Electrooxidation and Low-tech Determination of Pantoprazole on a Disposable Pencil Graphite Electrode by the use of Cationic Surfactant

Pınar Talay Pinar

doi:10.17344/acsi.2019.5367

Abstract

The electrochemical oxidation of pantoprazole, a selective proton pump inhibitor, was studied in aqueous as well as aqueous/surfactant media at a disposable pencil graphite electrode using cyclic and adsorptive stripping voltammetric techniques. The sensitivity of the stripping voltammetric measurements was significantly improved when the cationic surfactant, cetyltrimethylammonium bromide (CTAB) was present in the neutral electrolyte solution. For analytical purposes, well resolved voltammetric peaks at +1.05 V (versus Ag/AgCl) were obtained in Britton-Robinson buffer at pH 7.0 containing 3×10-4 M CTAB using square-wave stripping mode (after 30 s accumulation at open-circuit condition). The process could be used to determine pantoprazole concentrations in the range of 2.4×10-8 - 7.1×10-7 M (9.2 - 272 µg L-1) with a detection limit of 7.0×10-9 M (2.7 µg L-1). The proposed method was applied to the determination of pantoprazole in pharmaceutical formulation and in the spiked human urine samples with acceptable recoveries.

Highlights

Pantoprazole (PAN) (Fig. 1) is a substituted benzimidazole derivative which belongs to proton pump inhibitors (PPI)
cyclic voltammetry (CV) technique was used at different scan rates to test commercially available pencil leads as tools for the working electrodes
Where ip refers to the anodic peak current, n is the number of electrons transferred, A is the dynamic surface area of electrode, D0 is the diffusion coefficient, v is the scan rate, and C0 is the concentration of K3Fe(CN)[6]

Summary

Introduction

Pantoprazole (PAN) (Fig. 1) is a substituted benzimidazole derivative which belongs to proton pump inhibitors (PPI). PAN inhibits the acid secretion in the stomach via the specific effect on proton pumps of parietal cells. It was developed for the treatment of acid-related gastrointestinal disorders. PAN is a weak base that is converted to its active form by gastric acid before affecting on the proton pump. Its degradation rate increases with decreasing pH. The degradation half-life is approximately 220 h at pH 7.8 while it is approximately 2.8 h at pH 5.0. PAN is extensively metabolized in the liver. The main serum metabolite is formed by demethylation at the 4-position of the pyridine ring, followed by conjugation with sulphate.[1,2,3,4]

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