Fast determination of ethambutol in pharmaceutical formulations using capillary electrophoresis with capacitively coupled contactless conductivity detection.
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 (R(2), five data points), sensitivity of 1.26x10(-4) V min mumol(-1) L, and LOD and quantification of 23.5 and 78.3 mumol/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 mumol/L. The results obtained for the determination of EMB in pharmaceutical formulations were compared with those obtained by using CE with photometric detection.
da Silva
José Alberto Fracassi
JA
Chemistry Institute, University of Campinas, Campinas, Brazil. fracassi@iqm.unicamp.br
de Castro
Nathan Vitorazzi
NV
de Jesus
Dosil Pereira
DP
Faria
Adriana F
AF
De Souza
Marcus V N
MV
de Oliveira
Marcone Augusto Leal
MA
D000995:Antitubercular Agents / Q000737:chemistry*; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D004977:Ethambutol / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013997:Time Factors
D000995:Antitubercular Agents; D004364:Pharmaceutical Preparations; D004977:Ethambutol