THE EFFECT OF DIFFERENT CONCENTRATIONS OF MANNITOL IN SOLUTION ON SMALL-INTESTINAL TRANSIT - IMPLICATIONS FOR DRUG ABSORPTION

The aim of the present study was to investigate the effect that differ ent concentrations of mannitol have on small intestinal transit, and w hether any observed effect was concentration dependent. Eight, healthy male subjects each received 200ml of radiolabelled purified water, or a 200ml solution of mannitol at three different concentrations; 0.755 g/200ml, 1.509g/200ml and 2.264g/200ml, in a randomised, four way cros s-over study. Transit of the radiolabelled solutions was followed by g amma scintigraphy. The study demonstrated no significant differences b etween the gastric emptying times of the four solutions. Rapid gastric emptying was observed in most cases. The mean small intestinal transi t times for the 0.755g/200ml, 1.509g/200ml and 2.264gi200ml mannitol s olutions was reduced by 11%, 23% and 34% respectively, when compared t o the control solution. The intestinal transit data of the four soluti ons demonstrate that mannitol has a concentration dependent effect on small intestinal transit. Small concentrations of mannitol included in a pharmaceutical formulation could therefore lead to reduced uptake w ith any drug exclusively absorbed from the small intestine.