Liquid Chromatography/Tandem Mass Spectrometry for the Simultaneous Determination of Ursodiol and its Major Metabolites, Tauroursodeoxycholic Acid and Glycoursodeoxycholic Acid in Human Plasma

A rapid and sensitive method is described for the quantification of ursodiol and its major metabolites glycoursodeoxycholic acid (GUDCA) and tauroursodeoxycholic acid (TUDCA) in human plasma using single internal standard (Ursodeoxycholic Acid d4). Solid phase extraction was performed and chromatographic separation of 5 mu L injected sample was achieved using Waters Xterra, 5 mu m column with a mobile phase comprised of methanol and 5 mM ammonium formate with 0.1 % acetic acid (70 : 30, v/v). The mass spectrometer was used in negative ion mode and multiple reactions monitoring using electro spray ionization mode as an interface. The method was fully validated and the calibration curves were linear over the concentration range of 25.9 to 15300.1 ng/mL for ursodiol, 2.7 to 1587.5ng/mL for tauroursodeoxycholicacid and 25.4 to 15040.9 ng/mL for glycoursodeoxycholic acid. The method was sensitive and specific, with the lower limit of quantification of 25.9, 2.7 and 25.4 ng/ml for ursodiol, tauroursodeoxycholic acid and glycoursodeoxycholic acid respectively. The present method includes a simple and rapid sample preparation with shorter analysis run time and less flow rate compared to previously reported methods. The method was applied successfully for a bioequivalence study in healthy subjects.