In Vitro Permeability Assay

The use of our products manufactured with Caco-2, HT-29 and MDCKII cells for permeability assays will help you to investigate your compound absorption across a relevant barrier.

Cell-based assays with high flexibility and a ready-to-use system.
Highly predictive and useful in the in vitro to in vivo progression.
Worldwide shipments at room temperature thanks to our patented technology.


Ready-to-use cells for preclinical stages

caco cells

Caco-2 permeability assay

The CacoReady plate contains Caco-2 cells, a human colorectal cancer-derived cell line that has proven to successfully mimic the intestinal epithelial barrier.


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Caco-2 cells have been extensively used over the last thirty years to study drug absorption across the human intestinal mucosa. The cells are seeded at a very specific cell number and differentiated for 21-days on transwell plates containing a permeable membrane support which results in apical and basal compartments, which artificially simulate the intestinal absorption into the bloodstream.

Caco-2 cells are considered an in vitro gold standard  for assessing oral drug absorption. This model provides reliable predictive permeability data either by passive diffusion and/or active transport for hydrophilic to moderately lipophilic compounds and can easily be adapted for high-throughput screening purposes.

The Caco-2 model is also useful to assay active transport of drugs in the central nervous system (CNS) since it expresses two efflux transporters that play a relevant role in the permeation of compounds across the blood brain barrier (BBB).

Caco-2 and HT-29 permeabilty assay

The CacoGoblet model is the result of coculturing Caco-2 and HT29-MTX cells, two human colon cancer-derived cell lines that represent a barrier closer to the intestinal epithelium.
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As a result of the combination of cells with an absorptive and mucus-secreting phenotype, this model possesses a mucus that differentiates it from the Caco-2 cell model. The cell barrier of this co-culture, moreover, is not as tight as that formed by Caco-2 alone and has TEER values more similar to those of the human small intestine. The tight junctions of Caco-2 cells, in contrast, more closely resemble the electrical resistance of the colon.

CacoGoblet is also considered a relevant cellular model for studies of drug absorption across the gastrointestinal barrier, either by passive diffusion and/or by active transport. The model can be easily adapted for high-throughput screening purposes. In addition to drug permeability testing CacoGoblet respond well to inflammatory mediators, providing valuable information on the efficacy of anti-inflammatory drugs.

MDCKII permeability assay

Madin-Darby Canine Kidney Type II or MDCKII cells, included in our PreadyPort kit, are relevant to assess drug permeability by passive diffusion across a relevant barrier.
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This cells were isolated from normal kidney tissue of an adult dog and they are widely used as an in vitro model of the intestinal epithelium. These cells cultured for 12-days on transwell plates containing a permeable membrane have clear apico-basolateral polarity and well defined cell junctions.

In addition, MDCKII cells are also efficient for transient and stable gene transfection, making them especially relevant to overexpress uptake and efflux drug transporters such as two members of the ATP-binding Cassette (ABC) superfamily, MDR1 and BCRP.


ReadyCell permeability kits

We help you to determine your compound suitability for oral dosing

Studying the permeability of compounds across a cell monolayer is a well-established in vitro technique to screen for oral absorption and evaluate drug transporters.

Our range of pre-plated transwell products allows the rapid and accurate determination of drug transport across Caco-2, HT-29 and  MDCKII cell monolayers.


Reference values for Caco-2 permeability assay

If you want a comprehensive guide on conducting a Caco-2 permeability test procedure, check out this detailed protocol.



Frequently Asked Questions

Is the quality control data specific for each kit?
Yes, we provide a concrete quality control for each batch so the customer can have a reference for the kit before and after shipment.
What is the difference between CacoReady and CacoGoblet?
CacoReady and CacoGoblet are both, two cell-based kits to in vitro assay drug intestinal permeability. However, CacoReady only contains absortive epithelial cells (Caco-2 cells) while CacoGoblet is the result of coculturing Caco-2 cells and mucus-secreting cells (HT29-MTX cells), bringing it closer to the most physiological conditions.

Because they consist of different cell phenotypes, the barrier properties are also different being very tight for CacoReady with TEER values ≥ 1000 ohms x cm2 and looser for CacoGoblet (≥ 70 ohms x cm2), being the drug permeability assays for both models very consistent.

Does ReadyCell shipping medium affect permeability cell lines?
No, ReadyCell’s Shipping Medium consists of a semi-solid culture system specifically designed to preserve cells at room temperature (15-25ºC). This medium maintains a suitable physicochemical environment, keeping adequate moisture conditions for cellular homeostasis and forming a protective cushion that protects cell integrity and functionality during long-distance shipments up to seven days.
Is it possible to add a testing service to the order?
As a general rule, we act as a supplier and do not provide testing services. Nonetheless, feel free to contact us if you wish to test our plates externally. We can direct you to our partners who can assist you in conducting the assay effectively. Additionally, in certain situations, we are open to collaborating to try out new applications of interest to both of us.
What are the differences between transwell, no-transwell and individual transwell?
The integrated Transwell format is recommended for permeability assays by reference, since it enableds an apical-basal polarization. The non-Transwell format is used for other types of tests, including toxicity or cell culture for measurement of protein expression. The individual Transwell is recommended for permeability tests which require the individual mobility of each Transwell for different times or measurements.

For an effective permeability assay protocol, as well as a cytotoxicity assay protocol, it’s crucial to consider the choice of well system carefully.

What do the current regulations establish on the basis of permeability tests?
According to the European and the American Regulatory Agencies (EMA and FDA), permeability assays employing cultured Caco-2 are the reference model to estimate intestinal drug absorption in humans.
Which are the main reference compounds for CacoReady and what are the differences between them?
The reference compounds used in these tests are categorized as high permeability, low permeability and P-gp substrate. In the case of CacoReady, the main reference high permeability compound is metoprolol (Papp A-B >10 cm/s) and for the low, atenolol (Papp A-B <0.5 cm/s). Digoxin is used as P-gp substrate with a Papp A-B <1 cm/s.
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