Simulation of bile acids absorption in the human small intestine during in vitro digestion via a dialysis membrane process

Currently, a limited number of in vitro model systems simulate all the different aspects of human digestion, with the absorption of bile acids (BAs) being one of the greatest challenges. This study aimed to develop and model a dialysis membrane process for mimicking the intestinal absorption of BAs. An average meal digesta, obtained using the INFOGEST standardized static in vitro digestion method, was recirculated through a hollow fiber cartridge, while a dialysis solution was passed at the same flow rate in counterflow. Three different flow rates were examined, i.e., 20, 50 and 80 mL/min, to determine the most optimal flow rate for the most optimal reduction of BA concentration in the digesta. The results revealed that 80 mL/min was the most satisfactory flow rate, causing the highest decrease in the BA concentration of the digesta, and enabling the release of bound BAs throughout dialysis. The mathematical model of the BAs dialysis was able to capture the main effects that dictate this process.