The Caco-2 system has become the standard format to relate drug permeability to oral drug absorption. The Caco-2 cell model exhibits morphological as well as functional similarities to human intestinal enterocytes.
Features of Caco-2 cell monolayers:
- Express many of the transporters found in the small intestine (bile acid, amino acid, dipeptide, tri-peptide, etc.)
- Express the p-glycoprotein efflux pump and other ABC transporters
- Exhibit metabolizing enzymes on the brush border membrane and in the cytosol
- Form tight junctions between cells
Caco-2 permeability assays could be useful to predict
- Transport mechanisms — passive diffusion
- Transport mechanisms — carrier-mediated
- Assessment of prodrugs
- pH effects on transport
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Assay Methodology
Quintara Discovery offers a validated Caco-2 permeability assay to assess transport in both directions, apical to basolateral (A-B) and basolateral to apical (B-A), across the cell monolayer. The bi-directional format of the assay allows to understand any involvement of a transport systems on the efflux of a test compound. |
Caco-2 Permeability: Standard Assay Conditions (Customizable)
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Testing Compound Concentration |
10 μM |
Assay Buffer |
HBSS, pH 7.4 (or pH 6.5) on apical side; HBSS, pH 7.4 on basolateral side, 1-3% BSA optional on the receiving side |
Plate Format |
24-well or 96-well Transwell plates |
Transport Period |
1 hour at 37C |
Detection Method |
LC-MS/MS |
Control Compounds |
Digoxin |
Deliverables |
Papp value for A-B and B-A directions, efflux ratio |
Turnaround Time |
5-14 Days |
Compound requirements |
20 μL 10 mM DMSO stock |
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