Intestinal Metabolism Assay on Human Gut Tissue.
Measure first-pass metabolism on RepliGut® Planar, a human intestinal epithelium grown from donor stem cells. Track the CYP3A4, UGT, and SULT turnover the human gut actually performs.
Design your studyExplore RepliGut® PlanarWhy the gut clears drugs before the liver does
An intestinal metabolism assay measures how much drug the gut clears before it reaches the bloodstream. The intestine is a first-pass site, rich in CYP3A4 and conjugating enzymes that shape oral exposure.
Caco-2 barely expresses CYP3A4 and carries a distorted enzyme profile. So it can overpredict how much drug survives the gut. Regulators expect a clear metabolism read, set out in the FDA guidance on in vitro drug interaction studies.
Functional gut metabolism on human tissue
RepliGut® Planar grows from human donor stem cells and runs the metabolic enzymes the intestine actually expresses. You measure real turnover, then choose the gut region and donor that fit your question. That fits the move toward human-relevant alternative testing methods.
| Feature | Caco-2 | RepliGut® Planar |
|---|---|---|
| Phase I oxidation | Very low CYP3A4 activity. | Functional CYP3A4 and CYP3A5, and inhibitable. |
| Phase II conjugation | Limited glucuronidation and sulfation. | Active UGT and SULT conjugation. |
| Esterase profile | High CES1, unlike the human small intestine. | CES1 absent, matching human gut. |
| Regional profile | One fixed colon-tumor profile. | Duodenum, jejunum, ileum, or colon, and multiple donors. |
Caco-2 over-expresses CES1, an esterase barely present in the human small intestine. So it over-metabolizes prodrugs like temocapril and overpredicts clearance. RepliGut® Jejunum lacks CES1, just like real gut, so the metabolic read stays true to human biology.
What the intestinal metabolism assay delivers
The assay runs on mature RepliGut® Planar monolayers. We dose your compound, sample over time, and quantify parent loss and metabolite formation by accurate mass LC/MS.
CYP oxidation
Follow CYP3A4 and CYP3A5 turnover with probes like midazolam, and confirm activity with inhibitors.
Conjugation, UGT and SULT
Track glucuronidation and sulfation of substrates like raloxifene, the conjugation Caco-2 misses.
Metabolite identification
Accurate mass LC/MS resolves parent depletion and metabolite formation across the timecourse.
Region and donor options
Compare metabolic turnover across duodenum, jejunum, ileum, and colon, and across donors.
RepliGut® Planar runs both phases of metabolism: CYP3A4 oxidation in Phase I, then UGT and SULT conjugation in Phase II.
Real turnover across probe drugs
RepliGut® Planar metabolizes a panel of probe compounds over time. Testosterone and raloxifene clear quickly, while more stable drugs persist. That spread shows the tissue runs genuine intestinal metabolism, not a flat signal.
Enzyme expression Caco-2 cannot match
RNAseq shows RepliGut® Jejunum expressing key drug-metabolizing genes well above Caco-2. That spans Phase I oxidation and Phase II conjugation, the enzymes that drive first-pass clearance.
Because the enzymes are present and active, turnover reflects the human gut rather than a tumor line. See the method in our publications.
Intestinal metabolism, then the liver
The gut and liver together set oral bioavailability. Pair RepliGut® with a liver model in a gut-liver system to predict first-pass more completely. In one study, that approach predicted midazolam and temocapril clearance where Caco-2 could not. Explore the full workflow on our in vitro DMPK and ADME page.
Built to reflect the human gut
Human enzymes
CYP3A4, CYP3A5, UGT, and SULT are functional in an epithelium grown from human donor stem cells.
Correct esterase profile
No aberrant CES1, so prodrug clearance is not overpredicted the way Caco-2 can be.
Region and donor range
Study metabolism where it happens, from duodenum through jejunum, ileum, and colon.
Apical and basal access
The planar transwell format lets you sample metabolites from both sides of the tissue.
Run it in your lab or have us run it
RepliGut® Kits
Run metabolism studies in your own lab. Kits ship in 12-well and 96-well formats, complete with cells, plates, media, and technical support.
Explore kitsFull-service metabolism
Have our scientists run it. We deliver turnover, metabolite identification, and enzyme expression data, ready for your model.
Explore servicesPart of a broader program? See our permeability assay and drug transporter assay, or the full RepliGut® platform.
Ready to measure gut metabolism on human tissue?
Send us your compound. We will design an intestinal metabolism assay on RepliGut® Planar and quantify the first-pass clearance that matters.
Design your study