Assay of acebutolol in pharmaceuticals by analytical capillary isotachophoresis

Acebutolol [N-{3-acetyl-4-[(2-hydroxy-3-(isopropylamino)propoxy]phenyl} butanamide] is a cardioselective beta-blocker with a potent anti-hypertensive and antiarrhythmic effect. The optimised operational system of electrolytes for the newly developed ITP separation of acebutolol consisted of 10mM potassium acetate +10mM acetic acid (pH 4.65) as the leading electrolyte and 10mM beta-alanine with pH approximately 4 (adjusted with acetic acid) as the terminating electrolyte. The driving and detection currents were 75 and 20 microA, respectively and the analysis took approximately 13 min. Under these conditions the effective mobility of acebutolol was determined as 20.7 x 10(-9) m2 V(-1) s(-1). The calibration dependence was rectilinear in the range 0.14-1.4 mg ml(-1) of acebutolol base (r = 0.9995); relative standard deviation (RSD) values were 1.1% and 1.2% (n = 6) when determining 0.42 and 0.98 mg ml(-1) of acebutolol in a pure standard solution. The method, with the limit of detection (LOD) of 0.04 mg ml(-1) and limit of quantification (LOQ) of 0.12 mg ml(-1), was applied to the assay of acebutolol in Sectral tablets, Acecor tablets, Apo-acebutol tablets (nominal content 400 mg of acebutolol per tablet) and Acebirex tablets (nominal content 200 mg of acebutolol per tablet) with RSD = 0.7-1.7% (n = 6). No interference from any excipients present in the tablets was observed. The recoveries ranged from 98.8% to 102.4% as found by the standard addition technique.