Pharmacokinetic Interaction between Nifedipine and Coenzyme Q10 in Rats: A New Type of Drug-Supplement Interaction

Abstract

We examined pharmacokinetic (PK) and pharmacodynamic (PD) interactions between coenzyme Q 10 (CoQ 10 ) and nifedipine (NFP), which is a popular medicine for treating hypertension, and elucidated possible mechanisms for the interaction between CoQ 10 and NFP in rats. The mean plasma concentrations of NFP in rats after the oral administration of NFP (1 mg/kg) with CoQ 10 (75 mg/kg) were increased over the study period and the area under the plasma concentration-time curve (AUC), showed a 1.47-fold increase compared with that of the control. Rats that received NFP with CoQ 10 showed a continuous decrease in the mean blood pressure over the study period compared with the control. There were no significant changes in the PK parameters of NFP after intravenous administration (1 mg/kg) between with and without oral CoQ 10 pretreatment, and also no significant changes in the intestinal excretion of rhodamine 123 (Rho123) or NFP between with and without CoQ 10 were found. In contrast, the portal plasma concentration of NFP after intra loop administration in the presence of CoQ 10 (75 mg/kg) showed a 1.6-fold increase in the AUC value compared with that of the control. As for physicochemical properties, the partition coefficient of NFP showed a marked increase in the presence of CoQ 10 over 10 mg/ml in the organic phase (n-hexane). From on an analysis of the absorbance spectrum, CoQ 10 showed a shift towards a longer wavelength in hydrophobic environments with NFP, suggesting that CoQ 10 reacts with NFP to form a charge-transfer complex due to a pi-cloud between them. In conclusion, it was found that CoQ 10 increases the oral bioavailability of NFP and that this interaction between NFP and CoQ 10 is not caused by metabolism via cycochrome P450 (CYP) 3A in the liver or intestine or by the inhibition of P-glycoprotein function, by the physicochemical interaction between them. Therefore, the solubility of NFP in a hydrophobic environment could be enhanced by forming a chargetransfer complex with CoQ 10 , and it is considered that NFP deviating from a charge-transfer complex may migrate to the blood circulation from the intestinal tract. This mechanism of interaction is considered a new type of drugsupplement interaction.

Effects of HMG-CoA reductase inhibitors on the pharmacokinetics of nifedipine in rats: Possible role of P-gp and CYP3A4 inhibition by HMG-CoA reductase inhibitors

“…The results of these studies were also consistent with the report that oral diallyl trisulfide (major organosulfur compounds derived from garlic) significantly increased the bioavailability of nifedipine through inhibition of CYP3A4 in rats [46]. Our results are also consistent with those reported by Kuroha et al and Nishimura et al which showed that ketoconazole and Coenzyme Q 10 significantly increased the AUC 0-1 and C max of nifedipine [47,48].…”