Development and validation of a simple capillary zone electrophoresis method for the analysis of kanamycin sulfate with UV detection after pre-capillary derivatization

Capillary zone electrophoresis was successfully applied to separate eight r elated substances of kanamycin and several minor unknowns from the main com ponent. Strategies to enhance derivatization and selectivity and to optimiz e separation parameters involved the application of experimental designs. T his chemometrical approach considers main effects as well as interactions o f the influential parameters, thus conducting a more thorough investigation of the method than the common step-by-step approach. Central composite fac e centered designs established optimal separation conditions: 30 MM borax b uffer, pH 10.0 containing 16.0% (v/v) methanol and optimal composition of d erivatization reagent: 27 mg/ml 1,2-phthalic dicarboxaldehyde and 25 mul/ml mercaptoacetic acid in borate buffer, pH 10.4. The standard curves were li near over the concentration range of 0.007-1.01 mg/ml for the main componen t and 0.003-0.1 mg/ml for the related substances. The limit of quantitation was 0.14% (m/m) for the related substances and impurities (S/N=10). The as say method was used to determine the composition of several commercial samp les. Quantitative analysis indicates potential usefulness of capillary elec trophoresis as an alternative to the assay method prescribed in the Europea n Pharmacopoeia and the United States Pharmacopeia. (C) 2001 Elsevier Scien ce B.V. All rights reserved.