METAL-CHELATES OF PORPHYRIN DERIVATIVES AS SENSITIZERS IN PHOTOOXIDATION PROCESSES OF SULFUR-COMPOUNDS AND IN PHOTODYNAMIC THERAPY OF CANCER

A number of porphyrin derivatives based on hematoporphyrin, 5,10,15,20 -tetrasubstituted porphyrins, phthalocyanines, and naphthalocyanines w ere prepared either as low-molecular compounds or bonded with methoxyp oly(ethylene glycol) or attached to silica of low surface area. The lo w-molecular weight and the polymer-bonded porphyrins exhibit comparabl e triplet lifetimes and activities in the photosensitized formation of singlet oxygen. For photon-induced processes, the monomeric state of sensitizers is fundamentally important. The porphyrins have been inves tigated as sensitizers for photooxidation of thiolates and sulfides, w hich occurs via singlet oxygen, and, therefore, is much more efficient than the corresponding catalytic dark oxidation. Polymer-bonded porph yrins and long-wavelength absorbing naphthalocyanines incorporated in liposomes exhibit in vivo high accumulation in tumor tissues. Under ir radiation, singlet oxygen is produced, and efficient phototherapeutic effects are observed, which may be used for photodynamic cancer therap y.