Photodynamic activity of a number of photosensitizers in vitro

The comparative study of the photosensitizers with different chemical, spectral-luminescent and photophysical properties (phthalocyanines -- photosense, di- and trisulphonated zinc (II) phthalocyanines; chlorines -- chlorine p6, desvinyl-3- formyl-chlorine p6 and 3-desvinyl-3-acetyl-chlorine p6; xanthenes --rhodamine 123, rhodamine 6G-chloride, rhodamine 6G-acetate, rhodamine 6G-iodide; arylamines -- oxazinne perchlorate, oxazine-1 zinc salt, 9-diethylamino-5- ethylaminobenzophe-nothiazonium acetate, methylene blue) was performed. The cyto- and the phototoxicity of these compounds were studied on the cells of two human tumor cell lines (Raji B-cell lymphoma and A-549 lung adenocarcinoma) by MTT-test. It was shown that phthalocyanines and chlorines were not cytotoxic, whereas xanthenes and arylamines possessed dark toxicity. On the basis of the IC50 (the substance concentration, which induced 50% inhibition of cell proliferation in the cell culture) the rows of phototoxicity of the compounds of various classes were set out: in phthalocyanines: ZnPcS2 greater than Photosence greater than ZnPcS3; in chlorines: 3dV-3F-Chl p6 greater than 3 dV-3Ac Chl p6 greater than Chl p6; in xanthenes: R6G- Ac greater than R6G-Cl greater than R6G-I greater than R 123; in arylamines: Meth B greater than or equal to 9-DE-B- Ac greater than Ox1-1/2ZnCl42- very much greater than Ox1-ClO4-. Phototoxicity of the studied compounds depended on the nature of the substitutes and of the counter ions in photosensitizers molecules as well as on the concentration of the photosensitizer, on the light doses and on the regimes of irradiation. The fractionation of the light doses increased the efficiency of the phototoxic effect of the dyes on the tumor cells significantly. It was shown by the luminescent microscopy that the dynamics and the intensity of the accumulation of the rhodamines derivatives in lung adenocarcinoma cells depended on the nature of the counter ion in the photosensitizer molecule and correlated with their cyto- and pho-toxicity. Thus, photosense, di- and trisulphonated zinc phthalocyanines, 3- desvinyl-3-formyl-chlorine p6, rhodamine 6G-acetate and methylene blue turned out to be promising for their further study as photodynamic agents and efficient modifiers of chemoradiotherapy and of PDT.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.