Chlorophyll Sensitizers in Photodynamic Therapy

Photodynamic therapy (PDT) has proved to be a viable and interesting alternative to currently used less selective methods for palliative care of cancer and, in a limited number of cases, for curative treatment. Still, in spite of impressive progress and a few approvals for clinical applications, the great potential of PDT has not yet been fully realized because of current defi ciencies of applied sensitizers and of applied treatment strategies. Introduction of chlorophyll-and bacteriochlorophyll-derived sensitizers is expected to markedly change this situation in the coming decade. In this and the following chapter we provide an updated summary of these new sensitizers, their syntheses, relevant characteristics and pharmaceutical activity in vitro and in vivo. The fi rst chapter is focused on the general principles of photodynamic therapy with particular emphasis on the vascular-targeted approach to treatment. A general introduction is followed by a comprehensive description of chlorophyll based sensitizers. The following chapter (Chapter 33) is focused on the use of bacteriochlorophyll derivatives.