BIOLOGICAL ACTIVITIES OF PHTHALOCYANINES‐IX. PHOTOSENSITIZATION OFV–79 CHINESE HAMSTER CELLS ANDEMT–6 MOUSE MAMMARY TUMOR BY SELECTIVELY SULFONATED ZINC PHTHALOCYANINES

Abstract

Abstract— Zinc phthalocyanines sulfonated to different degrees are tested for their ability to sensitizeV–79 Chinese hamster cells andEMT–6 mouse mammary tumors to red light. In vitro , the lower sulfonated derivatives were the most active with the exception of the poorly water‐soluble monosulfonated dye. An isomeric mixture of tetrasulfonated derivatives obtained via direct sulfonation was ten times more active than the homogeneous tetrasulfo derivative prepared via the condensation of sulfophthalic acid. In vivo , the latter dye was completely inactive, whereas the remainder of the sulfonated preparations exhibited a similar structure‐activity pattern as observed with theV–79 cells in vitro . The disulfonated zinc phthalocyanine showed the best tumoricidal activity in the series and also appeared to be a more efficient photosensitizer of cell inactivation and tumor cure than the aluminum or gallium complexes as well as hematoporphyrin derivative preparations. No significant differences in skin phototoxicity were observed among the various dyes.