Comparison of the Intestinal Drug Permeation and Accumulation Between Normal Human Intestinal Tissues and Human Intestinal Tissues With Ulcerative Colitis

The purpose of this study was to examine drug absorption profile utilizing human intestinal tissues from ulcerative colitis (UC) patients and to compare with normal tissues from intestinal cancer patients. Human intestinal tissues from UC and cancer patients mounted in a mini-Ussing chamber were used to evaluate the permeation of drugs, including FD-4, a very low permeable marker, rebamipide, a low permeable marker, and metoprolol, a high permeable marker. The transport index, an index of sum of permeated and tissue-accumulated molecules, of the model drugs was in accordance with their absorption rank order, and was almost kept constant irrespective of autopsy grade based on tissue fibrosis. On the other hand, UC tissues of grade 2 showed the decreased X^corr, an index of permeated amount of molecules and increased T^corr, an index of tissue-accumulated molecules for every tested compound. Our finding of the transport characteristics in intestinal tissues of severe UC patients in mini-Ussing chamber system demonstrated that autopsy grade of UC patients did not drastically change membrane permeability of the tested compounds. Furthermore, it was suggested that morphological changes of intestinal tissues caused by fibrosis led to limited permeation and subsequently increased accumulation with little change of total absorption.

Establishment of novel prediction system of intestinal absorption in humans using human intestinal tissues

The objective of this study was to establish a novel prediction system of drug absorption in humans by utilizing human intestinal tissues. Based on the transport index (TI), a newly defined parameter, calculated by taking account of the change in drug concentrations because of precipitation on the apical side and the amounts accumulated in the tissue and transported to the basal side, the absorbability of drugs in rank order as well as the fraction of dose absorbed (Fa) in humans were estimated. Human intestinal tissues taken from ulcerative colitis or Crohn's disease patients were mounted in a mini-Ussing chamber and transport studies were performed to evaluate the permeation of drugs, including FD-4, a very low permeable marker, atenolol, a low permeable marker, and metoprolol, a high permeable marker. Although apparent permeability coefficients calculated by the conventional equation did not reflect human Fa values for FD-4, atenolol, and metoprolol, TI values were well correlated with Fa values, which are described by 100 · [1 - e (- f · (TI - α)) ]. Based on this equation, Fa values in humans for other test drugs were predicted successfully, indicating that our new system utilizing human intestinal tissues would be valuable for predicting oral drug absorption in humans.