Assay for the determination of low dosage form of formoterol dry syrup by capillary electrophoresis with head-column field-amplified sample stacking

The development of a capillary zone electrophoresis method with head-column field-amplified sample stacking injection for the determination of formote rol (FMTR) in a low dosage dry syrup form was described. To obtain the high est sensitivity, the sample solution was prepared by high content of organi c solvent with the presence of a small amount of H+ (60-100 mu M) and the c apillary inlet end was dipped in water before electroinjection. This method was fully validated in terms of repeatability (RSDs for migration time, pe ak area of FMTR and peak area ratio between FMTR and I.S. at 1 mu g/ml of F MTR was 0.76, 1.10 and 0.55% respectively), reproducibility (RSDs from diff erent capillaries, analytes, days and instruments were 1.52%, 1.04%, 1.16% and 1.93% respectively), linearity (y = 0.827 x 0.085, r = 0.9993 (n = 6) o ver the range of 0.25-2.0 mu g/ml), limits of quantitation, ruggedness and robustness. The method was applied to the determination of the drug in comm ercial dry syrup preparation (recovery was 100.9%, RSD = 1.5%, n = 5) and p roved to be fast and reliable for the quantitation analysis of FMTR in the pharmaceutical form. (C) 1999 Elsevier Science B.V. All rights reserved.