The permeability of compounds across cell membranes (e.g., intestinal epithelium) is a critical characteristic that determines the rate and extent of absorption and ultimately affects the bioavailability of a drug candidate. We provide bidirectional permeability assays in human Caco-2 and MDCK cells.
Parallel Artificial Membrane Permeability Assay (PAMPA)
Drugs often need to cross cell membranes in order to reach their target of action and this makes a compound’s ability to passively cross these membranes an important characteristic to evaluate. The Parallel Artificial Membrane Permeability Assay (PAMPA) is used as an in vitro model of passive, transcellular permeation. The assay allows for measuring the gastrointestinal permeability of oral therapies, blood-brain barrier permeability, and dermal/transdermal penetration potential.
| Pion PAMPA | |
| Detection method | Absorbance |
| Platform | Plate reader |
| Throughput | High |
| Multiplexing | No |
| Model system | Cell-free |
Caco-2/MDCK permeability assay
The Caco-2 permeability assay utilizes Caco-2 cell line derived from human colon carcinoma, which has many characteristics that resemble intestinal epithelial cells. This assay offers a measure of the permeability across the intestinal barrier in both directions: the compound is added to the apical or basolateral compartment and efflux across the monolayer of cells is monitored. The amount of compound that has permeated across the cells is measured by LC-MS/MS.
The Madin-Darby Canine Kidney (MDCK) cell is an epithelial cell line derived from the canine kidney. The expression of transporter proteins and metabolic activity are low for MDCK cells but compared to Caco-2 cells, they proliferate and differentiate more quickly. Hence, it becomes an attractive alternative assay compared to Caco-2 permeability assay to assess the human intestine barrier.
| CacoReady | PreadyPort | |
| Detection method | mass spectrometry | mass spectrometry |
| Throughput | High | High |
| Multiplexing | No | No |
| Measurement type | Endpoint | Endpoint |
| Model system | Caco-2 cell line | MDCKII cell line |