PHYSICOCHEMICAL CHARACTERIZATION OF MANGAFODIPIR TRISODIUM

Purpose: To determine the structure and various physicochemical proper ties of mangafodipir (MnDPDP) trisodium, the active ingredient of Tesl ascan, a new organ-specific contrast medium for MR imaging. Material a nd Methods: The structure of MnDPDP trisodium crystals was determined by X-ray crystallography. The possible existence of polymorphism in Mn DPDP trisodium was evaluated by powder X-ray diffraction, optical micr oscopy, thermal analysis and IR spectroscopy. In addition, various spe ctroscopic techniques and physicochemical measurements were used for c haracterisation of MnDPDP trisodium. Results: The crystallographic dat a obtained for MnDPDP trisodium show that the general core structure o f the MnDPDP anion is similar to that seen in related substances. The metal coordination geometry is a distorted octahedron defined by 2 phe nolate oxy gens, 2 carboxylate oxygens and 2 amine nitrogens. The unit cell contains 2 MnDPDP anions, 6 sodium ions and 50 water molecules. The various spectroscopic data are consistent with the structure deter mined by X-ray crystallography. The product (Teslascan) has low viscos ity, is isotonic with blood and has a physiological pH. Conclusion: Mn DPDP trisodium is a crystalline, hygroscopic solid which is readily so luble in water. No evidence of polymorphism was seen in the samples st udied.