title: Electrochemical determination of minoxidil in different pharmaceutical formulations by flow injection analysis.
abstract: The electrochemical behavior and amperometric-FIA quantification of minoxidil at a glassy carbon electrode is described. The procedure is based on electrochemical oxidation at 0.800 V (vs. Ag/AgCl/NaCl(3 M) in a phosphate buffer solution. Minoxidil was determined over the range 1 x 10(-7) - 1 x 10(-4) M. Different analytical parameters and electrode stability were analyzed to obtain the best electrode performance. The optimal conditions were: working potentials, 0.800 V; flow rate, 0.74 mL min(-1); and solution pH 7.0. This system allowed a sampling rate of 120 samples per hour without any pretreatment. The proposed method was used for minoxidil quantification in pharmaceutical preparations with satisfactory results. The accuracy of FIA-amperometric method was established by a comparison with the conventional UV determination technique using a paired t-test indicating the absence of systematic errors.
authors.affiliation: INFIQC, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Valeria
authors.initials: V
authors.lastname: Pfaffen
authors.forename: Patricia I
authors.initials: PI
authors.lastname: Ortiz
mesh_terms: D004563:Electrochemistry / Q000379:methods; D017022:Flow Injection Analysis / Q000379:methods; D008914:Minoxidil / Q000032:analysis*; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D004364:Pharmaceutical Preparations; D008914:Minoxidil