Novel Simultaneous Separation and Quantitative Determination of Four Sartans in Presence of Hydrochlorothiazide by Isocratic RP-HPLC

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.