ABSTRACT:
A simple, rapid, and precise method is developed for the quantitative simultaneous estimation of telmisartan and amlodipine in combined pharmaceutical dosage form. A chromatographic separation of the two drugs was achieved with a Kromasil C18 (250 mm×4.6 mm, 5um) column using Acetonitrile: Methanol: Triethylamine buffer, PH 5.0 adjusted with O-Phosphoric acid. The instrumental settings are flow rate of 1.5 mL/min, and detector wavelength of 237 nm using a variable wavelength detector. The resolution between amlodipine and telmisartan were found to be more than 5. Theoretical plates for amlodipine and telmisartan were 10547 and 6313. Tailing factor for amlodipine and telmisartan was 1.85 and 1.48. The described method shows excellent linearity over a range of 320–480 µg/ml for telmisartan and 50-60 µg/ml for amlodipine. The correlation coefficient for telmisartan and amlodipine are 0.9999. The relative standard deviation for six measurements in two sets of each drug in tablets was always less than 2%. The proposed method was found to be suitable and accurate for quantitative determination of telmisartan and amlodipine in pharmaceutical preparations.