Disturbed intestinal permeability is assessed by quantification of orally administered sugar probes (mannitol, lactulose and sucralose). We validated a gas chromatograph-mass spectrometry (GC-MS) (mannitol, lactulose and sucralose) and a high performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD) (mannitol and lactulose) method for the analysis of the sugars in urine. After validation, both methods were applied to a human and rat pilot study. Limits of quantification were < 15 mg/L for mannitol and lactulose, and 45 mg/L, 10 mg/L and 10 mg/L for mannitol, lactulose and sucralose, respectively, measured with HPLC-ELSD and GC-MS, respectively. Using HPLC-ELSD, recoveries varied between 89.8 and 109.5% for mannitol and lactulose. GC-MS analysis resulted in a recovery between 95.8 and 121.9% for all sugar probes. Imprecision was lower than 15% for all sugars measured with both techniques. Comparison of mannitol and lactulose concentrations measured with GC-MS and HPLC-ELSD by Bland-Altman and Deming regression resulted in a good agreement. In the human and rat pilot study, the lactulose mannitol ratio, and the 24-h sucralose excretion, increased significantly after oral administration of indomethacin. We can conclude that both methods can be used to accurately quantify urinary sugar concentrations in humans and rats to study intestinal permeability.
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