Volume 3

July-September 2011

In situ intestinal absorption of ursodeoxycholic acid from solid dispersions and β-cyclodextrin complexes in rats

Kamal Dua, Kavita Pabreja

Ursodeoxycholic acid (UDCA) is a water insoluble drug used for the dissolution of cholesterol gallstones because it reduces the cholesterol saturation of bile along with the treatment of other liver diseases, such as primary biliary cirrhosis, chronic hepatitis and biliary pains. However in vivo studies have shown that intestinal absorption and consequently the bioavailability of the drug are generally poor and erratic both among different subjects, and within the same subject. More than 50% is lost in the stool after a single oral dose of 300 mg. Aqueous solubility of UDCA was enhanced by preparing its solid dispersions using polyvinyl pyrrolidone (PVP) as water soluble carrier and cyclodextrin complexes with β-cyclodextrin. Absorption studies using in-situ rat gut technique exhibited greater rate of intestinal absorption with solid dispersions of UDCA when compared with βcyclodextrin. The intestinal absorption followed the first order rate kinetics. Statistical correlation of in vitro drug dissolution and in vitro drug absorption indicates a positive correlation. This increased absorption may be due to the solubilisation and improved wetting of UDCA in PVP rich micro-environment.

Keywords: Ursodeoxycholic Acid, Solid Dispersion, Complex, In-situ.