Nanoliposomes Mediate Coenzyme Q10Transport and Accumulation across Human Intestinal Caco-2 Cell Monolayer

The feasibility of using nanoliposomes as an oral delivery system to improve the intestinal absorption of coenzyme Q(10) (CoQ(10), ubiquinone-10) was examined using Caco-2 cell monolayers as the model of human intestinal epithelium. The apparent permeability coefficient of CoQ(10) with nanoliposomes as vehicles was increased to be 4.19 +/- 0.76 x 10(-6) cm/s, which was higher than the favorable intestinal absorption value (1 x 10(-6) cm/s). The kinetic data demonstrated that nanoliposomal CoQ(10) transport occurred via passive diffusion and carrier mediation routes. Nanoliposomes might suppress the modulation activity of the peptide transporter, organic anion transporter, and P-glycoprotein through fluidizing cell membrane. The transported CoQ(10) was still in the original oxidative form as ubiquinone-10. However, 70-80% of coenzyme Q(10) accumulated by the cells was in the reduced form (ubiquinol-10, CoQ(10)H(2)), suggesting that the conversion of CoQ(10) to CoQ(10)H(2) takes place in the enterocytes during its absorption. These results indicated that the absorption behavior of CoQ(10) was modified through nanoliposomes. The bioavailability of CoQ(10) following its oral administration might be improved with nanoliposomes as the delivery system.