Predicting the fraction of an oral dose absorbed in humans is of consi
derable interest at an early stage of a research program in the pharma
ceutical industry. Models described in the literature to predict the o
ral absorption in man include: the permeability in Caco-2 cells, absor
ption from a perfused segment of rat intestinal lumen and uptake into
everted rings. The present study used an isolated and vascularly perfu
sed rat small intestine to determine the permeability values of eleven
compounds across the intestinal epithelium. A good correlation was ob
tained between the permeability values determined in this model and th
e proportion of an oral dose absorbed in humans. Compared to the other
models, the present one could allow the appearance in the artificial
bloodstream and the intestinal metabolism of a compound to be studied
simultaneously.