Photodynamic Therapy Using Novel Zinc Phthalocyanine Derivatives and a Diode Laser for Superficial Tumors in Experimental Animals

Abstract

Photodynamictherapy (PDT) using a photo sensitizing agent and several light sources has been shown to have nonspecific and noninvasive effects on superficial cancers. Phthalocyanine (Pc) derivatives as novel photosensitizers, trifluoroethoxy-coatedzinc Pcconjugated with β -cyclodextrin ( β CD-4TFEO-Pc) was synthesized and its photodynamic effect in vitro and in vivo was evaluated. β CD-4TFEO-Pc alone was completely non-cytotoxic even at high concentrations, and showed excellentphotodynamic effects in B16-F10 and HT-1080 celllines. The in vivo antitumor effect of β CD-4TFEO-Pc against B16-F10 cells transplanted on to the chorioallantoic membranes of chickembryos was 52.7%, but that of laserirradiation alone and photosensitizer alone was <7% at thedose of 50 μg pereggand 100 J/cm 2 (50 mW). These data suggest that β CD-4TFEO-Pc is a useful photosensitizer for the treatment of superficial cancers. If a high-power LED with optimal wavelength is developed, excellent treatment of superficial cancers could be achieved by applying β CD-4TFEO-Pc for PDT.