scholarly journals Adsorptive stripping voltammetric determination of the anti-inflammatory drug tolmetin in bulk form, pharmaceutical formulation and human serum

2007 ◽  
Vol 5 (3) ◽  
Author(s):  
Amr Beltagi ◽  
Mona El-Attar ◽  
Enass Ghoneim
Keyword(s):  
Human Serum ◽  
Mercury Electrode ◽  
Direct Determination ◽  
Stripping Voltammetry ◽  
Pharmaceutical Formulation ◽  
Analyte Molecule ◽  
Square Wave ◽  
Limit Of Quantitation ◽  
Square Wave Stripping Voltammetry

AbstractThe electro-reduction of tolmetin at the hanging mercury drop electrode was studied in different supporting electrolytes using cyclic voltammetry and square-wave stripping voltammetry techniques. Voltammograms of tolmetin exhibited a single well-defined 2-electron irreversible cathodic peak in media of pH C=O double bond of the analyte molecule. Adsorption of tolmetin onto the surface of the hanging mercury electrode was identified and each adsorbed tolmetin molecule was found to occupy an area of 0.23 nm2. A square-wave adsorptive cathodic stripping voltammetric procedure was described for the direct determination of tolmetin in bulk form and pharmaceutical formulation (Rumatol® capsules) with a limit of quantitation of 2 × 10−9 M and a mean percentage recovery of 98.35 ± 1.21% to 99.57 ± 1.23. Moreover, the described procedure was successfully applied for the direct assay of tolmetin in spiked human serum without pretreatment or extraction prior to the analysis while a quantitation limit of 5 × 10−9 M tolmetin was achieved.

Three validated stripping voltammetric procedures for determination of the anti-prostate cancer drug flutamide in tablets and human serum at a mercury electrode

2004 ◽  
Vol 82 (9) ◽  
pp. 1386-1392 ◽  
Author(s):  
E Hammam ◽  
H S El-Desoky ◽  
K Y El-Baradie ◽  
A M Beltagi
Keyword(s):  
Prostate Cancer ◽  
Human Serum ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Pharmaceutical Formulation ◽  
Cancer Drug ◽  
Linear Sweep ◽  
Square Wave

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.

Voltammetric behavior and quantification of the anti-leukemia drug imatinib in bulk form, pharmaceutical formulation, and human serum at a mercury electrode

2004 ◽  
Vol 82 (7) ◽  
pp. 1203-1209 ◽  
Author(s):  
E Hammam ◽  
H S El-Desoky ◽  
A Tawfik ◽  
M M Ghoneim
Keyword(s):  
Cyclic Voltammetry ◽  
Human Serum ◽  
Electrochemical Behavior ◽  
Stripping Voltammetry ◽  
Pharmaceutical Formulation ◽  
Myelogenous Leukemia ◽  
Hanging Mercury Drop Electrode ◽  
Square Wave ◽  
Mercury Drop Electrode ◽  
Square Wave Stripping Voltammetry

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.

scholarly journals DETERMINATION OF PESTICIDE DIAZINON BY ADSORPTIVE SQUARE-WAVE STRIPPING VOLTAMMETRY WITH DROPPING MERCURY ELECTRODE

2009 ◽  
Vol 12 (13) ◽  
pp. 85-92
Author(s):  
Hien Dinh Thi Nhu Nguyen ◽  
Lam Bich Tran ◽  
Giao Trong Nguyen
Keyword(s):  
Detection Limit ◽  
Ammonium Acetate ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Square Wave ◽  
Dropping Mercury Electrode ◽  
Square Wave Stripping Voltammetry ◽  
Acetate Electrolyte ◽  
High Repeatability

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.

Voltammetric study of 2-guanidinobenzimidazole: Electrode mechanism and determination at mercury electrode

2011 ◽  
Vol 76 (12) ◽  
pp. 1699-1715 ◽  
Author(s):  
Sławomira Skrzypek ◽  
Valentin Mirceski ◽  
Sylwia Smarzewska ◽  
Dariusz Guziejewski ◽  
Witold Ciesielski
Keyword(s):  
Time Window ◽  
Mercury Electrode ◽  
Linear Sweep Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Protonated Form ◽  
Citrate Buffer ◽  
Square Wave ◽  
Biological Interest ◽  
Square Wave Stripping Voltammetry

Although 2-guanidinobenzimidazole (GBI; CAS: 5418-95-1) is a compound of biological interest, generally there is a lack of electrochemical studies and the methods of its determination. The GBI behavior at a mercury electrode was analyzed under conditions of linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), square-wave voltammetry (SWV) and square-wave stripping voltammetry (SWSV). Although GBI is electrochemically inactive at mercury electrode it adsorbs at the mercury surface and catalyzes effectively the hydrogen evolution reaction. Theoretical analysis of two possible pathways, according to which the GBI electrode mechanism can be explained, is performed. Simple analysis of peak current and potential with respect to available time window, i.e. change of frequency can be helpful in discerning the character of the recorded SW current. The established electrode mechanism is assumed to involve a preceding chemical reaction in which the adsorbed catalyst (GBIads) is protonated and the protonated form of the catalyst (GBIH+(ads)) is irreversibly reduced at potential about –1.18 V vs Ag|AgCl (citrate buffer pH 2.5). New methods of voltammetric determination of 2-guanidinobenzimidazole were developed. The detection and quantifications limits were found to be 1 × 10–7, 1 × 10–6 mol l–1 (SWV); 8 × 10–8, 9 × 10–7 mol l–1 (SWSV); 4 × 10–7, 2 × 10–6 mol l–1 (DPV) and 6 × 10–7, 3 × 10–6 mol l–1 (LSV), respectively.

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