Voltammetry

Raqi Shubietah's picture

Voltammetric and Spectrophotometric Determination of Nizatidi ne in Pharmaceutical Formulations

Journal Title, Volume, Page: 
Microchimica Acta August 2000, Volume 134, Issue 3-4, pp 153-160
Year of Publication: 
2000
Authors: 
Ali Z. Abu Zuhri
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
Nidal A. Zatar
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
Raqi M. Shubietah
Department of Pharmacy, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
Current Affiliation: 
Department of Pharmacy, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
Hala H. Arafat
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
Preferred Abstract (Original): 

Two methods are described for quantitative determination of nizatidine. The first is a cathodic stripping voltammetric method which is based on the accumulation of the compound at the hanging mercury drop electrode. The adsorptive stripping response was evaluated with respect of accumulation time, potential, concentration, pH and other variables. A linear calibration graph was obtained over the range 3.0×10−8–1.0×10−6 M with a detection limit 3.0×10−8  M after a 20s accumulation time at −0.2 V accumulation potential. On the other hand, it was found that the detection limit could be lowered to 1.0×10−8 M after 180s accumulation time at −0.2 V accumulation potential. The relative standard deviation was in the range 1.2−2.0% for six measurements. The tolerance amounts of the common excipients have also been reported.
The second is a spectrophotometric method which is based on the formation and extraction of the ion-pair complex formed between nizatidine and either bromocresol green or bromothymol blue. The extracted colored ion-pair complexes absorb at 416 nm. The effect of different factors such as: type of organic solvent, pH, reagent concentration, number of extraction times, shaking time, temperature and the tolerance amount of the common excipients have been reported. The calibration graph was linear in the range 6.0×10−7–1.8×10−5 M with a detection limit of 6.0×10−7 M and molar absorptivity of 2.1×104 lċmol−1ċcm−1 when using bromocresol green, while the calibration graph was linear in the range 3.0×10−7–1.1×10−5 M with a detection limit of 3.0×10−7 M and molar absorptivity of 3.2×104 lċmol−1ċcm−1 when using bromothymol blue. The spectrophotometric methods offer alternative methods with reasonable sensitivity, selectivity and accuracy with relative standard deviation in the range 2.1−6.0% and 1.2−4.7% (for six measurements) when using bromothymol blue and bromocresol green, respectively. The proposed two methods were applied for the determination of nizatidine in commercially available dosage forms. A comparison between the voltammetric and the extraction-spectrophotometric methods was also reported.

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