Anodic voltammetry of zolmitriptan at boron-doped diamond electrode and its analytical applications.
ABSTRACT The electrooxidative behavior and determination of zolmitriptan at a boron-doped diamond electrode were investigated using cyclic, linear sweep, differential pulse and square wave voltammetric techniques. Zolmitriptan undergoes irreversible oxidation at a peak potential of about +0.9 V (vs Ag/AgCl/3 M KCl). DPV and SWV techniques are proposed for the determination of zolmitriptan in phosphate buffer at pH 3.03, which allows quantitation over the two different ranges (8 x 10(-7) - 8 x 10(-6) M and 1 x 10(-5) - 1 x 10(-4) M) in supporting electrolyte for both methods. A linear response was obtained in phosphate buffer over two different ranges (6 x 10(-7) - 8 x 10(-6) M and 1 x 10(-5) - 1 x 10(-4) M) for spiked serum samples at pH 3.03 for both techniques. The repeatability and reproducibility of the methods for all media were determined. The standard addition method was used in serum. Precision and accuracy were also checked in all media. No electroactive interferences from the excipients and endegenous substances were found in the pharmaceutical dosage form and the biological sample, respectively.
- SourceAvailable from: Mostafa Shehata[Show abstract] [Hide abstract]
ABSTRACT: This work describes a simple and sensitive method for simultaneous determination of zolmitriptan, naproxen and propranolol in their dosage forms using HPLC. The drugs were separated isocratically on a Zorbax C8 (4.6 × 250 mm with 5 µm particle size) column using a mobile phase composed of 20 mM phosphate citrate buffer [0.1% TEA (pH 3.1)]:methanol:THF (5:3:2, by volumes). The detection was accomplished fluorometrically setting the excitation wavelength at 280 nm and emission wavelength at 360 nm. The method was validated over a linearity range of 100-900 ng/mL for zolmitriptan, 50-300 ng/mL for naproxen and 100-800 ng/mL for propranolol. The assay was successfully applied to the determination of the studied drugs in pharmaceutical dosage forms without interference from tablet excipients with high specificity. The method can be applied successfully in the future for the pharmacokinetic study of these drugs in the human plasma with high accuracy especially that LOQs of zolmitriptan and propranolol in the proposed method cover their Cmax.Journal of chromatographic science 07/2013; · 0.79 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Accurate, sensitive, and precise high performance thin layer chromatographic (HPTLC) methods were developed and validated for the determination of sumatriptan and zolmitriptan in presence of their degradation products. Sumatriptan was separated from its degradation products and analyzed on TLC silica gel 60 F254 plates using chloroform–ethyl acetate–methanol–ammonia (4:3:3:0.1, v/v) as a developing system followed by densitometric measurement of the bands at 228 nm. Zolmitriptan was determined using chloroform–ethyl acetate–methanol–ammonia (3:3:3:1, v/v) as a developing system followed by densitometric measurement at 222 nm. The methods were validated over a range of 0.5–4 μg/spot for sumatriptan and 0.5–3 μg/spot for zolmitriptan. The proposed methods were successfully applied for the determination of the studied drugs in bulk powder and in their pharmaceutical formulations.Chromatographia 01/2013; 76:187-194. · 1.44 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: A sensitive electroanalytical method for the determination of anticancer drug etoposide (ETP) using adsorptive stripping differential pulse voltammetry (AdSDPV) at a multi-walled carbon nanotube-modified glassy carbon electrode (MWCNT-modified GCE) is presented. The surface morphology of modified electrode was characterized by scanning electron microscopy. The effects of accumulation time and potential, pH, scan rate, and amount of MWCNT suspension were investigated. The calibration curve was linear in the concentration range of 2.0 × 10−8–2.0 × 10−6 M with the detection limit of 5.4 × 10−9 M. The reproducibility of the peak current was found at 1.55 % (n = 5) RSD value in pH 6.0 Britton–Robinson buffer for the MWCNT-modified GCE. The method was then successfully utilized for the determination of ETP in pharmaceutical dosage form, and a recovery of 99.55 % was obtained. The possible oxidation mechanism of ETP was also discussed. The proposed electroanalytical method using MWCNT-modified GCE is the most sensitive method for the determination of ETP with lowest limit of detection in the previously published electrochemical methods.Journal of Solid State Electrochemistry 11/2013; · 2.28 Impact Factor