Cardiotoxicity of free and liposomally encapsulated rubomycin (daunorubicin) in mice.

Different serum enzyme levels (creatine kinase, CK; lactate dehydrogenase, LDH; alanine amino-transferase, ALAT; aspartate aminotransferase, ASAT) were determined after treatment of mice with rubomycin in free or liposomally encapsulated form. Especially increase in CK activity, measure for cardiac toxicity, was significantly altered in animals that were treated with rubomycin-containing liposomes. Organ distribution studies showed a significantly lower uptake of encapsulated drug in heart tissues. Electron microscopic studies confirmed these results by indicating only small anthracycline-induced cardiac lesions using the liposomal form.