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At least 181 records · Page 10Linked to original sources
PubMed1992

Analysis of drugs by polarography, XXXV: The polarographic behaviour of cinolazepam[1-(2-cyanoethyl)-7-chloro-3-hydroxy-5-(2-fluorophe n yl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one] and assay of its tablets.

Cinolazepam is reduced at the Dropping Mercury Electrode (DME) over the entire pH range in Britton Robinson buffers (BRB) containing 20% DMF as a solubilizer. A well-defined cathodic wave is obtained over the pH range 3-5, which is very suitable for analytical purposes. The wave was characterized as being irreversible, diffusion-controlled and free from adsorption phenomena. In acid buffers, 4 electrons are consumed in the reduction process, while in alkaline buffers the electrode reaction is somewhat complicated. Tablets containing 40 mg cinolazepam were analysed using the polarographic and a developed HPLC method. The results obtained with both methods are in good accordance as revealed by statistical analysis. The details of the complicated mechanism of the reduction process at the DME are still under investigation but elucidated in principle.

Anti-Anxiety Agents↗
PubMed1976

Determination of tinidazole in tablets by dc polarography.

A polarographic method was developed for determining tinidazole in tablets. The substance is extracted from the sample with water, pH 6.8 Britton-Robinson buffer is added to an aliquot, and the solution is polarographed at the dropping mercury electrode versus the saturated calomel electrode. The polarographic wave is well developed and enables a fairly precise quantitative determination. The method of standard addition is used.

Hydrogen-Ion Concentration↗
PubMed1978

Effect of amitriptyline on polarography of chlordiazepoxide.

With increasing amounts of electroinactive amitriptyline, each of the three chlordiazepoxide reduction waves shifted to more cathodic half-wave potentials and decreased in limiting current. The shift was most pronounced up the 1:1 mole ratio but continued up to ratios of 200:1. This behavior was observed in several supporting electrolytes and was not due to change in pH since this factor was maintained constant as the amitriptyline concentration was increased. Shifts in E1/2 and reductions in limiting current may arise in several ways, such as complex formation between the two drugs or adsorption of the amitriptyline onto the surface of the dropping mercury electrode hindering chlordiazepoxide reduction. Most data point to adsorption as the cause.

Amitriptyline↗
PubMed1978

Determination of flucytosine in tablets by differential pulse polarography.

A differential pulse polarographic assay was developed for determining flucytosine in tablets. The drug is extracted from the sample with water and hydrochloric acid and, after the pH is adjusted, an aliquot is added to the cell and the solution is polarographed at the dropping mercury electrode versus the saturated calomel electrode with 0.066 M Sørensen phosphate buffer (pH 5.6) as the supporting electrolyte. The polarographic peak height enables precise quantitative determination. The Ep value for flucytosine is--1.54 v versus the saturated calomel electrode. The mean recovery of the drug is 101.5% +/- 1.9 (SD). The method is simple, rapid, and precise.

Cytosine↗
PubMed1979

Differential pulse polarography of tetracycline: determination of complexing tendencies of tetracycline analogs in the presence of cations.

The complexation tendencies, stoichiometries, and stability constants for tetracycline, minocycline, and demeclocycline with the metallic ions calcium(II), magnesium (II), zinc(II), aluminum(III), iron(II), and iron (III) were evaluated using a polarographic technique. Changes in pulse peak heights for each tetracycline deravative were measured as a function of cation concentration. The method provides an in vitro method of evaluating the selectivity of particular metal ions for different tetracycline analogs.

Aluminum↗
PubMed1988

Determination of tetracycline hydrochloride in presence of anhydrotetracycline by differential pulse polarography.

A differential pulse polarographic method is described for the determination of the antibiotic tetracycline HCl in the presence of its degradation product anhydrotetracycline. The method utilizes the large difference in their differential pulse polarograms at a peak potential of -1.39 V in 0.1 M phosphate buffer as the base electrolyte (pH 6.8). The assay was evaluated using synthetic mixtures and applied to the analysis of commercial tetracycline HCl samples. The results obtained with this method are in close agreement with those from the spectrophotometric absorbance ratio method.

Polarography↗