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.

An Approach to Improve Intestinal Absorption of Poorly Absorbed Water-Insoluble Components via Niemann-Pick C1-Like 1.

Dietary and biliary cholesterol absorption contributes to the maintenance of tight control of cholesterol homeostasis. Cholesterol is present as mixed micelles formed by bile salts and phospholipids in the intestinal lumen. Recently, Niemann-Pick C1-Like 1 (NPC1L1) transporter was identified as being critical for cholesterol absorption. However, the uptake mechanism of an enveloped substrate of NPC1L1 in whole lipid emulsion particles remains unclear. In this study, we investigated the uptake mechanism of a substrate of NPC1L1 in lipid emulsion particles. We also investigated whether these particles containing cholesterol can improve the intestinal absorption of other lipophilic components via NPC1L1. The uptake of lysophosphatidylcholine (LPC)-4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-propionic acid saccinimidyl ester (BODIPY), a fluorescently labeled phospholipid, in lipid emulsion particles containing cholesterol (1 µM) was significantly increased compared to that without cholesterol in Caco-2 cells. On the other hand, its increased uptake was significantly inhibited by ezetimibe, a selective inhibitor of NPC1L1. These results suggested that not only cholesterol but also some components in lipid emulsion particles are taken up into enterocytes via NPC1L1. We also examined an approach to improve intestinal absorption of a poorly absorbed water-insoluble component, coenzyme Q10 (CoQ10), by this mechanism. The uptake of CoQ10 in lipid emulsion particles containing cholesterol was significantly increased compared to that without cholesterol. Its increased uptake was significantly inhibited by ezetimibe. Though it is still not clear whether CoQ10 is a substrate of NPC1L1, there is a potential for improvement of the absorption of poorly absorbed components by lipid emulsion particles containing cholesterol.