Carlos Alberto Rossi Salamanca-Neto

Simultaneous Voltammetric Determination of Antihypertensive Drugs Amlodipine and Atenolol in Pharmaceuticals Using a Cathodically Pretreated Boron-Doped Diamond Electrode

The simultaneous voltammetric determination of antihypertensive drugs amlodipine besylate (AML) and atenolol (ATN) using a cathodically pretreated boron-doped diamond electrode (CP-BDDE) is reported for the first time. The anodic peak potentials of AML and ATN at a CP-BDDE were found to be 0.727 and 1.32 V (vs. Ag/AgCl (3.0 mol L-1 KCl)) in phosphate buffer (pH 7.0), respectively, by cyclic voltammetry. It was observed that the CP-BDDE possesses improved performance for the simultaneous determination of AML and ATN when compared to other carbon-based electrodes in these conditions. Using square-wave voltammetric technique, the obtained analytical curves were linear in the concentration range from 2.9-33 µmol L-1 for AML and 9.8-190 µmol L-1 for ATN, with limits of detection of 0.17 and 0.22 µmol L-1, respectively. The proposed method was successfully applied to the simultaneous determination of AML and ATN in pharmaceutical samples.

A simple square-wave voltammetric method for the determination of scopolamine in pharmaceuticals using a boron-doped diamond electrode

A simple procedure is described for the determination of scopolamine by square-wave voltammetry using a cathodically pretreated boron-doped diamond electrode. Cyclic voltammetry studies indicate that the oxidation of scopolamine is irreversible at a peak potential of 1.59 V (vs. Ag/AgCl (3.0 mol L-1 KCl)) in a 0.50 mol L–1 sulfuric acid solution. Under optimized conditions, the analytical curve obtained was linear (r = 0.9996) for the scopolamine concentration range of 1.0 to 110 µmol L–1, with a detection limit of 0.84 µmol L–1. The method was successfully applied to the determination of scopolamine in pharmaceutical formulations with minimum sample preparation.

Boron-doped diamond electrode: a modification-free platform for sensitive square-wave voltammetric determination of indapamide hydrochloride

A boron-doped diamond electrode (BDDE) was employed for indapamide hydrochloride (IND) determination. IND presented an irreversible and diffusion-controlled oxidation peak at 0.53 V in 0.01 mol L−1 H2SO4 by cyclic voltammetry. To develop the voltammetric method, the effect of electrochemical pretreatment of BDDE, pH of supporting electrolyte, type of electrolyte and its concentration were evaluated. Under optimized instrumental parameters of square-wave voltammetry, the IND current was linear over the concentration range of 0.099–4.3 μmol L−1, with limit of detection of 56 nmol L−1. The method was successfully applied to commercial tablets, and the obtained results were statistically similar to those obtained by a spectrophotometric method. Additionally, the determination of IND was accomplished in synthetic cerebrospinal fluid and tap water. The method proved to not suffer from matrix interference with excellent recoveries.