State of Research Tracks and Property Protection of Photodynamic Sensitizers and Delivery Methodologies

The development of photodynamic therapy is indebted to the work of chemistry researchers as well as to that of all experts in complementary areas such as physics, biology and clinical sciences. The search for new photosensitizer structures and improvements in delivery methodologies has deserved attention and has focused the efforts of several research groups. The first photosensitizer approved for use in PDT, in spite of its drawbacks, was a natural occurring compound. But soon, complete synthetic molecules with structures designed to fulfill physical and pharmacokinetic parameters appeared, and in some cases they showed strong anti-tumor potential. Search for better selectivity, recognizing structures were mainly addressed to photosensitizers or particular delivery systems designed to target cancer cells. All the contributions have been significant but somewhat dispersed. A general analysis of the state of the art and collection of the information related to the intellectual property area seems appropriate at this point. In this review, recent patents on State of research tracks and property protection of photodynamic sensitizers and delivery methodologies have been presented.