DETERMINATION OF FREE BILE-ACIDS IN RAW-MATERIALS AND BULK PRODUCTS BY HPLC AND GC

A procedure based on two chromatographic methods with different select ivities (HPLC and GC) was developed for the quality control assay of f ree bile acids in raw materials from animals and bulk products utilize d in the pharmaceutical industry. HPLC was carried out without prelimi nary derivatization using an Ultrasphere ODS column with UV detection at 210 nm and methanol-acetonitrile-acetate buffer as the mobile phase . For GC, bile acids were converted into their trifluoroacetyl-hexaflu oroisopropyl derivatives and analysed on a SE-52 capillary column with flame-ionization detection. Bile acid levels in hydrolysed ox bile, i n bulk cholic and deoxycholic acid determined by HPLC correlated with results obtained by GC, with the exception of the analytes present in low concentrations (less than 3% w/w) detectable only by GC. HPLC-UV i s the more suitable technique for routine analyses of free bile acids in pharmaceutical matrices owing to its simplicity and rapidity. Howev er, because of the low sensitivity and specificity of the UV detection , the accuracy of the HPLC assay should be verified by comparison with GC.