Rapid determination of salbutamol in pharmaceutical preparations by chiral capillary electrophoresis

Abstract

A fast and simple method of chiral capillary electrophoresis (CE) has been applied to the analysis of salbutamol in different pharmaceutical preparations. Using of a 25 mM acetate buffer (pH 5.0), containing 13.1 mg/mL carboxymethyl-β-cyclodextrin (CM-β-CD), an applied voltage of 20 kV and a temperature of 25°C, the enantiomers of salbutamol could be separated in about 2 min. Three different pharmaceutical preparations (two syrups, one oral solution, and two kind of tablets) containing a racemate of salbutamol were injected directly in the CE system, following dilution in dimethyl sulfoxide (DMSO). Appreciable differences in the retention times were observed for salbutamol enantiomers in the different formulations studied, which were attributed to the effect of the matrix components on the electrophoretic mobility. The standard addition method was used for the calibration due to the existence of matrix interferences. Finally, the stability of the enantiomers of salbutamol in the oral solution was studied calculating the enantiomeric ratio values when the solution was injected immediately after being opened in the first case and after being opened and stored in the fridge for two months in the second case.