The ability of a molecule to cross the intestinal barrier is one of the properties studied in the ADME-Tox study of a compound.
The Caco-2 cell line (derived from a human colorectal carcinoma) is the model used in vitro to assess the absorption of a compound through the intestinal barrier.
When grown on semi-permeable membranes, Caco-2 cells differentiate to form a highly functionalized epithelial barrier with remarkable morphological and biochemical similarity to the intestinal epithelium.
Caco-2 cells are grown on a membrane placed between two compartments.
The compounds are added to the apical side of the cell monolayer. Their progressive apparition is measured on the basolateral side. The permeability in this direction (apical to basolateral) represents the intestinal absorption.
Permeability can also be determined in the basolateral to apical direction.
A higher apical to basolateral permeability than basolateral to apical permeability is indicative of transport via a transporter.
Transport via the P-gp protein is suggested when basolateral to apical permeability is greater than apical to basolateral.
| Format | 24-well format | ||
| Cell model | Caco-2 (ATCC HTB-37) differentiated | ||
| Reference molecules | Antipyrin, Digoxin | ||
| Test concentration | 10 µM - 3 points | ||
| Incubation | 2H à 37°C under 5% CO2 | ||
| Analysis | LC-MS/MS (ADME-Tox department) | ||
Notes :
The apparent permeability Papp (cm/s) of the tested compounds is calculated for both directions
(apical to basolateral Papp A>B and basolateral to apical Papp B>A).
The efflux ratio is deduced from the formula : R = Papp B>A / Papp A>B.