Simple and sensitive fluorimetric liquid chromatography for simultaneous analysis of chenodiol and ursodiol in pharmaceutical formulations

Chenodiol and ursodiol are diastereomeric bile acids and widely used as anticholelithogenic. A sensitive method was established for the simultaneous determination of chenodiol and ursodiol by fluorigenic derivatization and liquid chromatography. The analytes were derivatized with 2-(2-naphthoxy)ethyl 2-(piperidino)ethanesulfonate (NOEPES) catalyzed by 18-crown-6 ether (18-crown-6) and potassium hydrogen carbonate. The resulting derivatives were analyzed by isocratic HPLC with fluorimetric detection (excitation at 235 nm and emission at 350 nm). The linear range for the analysis of the drugs was 1.0-30.0 μM with the detection limits (S/N=3) of 0.4 and 0.2 μM, respectively, for chenodiol and ursodiol each based on an injection volume of 10 μl sample. The method was demonstrated to the analysis of chenodiol in capsules and ursodiol in tablets. The results indicate that the method is sensitive and selective.