Tritiated and 14C-labeled tetraphenylporphinesulfonates (TTPS) were synthesized, purified, and characterized. The distribution of radioactivity and of the intact TPPS molecule was determined after injection of each compound into rats bearing the Walker carcinosarcoma. Intact TPPS accumulated in higher concentration in the tumor than in other tissues. The relative tissue concentrations of 14C administered as TPPS-14C was similar to that of intact TPPS. The tissue distribution of tritium, administered as TPPS-3H, was entirely different from both TPPS and 14C. The indissociably bound 14C attained sufficiently high relative concentrations in kidney and liver to preclude its use as a tumoricidal agent. The observed tumor: tissue concentration ratios for all other organs is sufficient for tumor localization by external scintillation scanning if an α-emitting isotope is similarly bound to TPPS.
This work was supported by USPHS Grant CA-08310.