title: Micellar electrokinetic capillary chromatography for the determination of Viagra and its metabolite (UK-103,320) in human serum.
abstract: Micellar electrokinetic capillary chromatography (MEKC) was investigated for the determination of Viagra (sildenafil citrate, SC) and its metabolite (UK-103,320) in human serum in a concentration range of clinical interest. For MEKC, human serum samples spiked with SC and UK were obtained directly after elution with methanol from a tC18 cartridge. The extract was evaporated and regenerated in a solution 1 mM of phosphate buffer (pH 12.3) which contained a methanol percentage of 20% that was analyzed using phosphate buffer (pH 12.3, 10 mM) containing 30 mM sodium dodecyl sulfate (SDS) as separation electrolyte and a fused-silica capillary. This method gave satisfactory interday precision with respect to migration times relative standard deviation (RSD < 1%) and linear responses for the concentration ranges investigated (0.50-3.50 mg L(-1) for the compound SC and 0.90-4.60 mg L(-1) for UK). An intraday RSD (n = 5 graphs) between the slopes of the calibration graphs was acceptable (6.40%) for SC and (3.37%) for UK. A satisfactory interday precision between slopes was also obtained (RSD 4.10% for SC and a RSD 2.72% for UK) which demonstrated the ruggedness of this method. Detection limits (S/N = 3) were about 200 ng/mL for both compounds in human serum. MEKC was shown as a good method with regards to simplicity, precision and sensitivity.
authors.affiliation: Departamento de Química Analítica y Tecnología de Alimentos, Facultad de Químicas, Universidad de Castilla-La Mancha, Ciudad Real, Spain. jjberzas@qata-cr.UCLM.es
authors.forename: J J
authors.initials: JJ
authors.lastname: Berzas Nevado
authors.forename: J
authors.initials: J
authors.lastname: Rodríguez Flores
authors.forename: G
authors.initials: G
authors.lastname: Castañeda Peñalvo
authors.forename: N
authors.initials: N
authors.lastname: Rodríguez Fariñas
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008823:Micelles; D009994:Osmolar Concentration; D010726:Phosphodiesterase Inhibitors / Q000097:blood / Q000378:metabolism; D010879:Piperazines / Q000097:blood* / Q000378:metabolism; D011687:Purines; D011744:Pyrimidinones / Q000097:blood* / Q000378:metabolism; D000068677:Sildenafil Citrate; D012967:Sodium Dodecyl Sulfate; D013450:Sulfones; D013696:Temperature
chemical_list: D008823:Micelles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D011744:Pyrimidinones; D013450:Sulfones; C109995:UK 103320; D012967:Sodium Dodecyl Sulfate; D000068677:Sildenafil Citrate