Adriamycin, aclacinomycin and thepirubicin intracardiac distribution examined by fluorescence microscopy.

Male Wistar rats received adriamycin, aclacinomycin or thepirubicin at a dose of 4 mg/kg b.w. by slow infusion. Cardiac tissue sections were examined by fluorescence microscopy to evaluate the distribution of the three anthracyclines. The nuclei regularly exhibited a stronger coloring with respect to the cytoplasm for all three drugs. Adriamycin cytoplasm fluoresced intensely, unlike aclacinomycin and thepirubicin. Our results indicate a lower uptake of these last two molecules into cardiac tissue, thus suggesting a different pharmacokinetic profile which might account for their lower cardiotoxicity.