title: Validated LC-MS/MS assay for the quantitative determination of vardenafil in human plasma and its application to a pharmacokinetic study.
abstract: A sensitive high-performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) assay has been developed for the quantitative analysis of vardenafil in human plasma. Vardenafil and the internal standard, alprazolam, were extracted from 0.2 mL aliquots of alkalinized plasma by a single solvent extraction into hexane : dichloromethane. Reversed-phase chromatographic separation was affected by gradient elution with mobile phases consisting of 10 mM ammonium formate pH 7.0 (solvent A) and methanol (100%, solvent B), delivered at a flow rate of 0.4 mL/min. The analytes were detected by using an electrospray ion source on a 4000 QTrap triple quadrupole mass spectrometer operating in positive ionization mode. The mass transitions were m/z 489.3 --> 312.2 for vardenafil and m/z 309.2 --> 281.0 for alprazolam. The assay was linear over the concentration range of 0.2-100 ng/mL, with correlation coefficients > or = 0.995. The intra- and inter-day precision was less than 5.4% in terms of relative standard deviation and the accuracy was within 12.7% in terms of relative error. The lower limit of quantitation was set at 0.2 ng/mL. The high sensitivity and acceptable performance of the assay allowed its application to the analysis of plasma samples obtained following the oral administration of vardenafil to healthy male volunteers in a pharmacokinetic study.
authors.affiliation: Centre for Integrated Preclinical Drug Development, University of Queensland, Level 7, Block 6, Royal Brisbane and Women's Hospital, Herston Rd, Brisbane, Qld 4029, Australia.
authors.forename: Simon T
authors.initials: ST
authors.lastname: Lake
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Altman
authors.forename: Jack
authors.initials: J
authors.lastname: Vaisman
authors.forename: Russell S
authors.initials: RS
authors.lastname: Addison
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D010879:Piperazines / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D013450:Sulfones / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014227:Triazines / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D000069058:Vardenafil Dihydrochloride
chemical_list: D007093:Imidazoles; D010879:Piperazines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride