Permeability

Evaluating compound permeability through cell a monolayer is a good indication of intestinal permeability and oral bioavailability. We have two different assays available to determine the relative permeability of test compounds that can indicate overall oral bioavailability.

PAMPA
Parallel artificial membrane permeability assay (PAMPA) provides a high throughput, non-cell based method for predicting passive, transcellular intestinal absorption, the process by which the majority drugs enter circulation. A lipid bilayer is established on a membrane filter and a test compound solution is added to the top of the membrane-lipid interface. The ability of compounds to passively diffuse through the lipid treated membrane is an indication of the compound’s overall permeability. This approach is helpful in compound profiling and supporting the relative rank ordering of compounds.

Caco-2
Caco-2 cells are derived from human colon carcinoma cells and retain many properties of the small intestine. These cells are commonly employed as a valuable method for the prediction of in vivo intestinal epithelial cell permeability and oral bioavailability of test compounds. A Caco-2 monolayer is established in plates as an intestinal surrogate. The test compound is typically added on the apical (top) side of the cell monolayer, which is in contact with buffer on the basolateral (bottom) side of monolayer. Passive and active transport of the compound through the cell layer is monitored by analyzing the basolateral relative to the apical concentration. In addition to apical to basolateral transport, basolateral to apical transport of compounds is also available.