3,4-dimethylphenyl)-3-methyl-5-oxo-1H-pyrazol-4(5H)-ylidene)hydrazinyl)-2`-hydroxy-[1,1`-biphenyl]-3-carboxylate;