4-Hydroxy-PAC 1-β-D-Glucopyranosiduronic Acid-d8 is deuterium labeled 4-Hydroxy-PAC 1-β-D-Glucopyranosiduronic Acid. 4-Hydroxy-PAC 1-β-D-Glucopyranosiduronic Acid is a metabolite of PAC-1 (P132000),which is a potential anti-tumor drug candidate that activates caspase 3 and induces apoptosis in both in vitro and in vivo against mice tumors. Metabolites andderivatives of PAC-1 are useful compounds to investigate the mechanism of action and toserve as standards(ie. LC/MS).