Rapid determination of telmisartan in pharmaceuticals and serum by the parallel catalytic hydrogen wave method

Abstract

The polarographic characteristics of telmisartan have been investigated in 0.8 mol L(-1) NH3.H2O-NH4Cl (pH 8.9)-0.01 mol L(-1) H2O2 as supporting electrolyte. The results demonstrate that the polarographic reduction wave at ca. -1.30 V in the absence of H2O2 is a catalytic hydrogen wave, and the reduction wave enhanced by H2O2 is a so-called parallel catalytic hydrogen wave. The analytical sensitivity of the parallel catalytic hydrogen wave is ca. 60 times higher than that of the corresponding catalytic hydrogen wave. Based on the parallel catalytic hydrogen wave a novel method has been developed for determination of telmisartan by linear sweep polarography. The calibration curve is linear in the range 2.0x10(-8)-2.0x10(-6) mol L(-1) and the detection limit is 1.0x10(-8) mol L(-1). The precision is excellent with relative standard deviations of 2.6% at a concentration of 1.0x10(-7) mol L(-1) telmisartan. The proposed method has been applied to the direct determination of the telmisartan in capsule forms and biological samples. The proposed method has been proved to be advantageous over existing CZE and MEKC methods in simplicity, rapidity, and reproducibility.

Voltammetric Behavior of Telmisartan and Cathodic Adsorptive Stripping Voltammetric Method for Its Assay in Pharmaceutical Dosage Forms and Biological Fluids

“…In all other electrochemical studies [19][20][21] and almost all chromatographic studies [5][6][7][8][9][10][11][12], relatively high concentration of TS was studied and limit of detection value was found to be higher than current study. Both LOD and LOQ values confirmed the sensitivity of the proposed methods.…”

“…All these reported methods require highly sophisticated instrumentation even they are sufficiently sensitive. TS is an electroactive molecule on different electrodes therefore there are three studies dealing with electrochemical determination of TS based on mercury [19,20] and carbon paste [21] electrodes. Reviewing the literature revealed that, up to the present time, there is no square-wave cathodic stripping voltammetric method using mercury electrode to assay of TS in pharmaceutical formulation and biological samples.…”

Telmisartan

“…The advance in experimental electrochemical techniques in the field of analysis of drugs is due to their simplicity, low cost, and relatively short analysis time as compared with the other techniques. However, since most drugs are less active electrochemically, little attention has been paid so far to the use of electrochemical detection methods [40][41][42][43].…”

“…Xu et al [42] investigated the polarographic characteristics of telmisartan in 0.8 mol/l NH 3 ÁH 2 O-NH 4 Cl (pH 8.9)-0.01 mol/l H 2 O 2 as supporting electrolyte. The calibration curve is linear in the range of 2.0 Â 10 À8 -2.0 Â 10 À6 mol/l and the detection limit is 1.0 Â 10 À8 mol/l.…”

Square-wave adsorptive stripping voltammetric determination of candesartan cilexetil in pharmaceutical formulations

“…Accordingly, it was deduced that the reduction wave of CAN at -1340 mV in the optimal supporting electrolyte should be the result of the reduction of the proton rather than that of the other groups; this produces a catalytic hydrogen wave. Owing to the ability of the nitrogen atom to combine with a hydrogen ion being higher than that of an oxygen atom, the nitrogen atom of CAN combines with a hydrogen ion in the benzimidazole and tetrazol groups, yielding electroactive compounds on the cathode [24,25].…”