Bioavailability of a controlled release formulation of ursodeoxycholic acid in man.

Several controlled release formulations of ursodeoxycholic acid (UDCA) are currently available. However, none of these results in an optimal bioavailability of the active ingredient as a function of the absorption windows for bile acids found at the gastroduodenal level. Nonsaturated passive absorption of bile acids occurs at these sites, while absorption in the rest of the intestinal tract is less consistent as it is limited by the presence of carriers. These considerations led to the development of an original delayed-release formulation of UDCA using the bioadhesive technique. This allows a longer residence time at the appropriate sites and hence a higher passive absorption of UDCA. The results of this pharmacokinetic study, which compared the new formulation with a traditional pH-dependent sequential release formulation, demonstrated that the new formulation had a greater area under the curve (AUC) during a 24 h period, when compared with that of the reference drug, reaching statistically significant values (p < 0.01) within the first 12 h.