Development of a micellar electrokinetic chromatography system applied to the quality control of ursodeoxycholic acid in oral pediatric suspensions

BOSCOLO, O; ESTEVEZ, P.; MARTINEFSKI M; TRIPODI V.; LUCANGIOLI S.

Congreso; RICiFA 2014: 4ta Reunión Internacional de Ciencias Farmacéuticas; 2014

Introduction: Ursodeoxycholic acid (UDCA), also known as ursodiol, is a secondary bile acid which is synthesized in the liver. UDCA lowers the cholesterol content of bile by reducing hepatic synthesis and reabsorption by the gut. Bile acids are derivatives hydroxylated 5β-cholan-24-oic acid, which are characterized by the absence of chromophore groups in its structure, which results in low absorption in the UV-visible region.In UDCA raw material may be present as impurities other bile acids, some of them toxic, like lithocholic acid (LCA), and others associated with numerous side effects such as chenodeoxicholic acid (CDCA). The official USP monograph describes the determination of related compounds such as CDCA and LCA by thin layer chromatography (TLC), where each impurity limit should not be more than 1.5% and 0.05% respectively. Purpose: the aim of this study was to optimize an analytical method by electrokinetic chromatography using cyclodextrins and micellar agents for determination of ursodeoxy cholic acid and its impurities in pharmaceutical pediatric suspensions. Method: the electrophoretic system consisted of 50 mM sodium dodecyl sulfate, 5mM β-cyclodextrin, 5mM hydroxypropyl-β-cyclodextrin, 5 mM borate/ 5 mM phosphate buffer, pH, 7.0 with 10% acetonitrile. A capillary of 60 cm length (50 cm to detector) and 75µm i.d. was used and the applied voltage was 28kV, a working temperature of 40˚C and 195 nm were applied. Results: different additives were optimized such as cyclodextrins, type and concentration, buffer solution and organic modifier. Instrumental parameters such as voltage, capillary length and temperature were evaluated. The final electrophoretic condition allowed the best resolution of the analytes. Content of UDCA in the suspensions was 98.9% (n=3;RSD 1.8%), 99.0% (n=3;RSD 1.6%), 99.5% (n=3;RSD 1.7%) and the percentage of CDCA and LCA correspond with the specification. Conclusion: the developed method is fast, simple and useful for the determination of ursodeoxycholic acid and its impurities. Using this analytical method provides good resolution of the analytes, adecuate LOD and LOQ, making it suitable for the quality control of pharmaceutical formulations according to the requirements of regulatory agencies.