Abstract
Capillary zone electrophoresis methods for the simultaneous determination of the ฮฒโblocker drugs, atenolol, chlorthalidone and amiloride, in pharmaceutical formulations have been developed. The influences of several factors (buffer pH, concentration, applied voltage, capillary temperature and injection time) were studied. Using phenobarbital as internal standard, the analytes were all separated in less than 4โmin. The separation was carried out in normal polarity mode at 25ยฐC, 25โkV and using hydrodynamic injection (10โs). The separation was effected in an uncoated fusedโsilica capillary (75โฮผm i.d. ร 52โcm) and a background electrolyte of 25โmm H~3~PO~4~ adjusted with 1โm NaOH solution (pH 9.0) and detection at 198โnm. The method was validated with respect to linearity, limit of detection and quantification, accuracy, precision and selectivity. Calibration curves were linear over the range 1โ250โฮผg/mL for atenolol and chlorthalidone and from 2.5โ250โฮผg/mL for amiloride. The relative standard deviations of intraโ and interโday migration times and corrected peak areas were less than 6.0%. The method showed good precision and accuracy and was successfully applied to the simultaneous determination of atenolol, chlorthalidone and amiloride in various pharmaceutical tablets formulations. Copyright ยฉ 2010 John Wiley & Sons, Ltd.