Photodynamic therapy using rhodamine-123 as a new laser dye: Biodistribution, metabolism and histology in new zealand rabbits

Prior to initiation of clinical studies of this technique, we evaluated the biodistribution, metabolism, and pathological changes of Rh-123 in rabbits after systemic, repetitive injections of the dye in escalating doses. At doses between 0.1 to 1 mg/kg of Rh-123 injected intramuscularly (LM) daily for 5 days, no local or systemic toxicity was observed during the 4 weeks of follow-up. The peak concentrations of Rh-123 in μg/g of tissue was distributed as follows: kidney (3.24)> heart (2.24)> spleen (1.77)> lung (0.61)> liver (0.38)> skin (0.30)> skeletal muscle (0.17)> genitals (0.13)> brain (0.04)