Synthesis and MRI Relaxation Enhancement of Mono-exter-amido Gadolinium Complexes

Four new ester-amido ligands were synthesized by esterification of mono-iso-butyl diethylenetriaminepentaacetate and mono-iso-butyl ethylenediaminetetraacetate with N,N'-ethylene bis-lactamide and NN'-1,6-hexamethylenebislactamide, respectively. The corresponding Gd(III) complexes were made by reacting the ligands with Gd2O3. All ligands and complexes were characterized: by FT-IR, H-1 NMR and elemental analysis. The measured longitudinal relaxivity of these complexes were all higher than that of Gd-DTPA. The investigation on cute toxicity and T-1-weighted imaging of complex derived from mono-N,N'-ethylenebislactamide ester diethlenetriaminepentaacetate were performed. No cute toxicity was found. The tested complex exhibited the higher enhancement on MRI signal intensity in rat liver, comparing with Gd-DTPA.