VALIDATION OF A CAPILLARY ELECTROPHORESIS METHOD FOR THE DETERMINATION OF POTASSIUM COUNTERION LEVELS IN AN ACIDIC DRUG SALT

This paper describes the first report of the Validation of a capillary electrophoresis methed for the quantitative determination of potassium levels in the potassium salt of an acidic drug. Validation criteria include precision, linearity, robustness and repeatability. The use of an internal standard enabled precision values of <1% RSD to be obtained for peak area ratios. Careful control of capillary conditioning and temperature enabled migration time precisions of <0.5% RSD. Results obtained by this method were in agreement with those generated by ion exchange chromatography and the theoretical potassium content of samples tested. Features of the method, compared to alternative analytical techniques, include simplicity, speed and accuracy. The method is now in routine use within our laboratories.