Differential Pulse Polarographic Analysis Research Articles

Differential Pulse Polarographic Behavior and Quantification of the Flucloxacillin in Pure and Pharmaceutical Dosage Forms Using a Static Mercury Drop Electrode

Differential pulse polarographic analysis (DPPA) by using static mercury drop electrode (SMDE) for quantification of flucloxacillin (FLUX) in pure and pharmaceutical dosage forms was studied. The optimum conditions for the polarographic signal were determined and a study was made of the different parameters affecting the electrochemical process. The best definition of the analytical signals was found in Britton–Robinson buffer (0.06 M) at pH 4.0 . Under the optimum conditions, liner calibration graph, Ip=f(CFLUX) was obtained in the concentration ranges of 0.1 mM (0.0494 ?g.mL-1) to 26 mM (12.8414 ?g.mL-1) at -940 to -1000 mV (versus Ag/AgCl) with relative standard deviations (RSD) did not exceed 2.4% for the concentrations of FLUX (0.0494 ?g.mL-1). Regression analysis showed a good correlation coefficient (R2=9998) between Ip and concentration over the mentioned range. The limit of detection (LOD) and the limit of quantification (LOQ) were to be 0.0040 and 0.0120 ?g.mL-1, respectively. The proposed method was validated for linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and specificity. The developed method is applicable for the determination of FLUX in pure and different dosage forms in presence a same amount of amoxicillin (AMOX) with average recovery of 99.4 to 102.2 % and the results are in good agreement with those obtained by the HPLC reference method.

Differential Pulse Polarographic Behavior and Determination of Simvastatin in Pure and Pharmaceutical Dosage Forms Using Dropping Mercury Electrode

The differential pulse polarographic behavior and determination of simvastatin (SMV) in pure and pharmaceutical dosage forms were investigated on dropping mercury electrode (DME). The method involves the reduction behavior of SMV has been studied in different supporting electrolytes within the pH range 3–9 at DME by differential pulse polarographic analysis (DPPA). The best definition of the analytical signals was found in sodium acetate buffer at pH 7.5 at -1378 to -1384 mV (vs. Ag/AgCl). Under optimized conditions the peak current (Ip) is linear over the range 0.1256- 8.731 µg.mL-1. The DPPA was used successfully for the determination of SMV in pure form. The relative standard deviation did not exceed 4.6% for the concentration of SMV 0.12556 µg.mL-1. Regression analysis showed a good correlation coefficient (R2=0.9997) between Ip and concentration over the mentioned range. The limit of detection (LOD) and the limit of quantification (LOQ) were to be 0.015 µg.mL-1 and 0.045 µg.mL-1, respectively. The proposed method was validated for linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and specificity with average recovery of 99.7-100.7%. The developed method is applicable for the determination of SMV in pure and different dosage forms with assay 99.0-103.0% and the results are in good agreement with those obtained by the HPLC reference method.

Electrochemical Behavior and Differential Pulse Polarographic Determination of Flucloxacillin in Pure and Pharmaceutical Dosage Forms Using Dropping Mercury Electrode

Electrochemical behavior and differential pulse polarographic determination of flucloxacillin (FLUX) in pure and pharmaceutical dosage forms using drop mercury electrode (DME) has been studied. The method involves the electrochemical behavior of flucloxacillin at DME by differential pulse polarographic analysis (DPPA). Various parameters (electrolyte, pulse time, pulse amplitude, etc.) affecting the FLUX determination were examined. Different buffer solutions were used over a wide pH range (2.5–10.0). The best definition of the analytical signals was found in Britton–Robinson buffer (0.04 M) at pH 4.0. Under the optimum conditions, liner calibration graph, Ip=f(CFLUX) was obtained in the concentration ranges of 1x10-7 M (0.0494 µg.mL-1) to 2x10-5 M (9.8780 µg.mL-1), at -975 to -1000 mV (versus Ag/AgCl) with relative standard deviations (RSD) did not exceed 2.1% for the concentrations of FLUX (0.0494 µg.mL-1). Regression analysis showed a good correlation coefficient (R2=9997) between Ip and concentration over the mentioned range. The limit of detection (LOD) and the limit of quantification (LOQ) were to be 0.0034 and 0.0102 µg.mL-1, respectively. The proposed method was validated for linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and specificity. The developed method is applicable for the determination of FLUX in pure and different dosage forms in presence a same amount of amoxicillin (AMOX) with average recovery of 99.8 to 101.2% and the results are in good agreement with those obtained by the HPLC reference method.

DEVELOPMENT AND VALIDATION OF DIFFERENTIAL PULSE POLAROGRAPHIC ANALYSIS OF FENOFIBRATE IN PURE AND PHARMACEUTICAL DOSAGE FORMS USING DROPPING MERCURY ELECTRODE

<p><strong>Objective: </strong>An easy, fast, accurate and sensitive differential pulse polarographic analysis for determination of fenofibrate (FEN) in pure and pharmaceutical dosage forms using dropping mercury electrode (DME) was applied.</p><p><strong>Methods: </strong>The method involves the electrochemical reduction of fenofibrate at DME by differential pulse polarographic analysis (DPPA). Different buffer solutions were used over a wide pH range (1.0–10.0). The best definition of the analytical signals was found in lithium perchlorate trihydrate buffer at pH 6.0 containing 24% (v/v) acetonitrile at-994 to-1025mV (versus Ag/AgCl).</p><p><strong>Results: </strong>Under optimized conditions the peak current (I<sub>p</sub>) is linear over the range 0.0361-3.608 μg/ml. The DPPA was used successfully for the determination of FEN in pure and pharmaceutical dosage forms. The relative standard deviation did not exceed 2.1% for the concentration of FEN 0.0361 μg/ml. Regression analysis showed a good correlation coefficient (R<sup>2</sup>= 0.9994) between Ip and concentration at the mentioned range. The limit of detection (LOD) and the limit of quantification (LOQ) was to be 0.0025 and 0.0076 μg/ml, respectively. The proposed method was validated for linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and specificity with an average recovery of 99.8-100.6%.</p><p><strong>Conclusion: </strong>The developed method is applicable for the determination of FEN in pure and different dosage forms with the assay of marketed formulations 99.8-104.0% and the results are in good agreement with those obtained by square-wave voltammetry (SWV) reference method.</p><p><strong>Keywords: </strong>Differential pulse polarographic analysis, Fenofibrate, Pharmaceutical formulations</p>

Kinetic studies of endosulfan photochemical degradations by ultraviolet light irradiation in aqueous medium

Kinetic studies of endosulfan photochemical degradation in controlled aqueous systems were carried out by ultraviolet light irradiation at λ = 254 nm. The photolysis of (α + β: 2 + 1) endosulfan, α-endosulfan and β-endosulfan were first-order kinetics. The observed rate constants obtained from linear least-squares analysis of the data were 1 × 10−4 s−1; 1 × 10−4 s−1; and 2 × 10−5 s−1, respectively, and the calculated quantum yields (φ) were 1, 1 and 1.6, respectively. Preliminary differential pulse polarographic (DPP) analysis allowed to observe the possible endosulfan photochemical degradation pathway. This degradation route involves the formation of the endosulfan diol, its transformation to endosulfan ether and finally the ether's complete degradation by observing the potential shifts.

Modification of natural, double-helical DNA by antitumor cis- and trans-[Cl 2(Me 2SO 4) 4Ru] in cell-free media

Modifications of natural DNA in cell-free media by the antitumor ruthenium compounds cis- and trans-[Cl 2(Me 2SO 4) 4Ru] were studied by various biochemical and biophysical methods. These methods included: binding studies by means of flameless atomic absorption spectrophotometry, mapping of DNA adducts by means of transcription assay, use of ethidium bromide as a fluorescent probe of DNA adducts of metal complexes, an interstrand cross-linking assay employing gel electrophoresis under denaturing conditions, measurements of DNA unwinding by gel electrophoresis, differential pulse polarographic analysis of DNA conformation, and analysis of liquid crystalline dispersions of DNA by circular dichroism. The results indicated that both ruthenium compounds irreversibly coordinated to DNA; the rate of binding of the cis isomer was considerably lower than that of the trans isomer. The DNA-binding mode of trans-[Cl 2(Me 2SO 4) 4Ru] included formation of bifunctional adducts such as intrastrand cross-links between neighboring purine residues and a small amount (∼1%) of interstrand cross-links. cis-[Cl 2(Me 2SO 4) 4Ru] formed mainly monofunctional lesions on natural DNA. Both ruthenium isomers induced conformational alterations of non-denaturational character in DNA, the trans compound being more effective. In addition, DNA adducts of trans-[Cl 2(Me 2SO 4) 4Ru] were capable of inhibiting RNA synthesis by DNA-dependent RNA polymerases, while the adducts of the cis isomer were not. Thus, several features of the DNA-binding mode of trans-[Cl 2(Me 2SO 4) 4Ru] were similar to those of antitumor cis-diamminedichloroplatinum (II), which may be relevant to the biological effects of this antitumor ruthenium drug. On the other hand, the different DNA-binding mode of cis-[Cl 2(Me 2SO 4) 4Ru] was consistent with its less pronounced biological effects.

Differential Pulse Polarographic Analysis of Lead and Chromium Content in Louisiana Waters

In this investigation, polarographic analyses of water, sediment, and animal samples from Devil's Swamp near Baton Rouge, Louisiana, have been conducted. The focus of this work has been on detection of lead and chromium levels. Lead has been found to be relatively uniformly distributed among the various size fractions of the sediment and is present at a mean level of 18.7 µg g-1. In the water the concentration is about 15 µg L-1 of which 75% is bound in suspended particulates and the remainder is dissolved. Preliminary results indicate that more chromium than lead is present in bone and muscle of bullfrogs, and, for each metal, there is a higher concentration in muscle than bone. The mean lead muscle tissue concentration is 550 µg kg-1, which suggests that bioaccumulation of this metal is occurring, assuming that water contact or ingestion are the main routes of exposure. An important aspect of this research has been optimizing polarographic methodology for performing chromium speciation studies. Methods for determining the amounts of hexavalent and trivalent chromium in mixtures containing the two have been developed.

Differential Pulse Polarographic Determination of Some (5-Nitro-2-Furl)Alkylidene-2-Hydrazinothiazole Derivatives

Abstract The differential pulse polarographic analysis of four (5-nitro-2-furyl)alkylidene-2-hydrazinothiazole derivatives are presented, 0.1 M tetramethylammonium tetrafluoroborate solution was found to be the best supporting electrolyte. At static mercury drop electrode the nitro group of the compounds studied was reduced to the amine in a six-electron process. Linear response was observed over 0.2 to 140 mg.L−1 with a relative standard deviation of 3.3%.

Differential Pulse Polarographic Analysis of Powders and Explosives

AbstractThis investigation demonstrates how mixtures of glycerol trinitrate, diethyleneglycol dinitrate, 2,4‐dinitrotoluene, 2,4,6‐trinitrotoluene, nitroguanidine, dibutyl phthalate, diethyl phthalate, cyclotrimethylene trinitramine (hexogen) and cyclotetramethylene tetranitramine (octogen) in powders and explosives can be analysed by differential pulse polarography. The analysis of, for example, glycerol trinitrate, 2,4‐dinitrotoluene and 2.4,6‐trinitrotoluene in powder is made as a three‐component system with overlapping polarograrns, while the analysis of dibutyl phthalate, nitroguanidine and glycerol trinitrate in powder is made as three independent single component systems.The polarographic reduction of organic compounds is effected both by the composition of the solvent and its pH value. By careful choice of the experimental conditions it is often possible to obtain sufficiently differing forms of differential pulse polarograms for the various compounds, which can be exploited for analytical purposes. Various water! methanol solutions have been studied to find the mixtures that give the greatest differences in the polarograms. The effect of ammonium acetate and tetramethyl ammoniumbromide as electrolyte has been studied.

Differential pulse polarographic analysis of lead nitroresorcinates

Abstract A differential pulse polarographic method for analysing the lead and nitroresorcinate contents of lead-2-mononitroresorcinate, lead-2,4-dinitroresorcinate and lead-2,4,6-trinitroresorcinate-monohydrate is described. The analysis is based on the fact that in the presence of a complexing agent the polarographic reduction of the formed lead complex is displaced toward more negative potentials relative to free lead ions. In the presence of both NTA (nitrilotriacetic acid) and EDTA (ethylenediaminetetraacetic acid) the lead peak is completely separated from the peaks for the nitro-groups in the nitroresorcinates. The method can also be used for a qualitative and quantitative analysis of mixtures of two different lead nitroresorcinates. The lead nitroresorcinates that are difficult to dissolve can be completely dissolved in the presence of both NTA and EDTA.

Polarographic and Colorimetric Methods for Determination of Cyclophosphamide

Polarographic and colorimetric methods for analysis of cyclophosphamide and its dosage forms were investigated. Both methods are based on the reaction of cyclophosphamide with nitrous acid. A single cathodic diffusion-controlled wave was used for dc polarographic determination of cyclophosphamide, with an accuracy of 99.98 +/- 1.09%. The wave was well defined and irreversible. By differential pulse polarographic analysis, as little as 10 ppm cyclophosphamide was determined; overall accuracy at 10-60 ppm was 100.16 +/- 0.99%. The linear relationship between absorbance for the lemon-yellow nitroso derivative and the concentration of cyclophosphamide was further used in colorimetric analysis; overall accuracy was 100.2 +/- 0.99%.

Polarographic Analytical Study of Oxyphenbutazone

The polarographic behaviour of the widely used anti-inflammatory agent, oxyphenbutazone, was studied. It is determined polarographically by conversion to the nitroso derivative characterized by a cathodic, irreversible, diffusion-controlled wave. The method is applied to the determination of 2.5-10 mg/100 mL of oxyphenbutazone, with an accuracy of 99.9 +/- 1.38%. By differential pulse polarographic analysis, as little as 10 ppm oxyphenbutazone can be determined with an accuracy of 99.70 +/- 0.99% in pure powder and in some pharmaceutical formulations.

Differential pulse polarographic determination of murine metallothionein induction kinetics.

Quantitative determination of tissue levels of metallothionein was performed using differential pulse polarographic analysis. Cadmium induction of mouse hepatic metallothionein was observed to be linear with respect to dose until a sharp saturation maximum was reached. This metal-stimulated synthesis was completely inhibited by actinomycin D. It was found that a 2- and 7-fold molar excess of copper and zinc, respectively, was necessary to induce hepatic metallothionein synthesis equivalent to a single dose of cadmium. Although liver was the most dynamic tissue in terms of synthetic production, the intestine had the highest basal level. However, induction in the latter tissue was greatly decreased relative to liver or kidney, with no measurable synthesis after a single metal dose. Induction kinetics was similar for all inducing metals with the exception of cadmium-induced hepatic protein, which remained unchanged for 2 weeks and decayed with an apparent t 1/2 of 32 days. Furthermore, with the exception of intravenous zinc dosing, which elicited no hepatic biosynthesis, initial induction kinetics was invariant with administration route. It was observed that chronic subcutaneous administration of sufficient cadmium to saturate hepatic metallothionein synthesis resulted in a coincident onset of toxic symptoms.

The electrochemical properties of three dipyridinium salts as mediators

The electrochemical properties of three dipyridinium salts were studied in order to assess their behavior for use as mediators in titrations of biological molecules. The compounds studied were 1,1′-trimethylene-2,2′-dipyridinium dibromide, 5,5′-dimethyl-1,1′-trimethylene-2,2′-dipyridinium dibromide and 4,4′-dimethyl-1,1′-trimethylene-2,2′-dipyridinium mide. Differential pulse polarographic analysis showed that each of these compounds undergoes two successive one-electron reductions, and that the formal potentials of these reduction steps are independent of pH. Cyclic voltammetry at the hanging mercury drop electrode (HMDE) indicated that in all cases the first reduction step is reversible. However, the sample potentials measured during controlled potential electrolysis of these compounds were not as negative as theoretically expected, indicating decomposition of the electrolysis products. This study concludes, however, that these mediators can be used in the indirect coulometric titration of large biological redox molecules if there is sufficient separation between the formal potential, E 1 0′, of the mediator and the E 0′ of the biological molecules. This condition prevents the accumulation of the product of the electrode reaction, the cation radical and therefore the decomposition of the mediator.

Differential Pulse Polarographic Analysis of Thyroid Hormone: Determination of Iodine, Thyroxine, and Liothyronine

A differential pulse polarographic method for the analysis of thyroid and thyroid tablets for total iodine, thyroxine, and liothyronine is described. The procedure for iodine, which is also applicable to individual tablet assay, consists of ashing the sample, converting iodide to iodate, and analyzing by differential pulse polarography. The procedure for thyroxine and liothyronine involves hydrolysis of the sample with barium hydroxide and isolation and separation of the iodoamino acids using ion exchangers, followed by differential pulse polarographic determination in a supporting electrolyte composed of 0.5 N Na2C03 in 20% propanol containing 1% tetrabutylammonium bromide. The differential pulse polarographic results for iodine agree with values obtained using the USP XIX procedure, and the quantities of thyroxine and liothyronine found agree with literature values.

Determination of metiamide (SKF 92058) by differential-pulse polarography

Metiamide (SKF 92058) undergoes anodic oxidation at the dropping-mercury electrode with the formation of mercury salt(s). Differential-pulse polarographic analysis has been carried out on several formulations in 0.1 M sodium hydroxide solution as supporting electrolyte using the peak corresponding to this oxidation process. The effects of degradation products and anti-oxidants on this determination have been investigated in addition to comparing the polarographic method with one involving high-performance liquid chromatography.

Collaborative Study of the Differential Pulse Polarographic Analysis of Cacodylate Injections

Abstract Samples containing cacodylate are heated with magnesium nitrate to decompose the cacodylate moiety, releasing pentavalent arsenic. The arsenic is reduced to the polarographically active trivalent state by heating with hydrobromic acid and hydrazine sulfate. Differential pulse polarography is performed in a 1M HQ supporting electrolyte, using a standard addition method for quantitation. The results from 6 collaborators showed an average of 97.00% of declared potency for commercial ampoules, with a relative standard deviation of 2.99%. Two synthetic cacodylic acid solutions prepared to contain 9.01 and 30.02 mg/ml gave averages of 100.03 and 99.38% of amount added, with relative standard deviations of 1.56 and 1.42%, respectively. The method has been adopted as official first action.

Differential Pulse Polarographic Analysis of Adriamycin in Plasma

Abstract A sensitive differential pulse polarographic method is described for the determination of adriamycin in plasma. No sample preparation or manipulation is required; polarograms are recorded after direct introduction of a dropping mercury electrode into a degassed, untreated plasma sample. The method does not distinguish between parent drug and its metabolites. The minimum detectable concentration of adriamycin is 400 ng of drug/ml of plasma. Eleven anti-neoplastic agents, often used therapeutically in combination with adriamycin, were evaluated with respect to their possible interference with this method.

A polarographic and spectral study of some c- and n- nitroso compounds

A wide range of N-nitroso compounds was investigated polarographically and spectrophotometrically. In general, the =N-N0 group is reduced in a 4-electron step in acidic media, which is most suitable for differential pulse polarographic analysis at the trace level. If the groups R and/or R' attached to the nitrosamine group are saturated entities, then the resulting differential pulse polarographic peaks are broad and of little use in the resolution of mixtures. The limit of detection is of the order of 10 -6 M. If R and R' are unsaturated, the polarographic peaks are much sharper, mixtures can be resolved and the limit of detection is of the order of 10 -7 M, C-Nitroso and C-nitro compounds are best determined by differential pulse polarography, because the waves are comparatively large and sharp, and because the reductions occur at relatively positive potentials where co-extractible interferences from foods, etc., will interfere to a minimal degree.

Differential Pulse Polarographic Analysis of Everninomicin Complex in Fermentation Broth

A direct, sensitive, and fast (15 min) method for following the laboratory fermentation course of everninomicins is described. It replaces the 20-hr elapsed-time agar-diffusion bioassay method.