| Photodynamic therapy is a very effective means of treating cancer, which by the photosensitizer is injected into a patient, when a certain concentration of photosensitizer accumulation in tumor cells with an appropriate wavelength of light is irradiated to produce singlet oxygen, it can kill tumor cells and has no effect on the surrounding healthy tissue.This article provides an overview of photodynamic therapy concept, mechanism and application development as well as introduced the species of chlorophyll photosensitizer, characteristics of ideal photosensitizer. It focuses on the extraction of chlorophyll –a as raw materials to give methyl Pyropheophorbide-a,and get methyl Pyropheophorbide-a acid under the action of sodium hydroxide and sulfuric acid,methyl pheophorbide-a can also react with phenylhydrazine hydrochloride,which can synthesize methyl Pyropheophorbide-a Phenyl hydrazone derivatives 7a and 7b through a series of multiple intermediate products, the maximum absorption wavelength of 668 nm from the original material increase to 682 nm and 689 nm, respectively, an increase of 14 nm and 19 nm, increasing the penetration of the photosensitizer.Studying the spectral properties of methyl Pyropheophorbide-a Phenyl hydrazone derivatives 7a and 7b, respectively, in dichloromethane, methanol, ethanol, N, Ndimethylformamide, toluene, and hexane and UV conditions at pH = 2,3,4,5,6,7,8,9,10-visible absorption and fluorescence spectra. We can see 31-131- methyl Pyropheophorbide-a p-bromo dihydrazone has a strong UV absorption in a polar solvent, strong acid environment, the maximum absorption wavelength may slight blue shift,under weak acidic and alkaline conditions,the wavelength remained unchanged; while the Soret peak of 31-131- methyl Pyropheophorbide-a p-bromo dihydrazone compared to the Soret peak of methyl Pyropheophorbide-a with a slight red shift. In a polar solvent,the fluorescent emission of this substance has strong spectral intensity;the 31-131- methyl Pyropheophorbide-a l p-bromo dihydrazone emission intensity at 410 nm with the pH value and the corresponding fluorescence at 688 nm the graph shows that the trend of this graphs is similar, pH increased from 2-7, fluorescence intensity increased gradually, wherein the pH 2-3, fluorescence intensity dramatically enhanced, by the pH 3-7, fluorescence intensity trend slightly slow,pH 7-10 by the fluorescence intensity decreased.31-131- methyl Pyropheophorbide-a o-terephthalic trifluoromethyl hydrazone in a polar solvent has a strong UV absorption, in strong acidic environment, the maximum absorption wavelength slight blue shift, under weak acid and alkali conditions,the wavelength essentially unchanged; while the Soret peak of 31-131- methyl Pyropheophorbide-a o-terephthalic trifluoromethyl hydrazone campares to the Soret peak of methyl Pheophorbide-a with slight red shift phenomenon. In a polar solvent, 31-131- methyl Pyropheophorbide-a o-terephthalic trifluoromethyl hydrazone has strong fluorescence emission spectrum intensity.The diagram of emission intensity and pH value of 31-131- methyl Pyropheophorbide-a o-terephthalic trifluoromethyl hydrazone at 411 nm of the corresponding fluorescence seen, we can see the pH value of 2-6, fluorescence intensity increased, the pH value of from 6 to 10, the fluorescence intensity remained unchanged; The diagram of emission intensity and pH value of 31-131- methyl Pyropheophorbide-a o-terephthalic trifluoromethyl hydrazone at 683 nm of the corresponding fluorescence seen, we can see the pH value of 2-6, fluorescence intensity increased, the pH value of from 6 to 7, the fluorescence intensity decreased; the pH value of from 7 to 10, the fluorescence intensity remained unchanged.In summary, the UV- visible absorption intensity and fluorescence intensity of these two substances are large, they are very potential photosensitizer in photodynamic therapy,they can be applied in biological and medical imaging.All structures of the new compounds described by NMR, MS characterization. |
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