title: Adsorptive cathodic stripping voltammetric determination of dexamethasone in formulations and biological fluids.
abstract: The electrochemical behavior of dexamethasone at a hanging mercury drop electrode (HMDE) in a universal buffer series of pH 2-10 was studied using cyclic voltammetry. Based on the interfacial adsorptive character of dexamethasone onto the HMDE (electrode surface coverage = 1.4 x 10(-10) mol/cm2), a fully validated simple square-wave adsorptive cathodic stripping voltammetric method is described for its determination in bulk form with a limit of detection (LOD) of 3.1 x 10(-9) M. The described method was successfully applied to analysis of dexamethasone in its pharmaceutical formulations (deltasone tablets and fortecortin ampule) and in spiked samples of human urine, bovine urine, and protein-free bovine milk. The achieved LODs of dexamethasone in human urine, bovine urine, and protein-free bovine milk were 1.5 x 10(-8), 2 x 10(-8), and 9 x 10(-9) M, respectively. The mean percentage recoveries of 4 x 10(-7) M dexamethasone in bulk form, spiked human urine, bovine urine, and bovine milk, based on the average of 3 replicate measurements, were 99.8 +/- 0.25, 100.4 +/- 0.96, 99.6 +/- 0.79, and 100.1 +/- 0.26, respectively.
authors.affiliation: Tanta University, Faculty of Science, Chemistry Department, Analytical and Electrochemistry Research Unit, 31527-Tanta, Egypt. enassmmghoneim@hotmail.com
authors.forename: Enass M
authors.initials: EM
authors.lastname: Ghoneim
authors.forename: Mona A
authors.initials: MA
authors.lastname: El-Attar
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Ghoneim
mesh_terms: D000327:Adsorption; D000818:Animals; D001826:Body Fluids / Q000737:chemistry; D002417:Cattle; D002626:Chemistry, Pharmaceutical; D003907:Dexamethasone / Q000032:analysis* / Q000652:urine; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D005504:Food Analysis / Q000379:methods; D005506:Food Contamination / Q000032:analysis; D006801:Humans; D008892:Milk / Q000737:chemistry
chemical_list: D003907:Dexamethasone