ASSAY OF FREE BILE-ACIDS IN PHARMACEUTICAL PREPARATIONS BY HPLC WITH ELECTROCHEMICAL DETECTION

A method was developed for the direct analysis of the common free bile acids by high-performance liquid chromatography coupled with electroc hemical detection (HPLC-ED). The compounds were separated on an Ultras phere ODS column with a methanol-acetonitrile-acetate buffer eluent an d detected at a porous graphite electrode set an an oxidation potentia l of +1.4 V. This new technique is applicable to the assay of ursodeox ycholic acid and related impurities in capsule and tablet formulations . Compared with conventional UV detection, the electrochemical detecto r was found to achieve enhanced specificity and sensitivity