Comparison of isotachophoresis, capillary zone electrophoresis and high-performance liquid chromatography for the determination of salbutamol, terbutaline sulphate and fenoterol hydrobromide in pharmaceutical dosage forms.

Reversed-phase high-performance liquid chromatography (RP-HPLC), isotachophoresis (ITP) and capillary zone electrophoresis (CZE) were applied to the determination of salbutamol, terbutaline sulphate and fenoterol hydrobromide in commercially available pharmaceutical dosage forms. The comparison showed that especially with the use of ITP, high concentrations of other charged sample components can disturb the separation process. If special attention is paid to ensure a complete separation, all methods give comparable results. For the regression lines of the calibration graphs, regression coefficients of at least ca. 0.999 and nearly zero intercepts are obtained with relative standard deviations of ca. 1-2% for peak area or zone lengths. By applying the different techniques, often different components of the sample matrix can be detected, i.e., a more complete impression of the sample composition can be obtained by using all the three techniques.