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Updated: Aug 19, 2026

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation
Published on: August 26, 2014
In vivo evaluation of a colonic delivery system using isotope techniques
K Verbeke1, V de Preter, K Geboes
1Department of Gastrointestinal Research, University Hospital Gasthuisberg, Leuven, Belgium. Kristin.Verbeke@uz.kuleuven.ac.be
Aim:
To evaluate, using isotope techniques, the in vivo effectiveness of a pH-dependent colonic delivery system.
Methods:
In order to dispose of differently labelled substrates for measurement of orocaecal transit time, inulin-14C-carboxylic acid was evaluated as an alternative substrate to inulin and lactose-13C-ureide. Secondly, the time of release of 13C- and 15N-urea from the colonic delivery system was compared with the orocaecal transit time, measured using inulin and inulin-14C-carboxylic acid. This study was repeated after a 2-week lactulose intake period.
Results:
The orocaecal transit time determined using inulin-14C-carboxylic acid (398 min) was not significantly different from the orocaecal transit time determined using inulin (420 min) or lactose-13C-ureide (396 min). Before lactulose intake, the 13CO2 excretion time was 358 min and the orocaecal transit times determined with the inulin-14C-carboxylic acid and inulin breath test were 376 and 375 min respectively. After lactulose, the 13CO2 excretion time was 383 min and orocaecal transit times were 354 min for inulin-14C-carboxylic acid and 392 min for inulin. A highly significant correlation was found. Good agreement was found between the urinary 15N excretion and the appearance of 13CO2 in breath.
Conclusion:
Isotope techniques provide an excellent non-invasive tool for the in vivo evaluation of a colonic delivery system.
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