Evaluation of boron-doped diamond electrode for simultaneous voltammetric determination of hydrochlorothiazide and losartan in pharmaceutical formulations

A method for the simultaneous determination of hydrochlorothiazide (HCTZ) and losartan (LOS) in pharmaceutical formulations using differential-pulse voltammetry (DPV) was developed. Two very wellresolved and reproducible oxidation peaks of HCTZ and LOS, with separation of 0.23 V, were obtained in Britton-Robinson (BR) buffer (pH 9.5) using an anodically pretreated boron-doped diamond electrode. Under the optimum analytical experimental conditions, the voltammetric method exhibited linear responses for simultaneous determination of HCTZ and LOS in the concentration range 3.0 x 10(-6) to 7.4 x 10(-5) mol L-1 for both compounds, with detection limits of 1.2 x 10(-6) mol L-1 and 9.5 x 10(-7) MOI respectively. The proposed method was successfully applied in the simultaneous determination of LOS and HCTZ content in pharmaceutical formulations, whose accuracy was attested by good agreement of the results (paired t-test at a 95% confidence level) with those obtained using high performance liquid chromatography (HPLC). (C) 2013 Elsevier B.V. All rights reserved.