(R)-6-((1R,3aS,7aR,E)-4-((Z)-2-((3S,5R)-3,5-dihydroxy-2-methylenecyclohexylidene)ethylidene)-7a-methyloctahydro-1H-inden-1-yl)-2-hydroxy-2-methylheptan-4-one; 1α,25-Dihydroxy-23-oxocholecalciferol; 1α,25-Dihydroxy-23-oxovitamin D3,vitamin D3 Impurity