Analytical Sciences

Development and Validation of a Stability-indicating Capillary Zone Electrophoretic Method for the Assessment of Entecavir and Its Correlation with Liquid Chromatographic Methods

Sergio Luiz DALMORA, Daniele Rubert NOGUEIRA, Felipe Bianchini D’AVILA, Ricardo Bizogne SOUTO, and Diogo Paim LEAL

Department of Industrial Pharmacy, Federal University of Santa Maria, Santa Maria-RS, Brazil

A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of entecavir in pharmaceutical formulations, using nimesulide as an internal standard. A fused-silica capillary (50 μm i.d.; effective length, 40 cm) was used while being maintained at 25°C; the applied voltage was 25 kV. A background electrolyte solution consisted of a 20 mM sodium tetraborate solution at pH 10. Injections were performed using a pressure mode at 50 mbar for 5 s, with detection at 216 nm. The specificity and stability-indicating capability were proven through forced degradation studies, evaluating also the in vitro cytotoxicity test of the degraded products. The method was linear over the concentration range of 1 – 200 μg mL⁻¹ (r² = 0.9999), and was applied for the analysis of entecavir in tablet dosage forms. The results were correlated to those of validated conventional and fast LC methods, showing non-significant differences (p > 0.05).

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