[Photodynamic effect of several hematoporphyrin derivatives and their production of singlet oxygen and retention in cancer cells].

Photodynamic effect of three hematoporphyrin derivatives (HpD) on cancer cells in Ehrlich ascites carcinoma (EAC) mice were tested both in vivo and in vitro. At the dose of 5 micrograms/ml, HpD-81 and HpD-83 plus light inhibited the increase of ascites at inhibition rates of 84.6% and 17.5%. Yet HpD-82 plus light showed no effect. Their capacity to retain themselves in cancer cells differed and was related to their photodynamic effect. HpD-81 had the greatest capacity and its distribution ratio was higher than the others. The accumulation of HpD in cancer cells was obviously decreased by the addition of serum in the medium. The production rate of singlet oxygen by HpD-81 was slightly greater than that of HpD-83, but this difference could hardly explain the difference in cytotoxic effect of these two HpD. We expect that the accumulation of HpD in cancer cells may be one of the determinants in the photodynamic effect of photosensitizers.