In Vitro ADME

       In addition to CaCO-2 cell permeability, MDCK-MDR1 cell permeability assay is another widely used assay for screening compound permeability. MDCK-MDR1 permeability assays can help researchers understand the mechanisms of drug efflux and identify potential problems in drug permeability at an early stage. In addition to intestinal permeability, MDCK-MDR1 permeability has been found to be a useful predictor of blood-brain barrier permeability. MDCK-MDR1 cells are stabilized in MDCK cells transferring expression of the MDR1 gene (ABCB1), which encodes for the expression of the efflux protein P-gp that causes multidrug resistance.

       Like the CaCo-2 cell permeability assay, the MDCK-MDR permeability assay calculates the Efflux Ratio by measuring translocation from two different directions, A-B as well as B-A, which allows for the determination of whether or not a molecule is subject to P-gp-mediated active efflux.