Potentiation of antitumor effect of bleomycin by lipid-surfactant mixed micelles. I. In vivo and tumor-neutralizing activity against mouse Ehrlich ascites tumor and rat ascites hepatoma AH66.

Mixed micelles (MM) composed of polyoxyethylated (60 mol) hydrogenated castor oil (HCO60) as a harmless surfactant and linoleic acid (LA) as an essential fatty acid potentiated the antitumor activity of bleomycin (BLM). In the in vivo experiment, intraperitoneal administration of BLM with MM significantly prolonged the survival time of male ddY mice bearing Ehrlich ascites tumor and male Donryu rats bearing ascites hepatoma AH 66 inoculated intraperitoneally, compared with that of animals treated with BLM alone, BLM with HCO60, and BLM with LA, respectively, whereas MM had no antitumor effect to both tumors. Also in Winn-type tumor-neutralizing assay in which 10 male ddY mice were innoculated intraperitoneally with Ehrlich ascites tumor cells preincubated with a test material, BLM with MM showed a more marked enhancing activity with 3 surviving tumor-free mice than did BLM alone.