The ability to predict the bioavailability of orally administered test items can be a powerful screening tool for potential new drug candidates. Differentiated Caco-2 human colon carcinoma cells express a wide range of transporter proteins on its cell surface similar to those of intestinal endothelium cells. Thus the permeability assay using the monolayer formed by Caco-2 cells is an adequate model system for the simulation of the absorption of orally administered drugs and their movement across the intestinal barrier. Therefore this assay can be served as a model system for pH 6.5/7.4 transport.
The purpose of this study is to measure the transport of a test item in apical to basolateral and basolateral to apical directions using the Caco-2 cell monolayer transport assay. During the measurement, test items with a known apparent permeability coefficient (Papp) are tested along with the test item to determine to what permeability class the test item belongs to on the basis of its calculated Papp value compared with that of the reference test item. The vectorial transport ratio is determined with the calculation of the influx and efflux values, and the possible role of the P-glycoprotein in the transcellular transport of the test test item is also investigated using P-glycoprotein specific inhibitor verapamil. Thus it can be characterized how the test item is transported through the monolayer, e.g. by active influx, active efflux or by passive transport.
In vitro test with differentiated Caco-2 human colon carcinoma cells.
The assay is performed in a special multiwell insert system plate.