RESUMO
A method for the preparation of pheophorbide a ( a novel photosensitizer for tumor photolocalization and photodynamic therapy) from silkworm excrement oily chlorophyll is reported for the first time. The chromatographic, sectroscopic and photochemical properties of pheophorbide a were studied, and its distribution in tissues of S180 tumor-bearing mice was determined. The UV/vis spectrum of the obtained pheophorbide a was identical with that reported by other authors, but it was still found to contain two components (probably two optical isomers) by HPLC analysis and 1H-NMR spectrometry. The results of a preliminary study on its distribution in tumor-bearing mice showed that it was accumulated selectively in tumor tissues after intravenous injection and at 24 hours after drug administration the tumor to skin ratio rose to as high as 15. These results suggest that it might be a a promising photosensitizer.