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Updated: Aug 24, 2026

A Standardized Ex Vivo Porcine Oromucosal Model for Evaluating Peptide Fluxes
Published on: June 9, 2026
Analysis of PEG 400 and 4000 in urine for gut permeability assessment using solid phase extraction and gel permeation
S Loret1, G Nollevaux, R Remacle
1Department of Biochemistry and General Physiology, University of Liege, B-4000 Liege, Belgium. suzanne.loret@fundp.ac.be
Abstract:
We developed a treatment of urine samples allowing the analysis of two intestinal permeability markers: polyethylene glycol (PEG) 400 (highly diffusible; basal permeability indicator) and PEG 4000 (poorly diffusible; indicator of an abnormal increase of permeability) by a unique gel permeation chromatography (GPC) with refractometric detection. Urinary PEG were extracted using a mixed-bed resin composed of C2 and C18 layers. Permeability mean values determined in 11 human healthy subjects were 24.20 +/- 9.30% and 0.12 +/- 0.08% for, respectively, PEG 400 and 4000. The percentage of the PEG 4000 permeability value to the one of PEG 400 corresponded to an intestinal permeability index (IPI) of 0.52 +/- 0.35 expressing a low diffusion of this poorly permeability marker.
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