Abstract: A new series of polyglycol-phosphate-EDTA ester terpolymer ligands were synthesized by the copoly merization of ethylene diamine tetraacetic dianhydride(EDTAA), ethyl phosphodichloridate (or methyl phosphodichloridate, n-butyl phosphodichloridate) with diethylene glycol or triethyleneglycol, and their Fe(Ⅲ) complexes were prepared. The structures of these new ligands and Fe (Ⅲ) complexes were comfirmed by ¹H NMR, IR and elemental a nalysis. The longitudinal relaxation measurements on these macromolecular complexes indicated that most of them have higher relaxivity as compared to Fe(Ⅲ)-EDTA. Moreover, the acute toxicity test using one of these Fe (Ⅲ) complexes was performed and no obvious toxicity was observed. Finally, T₁-weighted contrast imaging of rat liver showed clear MRI enhancement after injection the new complex.

Key words: Magnetic resonance imaging, Fe (Ⅲ) complex, Macromolecular contrast agent, Relaxivity, Acute toxicity