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Frank T Peters - One of the best experts on this subject based on the ideXlab platform.

  • Development and validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) procedure for screening of urine specimens for 100 analytes relevant in drug-facilitated crime (DFC)
    Analytical and Bioanalytical Chemistry, 2014
    Co-Authors: Daniela Remane, Diana Wetzel, Frank T Peters
    Abstract:

    In recent years, drug-facilitated crime (DFC) has become an increasing problem. A minimum list of 80 analytes to be monitored in such cases has been proposed by the Society of Forensic Toxicologists (SOFT) including the recommended minimum performance limits (RMPL). In the present study, two liquid chromatography-tandem mass spectrometry-based screening procedures, one in positive (method I) and one in negative (method II) electrospray ionization mode were developed and validated. Gradient elution was performed on a ZORBAX Eclipse XDB-C_18 column after protein precipitation of the urine samples. Detection was carried out in the scheduled multiple reaction monitoring (MRM) mode monitoring two transitions per compound. A total of 100 analytes (91 basic in method I and nine acidic in method II) could be identified using the described procedure. No interferences were observed in 30 tested blank urine samples. The RMPLs were achieved for all analytes and ranged from 1 ng/mL for fentanyl to 10 μg/mL for γ-hydroxybutyrate (GHB). Matrix effects (ME) were evaluated using the same 30 urine samples and ranged from −90 % for Tetrazepam to >6,000 % for the 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH). The relative standard deviations of ME were below 25 % for the vast majority of analytes. Results for urine specimens from nine authentic DFC cases were always negative with exception of drugs prescribed to the victims. Reanalysis with the developed procedure of 24 urine samples, with a positive screening result during routine clinical toxicology analysis, confirmed the routine findings. In an excretion study after a single oral doxylamine dose (30 mg), the parent drug and its nor metabolite could be detected in urine specimens from a young female volunteer for 10 days. The developed procedure allows a selective and sensitive screening of urine samples for almost all recommended analytes relevant in DFC cases.

  • screening library assisted identification and validated quantification of 23 benzodiazepines flumazenil zaleplone zolpidem and zopiclone in plasma by liquid chromatography mass spectrometry with atmospheric pressure chemical ionization
    Journal of Mass Spectrometry, 2004
    Co-Authors: Carsten Kratzsch, Oliver Tenberken, Frank T Peters, Armin A Weber, Thomas Kraemer, Hans H Maurer
    Abstract:

    A liquid chromatographic/mass spectrometric assay with atmospheric pressure chemical ionization (LC/APCI-MS) is presented for fast and reliable screening and identification and also for precise and sensitive quantification in plasma of the 23 benzodiazepines alprazolam, bromazepam, brotizolam, camazepam, chlordiazepoxide, clobazam, clonazepam, diazepam, flunitrazepam, flurazepam, desalkylflurazepam, lorazepam, lormetazepam, medazepam, metaclazepam, midazolam, nitrazepam, nordazepam, oxazepam, prazepam, temazepam and Tetrazepam, triazolam, their antagonist flumazenil and the benzodiazepine BZ1 (omega 1) receptor agonists zaleplone, zolpidem and zopiclone. It allows confirmation of the diagnosis of an overdose situation and monitoring of psychiatric patients' compliance. The analytes were isolated from plasma using liquid–liquid extraction and were separated on a Merck LiChroCART column with Superspher 60 RP Select B as the stationary phase. Gradient elution was performed using aqueous ammonium formate and acetonitrile. After screening and identification in the scan mode using the authors' LC/MS library, the analytes were quantified in the selected-ion monitoring mode. The quantification assay was fully validated. It was found to be selective proved to be linear from sub-therapeutic to over therapeutic concentrations for all analytes, except bromazepam. The corresponding reference levels the assay's accuracy and precision data for all studied substances are listed. The accuracy and precision data were within the required limits with the exception of those for bromazepam. The analytes were stable in frozen plasma for at least 1 month. The validated assay was successfully applied to several authentic plasma samples from patients treated or intoxicated with various benzodiazepines or with zaleplone, zolpidem or zopiclone. It has proven to be appropriate for the isolation, separation, screening, identification and quantification of the drugs mentioned above in plasma for clinical toxicology, e.g. in cases of poisoning, and forensic toxicology, e.g. in cases of driving under the influence of drugs. Copyright © 2004 John Wiley & Sons, Ltd.

Jan Tytgat - One of the best experts on this subject based on the ideXlab platform.

  • The evaluation of the applicability of a high pH mobile phase in ultrahigh performance liquid chromatography tandem mass spectrometry analysis of benzodiazepines and benzodiazepine-like hypnotics in urine and blood
    Journal of Chromatography A, 2012
    Co-Authors: Ruth Verplaetse, Eva Cuypers, Jan Tytgat
    Abstract:

    Abstract A sensitive liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous detection of benzodiazepines, benzodiazepine-like hypnotics and some metabolites (7-aminoflunitrazepam, alprazolam, bromazepam, brotizolam, chlordiazepoxide, chlornordiazepam, clobazam, clonazepam, clotiazepam, cloxazolam, diazepam, ethylloflazepate, flunitrazepam, flurazepam, loprazolam, lorazepam, lormetazepam, midazolam, N -desmethylflunitrazepam, nitrazepam, N -methylclonazepam (internal standard), nordiazepam, oxazepam, prazepam, temazepam, Tetrazepam, triazolam, zaleplon, zolpidem, zopiclone) in urine and whole blood. Sample preparation was performed on a mixed-mode cation exchange solid phase extraction cartridge. Electrospray ionization was found to be more efficient than atmospheric pressure chemical ionization. The use of a mobile phase of high pH resulted in higher retention and higher electrospray ionization signals than the conventional low pH mobile phases. Considering the benefits of a high pH mobile phase on both chromatography and mass spectrometry, its use should be encouraged. In the final method, gradient elution with 10 mM ammonium bicarbonate (pH 9) and methanol was performed on a small particle column (Acquity C18, 1.7 μm, 2.1 mm × 50 mm). The optimized method was fully validated.

Corinne Huchet - One of the best experts on this subject based on the ideXlab platform.

  • Skeletal muscle relaxant effect of a standardized extract of Valeriana officinalis L. after acute administration in mice
    Elsevier, 2018
    Co-Authors: Dorian Caudal, Aude Lafoux, Valérie Bardot, César Cotte, Isabelle Ripoche, Pierre Chalard, Isabelle Guinobert, Corinne Huchet
    Abstract:

    Valeriana officinalis L. root extracts are traditionally taken for their sedative and anxiolytic properties and are also used for muscle relaxation. Relaxant effects were clearly observed on smooth muscle whereas data on effects on skeletal muscle are scarce and inconsistent. The aim of this study was to assess whether a standardized extract (SE) of V. officinalis had myorelaxant effects by decreasing skeletal muscle strength and/or neuromuscular tone in mice. Mice received an acute dose of V. officinalis SE (2 or 5 g/kg per os) or Tetrazepam (10 mg/kg ip), a standard myorelaxant drug. Thirty minutes later, the maximal muscle strength was measured using a grip test, while global skeletal muscle function (endurance and neuromuscular tone) was assessed in a wire hanging test. Compared to Tetrazepam, both doses of V. officinalis SE induced a pronounced decrease in skeletal muscle strength without any significant effects on endurance and neuromuscular tone. This study provides clear evidence that the extract of V. officinalis tested has a relaxant effect on skeletal muscle. By decreasing skeletal muscle strength without impacting endurance and neuromuscular tone, V. officinalis SE could induce less undesirable side effects than standard myorelaxant agents, and be particularly useful for avoiding falls in the elderly. Keywords: Valeriana officinalis, Skeletal muscle relaxant, Strength, Hydroethanolic root extract, Acute treatment, Mous

  • Skeletal muscle relaxant effect of a standardized extract of Valeriana officinalis L. after acute administration in mice
    Journal of Traditional and Complementary Medicine, 2017
    Co-Authors: Dorian Caudal, Aude Lafoux, Valérie Bardot, César Cotte, Isabelle Ripoche, Pierre Chalard, Isabelle Guinobert, Corinne Huchet
    Abstract:

    Valeriana officinalis L. root extracts are traditionally taken for their sedative and anxiolytic properties and are also used for muscle relaxation. Relaxant effects were clearly observed on smooth muscle whereas data on effects on skeletal muscle are scarce and inconsistent. The aim of this study was to assess whether a standardized extract (SE) of V. officinalis had myorelaxant effects by decreasing skeletal muscle strength and/or neuromuscular tone in mice. Mice received an acute dose of V. officinalis SE (2 or 5 g/kg per os) or Tetrazepam (10 mg/kg ip), a standard myorelaxant drug. Thirty minutes later, the maximal muscle strength was measured using a grip test, while global skeletal muscle function (endurance and neuromuscular tone) was assessed in a wire hanging test. Compared to Tetrazepam, both doses of V. officinalis SE induced a pronounced decrease in skeletal muscle strength without any significant effects on endurance and neuromuscular tone. This study provides clear evidence that the extract of V. officinalis tested has a relaxant effect on skeletal muscle. By decreasing skeletal muscle strength without impacting endurance and neuromuscular tone, V. officinalis SE could induce less undesirable side effects than standard myorelaxant agents, and be particularly useful for avoiding falls in the elderly.

Hélène Fenet - One of the best experts on this subject based on the ideXlab platform.

  • Bioconcentration of two pharmaceuticals (benzodiazepines) and two personal care products (UV filters) in marine mussels (Mytilus galloprovincialis) under controlled laboratory conditions
    Environmental Science and Pollution Research, 2012
    Co-Authors: Elena Gomez, Morgane Bachelot, Clotilde Boillot, Dominique Munaron, Serge Chiron, Claude Casellas, Hélène Fenet
    Abstract:

    Bioaccumulation is essential for gaining insight into the impact of exposure to organic micropollutants in aquatic fauna. Data are currently available on the bioaccumulation of persistent organic pollutants, but there is very little documentation on the bioaccumulation of pharmaceuticals and personal care products (PPCPs). The bioconcentration of selected PPCPs was studied in marine mussels (Mytilus galloprovincialis). The selected PPCPs were two organic UV filters, i.e., 2-ethylhexyl-4-trimethoxycinnamate (EHMC) and octocrylene (OC), and two benzodiazepines (BZP), i.e., diazepam (DZP) and Tetrazepam (TZP). Laboratory experiments were performed in which M. galloprovincialis was exposed to these compounds either directly from water, for the less lipophilic substances (BZP) or via spiked food for lipophilic UV filters. M. galloprovincialis uptook and eliminated BZP following first-order kinetics. The biological half-life (t (1/2)) of TZP was 1.4 days, resulting in a bioconcentration factor of 64 and 99 mL g(-1) dry weight (dw), respectively, for 2.3 and 14.5 μg L(-1) of exposure, while the biological half-life (t (1/2)) of DZP was 0.4 days, resulting in a bioconcentration factor of 51 mL g(-1) dw for 13.2 μg L(-1) of exposure. The uptake of UV filter was rapid in mussels, followed by elimination within 24 h. EHMC increased from 15 to 138 ng g(-1) dw in 1 h and decreased to 25 ng g(-1) after 24 h for 11.9 μg L(-1) exposure. OC reached 839 ng g(-1) dw after 1 h and decreased to 33 ng g(-1) after 24 h for 11.6 μg L(-1) exposure. However, EHMC and OC were slightly accumulated in 48 h, i.e., 38 and 60 ng g(-1) dw, respectively.

Vincent Cirimele - One of the best experts on this subject based on the ideXlab platform.

  • screening method for benzodiazepines and hypnotics in hair at pg mg level by liquid chromatography mass spectrometry mass spectrometry
    Journal of Chromatography B, 2005
    Co-Authors: Marion Villain, Vincent Cirimele, Marta Concheiro, Pascal Kintz
    Abstract:

    Abstract A procedure is presented for the screening of 16 benzodiazepines and hypnotics in human hair by LC–MS/MS (alprazolam, 7-aminoclonazepam, 7-aminoflunitrazepam, bromazepam, clobazam, diazepam, lorazepam, lormetazepam, midazolam, nordiazepam, oxazepam, temazepam, Tetrazepam, triazolam, zaleplon and zolpidem). The method involves decontamination of hair with methylene chloride, hair cut into small pieces, incubation of 20 mg in phosphate buffer (pH 8.4) in the presence of 1 ng diazepam-d5 used as internal standard, liquid–liquid extraction with diethyl ether/methylene chloride (10/90) and separation using liquid chromatography–tandem mass spectrometry. The limits of quantification for all benzodiazepines and hypnotics range from 0.5 to 5 pg/mg using a 20-mg hair sample. Linearity is observed from the limit of quantification of each compound to 200 pg/mg (r2 > 0.99). Coefficients of variation measured on six points and at two concentrations (10 and 50 pg/mg) range from 5 to 20% for all drugs but one. Extraction recovery, measured at the two same concentrations range from 32 to 76%. These results were found suitable to screen for 16 benzodiazepines in hair and detect them at very low concentrations, making this method suitable to monitor single dose.

  • screening and confirmatory method for benzodiazepines and hypnotics in oral fluid by lc ms ms
    Forensic Science International, 2005
    Co-Authors: Pascal Kintz, Marion Villain, Marta Concheiro, Vincent Cirimele
    Abstract:

    A procedure is presented for the screening of 17 benzodiazepines and hypnotics in oral fluid after collection with the Intercept(R) device by LC-MS/MS (alprazolam, 7-aminoclonazepam, 7-aminoflunitrazepam, bromazepam, clobazam, diazepam, lorazepam, lormetazepam, midazolam, nordiazepam, oxazepam, temazepam, Tetrazepam, triazolam, zaleplon, zopiclone and zolpidem). The method involves extraction of 0.5 mL of oral fluid (previously stored in the Intercept blue buffer) treated with 0.5 mL of phosphate buffer (pH 8.4) in the presence of 5 ng diazepam-d(5) used as internal standard, with 3 mL of diethyl ether/methylene chloride (50/50) and separation using liquid chromatography-tandem mass spectrometry. The limits of quantification for all benzodiazepines and hypnotics range from 0.1 to 0.2 ng/mL. Linearity is observed from the limit of quantification of each compound to 20 ng/mL (r(2)>0.99). Coefficients of variation at 2 ng/mL, measured on 6 points range from 4 to 8% for all drugs, except zopiclone (34%). Extraction recovery, measured at the same concentration was higher than 90%. Ion suppression was evaluated for each compound and was lower than 10% for all drugs except zopiclone (93%). These results were found suitable to screen for 17 benzodiazepines in oral fluid and detect them at very low concentrations, making this method suitable for monitoring subjects under the influence.