PARAMAGNETIC METAL-CHELATES OF DTPA-DIPYRIDOXOL AND EDTA-DIPYRIDOXOL ESTER DERIVATIVES AND THEIR NMR T-1 RELAXIVITIES IN WATER

Several novel ligands of DTPA- and EDTA-dipyridoxolester derivatives h ave been synthesized by reaction of DTPA-dianhydride and EDTA-dianhydr ide with pyridoxol (vitamin Bg) in dry DMF. Their complexes of gadolin iun, manganese and iron were prepared and the measurements of T-1 rela xivities in solution of water in vitro were performed with the gadolin ium and the manganese complexes. The results show that all of the comp lexes are highly water soluble and very slightly light and air sensiti ve both in solid state and in solution, The T-1 relaxivities of the co mplexes, for example, gadolinium-DTPA-dipyridoxolester, GdDTPA-BPN, an d manganese-EDTA-dipyridoxolester, MnEDTA-BPN, were determined to be 5 . 5 and 3. 1 L . mmol(-1) . s(-1), respectively. These can be compared to the values of the corresponding complexes of their parent ligands, GdDTPA(2-) and MnEDTA(2-), indicating the complexes are potentially u seful contrast agents for magnetic resonance imaging.