Micellar electrokinetic capillary chromatography for the determination of Viagra and its metabolite (UK-103,320) in human serum

• Published in: Electrophoresis Vol. 22; no. 10; pp. 2004 - 2009
• Main Authors: Nevado, Juan J. Berzas, Flores, Juana Rodríguez, Peñalvo, Gregorio Castañeda, Fariñas, Nuria Rodríguez
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.06.2001
• Subjects: Electrophoresis, Capillary - methods; Electrophoresis, Capillary - statistics & numerical data; Human serum; Humans; Male; Micellar electrokinetic capillary chromatography; Micelles; Osmolar Concentration; Phosphodiesterase Inhibitors - blood; Phosphodiesterase Inhibitors - metabolism; Piperazines - blood; Piperazines - metabolism; Purines; Pyrimidinones - blood; Pyrimidinones - metabolism; Sildenafil Citrate; Sildenafil citrate (Viagra); Sildenafil metabolite (UK-103; Sildenafil metabolite (UK‐103,320); Sodium Dodecyl Sulfate; Sulfones; Temperature
• ISSN: 0173-0835; 1522-2683
• DOI: 10.1002/1522-2683(200106)22:10<2004::AID-ELPS2004>3.0.CO;2-W

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.