Novel mode of cytotoxicity obtained by coupling inactive anthracycline to a polymer

The inactive anthracycline analog 4-demethoxy-7,9-di-epi-daunorubicin was covalently coupled to polyglutaraldehyde microspheres. The polymer-bound analog acquired significant cytostatic activity as evaluated with doxorubicin resistant and sensitive murine L1210 leukemia cells. A suggested multiple membrane interaction at the cell surface may represent a novel mechanism of cytotoxicity.