Abstract: There is provided a synthesis and description of diprotonated diacid derivatives of pyridoxal isonicotinoyl hydrazone (PIH) of formula (I), wherein q is 1 or 2, DPA is 2 mols of a monoprotic acid HX or 1 mol of a diprotic acid H.sub.2 Y wherein X is a monovalent anion and Y is a divalent anion and both HX and H.sub.2 Y are pharmaceutically acceptable acids. The unique properties of the PIH.DPA molecule make it particularly suitable and pharmaceutically acceptable for formulation as an oral dosage form by virtue of its ready solubility in water. There are further provided methods of utilizing such chemically unique and isolable crystalline compounds, such as PIH.2HCI, as a pharmaceutical chelator. There are further provided pharmaceutical formulations specifically for the reduction of iron overload, and related chelatable metals, in subjects susceptible to such overload.