Synthesis and evaluation of radiolabeled porphyrin derivatives for cancer diagnoses and their nonradioactive counterparts for photodynamic therapy.

Radioiodinated porphyrin derivatives and the corresponding nonradioactive iodine introduced compounds, [ 125 I]I-TPP OH ([ 125 I]3), [ 125 I]I-l-tyrosine-TPP ([ 125 I]9), I-TPP OH (3), and I-l-tyrosine-TPP (9) were designed, synthesized, and evaluated by in vitro and in vivo experiments. In cytotoxicity assays, 3 and 9 exhibited significant cytotoxicity under light conditions but did not show significant cytotoxicity without light irradiation. Biodistribution experiments with [ 125 I]3 and [ 125 I]9 showed similar distribution patterns with high retention in tumors. In photodynamic therapeutic (PDT) experiments, 3 and 9 at a dose of 13.6 μmol kg -1 weight with 50 W single light irradiation onto the tumor area significantly inhibited tumor growth. These results indicate that the iodinated porphyrin derivatives [ 123/nat I]3 and [ 123/nat I]9 are promising cancer theranostic agents.