Benzoporphyrins and Acetylene-Substituted Porphyrins as Improved Photosensitizers in the Photodynamic Tumor Therapy with Porphyrin Platinum Conjugates

Summary.  A combination of a cisplatinum-like fragment and a porphyrin in the same molecule should not only result in the additivity of the dark toxicity of the platinum fragment and the phototoxicity of the porphyrin moiety, but also in the enrichment of the porphyrin platinum conjugates in tumor tissue, which cisplatinum alone does not show. To increase the penetration depth of the red light used in the photodynamic tumor therapy the conjugated system of the porphyrin components in porphyrin platinum conjugates had to be expanded. Sixteen new (NH₃)₂Pt derivatives of benzoporphyrins and acetylene-substituted porphyrins were synthesized, characterized, and tested with respect to their antitumor activity on the mammary carcinoma cell line MDA-MB-231. Received November 12, 2001. Accepted November 20, 2001