LABORATORI NAZIONALI DI LEGNARO
Boron-containing porphyrins are currently being investigated for application in the boron neutron capture therapy (BNCT) and the photodynamic therapy (PDT) of malignant brain tumors because of their high selectivity for tumor tissue and their ability to be activated by both light and low-energy neutrons. The in-situ cytotoxic species generated in BNCT and in PDT have very limited paths of travel in tissue (less than a cell diameter) and therefore the toxic effect is highly localized to the targeted porphyrin-containing tissue. Such selective therapies could lead to a significant enhancement of local control of the disease via targeting of different mechanisms for tumor cell destruction. Furthermore, BNCT and PDT have the advantage of being easy to apply with minimum invasiveness, compared with other forms of treatment. We recently reported that carboranyl-containing porphyrins have low toxicity, are efficient producers of singlet oxygen upon light activation, and display high selectivity for animal tumors. Chlorins, corroles and thiaporphyrins are of greater potential use in PDT than porphyrins due to their stronger absorption bands in the red region of the visible spectrum, which enables lower energy light to be used with concomitantly increased penetration through tissue. Therefore, we will describe new methodologies for the preparation of boron-containing porphyrins, chlorins, corroles and thiaporphyrins for application as dual sensitizers in the PDT and BNCT of tumors, their physicochemical and spectroscopic characterization, and investigation of their biological properties.

DATA: 06-06-2005