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Nele Samyn

Institut National de Criminalistique et de Criminologie

6 papers in the library · 370 citations · publishing 2003-2017

Papers

Dissociable Effects of a Single Dose of Ecstasy (MDMA) on Psychomotor Skills and Attentional Performance

Journal of Psychopharmacology December 1, 2003 C. T. J. Lamers, Johannes G. Ramaekers, N. D. Muntjewerff et al. 105 citations

A single 75 mg dose of MDMA improved psychomotor performance, including movement speed and tracking in both single and divided attention tasks, but impaired the ability to predict object movement under divided attention, which may indicate impairment of driving-relevant skills. No effect was found on visual search, planning, or semantic memory retrieval. Alcohol 0.5 g/kg was also tested but its effects are not described here. The findings suggest MDMA can both enhance and impair specific cognitive and motor functions relevant to driving.

Prevalence of new psychoactive substances and prescription drugs in the Belgian driving under the influence of drugs population

Drug Testing and Analysis June 22, 2017 Sarah M.r. Wille, Camille Richeval, M. Nachon‐phanithavong et al. 68 citations

Among drivers stopped in Belgium in 2015, 7% of blood samples and 11% of oral fluid samples contained new psychoactive substances (NPS), including diphenidine, ketamine, mephedrone, and synthetic cannabinoids. Additionally, 17% of blood samples contained an analgesic drug, 10% a benzodiazepine or hypnotic, and smaller proportions antidepressants, antipsychotics, antiepileptics, or methylphenidate. Poly-drug use combining NPS with licit drugs and drugs of abuse was common. The findings demonstrate that NPS are present in the predominantly young male driving-under-the-influence population and highlight the need for on-site detection methods and further research on combined drug effects on driving ability.

Concentrations and Ratios of Amphetamine, Methamphetamine, MDA, MDMA, and MDEA Enantiomers Determined in Plasma Samples from Clinical Toxicology and Driving Under the Influence of Drugs Cases by GC-NICI-MS*

Journal of Analytical Toxicology November 1, 2003 Frank T. Peters, Nele Samyn, Martin Wahl et al. 65 citations

The pharmacological effects of amphetamine, methamphetamine, MDA, MDMA, and MDEA depend on their mirror-image molecular forms (enantiomers), which differ in how they act in the body. Analysis of plasma from clinical toxicology cases and from drivers suspected of drug impairment showed that concentrations of most enantiomers were lower in routine screening samples than in intoxication or driving-under-the-influence cases. Drivers under the influence had higher levels of both amphetamine enantiomers than intoxicated patients. Differences in the ratio of R to S enantiomers for several drugs between groups suggest these ratios can help distinguish recent from past use. In one MDMA poisoning, the R form cleared more slowly (half-life 6.0 hours) than the S form (4.1 hours), and the ratio of R to S rose over time.

Drug Testing in Blood: Validated Negative-Ion Chemical Ionization Gas Chromatographic–Mass Spectrometric Assay for Enantioselective Measurement of the Designer Drugs MDEA, MDMA, and MDA and Its Application to Samples from a Controlled Study with MDMA

Clinical Chemistry August 11, 2005 Frank T. Peters, Nele Samyn, C. T. J. Lamers et al. 49 citations

An assay was developed to measure the enantiomers of the designer drugs MDA, MDMA, and MDEA in small plasma volumes (0.2 mL or less). After extraction and derivatization, the enantiomers were separated by gas chromatography and detected by mass spectrometry within 17 minutes. The method was linear for MDA at 1–50 μg/L and for MDMA and MDEA at 5–250 μg/L per enantiomer, with extraction yields of 82.1%–95.3%. Applied to samples from a controlled study after a single 75 mg dose of racemic MDMA, the assay showed that R-(−)-MDMA concentrations significantly exceeded those of S-(+)-MDMA, with ratios always above 1.0 and increasing over time. S-(+)-MDA concentrations exceeded those of R-(−)-MDA, with ratios also increasing but remaining below 1.0.

Liquid chromatography-tandem mass spectrometry method for the simultaneous analysis of multiple hallucinogens, chlorpheniramine, ketamine, ritalinic acid, and metabolites, in urine.

Journal of analytical toxicology October 1, 2007 Maria Del Mar Ramirez Fernandez, Marleen Laloup, Michelle Wood et al. 47 citations

A method for simultaneously measuring multiple hallucinogens, chlorpheniramine, ketamine, ritalinic acid, and several metabolites in human urine was developed and validated. The procedure uses solid-phase extraction followed by liquid chromatography-tandem mass spectrometry, with all drugs eluting within 14 minutes. Using 500 microliters of urine, limits of quantification ranged from 0.05 ng/mL for LSD to 10 ng/mL for other hallucinogens, with linear or quadratic regression from each compound's limit up to 500 ng/mL. Precision and accuracy were acceptable, and processed samples remained stable in the autosampler for at least 24 hours. The method was successfully applied to authentic urine samples containing chlorpheniramine, ketamine, LSD, and psilocin.

Negative-Ion Chemical Ionization Gas Chromatography–Mass Spectrometry Assay for Enantioselective Measurement of Amphetamines in Oral Fluid: Application to a Controlled Study with MDMA and Driving Under the Influence Cases

Clinical Chemistry March 2, 2007 Frank T. Peters, Nele Samyn, Thomas Kræmer et al. 36 citations

A gas chromatography–mass spectrometry method using negative-ion chemical ionization was developed to separately measure the left- and right-handed forms (enantiomers) of amphetamine, methamphetamine, MDA, MDMA, and MDEA in oral fluid. After adding a buffer and a derivatizing agent, the enantiomers were extracted and analyzed. The method was linear from 5–250 μg/L per enantiomer for MDA and from 25–1250 μg/L per enantiomer for the other drugs. Recoveries and precision were acceptable except for MDEA. When applied to samples from a controlled MDMA study and real driving-under-the-influence cases, the oral fluid concentrations and enantiomer ratios did not reliably predict plasma levels.