Biological Activities of Phthalocyanines—v. Photodynamic Therapy of Emt‐6 Mammary Tumors in Mice With Sulfonated Phthalocyanines

We tested water‐soluble sulfonated phthalocyanine and three metal chelate derivatives for their tumoricidal effect on the EMT‐6 mammary tumor in mice exposed to red light. The metal‐free sulfophthalocyanine had little effect, whereas the aluminum complex and the lower sulfonated fraction of the gallium complex exhibited tumoricidal activity similar to hematoporphyrin‐based photosensitizer (Photofrin II). The higher sulfonated fractions of the gallium complex were less active as compared to the lower sulfonated fraction. The cerium complex was the most active sensitizer in terms of dye and light doses required to induce tumor necrosis and cure but also showed the highest phototoxicity towards healthy skin. These results suggest that sulfonated phthalocyanines will offer a new alternative in photodynamic therapy of light‐accessible neoplasms.