Influence of verapamil and digoxin on the in vitro binding of doxorubicin to the rat heart.

A study has been carried out to characterize the binding of doxorubicin to heart homogenates and subcellular fractions. The technique chosen to perform the study was equilibrium dialysis and the levels of anthracycline in the samples obtained from the dialysis were assessed using HPLC. Doxorubicin has high affinity to heart homogenates and subcellular fractions such as nuclear, mitochondrial and microsomal. The binding was saturable and dose-dependent. Doxorubicin binding is decreased in the presence of digoxin and especially verapamil.