Enhancement of intestinal absorption of coenzyme Q10 using emulsions containing oleyl polyethylene acetic acids

Emulsions have often been prepared to improve absorption of lipophilic compounds that have poor solubility. Coenzyme Q10 (CoQ10) is a lipophilic compound that has been used as an anti-aging supplement. We focused on oleyl polyethyleneoxy acetic acid, an oxa acid derivative, to prepare emulsions of CoQ10 with the expectation of application to oral pharmaceutics. Oxa acids were purified and classified into four groups based on the average length of the ethylene oxide chain. The emulsion that were prepared using the four oxa acid groups were administered to rats and the plasma concentration profiles of CoQ10 were analyzed. The absorption of CoQ10 was improved in all emulsion groups compared with that in the powder group. The emulsion using oxa acid (n = 9.0) greatly increased the plasma concentration of CoQ10. Absorption was also improved by using emulsions containing larger percentage of oxa acids (6%, 15% and 23%) to compared with the same oxa acid (n = 9.0). The effects of oxa acids on cell viability were almost the same as those of conventional surfactants such as polyoxyethylene (20) sorbitan monooleate (Tween 80). The results showed that oxa acids are useful to prepare emulsions for oral administration and that the absorption of CoQ10 using oxa acids is significantly improved by using our formulations.