Development and Validation of a Capillary Electrophoretic Method for the Determination of Enalapril

A simple, rapid and sensitive capillary electrophoresis (CE) technique for the determination of Enalapril was developed and validated. The influence of buffer pH, buffer concentration, capillary temperature, applied voltage and injection time was investigated in a fused silica capillary (50 cm x 50 μm ID). Detection wavelength was set at 214 nm. Optimum results were found with 0.067 M phosphate buffer at pH 7.0, capillary temperature 25°C and applied voltage 25 kV. The samples were injected hydrodynamically for 10 s at 35 mbar. The proposed method was validated by testing linearity, precision, accuracy, recovery, detection limit and quantification limit. The method presented a good linearity in the concentration range 10 100 μg/ mL and the correlation coefficient was r = 0.9994. The relative standard deviation (RSD) for the precision system was 0.3864 %. The RSD value for the within-day and between-day precision was 1.7880 % and 1.8590 % respectively. The limit of detection (LOD) was 2.43 μg/mL and the limit quantification (LOQ) was 7.38 μg/mL. The percentage of recovery of the Enalapril was 100.91 %. The method was successfully applied to the quantitative determination of Enalapril from pharmaceutical forms.