Comparison of photosensitizers in saline and liposomes for tumor photodynamic therapy and skin phototoxicity.

Abstract

The uptake and distribution, skin phototoxicity, and direct tumor ablative potential of three porphyrin photosensitizers: hematoporphyrin derivative (HPD), dye hematoporphyrin ether (DHE), polyhematoporphyrin esters (PHE), and of Rhodamine-123 (Rh-123) have been studied in the AJ-CR inbred albino female mouse implanted with C-1300 neuroblastoma. Photosensitizer delivery was studied using saline and liposome carriers. The ratio of tumor uptake of the porphyrin compounds compared to the tumor-bed musculature and skin was favorable with both saline and liposome delivery. Rhodamine-123 precipitated in saline but was delivered effectively throughout the body in liposomes. There was no selective uptake by tumor cells of Rh-123 in this tumor model. Skin phototoxicity with the porphyrin compounds was mildly decreased using liposomes carriers while Rh-123 demonstrated no skin phototoxicity. DHE had the greatest tumoricidal effect among the porphyrin compounds. PHE has the potential of increased effect due to the ability to use higher light dosages in the activation of this porphyrin. Rhodamine-123 had no tumor effect in this animal model. Clinical implications of phototherapy with these four compounds are addressed.