A New Nonconjugated Naphthalene Derivative ofMeso‐tetra‐(3‐hydroxy)‐phenyl‐porphyrin as a Potential Sensitizer for Photodynamic Therapy

A new 5,10,15,20-tetra-(phenoxy-3-carbonyl-1-amino-naphthyl)-porphyrin was prepared by an isocyanate condensation reaction and its photophysical properties fully evaluated, both in terms of photostability and singlet oxygen production. It shows considerably enhanced photostability when compared with the parent 5,10,15,20-tetra-(3-hydroxy-phenyl)-porphyrin, with the photodegradation quantum yields for T(NAF)PP and T(OH)PP being 4.65×10(-4) and 5.19×10(-3) , respectively. Its photodynamic effect in human carcinoma HT-29 cells was evaluated. The new porphyrin showed good properties as a sensitizer in photodynamic therapy with an in vitro cytotoxicity IC(50) value of 6.80μg mL(-1) for a 24h incubation. In addition to the potential of this compound, the synthetic route used provides possibilities of extension to a wide range of new sensitizers.