Ursodeoxycholic acid is used to reduce the cholesterol saturation of bile and to promote the dissolution of gallstones. The cholesterol saturation of bile is reduced by Ursodeoxycholic acid, allowing gradual solubilization of cholesterol gallstones. Cholesterol of secretion into bile is reduced and bile acid secretion rate is increased during Ursodeoxycholic acid treatment without a reduction in phospholipids.

Pharmacology

Ursodeoxycholic Acid is a naturally occurring bile acid used to treat different hepatobilliary disorders. The activity of Ursodeoxycholic Acid is achieved through a decrease in secretion of cholesterol in bile. Ursodeoxycholic Acid achieves this through a few mechanisms: it reduces cholesterol absorption, suppresses liver cholesterol synthesis and it does not inhibit bile acid synthesis.

Therefore, alters bile composition from supersaturated to unsaturated. Ursodeoxycholic Acid also promotes the formation of liquid cholesterol crystal complexes which enhance removal of the cholesterol from the gallbladder into the intestine to be expelled. Ursodeoxycholic Acid improves cholestatic liver diseases by-

• Protecting cholangiocytes against cytotoxicity of hydrophobic bile acids
• Stimulating hepatobilliary secretion
• Protecting hepatocytes against bile acid-induced apoptosis

Ursodeoxycholic Acid is completely absorbed in the upper intestine. Time to peak serum concentration varies from 30 to 150 minutes. The rate of absorption ranges from 60-80%. After absorption Ursodeoxycholic Acid enters the portal vein and undergoes extraction from portal blood by liver where it is conjugated with amino acid & that may be either glycine or taurine and then secreted into the hepatic bile ducts. Small quantities of Ursodeoxycholic Acid appear in the circulation and very small amounts are excreted into urine. The biologic half life of Ursodeoxycholic Acid ranges from 3.5-5.8 days.