Voltammetric study and determination of buprenorphine in pharmaceuticals

Introducing of Li2FeMn3O8 /C-C3N4 /IL nanocomposite for electrochemical determination of pantoprazole sodium in real samples

A new electrochemical sensor based on Li₂FeMn₃O₈/C-C₃N₄ (LFMO/CCN)/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode (CPE) has been constructed to measure pantoprazole sodium (PNZS). The electrochemical impedance spectroscopy (EIS) method was employed to evaluate the electrode charge-transfer resistances. Moreover, the differential pulse voltammetry method was used to detect PNZS in phosphate buffer solution (PBS) at pH 7.0. The detection limit of 80.0 × 10^-9 M and 10.9 × 10^-7 M was obtained under optimal conditions in the linear concentration range of PNZS 0.09-100 μM and 100-900 μM. Chronoampermetry technique was utilized to determine the diffusion coefficient (D) of PNZS on the modified electrode surface. The CCN/LFMO/IL/CPE was successfully used to determine PNZS in various drug formulations such as tablets and vials. Finally, simultaneous determination of PNZS and acetaminophen was accomplished with no interference based on the proposed sensor.

Voltammetric analysis of drugs

A review on the voltammetric analysis of drugs is presented. The review includes a summary of the rules that must be considered for drug analysis and a survey of the use of voltammetry for drug analysis in the period from 1998 till 2002.

Determination of pantoprazole by adsorptive stripping voltammetry at carbon paste electrode

A voltammetric method was described for the determination of pantoprazole by differential-pulse adsorptive stripping voltammetry at a carbon paste electrode. Accumulation of pantoprazole was found to be optimized in Britton-Robinson buffer (0.04 M, pH 4.0) solution following 5 min accumulation time at open circuit condition. Under optimized conditions, the current showed a linear dependence with concentration in the range 1.0 x 10(-7)-1.0 x 10(-5) M. The detection limit was 2.0 x 10(-8) M. The method was applied successfully for the analysis of pantoprazole in tablet dosage form. The results of accuracy and precision were comparable to those obtained by spectrophotometry.

Voltammetric and flow amperometric methods for the determination of melatonin in pharmaceuticals

Melatonin can be sensitively detected in pharmaceuticals by two different and simple electrochemical methods: cyclic voltammetry (CV) and amperometric detection in a flow injection analysis system (FIA-ED). An adequate pre-treatment of the carbon paste electrode in the first case and the employ of a high flow rate in the second one were the key for obtaining a very good reproducibility (R.S.D. values of 1.5 (n=10) and 1.3% (n=20), respectively). Low limits of detection were achieved and with the coupling of a flow system a linear dynamic range of three orders of magnitude (from 10(-8) to 10(-5) M) was obtained. Both methods were applied to the determination of melatonin in pharmaceuticals. In order to best validate these methodologies a fluorescent procedure was developed to contrast the results. As no interferences from the matrix were found the employ of a separation technique is not necessary. In this way the procedure is fastened and simplified. Moreover, the low price, ease of handling, possibility of automation and high sample throughput are important advantages that convert the flow methodology in an attractive alternative for quality control of pharmaceuticals.