• The Intestinal barrier controls drug absorption

Oral delivery is the most convenient form of administration of pharmaceutical agents in patient compliance. However, intestinal absorption is a formidable barrier that restricts the oral bioavailability of many potential new drugs.

In the human intestine, absorption is controlled by a barrier composed of a single layer of polarized epithelial cells arranged on the intestinal wall. Among the factors influencing intestinal absorption of drugs, their solubility, intestinal permeability, and dissolution rate are the most influential.

• Why Caco-2 cells?

Caco-2 cell is a human colon epithelial cancer cell line. Under specific culture conditions, the Caco-2 cells become differentiated and polarized with intercellular tight junctions, a well-differentiated brush border, and typical small-intestinal nutrient transporters, resembling the enterocytes lining the small intestine, making it ideal for intestinal absorption simulations.

Caco-2 permeability assay is one of the recommended in vitro methods to evaluate drug permeability. It has become the gold standard method to evaluate both the passive and active transport and the absorption of orally administered drugs.