Electrochemical Determination of Terazosin in Pure Form and in Dosage Forms

Two methods have been developed for the determination of terazosin in pure form and in dosage forms- one based on a potentiometric sensor and the other a voltammetric technique. Terazosin-silicotungstic acid ion-association is developed as an ionophore in the fabrication of the potentiometric sensor. The optimum concentration range of the developed method was 7 x 10^(-2) to 8 X 10^(-4) M of the drug. The system gave a perfectly Nernstian slope (59.3 mV per decade) in the pH 4.2 with hardly any interference from the common cations and anions. The cyclic and linear sweep voltammetric studies of the drug on a glassy carbon electrode in the potential range -100 to +100 mV with a switching potential of 800 mV have also been carried out. The drug gave a well-defined irreversible anodic peak at 774 mV when sodium hydroxide was used as the supporting electrolyte. Influence of scan rate and concentration on current were studied and based on this, a voltammetric method has also been developed for the quantitative determination of the drug. Both the methods have been applied for the determination of the drug in two commercially available tablets and the results are highly precise and accurate.