|
The photodynamic therapy (PDT) of cancer is based on the reaction of dyes, light and oxygen in tumorous tissues. Currently mainly two types of photosensitizers [Photofrin II and Hematoporphirine derivatives (HPD)] are used in clinical investigations. But they are still far from being ideal for this purpose as they do not have the required specificity and the absorption maxima do not lie in the ideal region of 760 nm (maximal transmission for human tissue). Because of their absorption maxima, the high extinction coefficient and the good rate of singlet oxygen generation phthalocyanines (PCs) seem to be good photosensitizers for the photodynamic therapy of cancer. At this time the main problem for the use of PCs is the leak of solubility in physiological media. By partial sulfonation it is in fact possible to increase the hydrophilic attributes, but not seriously the selectivity to tumorous tissue. For these reasons it is absolutely necessary to synthesize monofunctionalized PCs, so that covalent coupling to carrier systems (e.g. monoclonal antibodies) are possible. By the synthesis of PCs via coupling to modified polystyrene as a carrier, it is possible, after linking a phthalodinitrile with a spacer (alkylchain C4 and longer) to the polymer to prepare exact defined monofunctionalized PCs.
|
