Effect of flunarizine on the delayed cardiotoxicity of doxorubicin in rats

Effect of coenzyme Q10 on the disposition of doxorubicin in rats

The effect of exogenous coenzyme Q10 (CoQ10) on the pharmacokinetic profiles and biliary excretion of doxorubicin and its main metabolites, doxorubicinol and doxorubicinolone, was investigated in rats. No statistically significant changes in the pharmacokinetic parameters of doxorubicin was observed following the intravenous bolus administration of 10 mg/kg doxorubicin to rats during a 6-day oral regimen of CoQ10 (20 mg/kg daily). Treatment with CoQ10 did not affect the formation of the doxorubicinol, but produced a 75% increase (P < 0.05) in the AUC of doxorubicinolone. Correspondingly, CoQ10 had no apparent effect on the biliary excretion of doxorubicin and formation clearance of doxorubicinol, whereas the formation clearance of doxorubicinolone was significantly increased by 69% in CoQ10-pretreated rats (P < 0.05). Overall, the results suggest that CoQ10 treatment has no significant effect on the pharmacokinetics of doxorubicin and the formation of the cytotoxic metabolite, doxorubicinol.

Prevention of doxorubicin induced cardiotoxicity by catechin

Doxorubicin (dox) is an anthracycline antibiotic which is broadly used in solid tumors. Long-term therapy with this drug is accompanied by potentially lethal, dose-dependent side effects. Several reports suggest that oxygen free radicals produced during the metabolic activation of dox may have toxic effects on heart muscle. We tried to protect dox cardiotoxicity in rats using catechin which is a known antioxidant and iron chelating agent. Different dose levels and combinations of catechin and doxorubicin have been studied in different experimental groups. Electrocardiograms, myocardial contractility, body weight and the electron microscope were used to assess the cardioprotective effect of catechin in dox-treated animals. We found significant prevention of dox-induced cardiotoxicity by catechin in rats.