Antitumor effect of new conjugates of anthracycline antibiotic carminomycin bound to chitosan

The antileukemic activities of two conjugates of the anthracycline antibiotic carminomycin – CX 1 and CX 2 , were investigated. The direct cytotoxic efficacies of the two conjugates and free carminomycin (C), were measured by an MTT-assay which provides excellent reproducibility and statistical significance. The treatment of HL-60 cells with the three compounds for 48 and 96 hours showed considerable sensitivity to the free carminimycin, as well as to its conjugates CX 1 and CX 2 . The ascetic form of leukemia P388 and leukemia L1210 (transplantation dose of 1·106 tumor cells) in hybrid mice BDF 1 was used as leukemic models. All compounds investigated showed a maximal cytotoxic response and strong concentration dependence. By comparing the cytotoxic profile of carminomycin to those of CX 1 and CX 2 , it can be assumed that a slower release of the active drug carminomycin have occurred. The criterion T/C showed a considerable antileukemic effect from 1.0 to 18.0 mg/kg. In conclusion, the conjugates CX 1 and CX 2 represent biologically active compounds with a putative depot-effect of slow release of the active intercalating agent carminomycin.