摘要：A drug absorption model was developed by using the two-dimensional laminar flow in a circular tube, considering a small water absorption or secretion in the intestinal perfusion experiment. The concentration in the intestinal tract was determined by the axial component of velocity, the radial component of velocity, the membrane permeability coefficient, the reflection coefficient and so on. According to the calculated values, the concentration decreased not only from the inlet to the outlet but also from the center of the intestinal tract to the intestinal wall. The concentration at the aqueous-intestinal membrane interface was changed by the radial component of velocity, so it was suggested that the effective thickness of the aqueous diffusion layer (unstirred water layer) varies with a small water absorption or secretion.
