Abstract: Diethylenetriaminepentaacetic dianhydride was co-polymerized with dodecyl ester and benzyl ester of lysine,and octodecyl ester and benzyl ester of lysine respectively to give two terpolymers. These two terpolymer ligands were reacted with GdCl₃ to afford amphiphilic oligomers of Gd(Ⅲ) complexes. These new ligands and Gd(Ⅲ) complexes were characterized by IR, ¹H NMR and elemental analysis. The oligomeric complexes show a higher relaxivity as compared to that of Gd(DTPA) which is widely used in clinic diagnoses. The Gd(Ⅲ) complex derived from octodecyl ester demonstrated liver-selective enhancement for MR imaging of Wistar rat. The ratios of signal to noise ( S/N ) in the proton intensity imaging were enhanced,respectively,by 15%,27%,and 36% at the time of 5,30 and 45 min after injection of this complex.

Key words: Amphiphilicity, Oligomeric terpolymer ligand, Gd(Ⅲ) complex, Liver-selective MR imaging