tetra(4-n-methylpyridyl)porphine and Melanoma

We performed the biodistribution and imaging studies of 111In and 67Ga labeled tetra(4-N-methylpyridyl)porphine, (T4NMPYP), and compared it to that of 67Ga-citrate in athymic mice bearing a human melanoma xenograft. The biodistribution results of both 111In and 67Ga labeled T4NMPYP (3, 6, 24 and 48 h) were similar but differed from that of 67Ga-citrate (48 h). The optimum tumor uptake of both radiolabeled porphyrins was at 6 h post-injection and was lower than the tumor uptake of 67Ga-citrate at 48 h post-injection. Kidney was the only organ showing higher uptake of radiolabeled porphyrin compared to that of 67Ga-citrate. The imaging studies performed with 111In-T4NMPYP and 67Ga-citrate correspond to the biodistribution results. Osteomyelitis present in one mouse showed good localization of 111In-T4NMPYP.

Topics: Animals; Citrates; Citric Acid; Female; Gallium Radioisotopes; Humans; Indium Radioisotopes; Melanoma; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Porphyrins; Radionuclide Imaging; Tissue Distribution; Transplantation, Heterologous

An indium complex of a cationic, water-soluble, synthetic porphyrin, tetra-4-N-methylpyridyl porphyrin tosylate, has been prepared and evaluated for its selective localization in tumors in Syrian Golden hamsters with flank transplanted malignant melanoma (Fortner MMI). Tumor-to-blood ratios of the compound increase from 42:1 at 6 hr postinjection, at which time activity levels in the tumor exceed those in all other tissues, to 162.1 at 72 hr. Images in one hamster at three time periods clearly delineated the tumor from nontarget background and also demarcated the viable and necrotic zones within the tumor itself.

Topics: Animals; Cricetinae; Female; Indium; Male; Melanoma; Mesocricetus; Mesoporphyrins; Neoplasm Transplantation; Porphyrins; Radioisotopes; Radionuclide Imaging; Tissue Distribution