liu.seSearch for publications in DiVA
Change search
Refine search result
1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Haage, Pernilla
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linköping Sweden.
    Kronstrand, Robert
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linköping Sweden.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Region Östergötland, Center for Diagnostics, Department of Clinical Pharmacology. Linköping University, Faculty of Medicine and Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linköping Sweden.
    Quantitation of the enantiomers of tramadol and its three main metabolites in human whole blood using LC-MS/MS.2016In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 119, p. 1-9Article in journal (Refereed)
    Abstract [en]

    The analgesic drug tramadol and its metabolites are chiral compounds, with the (+)- and (-)-enantiomers showing different pharmacological and toxicological effects. This novel enantioselective method, based on LC-MS/MS in reversed phase mode, enabled measurement of the parent compound and its three main metabolites O-desmethyltramadol, N-desmethyltramadol and N,O-didesmethyltramadol simultaneously. Whole blood samples of 0.5g were fortified with internal standards (tramadol-(13)C-D3 and O-desmethyl-cis-tramadol-D6) and extracted under basic conditions (pH 11) by liquid-liquid extraction. Chromatography was performed on a chiral alpha-1-acid glycoprotein (AGP) column preceded by an AGP guard column. The mobile phase consisted of 0.8% acetonitrile and 99.2% ammonium acetate (20mM, pH 7.2). A post-column infusion with 0.05% formic acid in acetonitrile was used to enhance sensitivity. Quantitation as well as enantiomeric ratio measurements were covered by quality controls. Validation parameters for all eight enantiomers included selectivity (high), matrix effects (no ion suppression/enhancement), calibration model (linear, weight 1/X(2), in the range of 0.25-250ng/g), limit of quantitation (0.125-0.50ng/g), repeatability (2-6%) and intermediate precision (2-7%), accuracy (83-114%), dilution integrity (98-115%), carry over (not exceeding 0.07%) and stability (stable in blood and extract). The method was applied to blood samples from a healthy volunteer administrated a single 100mg dose and to a case sample concerning an impaired driver, which confirmed its applicability in human pharmacokinetic studies as well as in toxicological and forensic investigations.

  • 2.
    Haage, Pernilla
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Kronstrand, Robert
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Calistri, Simona
    Department of Clinical Chemistry, Erasmus University Medical Center, Rotterdam, The Netherlands / Scuola di Scienze della Salute Umana, Università degli studi di Firenze, Florence, Italy.
    van Schaik, Ron H N
    Department of Clinical Chemistry, Erasmus University Medical Center, Rotterdam, The Netherlands.
    Green, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Enantioselective pharmacokinetics of tramadol and its three main metabolites; impact of CYP2D6, CYP2B6, and CYP3A4 genotype2018In: Pharmacology Research & Perspectives, ISSN 2052-1707, Vol. 6, no 4, article id e00419Article in journal (Refereed)
    Abstract [en]

    Tramadol is a complex drug, being metabolized by polymorphic enzymes and administered as a racemate with the (+)- and (-)-enantiomers of the parent compound and metabolites showing different pharmacological effects. The study aimed to simultaneously determine the enantiomer concentrations of tramadol, O-desmethyltramadol, N-desmethyltramadol, and N,O-didesmethyltramadol following a single dose, and elucidate if enantioselective pharmacokinetics is associated with the time following drug intake and if interindividual differences may be genetically explained. Nineteen healthy volunteers were orally administered either 50 or 100 mg tramadol, whereupon blood samples were drawn at 17 occasions. Enantiomer concentrations in whole blood were measured by LC-MS/MS and the CYP2D6,CYP2B6 and CYP3A4 genotype were determined, using the xTAG CYP2D6 Kit, pyrosequencing and real-time PCR, respectively. A positive correlation between the (+)/(-)-enantiomer ratio and time following drug administration was shown for all four enantiomer pairs. The largest increase in enantiomer ratio was observed for N-desmethyltramadol in CYP2D6 extensive and intermediate metabolizers, rising from about two to almost seven during 24 hours following drug intake. CYP2D6 poor metabolizers showed metabolic profiles markedly different from the ones of intermediate and extensive metabolizers, with large area under the concentration curves (AUCs) of the N-desmethyltramadol enantiomers and low corresponding values of the O-desmethyltramadol and N,O-didesmethyltramadol enantiomers, especially of the (+)-enantiomers. Homozygosity of CYP2B6 *5 and *6 indicated a reduced enzyme function, although further studies are required to confirm it. In conclusion, the increase in enantiomer ratios over time might possibly be used to distinguish a recent tramadol intake from a past one. It also implies that, even though (+)-O-desmethyltramadol is regarded the enantiomer most potent in causing adverse effects, one should not investigate the (+)/(-)-enantiomer ratio of O-desmethyltramadol in relation to side effects without consideration for the time that has passed since drug intake.

  • 3.
    Josefsson, Martin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Roman, Markus
    National Board of Forensic Medicine, Linköping.
    Skogh, Elisabeth
    Linköping University, Department of Clinical and Experimental Medicine, Psychiatry . Linköping University, Faculty of Health Sciences.
    Dahl, Marja-Liisa
    University Hospital, Uppsala.
    Liquid chromatography/tandem mass spectrometry method for determination of olanzapine and N-desmethylolanzapine in human serum and cerebrospinal fluid2010In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 53, no 3, p. 576-582Article in journal (Refereed)
    Abstract [en]

    A validated, accurate and sensitive LC-MS/MS method for determination of olanzapine and its metabolite N-desmethylolanzapine has been developed. The analytes were quantified by tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring. Olanzapine and desmethylolanzapine were extracted from serum or cerebral spinal fluid samples, 200 microl, with tert-butyl methyl ether using olanzapine-D3 as internal standard. Calibrations for olanzapine and desmethylolanzapine were linear within the selected range of 0.2-30 ng/ml (6-96 nM) in cerebral spinal fluid and for olanzapine in plasma, in the range of 5-100 ng/ml (16-320 nM). The method was successfully used for the analysis of samples from patients treated with olanzapine in the dose range of 2.5-25mg/day.

  • 4.
    Josefsson, Martin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Rydberg, Irene
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Determination of methylphenidate and ritalinic acid in blood, plasma and oral fluid from adolescents and adults using protein precipitation and liquid chromatography tandem mass spectrometry-A method applied on clinical and forensic investigations2011In: JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS, ISSN 0731-7085, Vol. 55, no 5, p. 1050-1059Article in journal (Refereed)
    Abstract [en]

    A validated, accurate and sensitive LC-MS/MS method for determination of racemic methylphenidate and its metabolite ritalinic acid has been developed. The analytes were quantified by tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring. Blood, plasma and oral fluid samples of 100 mu l were prepared by simple precipitation with 200 RI of an aqueous solution of zinc sulphate in methanol. Corresponding deuterated internal standards were used for quantification. Calibrations for methylphenidate and ritalinic acid were linear within the selected range of 0.2-30 ng/ml and 10-1500 ng/ml in blood or plasma and in the range of 1-500 ng/ml and 0.25-125 ng/ml in oral fluid, respectively. The method was successfully applied for the analysis of samples from patients treated with methylphenidate in the dose range of 36-72 mg/day and some representative ante mortem and post mortem samples from clinical and forensic toxicological investigations. A three to fourfold higher concentration of methylphenidate was found in oral fluid compared with blood while for ritalinic acid the concentrations were about 25-fold lower in oral fluid.

  • 5.
    Josefsson, Martin
    et al.
    National Board of Forensic Medicine.
    Sabanovic, A
    National Board of Forensic Medicine.
    Sample preparation on polymeric solid phase extraction sorbents for liquid chromatographic-tandem mass spectrometric analysis of human whole blood - A study on a number of beta-agonists and beta-antagonists2006In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1120, no 02-Jan, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Alternative strategies for sample preparation of human blood samples were evaluated including protein precipitation (PP) and solid phase extraction (SPE) on Waters Oasis® polymeric columns. Gradient chromatography within 15 min was performed on a Hypersil Polar-RP column combined with a Sciex API 2000 triple quadrupol instrument equipped with an electro-spray interface. Beta-agonists and beta-antagonists available on the Swedish market were included in the study. A combination of zinc sulphate and ethanol was found effective for PP. A clear supernatant was achieved that either could be injected directly on the LC–MS–MS system for analysis or transferred to a SPE column for further extraction and analyte concentration. Retention on the hydrophilic–lipophilic balanced sorbent HLB as well as the mixed mode cationic MCX and anionic MAX sorbents were investigated. On HBL the relative lipophilicity of the target analytes was investigated. At a high pH when the amino alcohols are deprotonised the more non-polar analytes (e.g., carvediol, betaxolol, bisoprolol and propranolol) were well retained on the sorbent and for the majority methanol content higher than 50% in water (v/v) was needed for elution. Some analytes though, with additional weak acidic functionalities (fenoterol, salbutamol, sotalol, and terbutaline) were poorly retained. On MAX the retention of these weak acids was improved when loaded under basic conditions but under neutral conditions analyte recoveries was comparable with HLB. On MCX all the analytes were well retained allowing a wash step of 100% methanol at neutral and low pH. By applying the supernatant from PP in combination with an additional portion of aqueous formic acid (2%) the analytes could be loaded and retained. High extraction recoveries were found for most analytes but for a few, significant losses were seen during PP (e.g., formoterol) and/or evaporation (e.g., fenoterol, formoterol, labetalol and terbutaline). The effectiveness of the sample preparation was evaluated by ESI ion-suppression studies by post column infusion of the target analyte. An ethanol zinc sulphate aq mixture was found to be more effective than acetonitrile, methanol or ethanol for PP of human whole blood samples. Beside suppression by salts in the front peak, only limited suppression from other artefacts such as more lipophilic compounds was found late in the chromatograms. Some tendency though to concentrate more lipophilic artefacts on the Oasis® sorbents was seen. These findings show that the Oasis MCX sorbent is well suited for sample preparation of beta-agonists and beta-antagonists from human whole blood if the objective is to cover a great number of the analytes in the same assay.

  • 6.
    Karlsson, Louise
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Schmitt, Ulrich
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Kugelberg, Fredrik C
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Hiemke, Christoph
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Blood-brain barrier penetration of the enantiomers of venlafaxine and its metabolites in mice lacking P-glycoprotein2010In: European Neuropsychopharmacology, ISSN 0924-977X, E-ISSN 1873-7862, Vol. 20, no 9, p. 632-640Article in journal (Refereed)
    Abstract [en]

    According to in vitro studies the enantiomers of venlafaxine display different degrees of serotonin and noradrenaline reuptake inhibition. Therefore, clarification of the enantiomeric drug distribution between serum and brain is highly warranted. To elucidate if P-glycoprotein (P-gp) in a stereoselective manner transports venlafaxine and its metabolites out of the brain we used abcb1ab double-knockout mice that do not express P-gp. A single dose of racemic venlafaxine (10 mg/kg bw) was intraperitoneally injected to knockout (-/-) and wildtype (+/+) mice. Serum and brain samples were collected 1, 3, 6 and 9 h following drug administration for analysis by LC/MS/MS. One to six hours post-dose, the brain concentrations of venlafaxine, O-desmethylvenlafaxine and N-desmethylvenlafaxine were 2-3, 2-6 and 3-12 times higher in abcb1ab (-/-) mice compared to abcb1ab (+/+) mice, respectively. No major differences in the serum and brain disposition of the S- and R-enantiomers of venlafaxine and its metabolites were found between the groups. We conclude that P-gp decreases the penetration of the S- and R-enantiomers of venlafaxine and its major metabolites into the brain. No evidence of a stereoselective P-gp mediated transport of these substances was observed.

  • 7.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Karlsson, Louise
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Kugelberg, Fredrik C
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Stereoselective determination of venlafaxine and its three demethylated metabolites in human plasma and whole blood by liquid chromatography with electrospray tandem mass spectrometric detection and solid phase extraction2010In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 53, no 3, p. 583-590Article in journal (Refereed)
    Abstract [en]

    A stereoselective method is described for simultaneous determination of the S- and R-enantiomers of venlafaxine and its three demethylated metabolites in human plasma and whole blood samples. This validated method involved LC/MS/MS with positive electrospray ionization and solid phase extraction. Chromatographic separation was performed on a 250 mm x 2.1mm Chirobiotic V column with a total run time of 35 min. In plasma, calibration curves were in the range of 1-1000 nM for the S- and R-enantiomers of venlafaxine and O-desmethylvenlafaxine, and 0.5-500 nM for N-desmethylvenlafaxine and N,O-didesmethylvenlafaxine. In whole blood the corresponding concentrations were 10-4000 and 5-2000 nM, respectively. The intra-day precision was <6.3% and the inter-day precision was <9.9% for plasma and <15% and <19% for whole blood. LLOQ ranged between 0.25 and 0.5 nM. No ion suppression/enhancement or other matrix effects were observed. The method was successfully applied for determination of venlafaxine and its metabolites in plasma from patients and whole blood samples from forensic autopsy cases.

  • 8.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Karlsson, Louise
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Josefsson, Martin
    Department of Forensic Genetics and Forensic Toxicology,National Board of Forensic Medicine.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Pharmacokinetic Differences in the Disposition of the Enantiomers of Venlafaxine and Its Metabolites in Sprague-Dawley and Dark Agouti RatsManuscript (preprint) (Other academic)
    Abstract [en]

    Venlafaxine is a frequently prescribed racemic antidepressant drug worldwide, consisting of two enantiomers that exhibit similar but not identical biological activity profiles. Venlafaxine is extensively metabolised by the cytochrome P450 (CYP) system. CYP2D6 is involved in the formation of O-desmethylvenlafaxine (Odm-venlafaxine) and CYP3A4 in the formation of Ndesmethylvenlafaxine (Ndm-venlafaxine). The female Dark Agouti and Sprague-Dawley rats are considered the animal counterparts of the human CYP2D6 poor and extensive metaboliser phenotypes, respectively. Since CYP2D6 seems to play a major role in the metabolism of venlafaxine, the aim of this work was to study possible differences in the pharmacokinetics of the enantiomers of venlafaxine and its metabolites in these two different rat strains. Following single administration of racemic venlafaxine (15 mg/kg) serum and brain samples were collected and the concentrations of the enantiomers of venlafaxine and its three major metabolites were determined using an enantioselective LC/MS/MS method. Higher serum and brain concentrations of venlafaxine were observed in Dark Agouti rats as compared to Sprague-Dawley rats (p=0.0002). In relation to the Odm-venlafaxine concentration, the Ndmvenlafaxine concentrations were much higher in Dark Agouti rats than in Sprague-Dawley rats (p<0.0001). The enantiomeric (S/R) venlafaxine ratios were almost two times higher in Dark Agouti rats than in Sprague-Dawley rats, which was observed in both serum and brain (p<0.0001). The present results give hints for possible differences in the pharmacokinetics of venlafaxine in human extensive and poor metaboliser CYP2D6 phenotype subjects.

  • 9.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Karlsson, Louise
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Zackrisson, Anna-Lena
    National Board of Forensic Medicine, Linköping, Sweden.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Health Sciences. National Board of Forensic Medicine, Linköping, Sweden.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Kugelberg, Fredrik C
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Influence of CYP2D6 genotype on the disposition of the enantiomers of venlafaxine and its major metabolites in postmortem femoral blood2012In: Forensic Science International, ISSN 0379-0738, E-ISSN 1872-6283, Vol. 214, no 1-3, p. 124-134Article in journal (Refereed)
    Abstract [en]

    Venlafaxine (VEN) is an antidepressant drug mainly metabolized by the cytochrome P450 (CYP) enzyme CYP2D6 to the active metabolite O-desmethylvenlafaxine (ODV). VEN is also metabolized to N-desmetylvenlafaxine (NDV) via CYP3A4. ODV and NDV are further metabolized to N,O-didesmethylvenlafaxine (DDV). VEN is a racemic mixture of the S- and R-enantiomers and these have in vitro displayed different degrees of serotonin and noradrenaline reuptake inhibition. The aim of the study was to investigate if an enantioselective analysis of VEN and its metabolites, in combination with genotyping for CYP2D6, could assist in the interpretation of forensic toxicological results in cases with different causes of deaths. Concentrations of the enantiomers of VEN and metabolites were determined in femoral blood obtained from 56 autopsy cases with different causes of death. The drug analysis was done by liquid chromatography tandem mass spectrometry (LC/MS/MS) and the CYP2D6 genotyping by PCR and pyrosequencing. The mean (median) enantiomeric S/R ratios of VEN, ODV, NDV and DDV were 0.99 (0.91), 2.17 (0.93), 0.92 (0.86) and 1.08 (1.03), respectively. However, a substantial variation in the relationship between the S- and R-enantiomers of VEN and metabolites was evident (S/R ratios ranging from 0.23 to 17.6). In six cases, a low S/R VEN ratio (mean 0.5) was associated with a high S/R ODV ratio (mean 11.9). Genotyping showed that these individuals carried two inactive CYP2D6 genes indicating a poor metabolizer phenotype. From these data we conclude that enantioselective analysis of VEN and ODV can predict if a person is a poor metabolizer genotype/phenotype for CYP2D6. Knowledge of the relationship between the S- and R-enantiomers of this antidepressant drug and its active metabolite is also important since the enantiomers display different pharmacodynamic profiles.

  • 10.
    Kronstrand, Robert
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden.
    Brinkhagen, Linda
    National Board for Forensic Medicine, Linkoping, Sweden .
    Birath-Karlsson, Carolina
    National Board for Forensic Medicine, Linkoping, Sweden .
    Roman, Markus
    National Board for Forensic Medicine, Linkoping, Sweden .
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden.
    LC-QTOF-MS as a superior strategy to immunoassay for the comprehensive analysis of synthetic cannabinoids in urine2014In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 406, no 15, p. 3599-3609Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to compare the performance of an immunoassay screening for synthetic cannabinoids with a newly developed confirmation method using liquid chromatography quadrupole time-of-flight mass spectrometry. The screening included metabolites from JWH-018, JWH-073, and AM-2201. The confirmation included metabolites from AM-2201, JWH-018, JWH-019, JWH-073, JWH-081, JWH-122, JWH-210, JWH-250, JWH-398, MAM-2201, RCS-4, and UR-144. The immunoassay was tested and found to have no cross-reactivity with UR-144 metabolites but considerable cross-reactivity with MAM-2201 and JWH-122 metabolites. Sensitivity and specificity for the immunoassay were evaluated with 87 authentic urine samples and found to be 87 % and 82 %, respectively. With a cutoff at 2 ng/ml, the confirmation showed 80 positive findings in 38 cases. The most common finding was JWH-122 5-OH-pentyl, followed by JWH-018 5-OH-pentyl. There were 9 findings of UR-144 metabolites and 3 of JWH-073 metabolites. In summary, the immunoassay performed well, presenting both high sensitivity and specificity for the synthetic cannabinoids present in the urine samples tested. The rapid exchange of one cannabinoid for another may pose problems for immunoassays as well as for confirmation methods. However, we consider time-of-flight mass spectrometry to be superior since new metabolites can be quickly included and identified.

  • 11.
    Kronstrand, Robert
    et al.
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Nyström, Ingrid
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Hodgins, Sheilagh
    Department of Psychology, Université de Montréal, Québec, Canada.
    Segmental Ion Spray LC-MS-MS Analysis of Benzodiazepines in Hair of Psychiatric Patients2002In: Journal of Analytical Toxicology, ISSN 0146-4760, E-ISSN 1945-2403, Vol. 26, no 7, p. 479-484Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to develop a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the analysis of benzodiazepines in human hair. The method was tested by analyzing hair samples from forensic and clinical psychiatric patients where benzodiazepines had been prescribed during hospitalization and after care. Hair samples were obtained at discharge from the clinic and then after six months. Two-centimeter segments of the hair samples (10–30 mg) were washed once with isopropanol, three times with phosphate buffer, and again with isopropanol, dried, weighed, and digested with proteinase K before solid-phase extraction with BondElut Certify columns. Diazepam, nordiazepam, oxazepam, alprazolam, OH-alprazolam, nitrazepam, 7-aminonitrazepam, flunitrazepam, 7-aminoflunitrazepam, clonazepam, and 7-aminoclonazepam were quantitated in MRM mode using one transition for each analyte and deuterated internal standard. The calibration range was 0.125–5 ng/mg for diazepam, nordiazepam, and oxazepam and 0.025–1.0 ng/mg for the other compounds. In the hair samples analyzed, diazepam, flunitrazepam, nitrazepam, and clonazepam was detected together with their metabolites. Alprazolam was not detected in any sample. Segmental hair analysis revealed differences in drug deposition in hair before and after release from psychiatric treatment. Both increases and decreases of hair drug concentrations were seen after release even though the prescribed dose was the same. This was taken as an indication of noncompliance during the after-care period. We conclude that the extraction and LC-MS-MS procedures were adequate to detect benzodiazepines in hair and that the results indicated that segmental hair analysis might provide retrospective information about medication intake.

  • 12.
    Naidu Sjöswärd, Kerstin
    et al.
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Faculty of Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Molecular and Clinical Medicine, Forensic Medicine. Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Molecular and Clinical Medicine, Forensic Medicine. Linköping University, Faculty of Health Sciences.
    Andersson, Rolf
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Schmekel, Birgitta
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Metabolism of salbutamol differs between asthmatic patients and healthy volunteers2003In: Pharmacology and Toxicology, ISSN 0901-9928, E-ISSN 1600-0773, Vol. 92, no 1, p. 27-32Article in journal (Refereed)
    Abstract [en]

    Patients with asthma are a target group for medication with β2-agonists, often in combination with corticosteroids. Salbutamol is commonly marketed as racemate. R-Salbutamol carries β2-agonistic property whereas S-salbutamol does not. The racemate undergoes stereoselective sulphatisation by sulfotransferases mainly in the gut and liver, so that S-salbutamol rests for a longer time in the body and reaches higher plasma levels than R-salbutamol. Ten patients with mild stable asthma and at present without cortisone medication were given racemic salbutamol as ventoline 4 mg orally. Plasma and urine levels were estimated until 24 hr after ingestion. For comparison healthy volunteers were treated in the same way.The group of asthma patients was then treated with budesonide inhalations 800 μg daily for one week and the initial programme resumed. Non-cortisone-treated asthmatic patients displayed higher levels of both R- and S-salbutamol in plasma than did healthy volunteers after one single ingestion of racemic salbutamol (CMAX both comparisons P<0.05). Plasma levels of salbutamol isomers in cortisone-treated asthmatic patients resembled the levels in volunteers. The most plausible explanation for the discrepancy in values between asthmatic patients and volunteers is a defective metabolic function by asthmatic patients possibly enzymatic in origin.

  • 13.
    Naidu Sjöswärd, Kerstin
    et al.
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Faculty of Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Molecular and Clinical Medicine, Forensic Medicine. Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Molecular and Clinical Medicine, Forensic Medicine. Linköping University, Faculty of Health Sciences.
    Schmekel, Birgitta
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Preserved bronchial dilatation after salbutamol does not guarantee protection against bronchial hyperresponsiveness2003In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 23, no 1, p. 14-20Article in journal (Refereed)
    Abstract [en]

    Racemic salbutamol, a β2-adrenoceptor agonist used for dilatation of airways, has recently been shown to induce lessened relaxation of bronchial smooth muscle and partial loss of bronchoprotection, seen as increased hyperresponsiveness, after regular treatment. The racemate undergoes stereo-selective disposition, giving higher plasma levels of S-salbutamol than that of bronchodilating R-salbutamol, thus raising S : R ratios after repeated administration. Our aim was to evaluate whether increased bronchial hyperresponsiveness (BHR) could be found even after 1 day of repeated salbutamol inhalations, with β2-receptor-induced bronchial smooth muscle relaxation remaining and whether this would be associated with plasma levels of either enantiomer. Fifteen patients with stable asthma, aged 19–54 years, were included in a randomized, cross-over study. An indirect bronchial challenge method was used [voluntary isocapnic hyperventilation of cold air (IHCA)], and airway condition tested by means of impulse oscillometry. Racemic salbutamol was inhaled three times during a 6-h period. IHCA was performed and plasma concentrations of enantiomers were measured 4 h after the last dose. Tests were also performed without preceding drug treatment. β2-Agonist-produced bronchial dilatation and protection persisted in the majority of the 15 patients 4 h after repeated inhalations of salbutamol during 1 day. In only two of the 15 patients we could trace increased BHR after salbutamol. Neither dilatation nor protection could be linked to plasma levels of either R- or S-salbutamol. The underlying mechanisms of BHR remain unknown and are dissociated from β2-receptor-mediated dilatation.

  • 14.
    Persson, Ingrid
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Josefsson, Martin
    Linköping University, Department of Medicine and Care. Linköping University, Faculty of Health Sciences.
    Persson, Karin
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Andersson, Rolf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Tea flavanols inhibit angiotensin-converting enzyme activity and increase nitric oxide production in human endothelial cells2006In: Journal of Pharmacy and Pharmacology (JPP), ISSN 0022-3573, E-ISSN 2042-7158, Vol. 58, no 8, p. 1139-1144Article in journal (Refereed)
    Abstract [en]

    A diversity of pharmacological effects on the cardiovascular system have been reported for Camellia sinensis: antioxidative, antiproliferative and anti-angiogenic activity, and nitric oxide synthase activation. The purpose of this study was to investigate if the connection between tea and angiotensin-converting enzyme (ACE) and nitric oxide (NO) might be an explanation of the pharmacological effects of tea on the cardiovascular system. Cultured endothelial cells from human umbilical veins (HUVEC) were incubated with extracts of Japanese Sencha (green tea), Indian Assam Broken Orange Pekoe (black tea) and Rooibos tea, respectively. The main flavanols and purine alkaloids in green and black tea were examined for their effects on ACE and NO. After incubation with green tea, black tea and Rooibos tea for 10 min, a significant and dose-dependent inhibition of ACE activity in HUVEC was seen with the green tea and the black tea. No significant effect on ACE was seen with the Rooibos tea. After 10-min incubation with (-)-epicatechin, (-)- epigallocatechin, (-)-epicatechingallate and (-)-epigallocatechingallate, a dose-dependent inhibition of ACE activity in HUVEC was seen for all four tea catechins. After 24-h incubation, a significantly increased dose-dependent effect on NO production in HUVEC was seen for the green tea, the black tea and the Rooibos tea. After 24-h incubation with (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechingallate and (-)-epigallocatechingallate, a dose-dependent increased NO production in HUVEC was seen. In conclusion, tea extracts from C. sinensis may have the potential to prevent and protect against cardiovascular disease. © 2006 The Authors.

  • 15.
    Roman, Markus
    et al.
    Natl Board Forens Med, Dept Forens Genet and Forens Toxicol, S-58758 Linkoping, Sweden .
    Strom, Lena
    Natl Board Forens Med, Dept Forens Genet and Forens Toxicol, S-58758 Linkoping, Sweden .
    Tell, Helena
    Natl Board Forens Med, Dept Forens Genet and Forens Toxicol, S-58758 Linkoping, Sweden .
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology. Linköping, .
    Liquid chromatography/time-of-flight mass spectrometry analysis of postmortem blood samples for targeted toxicological screening2013In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 405, no 12, p. 4107-4125Article in journal (Refereed)
    Abstract [en]

    A liquid chromatography/time-of-flight mass spectrometry (LC-TOF-MS) method for targeted toxicological screening in human postmortem blood samples from forensic autopsy cases has been developed, validated and compared with a previously used method using gas chromatography with nitrogen-phosphorus detection (GC-NPD). Separation was achieved within 12 min by high-resolution gradient chromatography. Ions were generated in positive and negative electrospray ionization mode and were detected in 2-GHz single mass spectrometry mode, m/z range 50-1,000. Before injection, 0.25 g blood was prepared by protein precipitation with 500 mu L of a mixture of acetonitrile and ethanol containing deuterated internal standards. An in-house database comprising 240 drugs and metabolites was built by analysing solutions from certified standards or other documented reference material available. Identification was based on scoring of retention time, accurate mass measurement and isotopic pattern. Validation was performed on spiked blood samples and authentic postmortem blood samples. The thresholds defined as minimum required performance levels were for most compounds in the range from 0.01 to 0.10 mu g/g. Typically, a mass error of less than 2 ppm and a precision of area measurements of less than 5 % coefficient of variation were achieved. Positive identification was confirmed at concentrations up to 500 mu g/g. Most compounds were determined in positive ionization mode, but for a limited number of compounds (fewer than 4 %) negative ionization was needed and a few early-eluted compounds could not be identified owing to substantial influence of interferences from the matrix and were thus not included in the screening. A robust and valid toxicological screening by LC-TOF-MS for postmortem blood samples, covering 50 % more compounds, and with higher precision and sensitivity than the previously used screening by GC-NPD was achieved.

  • 16.
    Skogh, Elisabeth
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Sjödin, Ingemar
    Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dahl, Marja-Liisa
    University Uppsala Hospital.
    High Correlation Between Serum and Cerebrospinal Fluid Olanzapine Concentrations in Patients With Schizophrenia or Schizoaffective Disorder Medicating With Oral Olanzapine as the Only Antipsychotic Drug2011In: Journal of Clinical Psychopharmacology, ISSN 0271-0749, E-ISSN 1533-712X, Vol. 31, no 1, p. 4-9Article in journal (Refereed)
    Abstract [en]

    The primary aim of the present study was to investigate the relationship between steady state serum and cerebrospinal fluid (CSF) concentrations of olanzapine (OLA) and its metabolite 4-N-desmethylolanzapine (DMO) in patients with schizophrenia or schizoaffective disorder treated with oral OLA as the only antipsychotic drug. The influence of smoking, gender, age, as well as polymorphisms in cytochrome P450 CYP2D6, CYP1A2, and ABCB1 genes on the serum and CSF drug levels was also analyzed. Thirty-seven white outpatients (10 smokers and 27 nonsmokers) were included. From 29 of them, CSF was collected successfully. A strong correlation (Spearman rank correlation [r(s)] = 0.93; P = 0.05) was found between serum and CSF concentrations of OLA and a somewhat weaker correlation (r(s) = 0.5; P = 0.05) between those of DMO. The CSF concentrations of OLA and DMO were on average 12% and 16% of those in serum. Extensive metabolizers of CYP2D6 had higher (P = 0.05) daily doses than poor metabolizers when the influence of smoking was taken into account. Smokers had lower (P = 0.01) concentration-to-dose ratios of OLA in serum (mean, 2.23 ng/mL per mg vs 3.32 ng/mL per mg) and CSF (0.27 ng/mL per mg vs 0.41 ng/mL per mg) than nonsmokers. The concentration-to-dose ratio for serum DMO decreased with increasing age (r(s) = -0.41; P = 0.05). Carriers of ABCB1 1236T/2677T/3435T haplotype had higher serum (mean, 37.7 ng/mL vs 22.5 ng/mL; P = 0.035) and CSF (4.7 ng/mL vs 2.6 ng/mL; P = 0.018) OLA concentrations than patients without this haplotype. The present study shows a strong correlation between serum and CSF concentrations of OLA, indicating that concentrations of OLA in serum reflect those in CSF.

  • 17.
    Skogh, Elisabeth
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Sjödin, Ingemar
    Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Josefsson, Martin
    National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linköping, Sweden.
    Dahl, M.L.
    Karolinska University Hospital, Department of Clinical Pharmacology, Stockholm, Sweden.
    Olanzapine in serum and cerebrospinal fluid in patients with schizophrenia or schizoaffective disorder2010In: European Neuropsychopharmacology, ISSN 0924-977X, E-ISSN 1873-7862, Vol. 20, no Suppl. 3, p. S469-S469Article in journal (Other academic)
    Abstract [en]

    Background:  The relationship  between serum and CSF concentrations  of olanzapine  (OLA)  in humans  has  to our  knowledge not been described earlier. Few studies have investigated how the CYP2D6 and CYP1A2 polymorphisms affect OLA pharmacoki- netics in humans [1] [2]. Polymorphisms in the ABCB1 gene have been associated with altered pharmacokinetics of certain drugs including risperidone [3].The aim of the present study was to investigate the relationship between steady state serum and cerebrospinal fluid (CSF) con- centrations of OLA and its metabolite 4t -N-desmethylolanzapine (DMO) and to address the influence  of smoking,  gender, age as well as polymorphisms in genes coding for OLA metabolism (CYP2D6, CYP1A2) and transport (ABCB1) in patients with schizophrenia  or schizoaffective  disorder, treated with oral OLAas the only antipsychotic  drug.

    Methods: Thirty seven Caucasian outpatients (10 smokers and27 non-smokers),  suffering from schizophrenia or schizoaffective disorder according to DSM-IV criteria were included in the study. From 29 out of them, CSF was collected successfully.Fasting blood samples were collected in the morning for analy- ses of OLA and DMO and for genotyping (polymorphisms of CYP2D6,  CYP1A2  and  ABCB1).  Lumbar  puncture  was  per- formed  at close  connection  to blood  sampling  at the minimum of eight hours in the fasting state. The blood and CSF samples were stored at −70ºC until analysed.A validated accurate and sensitive LC-MS/MS method was used for the analysis of OLA and DMO. Analytes were quantified  by using linear gradient reversed phase chromatography with tandem mass  spectrometry  detection  operating  in  positive  electro-sprayionization mode with multiple reactions monitoring (MRM).

    Results:  A  strong  correlation  (rs =0.93;  p < 0.05)  was  foundbetween serum and CSF concentrations  of OLA and a somewhatweaker (rs =0.5; p < 0.05) between those of DMO. The CSF con- centrations  of  OLA  and  DMO  were  in  average  13%  and  16% of those in serum. Extensive metabolizers of CYP2D6 were pre- scribed higher (p < 0.05) daily doses than poor metabolizers when the influence of smoking habits was taken into account. Smokers had  lower  concentration-to-dose   ratios  (C/D)  of  OLA  both  in serum and CSF than non-smokers  (median  7 vs. 10 nmol/L/mg in serum and 0.8 vs. 1.3 nmol/L/mg  in CSF; p < 0.01). C/D for serum DMO decreased with increasing age (rs = −0.41; p < 0.05). Carriers of ABCB1 1236T/2677T/3435T haplotype had higher serum (median 112 vs. 80 nmol/L; p < 0.05) and CSF (13.7 vs. 8.1 nmol/L; p < 0.05) OLA concentrations  than patients without this haplotype. Patients treated with benzodiazepines and/or zopiclone (n = 8) had higher DMO and DMO/OLA ratio (p < 0.05 for both) in CSF compared to patients not co-medicating  with these drugs (n = 21), even when smoking habits were taken into account.

    Conclusion:  The present study shows a very good correlation between  serum and CSF concentrations  of OLA, indicating  thatconcentrations  of OLA in serum reflect the situation in CSF.

    References

    [1]  Hägg S, Spigset O, Lakso H, et al. Olanzapine disposition in humans is unrelated to CYP1A2 and CYP2D6 phenotypes. Eur J Clin Pharmacol2001;57:493−97.

    [2]  Carrillo  JA, Herra´iz  AG, Ramos SI, et al. Role of smoking-inducedcytochrome P450 (CYP)1A2 and polymorphic CYP2D6 in steady-stateconcentration of olanzapine. J Clin Psychopharmacol 2003;23:119−27.

    [3]  Gunes A, Spina E, Dahl M-L, et al. ABCB1 polymorphisms influencesteady-state  plasma  levels  of  9-hydroxyrisperidone   and  risperidoneactive moiety. Ther Drug Monit 2008;30:628−33.

  • 18.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Almer, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Gastroentorology.
    Peterson, Curt
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monitoring of thiopurine metabolites - A high-performance liquid chromatography method for clinical use2013In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 75, p. 145-152Article in journal (Refereed)
    Abstract [en]

    A high-performance liquid chromatography method capable of measuring thiopurine mono-, di-, and triphosphates separately in red blood cells (RBCs) was developed. RBCs were isolated from whole blood using centrifugation. Proteins were precipitated using dichloromethane and methanol. The thioguanine nucleotides (TGNs) were derivatised using potassium permanganate before analysis. Analytes were separated by ion-pairing liquid chromatography using tetrabutylammonium ions and detected using UV absorption and fluorescence. The method was designed for use in clinical trials. Ten patient samples were analysed to demonstrate clinical application and to establish pilot ranges for all analytes. less thanbrgreater than less thanbrgreater thanThe method measured thioguanosine mono-(TGMP), di-(TGDP), and triphosphate (TGTP), as well as methylthioinosine mono- (meTIMP), di- (meTIDP) and triphosphate (meTITP) in RBCs collected from patients treated with thiopurine drugs (azathioprine, 6-mercaptopurine, and 6-thioguanine). less thanbrgreater than less thanbrgreater thanLOQ was 0.3, 3, 2, 30, 30 and 40 pmol/8 x 10(8) RBC, for TGMP, TGDP, TGTP, meTIMP, meTIDP and meTITP, respectively. Between-day precision were below 14% for all analytes at all concentrations and samples were stable at 4 degrees C for 8 h after sampling.

  • 19.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Almer, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    Peterson, Curt
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology UHL.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monitoring of thiopurine metabolites: A high-performance liquid chromatography method for clinical useManuscript (preprint) (Other academic)
    Abstract [en]

    high-performance liquid chromatography method capable of measuring thiopurine mono-, di-, and triphosphates separately in red blood cells (RBCs) was developed. RBC:s were isolated from whole blood using centrifugation. Proteins were precipitated using dichloromethane and methanol. The thioguanine nucleotides (TGNs) were derivatised using potassium permanganate before analysis. Analytes were separated by ion-pairing liquid chromatography using tetrabutylammonium ions and detected using UV absorption and fluorescence. The method was designed for use in clinical trials in thiopurine therapy and proven valid by analysis of authentic patient samples.

    The method measured thioguanosine mono- (TGMP), di- (TGDP), and triphosphate (TGTP), as well as methylthioinosine mono- (meTIMP), di- (meTIDP) and triphosphate (meTITP) in RBCs collected from patients treated with thiopurine drugs (azathioprine, 6-mercaptopurine, and 6-thioguanine).

    LOQ was 0.3, 3, 2, 30, 30 and 40 pmol/8x10^8 RBC, for TGMP, TGDP, TGTP, meTIMP, meTIDP and meTITP, respectively. Between-day precision were below 14% for all analytes at all concentrations and samples were stable at 5 °C for 8 hours after sampling.

  • 20.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Coulthard, S
    Newcastle University, Northern Institute for Cancer Research.
    Josefsson, Martin
    National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linkoping.
    Almer, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology and Gastroenterology UHL.
    Peterson, Curt
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Rapid Method to Measure Thioguanine Incorporation Into DNA2011In: European Journal of Cancer, ISSN 0959-8049, E-ISSN 1879-0852, Vol. 47, no Supplement 1, p. S650-S650Article in journal (Other academic)
    Abstract [en]

    Background: The thiopurine drugs, 6-mercaptopurine, azathioprine, and thioguanine, are used in the treatment of acute lymphoblastic leukaemia (ALL). During treatment the thioguanine nucleotides formed are incorporated into the DNA, causing apoptosis due to the cells inability to repair the resulting damage. This mechanism is believed to be important for the effects of thiopurine drugs. We have developed a novel method for the determination of thioguanine incorporation into DNA which is both faster and cheaper than earlier methods.

    Monitoring the effects of thiopurine treatment by measuring thiopurine metabolites in erythrocytes has proven to be elusive due to the lack of good correlation between measured concentrations and thiopurine effects. If the incorporation is the main mechanism of thiopurine action, a reliable method capable of measuring the incorporation in an ordinary blood sample, such as the method we have developed, should provide a significantly better correlation with treatment effect.

    Material and Methods: Briefly, DNA extracted from buffy coat is degraded using nuclease P1 and alkaline phosphatase to produce free nucleosides which are purified by filtration. Thioguanosine and thymidine are separated and detected using an LC-MS/MS system and the ratio between the bases provides a measurement of the extent of thioguanine incorporation in DNA. The method has been successfully applied to cell culture samples as well as samples from patients treated orally with thiopurines.

    Results: In 8 inflammatory bowel disease patients treated with azathioprine the measured incorporation ranged from 2.2 to 8.4 thioguanine bases for every 10 000 thymidine bases (median 5.2). This is in agreement with earlier reports on incorporation in childhood leukemia patients.

    Conclusions: With the presented method it is possible to determine the incorporation of thioguanine into DNA during thiopurine treatment in a cost effective manner, but further research is needed to determine if there is a place for this type of methods in the monitoring of thiopurine treatment.

    An ongoing study aims to compare the incorporation to treatment effects as well as conventional measurements of erythrocyte metabolite levels. By this study we hope to determine if incorporation is a more reliable measurement to predict treatment effect and if the erythrocyte metabolite levels correlate with the incorporation.

  • 21.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Gréen, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping Sweden.
    Brinkhagen, Linda
    Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping Sweden.
    Mukhtar, Shahzabe
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping Sweden.
    Identification of AB-FUBINACA metabolites in authentic urine samples suitable as urinary markers of drug intake using liquid chromatography quadrupole tandem time of flight mass spectrometry.2016In: Drug Testing and Analysis, ISSN 1942-7603, E-ISSN 1942-7611, Vol. 8, no 9, p. 950-956Article in journal (Refereed)
    Abstract [en]

    Synthetic cannabinoids are a group of psychoactive drugs presently widespread among drug users in Europe. Analytical methods to measure these compounds in urine are in demand as urine is a preferred matrix for drug testing. For most synthetic cannabinoids, the parent compounds are rarely detected in urine. Therefore urinary metabolites are needed as markers of drug intake. AB-FUBINACA was one of the top three synthetic cannabinoids most frequently found in seizures and toxicological drug screening in Sweden (2013-2014). Drug abuse is also reported from several other countries such as the USA and Japan. In this study, 28 authentic case samples were used to identify urinary markers of AB-FUBINACA intake using liquid chromatography quadrupole tandem time of flight mass spectrometry and human liver microsomes. Three metabolites suitable as markers of drug intake were identified and at least two of them were detected in all but one case. In total, 15 urinary metabolites of AB-FUBINACA were reported, including hydrolxylations on the indazole ring and the amino-oxobutane moiety, dealkylations and hydrolysis of the primary amide. No modifications on the fluorobenzyl side-chain were observed. The parent compound was detected in 54% of the case samples. Also, after three hours of incubation with human liver microsomes, 77% of the signal from the parent compound remained. Copyright © 2015 John Wiley & Sons, Ltd.

  • 22.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering. National Board Forens Med, Department Forens Genet and Forens Toxicol, Linkoping, Sweden.
    Green, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. National Board Forens Med, Department Forens Genet and Forens Toxicol, Linkoping, Sweden.
    Identification of AKB-48 and 5F-AKB-48 Metabolites in Authentic Human Urine Samples Using Human Liver Microsomes and Time of Flight Mass Spectrometry2015In: Journal of Analytical Toxicology, ISSN 0146-4760, E-ISSN 1945-2403, Vol. 39, no 6, p. 426-435Article in journal (Refereed)
    Abstract [en]

    The occurrence of structurally related synthetic cannabinoids makes the identification of unique markers of drug intake particularly challenging. The aim of this study was to identify unique and abundant metabolites of AKB-48 and 5F-AKB-48 for toxicological screening in urine. Investigations of authentic urine samples from forensic cases in combination with human liver microsome (HLM) experiments were used for identification of metabolites. HLM incubations of AKB-48 and 5F-AKB-48 along with 35 urine samples from authentic cases were analyzed with liquid chromatography quadrupole tandem time of flight mass spectrometry. Using HLMs 41 metabolites of AKB-48 and 37 metabolites of 5F-AKB-48 were identified, principally represented by hydroxylation but also ketone formation and dealkylation. Monohydroxylated metabolites were replaced by di- and trihydroxylated metabolites within 30 min. The metabolites from the HLM incubations accounted for on average 84% (range, 67-100) and 91% (range, 71-100) of the combined area in the case samples for AKB-48 and 5F-AKB-48, respectively. While defluorinated metabolites accounted for on average 74% of the combined area after a 5F-AKB-48 intake only a few identified metabolites were shared between AKB-48 and 5F-AKB-48, illustrating the need for a systematic approach to identify unique metabolites. HLMs in combination with case samples seem suitable for this purpose.

  • 23.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Kronstrand, Robert
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Josefsson, Martin
    Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Artillerigatan 12, SE-581 33 Linköping, Sweden.
    Retention of opioids and their glucuronides on a combined zwitterion and hydrophilic interaction stationary phase2008In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1187, no 01-Feb, p. 46-52Article in journal (Refereed)
    Abstract [en]

    A stationary phase combining zwitterionic ion chromatography and hydrophilic interaction chromatography (ZIC-HILIC) from SeQuant was evaluated for the chromatography of some opiates and their polar metabolites. The effects of mobile phase constitution on retention and resolution were extensively evaluated. Different aspects of mobile phase constitution such as ion strength and type of buffer, type and amount of organic modifier and pH were examined. The selectivity and retention of the opiates compared to their glucuronides could be substantially altered with small changes of the mobile phase, especially when the type of buffer, i.e., formate, or acetate and organic modifier, i.e., acetonitrile or methanol were changed. The retention on the ZIC-HILIC was dominated by hydrophilic interaction chromatography (HILIC) but considerable effects on the selectivity was observed, possibly caused by an ion exchange mechanism due to interactions with the charges on the stationary phase.

1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf