A team of scientists from the Institute of Legal Medicine at the University of Santiago de Compostela (USC) has developed a technique for detecting the presence of 23 illicit drugs and medicines in saliva samples. The method, published in the journal Analytical and Bioanalytical Chemistry, is already being used by the DGT in Spain, as part of a European study on the frequency of alcohol and drug consumption amongst drivers.
"The saliva samples are collected by putting some cotton on the end of a special device placed under the tongue as if it were a lollipop, with an indicator that turns blue when there is a sufficient sample (0.5 millilitres)", so SINC was informed by Manuel López Rivadulla, one of the creators of the technique and researcher from the Institute of Legal Medicine at the USC. Each piece of cotton is then placed in a tube and labelled for analysis.
Rivadulla commented that when it is the traffic police who take samples from drivers, the tubes are placed in specially prepared containers and transported refrigerated to the laboratory. The saliva is therefore processed and analysed using two combined systems: liquid chromatography (LC), by means of which the molecules searched for are separated, and tandem mass spectrometry (MS/MS), which enables the "unmistakable" identification of the different chemical compounds.
This new method, which has been published in the journal Analytical and Bioanalytical Chemistry makes it possible to determine up to 23 substances in saliva at the same time, both illicit drugs (such as cocaine, cannabis and amphetamines) and medicinal drugs (morphine, methadone, codeine and diazepam).
The research group pointed out that drug and medicine detection in oral fluids is a non-intrusive technique, in contrast to blood or urine analyses. The individual can also be observed directly while taking the samples.
More than 3,000 drivers will be controlled
Rivadulla has informed SINC that this method is already being used for analysing saliva as part of a Directorate General of Traffic (DGT) study on the number of drivers that drive under the effects of psychoactive substances.
According to Juan Carlos González Luque, medical adviser at the DGT's National Observatory for Road Safety, the aim of the study is to determine the prevalence of the consumption of alcohol, other drugs and medicines amongst Spanish drivers. "Two samples will be taken during the controls: one will be analysed in situ, using rapid antigen-antibody immunological techniques, and another sent to the USC's laboratory in Galicia", he explained.
The taking of saliva samples began in September 2008 at 32 points around Spain (except the Canary Islands, Ceuta and Melilla). Those responsible for this initiative, which will finish in September 2009, aim to carry out this random selection control in 3,000 to 3,500 drivers.
González Luque added that the study has a dual aspect: legal and research. Legally, the relevant disciplinary penalties and punishments will be imposed on drivers in whom the presence of drugs is detected. "And we have already detected various cases", commented the DGT medical adviser.
But the main aim is to determine how many Spanish drivers consume both drugs and alcohol. The conclusions of the report will also help to improve the controls. González Luque intimated that it is highly likely that a simple and quick procedure will be ready this year which any traffic policeman can use.
Drugs a bigger problem than alcohol amongst drivers
The DGT adviser also warned that the information obtained to date indicates that drug consumption by drivers is an "even bigger problem than alcohol". The researcher highlighted that in 2007 the presence of psychoactive substances was detected in 10% of drivers who died on the road, without including the number of people who had an accident, were injured or died away from the scene of the accident, on whom no data is available.
This research forms part of the DRUID (Driving under the Influence of Drugs, Alcohol and Medicines) European project, involving 37 international research centres working in different lines.
In addition to the DGT and University of Santiago, the research work in Spain also includes the University of Valladolid, whose experts classify the drugs according to their effect on the ability to drive. This information could be of great help to doctors and pharmacists when it comes to giving prescriptions to drivers.
- Concheiro et al. Determination of illicit and medicinal drugs and their metabolites in oral fluid and preserved oral fluid by liquid chromatography–tandem mass spectrometry. Analytical and Bioanalytical Chemistry, 2008; 391 (6): 2329 DOI: 10.1007/s00216-008-2135-4
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