Experimental apparent Caco-2 and MDCK cell permeabilities (pH 7.4) vs calculated values, differentiated according to the most permeable route (i.e., the route with the lowest resistance).

<p>The symbol form is according to the permeation route which has the highest permeability as shown in the legend (a circle for the cytosolic route, a triangle for the lateral route, and a plus for the paracellular route. For the 95 chemicals which permeate the cell monolayer predominantly via the cytosolic route, the main resistance within the cytosolic route is color-coded as follows: for the blue circles the UWL is the main resistance, while for red circles the sum of the two membranes (apical plus basolateral) is the main resistance. Quercetin has been removed as discussed above.