Transport of high concentration of thiamin, riboflavin and pyridoxine across intestinal epithelial cells Caco-2.

In this study, we examined the intestinal uptake of thiamin (vitamin B(1)), riboflavin (vitamin B(2)) and pyridoxine (vitamin B(6)) administered at high concentration using intestinal epithelial Caco-2 cells as an in vitro model of drugs and food absorption. The effect of vitamin concentration, culture age, transport direction and incubation temperature on vitamin transport was determined. The vitamin transport was expressed as an apparent permeability coefficient and changes in cumulative fraction transported across epithelial membrane in time. It was found that transepithelial transport of these vitamins is dependent on the experimental factors. At low concentrations an active transport mechanism was observed, whereas at high vitamin concentration a passive transport dominated. At high vitamin concentration the transepithelial flux of vitamins in both directions was similar, which proves the mechanism of passive transport.