title: A fully validated method for the determination of vardenafil in blood using gas chromatography/mass spectrometry.
abstract: Vardenafil (VDN) is one of the three commercially available phosphodiesterase type 5 inhibitors and it is mainly used in the treatment of erectile dysfunction. A sensitive and specific gas chromatography/mass spectrometry (GC/MS) method for the determination of VDN in blood has been developed and validated. Sample preparation included solid-phase extraction and derivatization with N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide (MTBSTFA) and 1% tert-butyldimethylsilylchloride (TBDMSCl). Protriptyline was used as the internal standard for this assay. Limits of detection and quantification for VDN were 0.70 and 2.00 µg/l, respectively. The calibration curves were linear within the dynamic range 2.00-200.0 µg/l with a correlation coefficient higher than 0.991. Absolute recovery ranged from 88.6% to 95.7% for the analyte of interest at three quality control levels. Intra- and inter-day accuracy was found to be between - 6.1% to 10.8% and - 9.3% to 11.6%, respectively, whereas intra- and inter-day precision was < 7.8% and 9.7%, correspondingly. The proposed method is the first fully validated GC/MS method for the determination of VDN in blood samples and it can be used in routine every day analysis by clinical and forensic laboratories for pharmacokinetic studies, for therapeutic drug level monitoring or for the investigation of related forensic cases. A few blood samples analyzed using the developed method is reported herein to demonstrate the suitability of the method.
authors.affiliation: Department of Forensic Medicine and Toxicology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Papoutsis
authors.forename: Panagiota
authors.initials: P
authors.lastname: Nikolaou
authors.forename: Sotirios
authors.initials: S
authors.lastname: Athanaselis
authors.forename: Constantinos
authors.initials: C
authors.lastname: Pistos
authors.forename: Constantinos
authors.initials: C
authors.lastname: Maravelias
authors.forename: Chara
authors.initials: C
authors.lastname: Spiliopoulou
mesh_terms: D016903:Drug Monitoring / Q000379:methods; D004355:Drug Stability; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007093:Imidazoles / Q000097:blood*; D016014:Linear Models; D058986:Phosphodiesterase 5 Inhibitors / Q000097:blood; D010879:Piperazines / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013450:Sulfones / Q000097:blood; D014227:Triazines / Q000097:blood; D000069058:Vardenafil Dihydrochloride
chemical_list: D007093:Imidazoles; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride