Localization of meso-tetra(p-sulfophenyl)porphine in murine sarcoma virus-induced tumor-bearing mice.

meso-Tetra(p-sulfophenyl)porphine (TPPS4) has been found to accumulate in the tumors of mice bearing a murine sarcoma virus-induced rhabdomyosarcoma to a greater degree than in all other tissues except for the kidney. Tumor to tissue ratios of from 3:1 (tumor to liver) to 9:1 (tumor to muscle) were observed. The uptake of TPPS4 was found to be dose dependent, and the highest tumor to tissue ratios were found 96 hours after injection. The water-soluble TPPS4 appears to be cleared through the kidneys and absolute concentrations there are reduced with increasing time after injection. These data are compared with previous studies on TPPS4 localization in Walker 256 carcinosarcoma-bearing mice. In view of this localizing ability and its relative lack of toxicity, TPPS4 seems to represent an ideal candidate for a tumor-localizing agent if high levels of the porphyrin in the kidneys can be reversed.