Validated RP-HPLC Method for Simultaneous Determination of Amlodipine Besylate and Hydrochlorothiazide from Pharmaceutical Preparation and Biological Samples

A simple sensitive, rapid, accurate and precise reverse phase high performance liquid chromatographic method has been developed for the simultaneous estimation of amlodipine besylate and hydrochlorothiazide from pharmaceutical preparation, blood sample and urine The method involves HIQ Sil C₁₈ 5μm column (250 mm x 4.6 mm i.d.) using pphosphate buffer pH 3.5: Acetonitrile (60:40V/V) as mobile phase at a flow rate of 1ml/min with wavelength detection at 240nm. Losartan potassium was used as an internal standard. The retention time of hydrochlorothiazide, amlodipine besylate and Losartan potassium were 3.7, 5.5 and 8.7 ±0.02 minutes respectively. The developed method was applied for simultaneous estimation of the two drugs from pharmaceutical formulation, plasma and urine and was validated according to ICH and USFDA guidelines. The recovery of both the drugs was found to be greater than 98% and % RSD did not exceed 2% indicating high degree of accuracy of the proposed HPLC method.