DETERMINATION OF THE NON-THIAZIDE DIURETIC XIPAMIDE IN PHARMACEUTICALS AND URINE BY HPLC WITH AMPEROMETRIC DETECTION

Abstract

A high performance liquid chromatographic method with amperometric detection has been developed for the determination of the diuretic xipamide using a μ-Bondapak C₁₈ column. The mobile phase consisted of a mixture water:acetonitrile 50:50, 5 mM in KH₂PO₄/K₂HPO₄, pH 4.3. The compound is monitored at +1325 mV with an amperometric detector equipped with a glassy carbon working electrode. A liquid-liquid or solid-liquid extraction prior to chromatographic analysis was done to avoid the interferences found in urine matrix. Percentages of recovery were (99.3±4.7) and (99.4±4.2) for liquid-liquid and solid-liquid extraction, respectively. The method developed has a linear concentration range from 0.05 to 0.50 μg/mL, with a reproducibility in terms of relative standard derivation (RSD) for a concentration level of 1 μg/mL of 4% and a quantitation limit of 0.50 ng/mL. The method was applied to the determination of xipamide in tablets and urine obtained from hypertensive patients after the ingestion of Demiax (xipamide 20 mg).

ACKNOWLEDGMENTS

The authors want to thank Dr. Segura and R. Ventura for the facilities offered in the Institut Municipal d'Investigació Médica, Barcelona and the collaboration in the part of the work corresponding to HPLC-DAD and Dr. Ortiz for the supply of urine samples from hypertensive patients. The authors wish also to thank the Interministerial Commision of Science & Technology (project DEP 91–0552) for financial support.