Photodynamic therapy (PDT) is a novel therapeutic modality for the treatment of cutaneous tumors. Researches in this field are focused on studying photosensitizing agents and delivery systems which improve their penetration and localization into the target tissue. Phthalocyanines have been used as a systemic photosensitizing agent due to some advantages of it, such as high affinity to the tumoral tissue and high effect after irradiation with light. However, the high solubility in oil and low water/oil partition coefficient of these substances makes difficult their topical administration for the skin cancer treatment. Thus charged phthalocyanines have been synthesized in attempting to increase their hydro solubility as well as to improve their capitation by the tumoral cells. Charged molecules, however, not easily cross biological membranes, especially the stratum corneum. Iontophoresis is a non-invasive technique which is able to increase and control the permeation of big and charged molecules through the skin by the application of a weak electric current. The use of iontophoresis as a delivery system for the anionic zinc phthalocyanine tetrasulfonic acid (ZnPcSO4) seems to be an alternative for improving the topical administration of this substance in the treatment of cutaneous tumors using PDT. In this way, it will be developed suitable stable formulations for the topical delivery of ZnPcSO4, and its iontophoretic delivery will be evaluated in vitro and in vivo using both healthy tissues and cutaneous tumors previously induced in animals.
News published in Agência FAPESP Newsletter about the scholarship: