Nonaqueous capillary electrophoresis conditions for the simultaneous separation of eight alpha-adrenergic blocking agents

The analysis is described for the first time for separating eight alpha-adrenergic blocking agents (oxymetazoline, 5-methylurapidil, prazosin, phentolamine, RS-17053, methoxamine, yohimbine, and BMY7378) by capillary electrophoresis (CE) with UV detection. Optimum separation of the analytes was obtained on a 50 cm × 75 μm i.d. capillary using a buffer containing 20% acetonitrile, 60 mM ammonium acetate, and 1.0% glacial acetic in methanol medium, with applied voltage and capillary temperature of 23 kV and 25 °C, respectively. The relative standard deviations of the migration times and the peak areas of the eight analytes were in the ranges of 0.12–1.29% and 1.02–2.53%, respectively. Detection limits of oxymetazoline, 5-methylurapidil, prazosin, phentolamine, RS-17053, methoxamine, yohimbine, and BMY7378 were 0.5–1.0 μg mL⁻¹. In the tested concentration range, good linear relationships (correlation coefficients >98%) between peak areas and concentrations of the analytes were observed. This method has been successfully applied for determination of prazosin and phentolamine with recoveries of 97.30% and 98.12%, respectively. The proposed method was successfully applied for the rapid CE determination of the frequently applied alpha-adrenergic blocking compounds phentolamine and prazosin in general pharmaceutical preparation.