TABLE 4

A comparison of the various in vitro experimental systems in their applications, strengths, and limitations for the evaluation of enteric drug properties

Model classificationExperimental systemsApplicationsStrengthsLimitations
PermeabilityUptake transportEfflux transportDrug metabolismMetabolic DDITransporter DDIEnterotoxicity
Cell linesCaco-2YesYesYes (P-gp)NoNoYesLimited due to incomplete drug metabolism enzyme pathwaysExtensive database; applied extensively in BCS drug characterization; expression of uptake and efflux transportersRequires prolonged culturing (14 days) for establishment of barrier characteristics
Lacks drug metabolizing enzymes
Crypt cell/iPSC–derived modelsEnteroidsPossiblePossibleYesNoNoPossibleLimited due to incomplete drug metabolism enzyme pathwaysHuman enteric cells appropriate for the elucidation of enteric differentiationLacks drug metabolizing enzyme activities
Monolayer culturesPossiblePossibleYesNoNoPossibleLimited due to incomplete drug metabolism enzyme pathways
Primary cell/organ modelsIntestinal slicesPossiblePossiblePossibleYesYesPossibleYesComplete enteric drug metabolizing enzyme activitiesRequires slice preparation on day of experimentation
Cryopreserved enterocytesPossiblePossiblePossibleYesYesPossibleYesComplete enteric drug metabolizing enzyme activitiesRelatively low drug metabolizing enzyme activities compared with MetMax enterocytes and CHIM
MetMax enterocytesPossibleNoNoYesYesNoYesComplete enteric drug metabolizing enzyme activities; simple use proceduresCannot be used for transport studies due to permeabilized plasma membranes (but can be used in conjuction with intact enterocytes to delineate role of permeability on experimental endpoints)
Cryopreserved intestinal mucosaPossiblePossiblePossibleYesYesPossibleYesComplete enteric drug metabolizing enzyme activities; complete mucosa allowing experimentation with all mucosal cell typesApproaches for uptake and efflux transport, though theoretically feasible, have not yet been developed
  • DDI, drug-drug interactionBCS, biopharmaceutics classification system