Liposomal surface-loading of water-soluble cationic iron(III) porphyrins as anticancer drugs.

A novel design of anticancer drug delivery system, based on an electrostatic binding of negatively charged liposomes and cationic metalloporphyrins under physiological conditions, is reported. A lack of cytotoxicity of the iron(III) porphyrin-loaded liposomes and an efficient generation of a toxic hydroxyl radical (OH*) from a superoxide anion radical (O2-*) through the iron(III)-catalyzed dismutation and the Fenton-like reaction allow for a targeted necrosis of tumor cells where the concentration of O2-* is locally increased as a result of the reduced activity of superoxide dismutase and catalase in these cells.