title: Development and validation of a GC/MS method for the determination of tadalafil in whole blood.
abstract: Tadalafil is a phosphodiesterase type 5 (PDE-5) inhibitor and it is used in the treatment of pulmonary arterial hypertension and erectile dysfunction. A sensitive and specific method is described for the determination of tadalafil in whole blood. Tadalafil and its internal standard (protriptyline) were isolated from the matrix by solid phase extraction, and were analyzed by gas chromatography/mass spectrometry (GC/MS) after derivatization by N,O-bis(trimethylsilyl)-trifluoracetamide (BSTFA) with 1% trimethylchlorsilane (TMCS). Limits of detection and quantification for tadalafil were 0.70 and 2.00 μg/L, respectively. The calibration curve was linear between 2.00 and 500.0 μg/L, with a correlation coefficient higher than 0.991. The values obtained for intra- and inter-day accuracy was found to be between -10.5 to 8.5% and -4.2 to 4.5%, respectively, while intra- and inter-day precision were less than 8.4 and 11.2%, correspondingly. Absolute recovery was determined at three concentration levels and ranged from 92.1 to 98.9%. The proposed method is the first fully validated GC/MS method for the determination of tadalafil in whole blood and it can be routinely applied by toxicological laboratories, for pharmacokinetic studies, for therapeutic drug level monitoring or for the investigation of related forensic cases.
authors: Department of Forensic Medicine and Toxicology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias, Athens 115 27, Greece. pan_nik@hotmail.com
authors: Panagiota
authors: P
authors: Nikolaou
authors: Ioannis
authors: I
authors: Papoutsis
authors: Sotirios
authors: S
authors: Athanaselis
authors: Giorgos
authors: G
authors: Alevisopoulos
authors: Alaa
authors: A
authors: Khraiwesh
authors: Constantinos
authors: C
authors: Pistos
authors: Chara
authors: C
authors: Spiliopoulou
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D002138:Calibration; D002243:Carbolines / Q000097:blood*; D016903:Drug Monitoring / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D058986:Phosphodiesterase 5 Inhibitors / Q000097:blood; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods; D000068581:Tadalafil
chemical_list: D002243:Carbolines; D058986:Phosphodiesterase 5 Inhibitors; D000068581:Tadalafil