The distribution of a photosensitizer(PH-1126) in the tisse and the effects of photodynamic therapy(P. D. T.) on transplanted colon cancer in mice.

Abstract

We subcutaneously transplanted colon 26 cells into mice to producea tumorl cm in diameter. Next, we intravenously administered PH-1126 to the cancer-bearing mice at dose levels of 5 mg/kg, 10 mg/kg, and 20 mg/kg, then observed the degree of distribution and accumulation of PH-1126 at the tumor sites and the individual normal intestial sites 24, 48, and 72 hours after administration. In a comparative study on the accumulation of PH-1126 in the skin, duodenum, ileum, rectum, and colon 26-induced tumor, we noted accumulations in the small intestine and colon, and to a small degree, in the rectum. The greatest accumulation was in the colon 26-induced tumor.
Next, we intravenously administered PH-1126 to mice bearing 1cm-diameter tumor at dose levels of 5 mg/kg and 10 mg/kg. 48 hours after the administration, we carried out P.D.T. using a krypton-ion lasr. We observed the changes in mice over time after the laser radiation. We then made a comparison between the P. D. T. group and the control group. As a result, we were able to obtain the antitumoral and survival effects of PH-1126 and P. D. T. These results suggest that P. D. D.·P. D. T. together with the administration of PH-1126 is useful in treating cancer of the rectum.