Non-invasive method for evaluation of gastrocecal transit time by using a breath test in conscious rats

pH-dependent ileocolonic drug delivery, part II: preclinical evaluation of novel drugs and novel excipients

Novel drugs and novel excipients in pH-dependent ileocolonic drug delivery systems have to be tested in animals. Which animal species are suitable and what in vivo methods are used to verify ileocolonic drug delivery?

A new point-of-care portable immunosensor for non-invasive assessment of oro-ileal transit time by oral fluid tauroursodeoxycholate measurement after its oral load

A non-invasive test for oro-ileal transit time (OITT) evaluation was developed, based on the measurement of tauroursodeoxycholic acid (TUDCA) oral fluid concentration profile after its oral administration. Exploiting the fact that TUDCA is actively absorbed only in the ileum, OITT is measured as the time corresponding to TUDCA maximum oral fluid concentration (tmax). To measure oral fluid TUDCA concentration in a point-of-care setting, an ultrasensitive portable immunosensor was developed, based on a competitive chemiluminescent enzyme immunoassay (CL-EIA), using immobilized anti-TUDCA antibody and an ursodeoxycholic acid (UDCA)-peroxidase conjugate as tracer, detected by enhanced chemiluminescence employing a portable charge-coupled device (CCD)-based device. The test was validated in 24 healthy subjects before and after treatment with Loperamide, a drug that increases OITT. The developed CL-EIA was accurate and precise, with a LLOQ of 50 pmol L(-1). The measured OITT for healthy subjects (291 ± 50 min) was fairly well correlated with OITT values obtained by measuring TUDCA in serum (r=0.89). An increased OITT was observed in all the studied subjects after Loperamide treatment. The CL immunosensor can be employed directly in gastroenterology and paediatric units and it can thus represent a new non-invasive simple test for OITT evaluation in a point-of-care setting, with improved diagnostic utility.

Effect of atropine sulfate on gastric emptying and gastrocecal transit time evaluated by using the [1-(13)C]acetic acid and lactose-[(13)C]ureide breath test in conscious rats

Breath tests have been used to investigate many physiological functions. Recently, we have developed a breath test system by using a non-invasive technique in conscious rats. In this study, we investigated the effect of atropine sulfate on the gastric emptying and gastrocecal transit time using [1-(13)C]acetic acid and lactose-[(13)C]ureide, respectively. Gastric emptying was significantly delayed by atropine sulfate in a dose-dependent manner (0.03-0.3 mg kg(-1)), but the effects of 0.1 and 0.3 mg kg(-1) were almost equal. C(max) and T(max) values were also significantly and dose-dependently decreased and delayed, respectively. However, AUC(120 min) values were not significantly different for the three doses of atropine sulfate. This suggests that although atropine sulfate slows the emptying of the gastric content, it is excreted eventually to the same content as the control. The gastrocecal transit time was significantly delayed by atropine sulfate at a dose of 1 mg kg(-1), but not at a dose of 0.1 mg kg(-1). These findings demonstrate that the breath tests can evaluate the effect of atropine sulfate on the gastric emptying and gastrocecal transit time. The effective dose of atropine sulfate may be different for gastric emptying and gastrocecal transit time.