Analysis Of Losartan Potassium

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INTRODUCTION: Losartan Potassium (LSP)[FIG.1.A], 2-n-butyl-4-chloro-1-[p-(o-1Htetrazol- 5-ylphenyl) benzyl]-imidazole-5 methanol monopotassium salt is a highly selective, orally active, non-peptide angiotensin II receptor antagonist indicated for the treatment of hypertension. It has a more potent active metabolite (II, 2-n-butyl-4-chloro-1-[2- (1H-tetrazol-5 yl) biphenyl- 4-yl) methyl] imidazole-5- carboxyl acid)[1]. The determination of Losartan has been carried out in tablets by HPLC, capillary electrophoresis and super-critical fluid chromatography[2,3], in urine by gas chromatography- mass spectrometry[4] and, simultaneously with its active metabolite in biological fluids, by HPLC[5- 10]. Amlodipine Besylate (ADB) )[FIG.1.B], chemically, …show more content…
METHOD DEVELOPMENT: To develop a suitable and robust LC assay method for losartan potassium and amlodipine, different mobile phases were employed to achieve the best separation and resolution. The method development was started with Aligent,Zorbax column (250 mmx4.6 mm I.D; particle size 5µm) with the following mobile phase of degassed mixture of buffer [pH - 4.0] and acetonitrile in the ratio of 500:500 v/v. Losartan potassium and amlodipine peaks was eluted at void volume respectively. For next trial the mobile phase composition was changed slightly. The mobile phase composition was buffer and acetonitrile in the ratio of 550:450 v/v. The above trail resulted in the little broad peak shape with long retention time. Again the mobile phase composition changed slightly to buffer and acetonitrile in the ratio of 600:400 v/v respectively with the eluent at flow rate set at 1.0mL/min. In this trail losartan potassium and amlodipine eluted with a retention time of 2.051&3.249 minutes resulting in sharp peak which is detected at 221 and 226nm and the validative chromatogram of losartan potassium and amlodipine standard using the proposed method is represented in (Fig.2). Losartan potassium and amlodipine showed a significant UV absorbance at wavelength 225nm and hence, this wavelength has been chosen for detection in analysis of losartan potassium and amlodipine respectively. The system suitability results of the developed RP-HPLC method are presented in …show more content…
LINEARITY & DETECTOR RESPONSE(LOD&LOQ): Replicate analysis of solution containing 300-900µg/ml and 30-90µg/ml of losartan potassium and amlodipine sample solutions respectively were injected into HPLC according to the procedure in a sequence and chromatograms were recorded. Calibration curves were constructed by plotting by taking concentrations on X-axis and ratio of peak areas of standards on Y-axis (Figs.3.A&B) and regression equation were computed for both drugs and represented in Table.2. The LOD and LOQ of losartan potassium and amlodipine was found to be 2.941, 2.903μg mL‐1 and 9.80,9.675μg mL‐1

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