Drugs in oral fluid Part I. Validation of an analytical procedure for licit and illicit drugs in oral fluid.

A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu.

Drugs in oral fluid Part II. Investigation of drugs in drivers.

As part of the European project, Impaired Motorists, Methods of Roadside Testing and Assessment for Licensing, otherwise known as IMMORTAL (Deliverable R4.2), the University of Glasgow was required to analyse 1396 oral fluid samples, collected from drivers, for a wide range of drugs. A previously described method to include 49 drugs and metabolites was used. To include cannabis in the study a separate extraction method was required because of interferences caused by the collection device. The study group included drivers who were stopped at random and participation was entirely voluntary. The results showed that out of the 1396 samples tested, 16.8% were positive for at least one drug. In the majority of positive cases (85%), monodrug use was found and the most commonly detected drug was 3,4-methylenedioxymethamphetamine. This study showed that a significant number of the driving population are positive for at least one drug.