Cyclic voltammograms of irbesartan at the hanging mercury dropping electrode in the Britton-Robinson buffer of pH values lower than 4.5 exhibited a single 2-electron irreversible cathodic peak corresponding to the reduction-saturation of the C=N double bond of its tetrazolyl moiety. Over the pH range 4.5-5.5, the voltammograms exhibited two irreversible cathodic peaks (1st and 2nd peaks) of lower peak current but of relatively equal heights which were attributed to reduction of the C=N group of the acidic and basic forms of irbesartan, respectively. A validated square-wave adsorptive cathodic stripping voltammetric method was developed for quantification of irbesartan in the bulk form. The developed stripping voltammetric method was successfully applied for quantitation of irbesartan in pharmaceutical formulations and spiked human serum, without the necessity for samples pretreatment and/or time-consuming extraction steps prior to the analysis. Insignificant interferences from its active ingredient "hydrochlorothiazide", excipients, common metal ions and co-administrated drugs were obtained during the analysis. Limits of detection of 9.0x10-10 and 2.1x10-9 mol L-1 and limits of quantitation of 3.0x10-9 and 7.0x10-9 mol L-1 irbesartan in the bulk form and in spiked human serum were achieved, respectively, by the developed stripping voltammetric method. Moreover, pharmacokinetic parameters of irbesartan in plasma of healthy volunteers following an oral administration of a single dose of Aprovel® tablets were also estimated.
irbesartan; tablets; human blood; stripping voltammetry; pharmacokinetics
