Intestinal Epithelial Model - the Caco-2 Cell Monolayer

The absorption of orally administered drugs requires their movement across the intestinal epithelial barrier. Poor intestinal permeability leads to limited absorption. Generally, if a compound achieves a 90% or greater oral absorption, it is considered highly permeable (for example, propranolol or metoprolol). Drugs that display 50% or less oral absorption are considered poorly permeable (for example, ranitidine and atenolol). Compounds with extremely poor permeability are likely to have limited in vivo absorption. Permeability assessment in the early drug discovery stage will help to identify compounds that are likely to pose challenges during preclinical and clinical development.