Spectroscopic characteristics of metalloporphyrins used in photodynamic therapy.

The photodynamic therapy (PDT) became more and more widely used in the treatment of different malignant tumors. For present studies, porphyrins and haematoporphyrin derivatives, in the conditions of N2 laser radiation, were chosen because their strong absorption along a large spectral range; this makes possible the excitation of their fluorescence at 337.1 nm, which is the wavelength of the N2 pulsed laser radiation. The photophysical and photochemical properties depend on the central metal and the peripheral substituents. Trying to find an optimal sensitizer to be used with N2 laser in photodynamic therapy (PDT), a spectroscopic study of these dyes was performed. The obtained data show that the UV radiation emitted by a N2 pulsed laser may be used for PDT application; among other dyes having interesting characteristics, Zn-TSPP and Zn-TNP in DMSO at 0.5% concentration seem to be more relevant.