THE INDIRECT UV DETECTION IN THE ANALYSIS OF URSODEOXYCHOLIC ACID ANDRELATED-COMPOUNDS BY HPCE

A high-performance capillary zone electrophoretic (HPCE) assay has bee n developed for the determination of ursodeoxycholic acid (UDCA) and i ts usual impurities. Considering the low molecular absorptivity of UDC A and its related compounds indirect UV detection was used. The electr ophoretic capillary was filled with a background electrolyte (BGE) con taining an UV absorbing ion: benzoic acid (BA) or 5,5-diethylbarbituri c acid (DBA). To enhance the selectivity of the assay diimethyl-beta-c yclodextrines (D-beta-CDs) or trimethyl-beta-cyclodextrines (T-beta-CD s) have been added to the running buffer together with methylcellulose or urea. All considered impurities were well resolved with two buffer s studied, with the exception of methylursodehoxycholate, a neutral co mpound. (C) 1997 Elsevier Science B.V.