Testconditions greatly influence permeation of watersoluble molecules through theintestinal mucosa: needforstandardisation

Permeability testsarewidelyusedto investigate thepathogenesis ofvarious gastrointestinal diseases including coeliac disease, infectious diarrhoea, andinflammatoryboweldisease. InCrohn'sdisease theyareusedasactivity parameters by someinvestigators. Lackofstandardisation, however, makesitverydifficult to compare datareported in different studies. The aim ofthisstudywas to gather permeation datainwellcontrolled test conditions to standardise the methods.Ninehealthy volunteers each received fiveconsecutive permeability tests bymouthusingpolyethylene glycol400(PEG-400) and51Cr-EDTA asprobe molecules. The probeswere dissolved inwater,a glucose solution, a starch solution, a hyperosmolar lactulosemannitol solution, anda liquid meal.A significantly decreased permeation for bothprobeswas foundwhen given withthehyperosmolar solution. The 51Cr-EDTApermeationwas also decreased withwater.Thepermeability index,51Cr-EDTA/PEG-400, corrected