title: Liquid chromatography/tandem mass spectrometry method for the simultaneous determination of vardenafil and its major metabolite, N-desethylvardenafil, in human plasma: application to a pharmacokinetic study.
abstract: A rapid and sensitive LC-MS/MS method for the determination of vardenafil and its major metabolite, N-desethylvardenafil, in human plasma using sildenafil as an internal standard was developed and validated. The analytes were extracted from 0.25-mL aliquots of human plasma by liquid-liquid extraction, using 1 mL of ethyl acetate. Chromatographic separation was carried on a Luna C(18) column (50 mm x 2.0 mm, 3 microm) at 40 degrees C, with an isocratic mobile phase consisting of 10 mM ammonium acetate (pH 5.0) and acetonitrile (10:90, v/v), a flow rate of 0.2 mL/min, and a total run time of 2 min. Detection and quantification were performed using a mass spectrometer in the selected reaction-monitoring mode with positive electrospray ionization at m/z 489.1-->151.2 for vardenafil, m/z 460.9-->151.2 for N-desethylvardenafil, and m/z 475.3-->100.1 for the internal standard (IS), respectively. This assay was linear over a concentration range of 0.5-200 ng/mL with a lower limit of quantification of 0.5 ng/mL for both vardenafil and N-desethylvardenafil. The coefficient of variation for the assay precision was <13.6%, and the accuracy was >93.1%. This method was successfully applied to a pharmacokinetic study after oral administration of vardenafil 20mg tablet in Korean healthy male volunteers.
authors.affiliation: Department of Pharmacology, Inje University College of Medicine, Jin-Gu, Busan, South Korea.
authors.forename: Hei-Young
authors.initials: HY
authors.lastname: Ku
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Shon
authors.forename: Kwang-Hyeon
authors.initials: KH
authors.lastname: Liu
authors.forename: Jae-Gook
authors.initials: JG
authors.lastname: Shin
authors.forename: Soo Kyung
authors.initials: SK
authors.lastname: Bae
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D007093:Imidazoles / Q000097:blood* / Q000493:pharmacokinetics; D010726:Phosphodiesterase Inhibitors / Q000097:blood* / Q000493:pharmacokinetics; D010879:Piperazines / Q000097:blood* / Q000493:pharmacokinetics; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013450:Sulfones / Q000097:blood / Q000493:pharmacokinetics; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014227:Triazines / Q000097:blood / Q000493:pharmacokinetics; D000069058:Vardenafil Dihydrochloride
chemical_list: D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; C539021:N-desethylvardenafil