Synthesis And Property Of MRI Contrast Agents Based On Gd-DTPA Modified By Hydrophobic Groups

Magnetic resonance imaging(MRI) has become an indispensable clinical diagnostic imaging technology in early disease detection due to its advantages of no ionization, non- invasion, providing any direction of tomo graphy images and high spatial resolution. Contrast agents are an unique part of MRI which can shorten imaging time and increase the image contrast. Some contrast agents which have been used in clinic are short of high relaxation rate and organ-selectivity. In order to conquer these defects, Gd-DTPA was modified by hydrophobic groups, which can improve the relaxation rate and organ-selectivity. In this paper, nine stability, low toxicity and targeted MRI contrast agents were designed and synthesized. The main work of this thesis was summarized as follows:(1) The research progress of MRI technique and its working principle was reviewed briefly; The principle, classification, influencing factors and development trend of MRI contrast agents were described in detail; The research progress of MRI contrast agent was reviewed briefly;(2) By introducing hydrophobic group of phenyl to modified DTPA, three molecular MRI contrast agents of CA1, CA2, CA3 were synthesized; By introducing hydrophobic group of quinolone to modified DTPA, four metal-sensitive MRI contrast agents of CA4, CA5, CA6, CA7 were synthesized; By introducing hydrophobic of phenyl and porphyrin group to modified DTPA, two multi- nuclear MRI contrast agents of CA8, CA9 were synthesized;(3) These compounds were further characterized by FT-IR, 1H NMR, 13 C NMR and ESI-MS et al. N ine MRI contrast agents' relaxivity, toxicity were studied. Imaging effect of CA7 was studied. The results showed that: the relaxivity of MRI contrast agents CA1, CA2, CA3, CA4, CA5, CA6, CA7,CA8, CA9 is 8.64 Lmmol-1s-1,4.97 Lmmol-1s-1, 5.64 Lmmol-1s-1, 9.59 Lmmol-1s-1, 8.78 Lmmol-1s-1, 9.20 Lmmol-1s-1, 10.12 Lmmol-1s-1, 14.42 Lmmol-1s-1, 5.83 Lmmol-1s-1 respectively. N ine contrast agents' biological toxicity is low. CA7 which used as imaging contrast agent can improve the imaging resolution and contrast.