Densitometry, video-scanning and capillary electrophoresis for determination of valsartan and amlodipine in a combined dosage form: A comparative study

Summary Comparison of classical densitometry, video-scanning, and capillary electrophoresis was performed for determination of angiotensin II receptor antagonist, valsartan, and calcium channels blocker, amlodipine, in a combined dosage form. Thin layer chromatography was performed on RP8F254 TLC plates with a mobile phase consisting of acetonitrile-phosphate buffer at pH 9.0 (5:5, v/v) and temperature 20 °C. Densitometry was done in the reflectance mode at 217 nm for valsartan and in the absorbance mode at 370 nm for amlodipine. Video-scanning was elaborated at 254 and 366 nm for valsartan and amlodipine, respectively. For chromatographic analysis, calibration plots were constructed in the range of 0.4–2.8 μg per spot for valsartan and 0.02–0.14 μg per spot for amlodipine. Capillary electrophoresis (CE) was performed using a 75 μm × 94 cm fused silica capillary (72 cm effective length), 0.01 mol L−1 borate buffer at pH 8.0, 20 kV voltage, 30 °C temperature, hydrodynamic injection (10 mbar, 6 s) and UV de...