Determination of the R-enantiomer of valsartan in pharmaceutical formulation by capillary electrophoresis

초록

Capillary zone electrophoresis was successfully applied to the enantiomeric purity determination of valsartan using acetyl-beta-cyclodextrin (A-beta-CD) as a chiral selector. Separations were carried out in a 50 mu m, 64/56 cm fused-silica capillary. The optimized conditions included 25 mM phosphate buffer, pH 8.0, containing 10 mM A-beta-CD as background electrolyte, an applied voltage of +30 kV and a temperature of 30 degrees C. Ibuprofen was used as an internal standard. The assay was validated for the R-enantiomer of valsartan in the range of 0.05-3.0 %. The limit of detection was 0.01 %, the limit of quantitation was 0.05 %, relative to a concentration of valsartan of 1 mg/ml. Intra-day precision varied between 2.57 and 5.60 %. Relative standard deviations of inter-day precision ranged between 4.46 and 6.76 % for peak area ratio. The percentage recovery of the R-enantiomer of valsartan ranged between 97.0 and 99.6 % in valsartan product. The assay was applied to the determination of the chiral purity of valsartan tablets and R-enantiomer of valsartan was found as an impurity.

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