A simple, reliable, sensitive, reproducible and novel isocratic RP-HPLC method was developed and validated for the separation and quantitative estimation of four angiotensin II-receptor antagonists namely Telmisartan (TELM), Losartan (LOSA), Olmesartan (OLME) and Valsartan (VALS) that are utilized in treating hypertension alone or along with some other drugs like thiazide diuretics mostly Hydrochlorothiazide (HCTZ). The key important benefit of developed method was that the five individual drugs can be determined on a single chromatographic system without alteration in detection wavelength and mobile phase. All the above said drugs were separated by using Welchrom C18 column having internal diameter of 4.6 X 250 mm with 5 µm particle size as stationary phase with mobile phase consisting a mixture of acetonitrile and phosphate buffer (pH-3.3, 50:50 v/v). The mobile phase was pumped at a flow rate of 1 ml/min. The wave length of the UV detection was done at 238 nm. The total run time was eight minutes and the elution window of only three minutes. The calibration curves were linear (r2 = 0.9998) in all cases. The relative standard deviation was less than 2% and average recovery was above 99.95%. This method was statistically validated in different parameters like linearity, precision, specificity, accuracy, robustness and ruggedness. The optimized method proved to be accurate, specific and robust for the quality control of four angiotensin-II receptor blockers alone or in combination with HCTZ in bulk drug and tablet dosage forms.
Prof. Panchumarthy Ravisankar
Department of Pharmaceutical Analysis, Vignan Pharmacy College, Vadlamudi, Guntur District – 522 213, Andhra Pradesh, India.
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