Fast determination of ethambutol in pharmaceutical formulations using capillary electrophoresis with capacitively coupled contactless conductivity detection |
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| Authors: | José Alberto Fracassi da Silva Nathan Vitorazzi de Castro Dosil Pereira de Jesus Adriana F Faria Marcus V N De Souza Marcone Augusto Leal de Oliveira |
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| Institution: | 1. Chemistry Institute, University of Campinas, Campinas, Brazil;2. Instituto Nacional de Ciência e Tecnologia de Bioanalítica, UNICAMP, Brazil;3. Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, Cidade Universitária, Brazil;4. Instituto de Tecnologia em Fármacos‐Far Manguinhos, Funda??o Oswaldo Cruz, Rio de Janeiro, Brazil |
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| Abstract: | A method for the determination of ethambutol (EMB), a first‐line drug against tuberculosis, based on CE with capacitively coupled contactless conductivity detection is proposed. The separation of EMB and its main product of degradation were achieved in less than 3 min with a resolution of 2.0 using a BGE composed of 50 mmol/L histidine and 30 mmol/L MES, pH 6.30. By raising the pH to 8.03, the analysis time was reduced to 1.0 min, but with a significant loss of resolution (0.7). Using the best separation conditions, linearity of 0.9976 (R2, five data points), sensitivity of 1.26×10?4 V min μmol?1 L, and LOD and quantification of 23.5 and 78.3 μmol/L, respectively, were obtained. Recoveries at four levels of concentration ranged from 95 to 102% and the concentration range studied ranged from 100 to 500 μmol/L. The results obtained for the determination of EMB in pharmaceutical formulations were compared with those obtained by using CE with photometric detection. |
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| Keywords: | CE Contactless conductivity detection Drug analysis Electrochemical detection Tuberculosis |
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