Emulsification Using Highly Hydrophilic Surfactants Improves the Absorption of Orally Administered Coenzyme Q10

Coenzyme Q10 (CoQ10) is an essential component in the electron-transport systems of mitochondria and bacteria and is often used as a supplementary treatment for some diseases. We previously reported that the bioavailability of CoQ10 powder was less than 10%. In this study, we investigated various preparations to improve the intestinal absorption of CoQ10 with focus on the effect of emulsification. We prepared a suspension and some emulsions with four types of surfactants and investigated the plasma concentration profile after oral administration to rats. The absorption of CoQ10 was improved by an emulsion formulation although there was little absorption of CoQ10 when a suspension was administered. However, little CoQ10 was absorbed in the bile duct-ligated group even when the emulsion formulation was administered (about 50% of the control group). Bile and emulsion formulation are essential for absorption of CoQ10. When the preparations containing Tween20 (polysorbate (20) sorbitan monolaurate) and Tween80 (polyoxyethylene (20) sorbitan monooleate) were administered, plasma concentrations of CoQ10 were higher than those obtained with preparations containing Tween65 (polyoxyethylene (20) sorbitan tristearate) and Span20 (sorbitan monolaurate). Tween20 and Tween80 have higher hydrophile-lipophile balance (HLB) values than those Tween65 and Span20. Our study suggests that highly lipophilic compounds like CoQ10 would diffuse the unstirred water layer and would easily access the intestinal apical membrane by an emulsion containing a surfactant with a high HLB value. Attention must be given to CoQ10 supplementation for patients whose bile is not excreted to the intestine such as patients with cholestasis.