Validated capillary electrophoresis method for the determination of atropine and scopolamine derivatives in pharmaceutical formulations

The simultaneous determination of atropine and scopolamine derivatives, whi ch have similar structures, was investigated by using capillary zone electr ophoresis. The effects of buffer pH, buffer concentration and hydroxypropyl -beta-cyclodextrin concentration on migration time and resolution of the in vestigated compounds were systematically studied. The selected electrophore tic buffer consisted of a 80 mM sodium citrate pH 2.5, containing 2.5 mM hy droxypropyl-beta-cyclodextrin as the complexing agent. Quantitative analysi s was validated by testing the reproducibility of the method, giving a rela tive standard deviation less than 1 and 2% for the intermediate precision o f migration times and peak area ratios, respectively. The linearity of the method was assessed between 50 and 150% of the theoretical content (coeffic ient of correlation greater than 0.99). The proposed method was found to be suitable and accurate for the determination of these basic drugs in pharma ceutical preparations. (C) 1998 Elsevier Science B.V. All rights reserved.