Synthesis On Phthalocyanines-based Bifunctional Agents Of Contrast Agent For MRI And Photosensitizer For PDT

Contrast agent is playing an increasingly important role in magnetic resonance imaging (MRI), which is recently highly regarded as a new scatheless modality with high resolution and good flexibility in clinical diagnose. Meanwhile, a novel cancer treatment with less poisonous side-effect called photodynamic therapy (PDT) is developed recently, which destroys cancer tissue selectively to avoid injuring surrounding cells, and of which the key problem is to select an appropriate photosensitizer. Hence, it will greatly promote the diagnosis-treat union of MRI and PDT if a new family of bi-functional agents is found which combines the effect of contrast agent in MRI and that of photosensitizer in PDT, and will bring great improvement to the cancer diagnosis and treatment.Phthalocyanine has gradually displayed formidable superiority in photodynamic therapy due to its favorable photophysical efficiency and less side effect. This paper briefly introduces the synthetic methods of phthalocyanine as photosensitizer applied in PDT and the research progress on phthalocyanine, and also reviews the recent progress of research on bi-functional agents of MRI-PDT.In order to find new products as bi-functional agents of MRI-PDT with good water-solubility, high relaxation potency and ability of liver selection, two series of compound of phthalocyanine have been synthesized in tests. One is the company with carboxyl group saturated alkyl amino metal phthalocyanine (MPc-N(CH2CH2COOH)2), the other is the DTPA monoamides metal phthalocyanine (MPc-NHDTPA), which has similar structure but some different properties when obtained by two different approaches. Next, the Gd(III) complexes is obtained by the reaction of the two kinds of phthalocyanines with GdCl3?6H2O. The phthalocyanines were characterized with FT-IR and 1H NMR, while the complexes were confirmed by FT-IR. Then, Some phthalocyanines and Gd (III) complexes were tested with UV-visible light and the phenomenon of fluorescence is observed. Finally, the proton longitudinal relaxivity of several kinds of the complexes were tested.It is revealed from the experiment that the water-solubility of the second kind of phthalocyanine is better than that of the first kind of phthalocyanine, though the water-solubility and the difficulty in preparation of the second one are subjected to the center metallic ion. Among all the phthalocyanine, Zn-Pc-NHDTPA and Al-Pc-NHDTPA possess excellent water-solubility. But all the Gd (III) complexes can dissolve in water. Furthermore, the test results of the proton longitudinal relaxivity show that the R1 of Cu-Pc-N(CH2CH2COOH)2?Gd(â…¢)?H2O and Co-Pc-N(CH2CH2COOH)2?Gd(â…¢)?H2O are respectively more than 81.1% and 149.3% higher than that of Gd-DTPA, which may indicates that the Gd(III) complexes is hopefully expected to be the ideal model of the bi-functional agent of MRI-PDT.