Photosensitizing Potency of Structural Analogs of Benzoporphyrin Derivatives (BPD) in a Mouse Tumor Model
Richter, A.M., Waterfield, E.M., Jain, A.K., Sternberg, E.D., David Dolphin, and Levy, J.
British J. Cancer.
The in vivo characteristics of four analogs of benzoporphyrin deriv. (BPD) were investigated. Biodistribution data obtained in DBA/2J mice with BPD-MA (monoacid ring A analog) which had been tritiated or internally labeled with 14C showed that both labeled materials acted in an essentially identical manner during the period of study. Biodistribution and clearance studies showed that relative distribution in a variety of mouse tissues was similar for all BPD analogs. M 1 tumor cells (rhabdomyosarcoma in DBA/2J mice) taken from tumors excised from animals treated 3 h earlier with BPD, and tested in vitro for photosensitivity provided evidence that significant levels of photosensitizer detected in tumor was both active and associated with tumor cells. The monoacid forms of BPD were found to be much more photodynamically active in this test were the diacid analogs. The ability of the analogs to ablate tumors in mice by photodynamic therapy was also tested. Again, BPD-MA and BPD-MB proved to be measurably better than the diacid analogs. These findings are discussed in ref. to structural and physical differences between the analogs.