Enhancement of oral bioavailability of coenzyme Q10 by complexation with γ-cyclodextrin in healthy adults

The objective of this study was to determine the effect of molecular encapsulation of coenzyme Q10 (CoQ10) by complexation with γ-cyclodextrin (γ-CD) (CoQ10-γ-CD) compared with a mixture of CoQ10 with microcrystalline cellulose (CoQ10-MCC) on absorption and bioavailability of CoQ10 in supplement form in healthy adults. Twenty-two volunteers received a single dose of a 150-mg capsule containing 30 mg CoQ10 under fasting conditions in an open-label, crossover design with a 2-week washout period. Blood was collected before dosing and after dosing periodically over 48 hours. Plasma levels of CoQ10 were determined by high-performance liquid chromatography using an electrochemical detector and an online reduction system. After 6 and 8 hours of dosing there was a significant increase in mean CoQ10 plasma levels of subjects after a single oral administration of the CoQ10-γ-CD capsule compared with those with the CoQ10-MCC capsule. In addition, the mean plasma levels at 24 and 48 hours tended to be higher after CoQ10-γ-CD administration in comparison with CoQ10-MCC administration. The area under the plasma CoQ10 concentration curve and the maximum plasma concentration (Cmax) values as well as their corresponding log-transformed values, log area under the plasma CoQ10 concentration curve, and log Cmax for the CoQ10-γ-CD formulation were significantly higher than those for the CoQ10-MCC formulation. These results indicate that the oral absorption and bioavailability of CoQ10 in healthy adult volunteers could be significantly enhanced by complexation with γ-CD, suggesting the potential use of γ-CD as formulation aid for orally administered CoQ10.