Voltammetric studies and assay of the anti-inflammatory drug ketoprofen in pharmaceutical formulation and human plasma at a mercury electrode

2003 ◽  
Vol 81 (8) ◽  
pp. 889-896 ◽  
Author(s):  
M M Ghoneim ◽  
A Tawfik

The electrochemical reduction of the anti-inflammatory drug ketoprofen was studied in a Britton-Robinson (B-R.) buffer series of pH 2–11 using dc-polarography, cyclic voltammetry, and coulometry techniques. The electrode reaction pathway of the drug at the dropping mercury electrode was proposed and discussed. A new adsorptive cathodic stripping square-wave voltammetric procedure was optimized for the assay of bulk drug in a B-R. buffer of pH 2.0. The peak current was linear with the drug concentration over the ranges 2 × 10–9 to 2 × 10–7 M of the bulk drug, using a 60 s accumulation time period at –0.6 V (vs. Ag/AgCl/KCls). The percentage recovery of the bulk drug was 99.57 ± 0.54 and a detection limit of 0.10 ng mL–1 was achieved. The proposed procedure was successfully applied for the assay of ketoprofen in pharmaceutical formulation (Ketofan®) and human plasma. The percentage recoveries were 99.66 ± 0.47 and 101.76 ± 0.64 in pharmaceutical formulation and human plasma, respectively. A detection limit of 0.14 ng mL–1 plasma was achieved which was below that reported in literature using the different analytical techniques.Key words: ketoprofen (Ketofan®) determination, polarography, cyclic voltammetry, adsorptive cathodic stripping square-wave voltammetry, human plasma.

Author(s):  
Jenny Gómez Avila ◽  
Jhan Carlos Burgos Gómez ◽  
Angélica C. Heredia ◽  
Mónica E. Crivello ◽  
Fernando Garay

2004 ◽  
Vol 82 (7) ◽  
pp. 1203-1209 ◽  
Author(s):  
E Hammam ◽  
H S El-Desoky ◽  
A Tawfik ◽  
M M Ghoneim

Imatinib (GleevecTM, ST1571) exemplifies the successful development of a rationally designed molecularly targeted therapy for treatment of a specific cancer. It is a highly promising new drug for the treatment of chronic myelogenous leukemia in blast crisis, in the accelerated or chronic phase after interferon failure or intolerance. The electrochemical behavior of imatinib was studied in Britton–Robinson (B–R) buffers of pH 2 to 11 by means of cyclic voltammetry at a hanging mercury drop electrode. The voltammograms showed a single 2-electron irreversible cathodic peak, which may be attributed to reduction of the C=O double bond of the imatinib molecule. Imatinib exhibited a strong adsorption onto the electrode surface especially in B–R buffers of pH 6 and 7. The adsorptive response of the drug was optimized with respect to the pH of the electrolysis medium, accumulation variables, and instrumental parameters using a square-wave stripping voltammetry technique. A fully validated, simple, sensitive, precise, and selective square-wave adsorptive cathodic stripping voltammetric procedure is described for trace determination of imatinib. The limits of detection (LOD) and quantitation (LOQ) of the bulk imatinib, following preconcentration for 150 s onto the hanging mercury drop electrode, were found to be 2.6 × 10–10 and 8.7 × 10–10 mol/L, respectively. The proposed procedure was successfully applied for quantitation of imatinib in pharmaceutical formulation (Glivec®) and spiked human serum, without the necessity for sample pretreatment or time-consuming extraction or evaporation steps prior to analysis of the drug. LOD and LOQ of 4.6 × 10–10 and 1.5 × 10–9 mol/L, respectively, were achieved after 120 s of preconcentration of the drug spiked in human serum.Key words: imatinib, GleevecTM, Glivec®, ST1571, cyclic voltammetry, square-wave stripping voltammetry, electrochemical behavior, quantification, pharmaceutical formulation, human serum.


2004 ◽  
Vol 82 (9) ◽  
pp. 1386-1392 ◽  
Author(s):  
E Hammam ◽  
H S El-Desoky ◽  
K Y El-Baradie ◽  
A M Beltagi

Flutamide is a nonsteriodal anti-androgen drug, which is commonly used in the treatment of advanced prostate cancer. Based on the reduction of the nitro organic moiety of the drug molecule in acetate buffer of pH 5 at the hanging mercury drop electrode, three adsorptive cathodic stripping voltammetric procedures were optimized for determination of flutamide in bulk, tablets, and human serum applying linear-sweep, differential-pulse, and square-wave waveforms. The achieved limits of detection of the bulk drug were 1.9 × 10–7, 8.7 × 10–8, and 9.7 × 10–9 mol L–1 by using the optimized differential-pulse, linear-sweep, and square-wave adsorptive stripping voltammetric procedures, respectively. Repeatability of the results was studied for 1 × 10–6 mol L–1 of the drug and the recoveries obtained were 98.51 ± 1.56% (LSV), 98.89 ± 0.87% (DPV), and 99.21 ± 1.03% (SWV). The proposed procedures were successfully applied to the determination of the drug in pharmaceutical formulation (Eulexin® tablets) and human serum. The detection limits of the drug in bulk, pharmaceutical formulation, and human serum achieved by means of the proposed procedures showed that the square-wave mode was more reliable for determination of the drug especially in its low concentration levels.Key words: flutamide, linear-sweep, differential-pulse, square-wave, cathodic adsorptive stripping voltammetry, determination, Eulexin® tablets, human serum.


2009 ◽  
Vol 12 (13) ◽  
pp. 85-92
Author(s):  
Hien Dinh Thi Nhu Nguyen ◽  
Lam Bich Tran ◽  
Giao Trong Nguyen

A method for trace determination of the pesticide Diazinon using adsorptive square-wave stripping voltammetry (AdSWSV) at the dropping mercury electrode (DME) was described. The pesticide was accumulated at the DME and a well-defined stripping peak was obtained at -1012 mV vs Ag/AgCl/KCI electrode in 0.4 N ammonium acetate electrolyte soluti pH 4.3. Peak current was linear over Diazinon concentration range of 800 – 3200 ppb. Detection limit was 16.49 ppb. Effects of some other pesticides (Chlorpyrifos and Cypermethrin) on Diazinon peak and the recovery of Diazinon from artichoke leaves were studied. The method was extended to the determination of Diazinon in artichoke leaves. The recovery of Diazinon from artichoke leaves was 90.31 - 93.55%. Detection limit was 29.82 ppb. Method had high repeatability and selectivity.


2008 ◽  
Vol 62 (2) ◽  
Author(s):  
Mohammed Ghoneim ◽  
Hanaa El-Desoky ◽  
Mohammed El-Ries ◽  
Ashraf Abd-Elaziz

AbstractTetrazepam dissolved in the Britton-Robinson universal buffer of various pH values (2.5–11.5) containing 10 vol. % of ethanol was reduced at the mercury electrode in a single 2-electron irreversible step due to reduction of the 4,5 C=N double bond of the seven-membered ring. Differential pulse polarography (DPP) and adsorptive cathodic stripping voltammetry (AdCSV) techniques (Linear sweep LS, differential pulse DP and square-wave SW modes) for quantification of tetrazepam in bulk form and in myolastan tablets are presented. Moreover, the described linear sweep, differential pulse, and square-wave adsorptive cathodic stripping voltammetry was successfully applied in quantification of tetrazepam in spiked human serum without any prior extraction of the drug. The obtained results showed an increased sensitivity of the described electro-analytical procedures for the quantification of tetrazepam in the following order DPP, DP-AdCSV, LS-AdCSV, and SW-AdCSV, since the observed limits of tetrazepam quantitation by these electroanalytical techniques were 5 × 10−6 mol L−1, 3 × 10−7 mol L−1, 1 × 10−8 mol L−1, and 3 × 10−9 mol L−1, respectively.


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