Comparison of capillary electrophoresis (CE) and classical spectrophotometry (UV) for determination of two sartans in pharmaceutical formulations

Abstract

Two new methods, capillary electrophoresis (CE) and classical spectrophotometry (UV), were developed and validated for determination of two AT₁ receptor antagonists, candesartan and valsartan in pharmaceutical formulations. CE was performed using a 75 µm x 94 cm fused silica capillary (72 cm effective length). The phosphate buffer at pH 9.0 (50 mmol/l), 25 kV voltage, 30°C temperature and hydrodynamic injection (10 mbar, 6 s) were chosen as CE parameters. The solutions of both drugs were prepared in water-methanol mixture (1:1). Detection was done spectrophotometrically at 233 nm for candesartan and 217 nm for valsartan. UV spectrophotometry was carried out at 211 and 206 nm for methanolic solutions of both drugs. The precision and accuracy of both methods were compared. Despite some differences, the results showed that they both are suitable for quantitative determination of these drugs for different pharmaceutical purposes.