ELECTROCHEMICAL AND DENSITOMETRIC DETERMINATION OF ZOLMITRIPTAN IN PHARMACEUTICAL DOSAGE FORMS

Document Type : Original Article

Authors

National Organization for Drug Control and Research

Abstract

Two methods for the determination of antimigrain drug zolmitriptan in bulk powder and in pharmaceutical dosage forms by voltammetric and densitometric methods are developed. Voltammetric method depends on the oxidation of zolmitriptan on an activated carbon paste electrode. The compound is oxidized irreversibly at high positive potential. The response was evaluated with respect to pH; scan rate, nature of the buffer and other variables. The peak current at about 0.76V, with the maximum current at pH 5 ±0.2 acetate buffer. The mechanism of the reaction is controlled by oxidation of the N-H group in the indole ring. By differential pulse voltammetry, the calibration plot was linear in the range 3.99 x10-7 – 2.90 x10-6 M.
The second method is based on the application of thin layer chromatographic separation of the studied drug in the presence of its degradation product followed by the densitometric measurements of the spot areas of the drug. After separation on silica gel GF254 plates using methanol: ammonia 25% (100:1.5 v/v) as mobile phase, the chromatographic zones corresponding to the spots of zolmitriptan were scanned at 285nm. The calibration function was established in the range of 1.00- 9.00 µg/ spot. The suggested methods were used to determine the cited drug in bulk powder, and pharmaceutical dosage forms. Results were compared statistically with the reported method.

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