Journal of Pharmaceutical and Biomedical Analysis 44 (2007) 594–601 A simple and reliable procedure for the determination of psychoactive drugs in oral fluid by gas chromatography–mass spectrometry Mitona Pujadas a,1 , Simona Pichini b , Ester Civit a,1 , Elena Santamari ˜ na c,1 , Katherine Perez c,1 , Rafael de la Torre a,d,∗,1 a Grup de Recerca Cl´ ınica en Farmacologia Humana i Neurociencies, Unitat de Farmacologia, Institut Municipal d’Investigaci´ o M` edica, Dr. Aiguader 88, 08003 Barcelona, Spain b Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanit` a, V.le Regina Elena 299, 00161 Rome, Italy c Agencia de Salut Publica de Barcelona, Barcelona, Spain d Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain Received 7 November 2006; received in revised form 14 February 2007; accepted 15 February 2007 Available online 23 February 2007 Abstract A simple and reliable gas chromatography–mass spectrometry method for identifying and quantifying psychoactive drugs in oral fluid is described. Substances under investigation were: psychostimulant drugs (amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4- methylenedioxiamphetamine, 3,4-methylenedioxy-N-ethylamphetamine, phentermine), cocaine and metabolites (benzoylecgonine, cocaethylene, and ecgonine methyl esther), cannabinoids (delta-9-tetrahydrocannabinol, 11-nor-9-carboxy-delta-9-tetrahydrocannabinol, 11-hydroxy-delta-9- tetrahydrocannabinol, cannabinol and cannabidiol), opiates (6-monoacetylmorphine, morphine and codeine), hypnotics (flurazepam, flunitrazepam, dipotassium chlorazepate, alprazolam, diazepam and oxazepam), antidepressant drugs (amitryptiline, paroxetine and sertraline), antipsychotic drugs (haloperidol, chlorpromazine and fluphenazine) chlormethiazole, loratidine, hydroxyzine, diphenhydramine, valproic acid and gabapentin. After the addition of deuterated analogues of morphine, 3,4-methylenedioxymethamphetamine, (±)-11-nor-9-carboxy-delta-9-tetrahydrocannabinol and clonazepam as internal standards, all the compounds were simultaneously extracted from oral fluid by solid-phase extraction procedure. Acid compounds were eluted with acetone while basic and neutral compounds with dichloromethane:isopropanol:ammonium (80:20:2, v/v/v). Chro- matography was performed on a methylsilicone capillary column and analytes, derivatized with N-Methyl-N-(trimethylsilyl)trifluoroacetamide, were determined in the selected-ion-monitoring (SIM) mode. Mean recovery ranged between 44.5 and 97.7 % and quantification limit between 0.9 and 44.2 ng/ml oral fluid for the different analytes. The developed analytical methodology was applied to investigate the presence of psychoactive drugs in oral fluid from injured individuals attending the emergency room (MACIUS project). © 2007 Elsevier B.V. All rights reserved. Keywords: Psychoactive drugs; Oral fluid; Gas chromatography–mass spectrometry 1. Introduction Biological matrices alternative to urine and plasma have recently been introduced for assessing drug exposure [1]. Oral ∗ Corresponding author at: Grup de Recerca Cl´ ınica en Farmacologia Humana i Neurociencies, Unitat de Farmacologia, Institut Municipal d’Investigaci´ o M` edica, Dr. Aiguader 88, 08003 Barcelona, Spain. Tel.: +34 93 3161484; fax: +34 93 3160410. E-mail address: rtorre@imim.es (R. de la Torre). 1 Investigators of the MACIUS Project. fluid (saliva), sweat and hair are alternative biologic matrices, which have been extensively and successfully used to assess recent and past and/or acute and chronic exposure to drugs of abuse. Oral fluid is the only fluid that has been successfully used as an alternative to blood in several pharmacokinetic and phar- macotoxicologic studies including drugs of abuse [2–4] and there is evidence that when a given drug is dectected in oral fluid specimens, there is a high likelihood for a subject being under the pharmacologic effects of the drug [5]. In addi- tion, there are a number of reports suggesting that oral fluid 0731-7085/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jpba.2007.02.022