title: Cathodic adsorptive stripping square-wave voltammetric determination of nifedipine drug in bulk, pharmaceutical formulation and human serum.
abstract: Nifedipine is a calcium-channel antagonist drug used in the management of angina pectoris and hypertension through inhibition of calcium influx. A fully validated sensitive cathodic adsorptive stripping square-wave voltammetry procedure was optimized for the determination of the drug at trace levels. The procedure was based on the reduction of the nitrophenyl group after the interfacial accumulation of the drug onto a hanging mercury drop electrode in Britton-Robinson buffer of pH 11.0. The optimal conditions of the procedure were found to be: accumulation potential=-0.9 V vs. Ag/AgCl/KCl(s)), accumulation time=30 s, scan increment=10 mV, pulse amplitude=50 mV and frequency=120 Hz. Under these conditions, a well-defined peak was obtained; its peak current showed a linear dependence on drug concentration in the range of 2x10(-9)-2x10(-7) mol L(-1) bulk nifedipine. The mean recoveries based on eight replicate measurements for 1x10(-8) and 5x10(-8) mol L(-1) bulk nifedipine solutions were 98.46+/-0.86% and 98.23+/-0.92%, respectively. A detection limit of 3.42x10(-10) mol L(-1) bulk nifedipine was achieved. The procedure was successfully applied for assay of the drug in tablets and spiked human serum with mean recoveries of 101.95+/-1.42% and 98.70+/-0.63%, respectively. The limit of detection of the drug in spiked human serum was found to be 3.90x10(-10) mol L(-1).
authors.affiliation: Department of Chemistry, Faculty of Science, Tanta University, Egypt. mmghoneim@usa.net
authors.forename: M M
authors.initials: MM
authors.lastname: Ghoneim
authors.forename: A
authors.initials: A
authors.lastname: Tawfik
authors.forename: P Y
authors.initials: PY
authors.lastname: Khashaba
mesh_terms: D002121:Calcium Channel Blockers / Q000032:analysis* / Q000097:blood; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D006801:Humans; D009543:Nifedipine / Q000032:analysis* / Q000097:blood; D010084:Oxidation-Reduction; D004364:Pharmaceutical Preparations / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013607:Tablets / Q000032:analysis
chemical_list: D002121:Calcium Channel Blockers; D004364:Pharmaceutical Preparations; D013607:Tablets; D009543:Nifedipine