Journal of Pharmaceutical and Biomedical Analysis 70 (2012) 557–562 Contents lists available at SciVerse ScienceDirect Journal of Pharmaceutical and Biomedical Analysis jou rn al h om epage: www.elsevier.com/locate/jpba Short communication A fully validated method for the simultaneous determination of 11 antidepressant drugs in whole blood by gas chromatography–mass spectrometry Ioannis Papoutsis ∗ , Alaa Khraiwesh, Panagiota Nikolaou, Constantinos Pistos, Chara Spiliopoulou, Sotirios Athanaselis Department of Forensic Medicine and Toxicology, School of Medicine, National and Kapodistrian University of Athens, Greece a r t i c l e i n f o Article history: Received 15 February 2012 Received in revised form 3 May 2012 Accepted 6 May 2012 Available online 15 May 2012 Keywords: Antidepressants Gas chromatography Mass spectrometry Whole blood a b s t r a c t Antidepressant drugs are widely used for the treatment of depression and other psychiatric dis- orders and as a result they are involved in numerous clinical and forensic cases. The aim of this study was the development, optimization and validation of a simple, specific and sensitive GC/MS method for the simultaneous determination of 11 antidepressant drugs and 4 of their metabolites (amitriptyline, citalopram, clomipramine, fluoxetine, fluvoxamine, maprotiline, desmethyl-maprotiline, mirtazapine, desmethyl-mirtazapine, nortriptyline, paroxetine, sertraline, desmethyl-sertraline, ven- lafaxine and desmethyl-venlafaxine) in whole blood. The combination of solid-phase extraction with derivatization using heptafluorobutyric anhydride efficiently reduced matrix effect and improved sensi- tivity of the method. In this assay, protriptyline was used as internal standard. Absolute recovery values for all analytes were ranged from 79.2 to 102.6%. LODs and LOQs were found to be between 0.30–1.50 g/L and 1.00–5.00 g/L, respectively. The calibration curves were linear (R 2 ≥ 0.990) within the range of 5.00–1000 g/L for all analytes. Accuracy expressed as the % E r was found to be between -12.3 and 12.2%. Precision expressed as the % RSD was found to be less than 11.7% for all antidepressants. The developed method proved to be suitable for routine work and it was used to successfully analyze more than 2500 clinical and forensic blood samples. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Antidepressant (ATD) drugs are widely used in clinical prac- tice for the treatment of different types of depression and other psychiatric disorders like phobias and anxiety [1–3]. These drugs are frequently prescribed in numerous combinations, leading to more possible drug–drug interactions, while dosage is largely based on trial-and-error [4,5]. Involvement of ATD drugs is common in many forensic cases such as driving under the influence of drugs, cases of violent crime, cases of drug-facilitated sexual assault and other cases of sudden or violent deaths [6,7]. Therapeutic drug monitoring (TDM) of ATDs is of critical importance in situations where patients under treatment do not respond as expected, in cases of drug interactions with co-medication either with inhibitors or inducers of CYP450, non-compliance, and in patients at risk, such as elderly, poor metabolisers or with liver impairment [4]. In such cases, monitoring of ATDs is of a great importance for ∗ Corresponding author at: Department of Forensic Medicine and Toxicology, School of Medicine, National and Kapodistrian University of Athens, 75 Mikras Asias, Athens 115 27, Greece. Tel.: +30 21 0746 2419; fax: +30 21 0771 6098. E-mail address: jopamal@hotmail.com (I. Papoutsis). therapy optimization and dose adjustment, considering also the inter-individual variability of drug metabolism [8]. Several chromatographic methods have been developed for the determination of ATDs in biological fluids separately or with their metabolites [9,10] and in combinations [1–4,6,7,11–15]. All the above assays are mainly based on gas chromatography (GC) [1,4,9,12–15] or liquid chromatography (LC) [2,3,5–7,10,11]. These already published methods are used either for only screening purposes or suffer from disadvantages like that not all common ATDs are included in the same method, too long chromato- graphic runs or low sensitivity. The aim of our study was the development, optimization and validation of a simple, sensi- tive and specific method, based on GC/MS for the simultaneous identification and quantification of the 11 most commonly pre- scribed ATDs and 4 active metabolites of them (amitriptyline, citalopram, clomipramine, fluoxetine, fluvoxamine, maproti- line, desmethyl-maprotiline, mirtazapine, desmethyl-mirtazapine, nortriptyline, paroxetine, sertraline, desmethyl-sertraline, ven- lafaxine and desmethyl-venlafaxine) in whole blood samples, that are normally available in forensic cases. This method was successfully applied in routine framework of our labo- ratory and proved to be useful for the toxicological analysis during the investigation of different clinical and forensic cases. 0731-7085/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jpba.2012.05.007