Determination of formoterol by capillary electrophoresis and its application to inhaler capsules

A capillary electrophoretic (CE) method for the determination of formoterol (FOR) in a pharmaceutical preparation is described. Analysis was made in a background electrolyte consisting of 20 % acetonitrile and 50 mM phosphoric acid at pH 2.5, using fused silica capillary (86 cm x 75 microm ID), 27 kV potential, and detecting at 200 nm. Under these electrophoretic conditions 3, 4-dihydroxybenzylamine used as an internal standard (IS) and FOR showed symmetrical peaks at 6.1 and 8.3 min., respectively. The inter-day and intra-day precision was examined in the concentration range of 2.98 x 10(-6) M to 8.94 x 10(-6) M. Good correlation and accuracy were obtained. Limit of detection, (LOD) and limit of quantitation (LOQ) values were 3.71 x 10(-7) M and 1.11 x 10(-6) M, respectively. The method was applied for the analysis of FOR in pharmaceutical inhaler capsules. The proposed method is reliable, precise, accurate, fast, and cost effective.