Interaction of dexrazoxane with red blood cells and hemoglobin alters pharmacokinetics of doxorubicin

• Published in: Cancer chemotherapy and pharmacology 2000, Vol.46 (2), p.93-100
• Main Authors: VAIDYANATHAN, S, BOROUJERDI, M
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Chelating Agents - pharmacokinetics; Chelating Agents - pharmacology; Doxorubicin - blood; Doxorubicin - pharmacokinetics; Drug toxicity and drugs side effects treatment; Endothelins - blood; Erythrocyte Membrane - drug effects; Erythrocyte Membrane - metabolism; Erythrocytes - drug effects; Erythrocytes - metabolism; Ethylenediamines - pharmacokinetics; Ethylenediamines - pharmacology; Female; Glycine - analogs & derivatives; Glycine - pharmacokinetics; Glycine - pharmacology; Hemoglobins - drug effects; Hemoglobins - metabolism; Kinetics; Medical sciences; Pharmacology. Drug treatments; Rats; Rats, Sprague-Dawley; Razoxane - pharmacology; Toxicity: cardiovascular system
• ISSN: 0344-5704; 1432-0843
• DOI: 10.1007/s002800000122

The mechanism of the cardioprotective action of dexrazoxane against doxorubicin cardiotoxicity is not fully understood. It has been suggested that its hydrolysis product, ICRF-198, chelates and removes free iron and iron associated with doxorubiciniron complex and, therefore, prevents the formation of free radical, lipid peroxidation and cardiotoxicity. Dexrazoxane is also known to inhibit topoisomerase II, to prevent the inactivation of cytochrome c oxidase by Fe3+ -doxorubicin and to increase the levels of transferrin receptor (trf-rec) mRNA and cellular iron uptake. This sequestration of iron and its effect on cellular iron homeostasis may also contribute to its protective effect against doxorubicin cardiotoxicity. The present project was designed to investigate the interaction of dexrazoxane with hemoglobin and red blood cells and the subsequent effect on the pharmacokinetics and toxicodynamics of doxorubicin. In an in vitro investigation the binding of doxorubicin (0.5-25 microg/ml) to red blood cells, erythrocyte ghosts and hemoglobin in the presence of dexrazoxane was evaluated. In an in vivo study female Sprague Dawley rats were pretreated with 100 mg/kg of dexrazoxane by intravenous injection 1 h before the injection of 14C-doxorubicin (specific activity 0.4 microCi/mg, 10 mg/kg). The time-course of doxorubicin associated with blood cells and plasma was evaluated with simultaneous characterization of doxorubicin and its metabolites in the bile and urine. The serum concentration ofendothelin was measured as a biomarker of cardiotoxicity in separate groups of animals. The in vitro data indicated that dexrazoxane inhibited the binding of DOX to red blood cells in a concentration-dependent manner. At 1 microg/ml it reduced the binding of doxorubicin to red blood cells by about 30% and at 100 microg/ml by about 60%. It had no effect on the association of doxorubicin with erythrocyte ghosts. The investigation of binding of doxorubicin to hemoglobin revealed the existence of two distinct binding sites and dexrazoxane reduced the association constant of doxorubicin with the low-affinity and high-capacity class of binding sites significantly. The pharmacokinetic analysis showed that pretreatment with dexrazoxane (100 mg/ kg) reduced the area under plasma concentration-time curve of doxorubicin, its mean residence time and plasma clearance significantly. Similar reductions were also shown with the pharmacokinetic analysis of doxorubicin associated with bloo