DEVELOPMENT OF A SENSOR BY ELECTRO-POLYMERIZATION OF ERICHROME BLACK-T ON GLASSY CARBON ELECTRODE AND DETERMINATION OF AN ANTI-INFLAMMATORY DRUG DICLOFENAC

Objective: The aim of this study was to develop a simple, reliable voltammetric method and its validation for determination of nonsteroidal anti-inflammatory drug diclofenac (DFC). Methods: The proposed method was based on electro-oxidation of DFC at poly (erichrome black T) modified glassy carbon electrode (PEBT/GCE) in 0.2 M phosphate buffer solution of pH 7.0. Cyclic voltammetry and differential pulse voltammetric techniques were employed to study electro-oxidation behavior. Under the optimal conditions, variations of EBT concentration, effect of pH, scan rate on the oxidation of DFC was studied. Results: A well-defined oxidation peak at about +0.59 V vs. standard calomel electrode was observed for voltammetric detection of DFC. pH effect shows the participation of an equal number of protons and electrons in the mechanism. The relation between a logarithm of peak current with the logarithm of scan rate indicated adsorption controlled behavior of electrode process. Concentration variations show a good linear response in the range 0.05 µM to 40 µM with the detection limit of 5.25 × 10-8 M. Conclusion: The prepared sensor exhibited good selectivity, sensitivity, and stability for the detection of DFC in the pharmaceutical dosage form and real samples. The developed method could possibly be adopted for pharmacokinetic studies and also in clinical and quality control laboratories where time and economy were important

ELECTROCHEMICAL DETERMINATION OF KETOROLAC - A NON-OPIOID ANALGESIC AT GLASSY CARBON ELECTRODE

Objectives: The study has been carried to investigate the electro-oxidation mechanism and to develop a selective and sensitive method for determination of ketorolac (KTL), a non-opioid analgesic drug,.Methods: A simple electro analytical method was used for the determination of ketorolac (KTL) using glassy carbon electrode by cyclic and differential pulse voltammetric techniques (DPV). The effect of various experimental parameters such as accumulation time, pH, scan rate, on the voltammetric responses of KTL was evaluated.Results: In the optimized conditions, variation of peak current with respect to concentration was studied and the calibration curve of the peak current vs. KTL concentration was drawn with a linear range of 10- 350 μM with an excellent detection limit of 8.08×10-8 M. This method was successfully tested for the determination of KTL in pharmaceuticals and human urine samples.Conclusion: From the results, it was observed that, the selected method is rapid, sensitive and low cost

Electro-chemical oxidation and determination of granulocytosis risk inducing drug 4-aminoantipyrine at gold electrode

228-235A voltammetric technique for electrochemical sensing and quantification of granulocytosis risk inducing metabolite of aminopyrine, 4-Aminoantipyrine (4-AAP) at gold electrode has been developed. The gold electrode shows excellent selectivity and sensitivity towards the oxidation of 4-AAP in phosphate buffer solution (PBS) of pH=3.0. It is observed from the electrochemical studies of scan rate that overall electrode process is diffusion controlled and pH effect suggests involvement of protons in electrochemical oxidation of 4-AAP. A linear current response towards the electrochemical oxidation of 4-AAP in the concentration range of 1.0 × 10-6 – 2.5 × 10−5 M is observed with limit of detection of 3.8 × 10-8 M (S/N = 3). The interference studies have shown that the gold electrode exhibited excellent selectivity in presence of large excess of interferents. The method is employed to recovery study of 4-AAP in spiked urine and serum samples

Electro-chemical oxidation and determination of granulocytosis risk inducing drug 4-aminoantipyrine at gold electrode

A voltammetric technique for the electrochemical sensing and quantification of granulocytosis risk inducing metabolite of aminopyrine, 4-Aminoantipyrine (4-AAP) at a gold electrode (GE) was developed. The gold electrode showed excellent selectivity and sensitivity towards the oxidation of 4-AAP in phosphate buffer solution (PBS) of pH=3.0. It was observed from the electrochemical studies of scan rate that overall electrode process was diffusion controlled and pH effect suggested equal number of protons and electrons were involved in the electrochemical oxidation of 4-AAP. A linear current response towards the electrochemical oxidation of 4-AAP in the concentration range of 3.8 × 10-8 M and 1.61 × 10−7 M was observed with limit of detection of 3.8 × 10-8 M (S/N = 3). The interference studies showed that the gold electrode exhibited excellent selectivity in the presence of large excess of interferents. The method was employed to recovery study of 4-AAP in spiked urine and serum samples

Development of manganese oxide nanoparticles based chemical sensor for sensitive determination of an antiviral drug valaciclovir

The electrochemical analysis of valaciclovir (VAL) was carried out by electro-deposition of manganese oxide nanoparticles on glassy carbon electrode (MnO2/GCE). The surface morphology of prepared sensor material was analysed by scanning electron microscopy (SEM). Effects of scan rate, solution pH, and concentration variation on the electrochemical behaviour of VAL were studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The increase in anodic current by the use of a modified electrode (5.76 μA) compared with the peak current of bare GCE (1.18 μA) confirms the enhancement of the surface area and catalytic property of manganese oxide nanoparticles. A linear response in the concentration of VAL was observed by DPV from 1.0 × 10−8 M to 14.0 × 10−6 M at the sensor. The limit of detection and quantification were found to be 0.95 nM and 3.17 nM, respectively. The real-world application of the sensor was validated by applying for pharmaceutical and real sample analysis. Thus, it has been proved that the proposed electrochemical sensor has a strong potential to be employed in quality control laboratories for the testing of pharmaceutical products

Oxidation of glycine by diperiodatocuprate(III) in aqueous alkaline medium

200-206Oxidation of the amino acid, glycine, by diperiodatocuprate(III) is studied spectrophotometrically in alkaline medium at constant ionic strength (0.20 mol dm-3) and at varying temperatures (298-318 K). The reaction between diperiodatocuprate(III) and glycine in aqueous alkaline medium exhibits 1:4 stoichiometry. Intervention of free radicals is observed in the reaction. Mechanism involving monoperiodatocuprate(III) as the reactive oxidant species, proceeding through the formation of a complex is proposed. The reaction constants involved in the different steps of the mechanism and activation parameters with respect to the slow step of the mechanism are computed and discussed. The thermodynamic quantities are also determined for the various equilibrium steps. The isokinetic temperature is found to be 381 K