The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Vieira, Duarte Nuno - One of the best experts on this subject based on the ideXlab platform.
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Solid-phase extraction and gas chromatographic- mass spectrometric determination of the veterinary drug xylazine in human blood
'Oxford University Press (OUP)', 2007Co-Authors: Barroso Mário, Gallardo Eugenia, Margalho Cláudia, Devesa N, Pimentel J, Vieira, Duarte NunoAbstract:This paper presents a method for the determination of xylazine in whole blood using solid-phase extraction and gas chromatography-mass spectrometry. This technique required only 0.5 mL of sample, and Protriptyline was used as internal standard (IS). Limits of detection and quantitation (LOQ) were 2 and 10 ng/mL, respectively. The method was found to be linear between the LOQ and 3.50 microg/mL, with correlation coefficients higher than 0.9922. Precision (intra- and interday) and accuracy were in conformity with the criteria normally accepted in bioanalytical method validation. The analyte was stable in the matrix for at least 18 h at room temperature and for at least three freeze/thaw cycles. Mean recovery, calculated at three concentration levels, was 87%. To the best of our knowledge, this is the first time that solid-phase extraction is used as sample preparation technique for the determination of this compound in biological media. Because of its simplicity and speed when compared to other extraction techniques, the herein described method can be successfully applied in the diagnosis of intoxications by xylazine.info:eu-repo/semantics/publishedVersio
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Solid-phase extraction for gas chromatographic mass spectrometric determination of the veterinary drug xylazine in human blood.
2007Co-Authors: Gallardo Eugenia, Barroso Mário, Devesa N, Pimentel J, Margalho C., Vieira, Duarte NunoAbstract:This paper presents a method for the determination of xylazine in whole blood using solid-phase extraction and gas chromatography–mass spectrometry. This technique required only 0.5 mL of sample, and Protriptyline was used as internal standard (IS). Limits of detection and quantitation (LOQ) were 2 and 10 ng/mL, respectively. The method was found to be linear between the LOQ and 3.50 ìg/mL, with correlation coefficients higher than 0.9922. Precision (intra- and interday) and accuracy were in conformity with the criteria normally accepted in bioanalytical method validation. The analyte was stable in the matrix for at least 18 h at room temperature and for at least three freeze/thaw cycles. Mean recovery, calculated at three concentration levels, was 87%. To the best of our knowledge, this is the first time that solid-phase extraction is used as sample preparation technique for the determination of this compound in biological media. Because of its simplicity and speed when compared to other extraction techniques, the herein described method can be successfully applied in the diagnosis of intoxications by xylazine
Sotirios Athanaselis - One of the best experts on this subject based on the ideXlab platform.
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a fully validated method for the simultaneous determination of 11 antidepressant drugs in whole blood by gas chromatography mass spectrometry
Journal of Pharmaceutical and Biomedical Analysis, 2012Co-Authors: Ioannis Papoutsis, Alaa Khraiwesh, Panagiota Nikolaou, Constantinos Pistos, Chara Spiliopoulou, Sotirios AthanaselisAbstract:Antidepressant drugs are widely used for the treatment of depression and other psychiatric disorders and as a result they are involved in numerous clinical and forensic cases. The aim of this study was the development, optimization and validation of a simple, specific and sensitive GC/MS method for the simultaneous determination of 11 antidepressant drugs and 4 of their metabolites (amitriptyline, citalopram, clomipramine, fluoxetine, fluvoxamine, maprotiline, desmethyl-maprotiline, mirtazapine, desmethyl-mirtazapine, nortriptyline, paroxetine, sertraline, desmethyl-sertraline, venlafaxine and desmethyl-venlafaxine) in whole blood. The combination of solid-phase extraction with derivatization using heptafluorobutyric anhydride efficiently reduced matrix effect and improved sensitivity of the method. In this assay, Protriptyline was used as internal standard. Absolute recovery values for all analytes were ranged from 79.2 to 102.6%. LODs and LOQs were found to be between 0.30-1.50 μg/L and 1.00-5.00 μg/L, respectively. The calibration curves were linear (R(2)≥0.990) within the range of 5.00-1000 μg/L for all analytes. Accuracy expressed as the % E(r) was found to be between -12.3 and 12.2%. Precision expressed as the % RSD was found to be less than 11.7% for all antidepressants. The developed method proved to be suitable for routine work and it was used to successfully analyze more than 2500 clinical and forensic blood samples.
David J. Heal - One of the best experts on this subject based on the ideXlab platform.
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3h nisoxetine a radioligand for noradrenaline reuptake sites correlation with inhibition of 3h noradrenaline uptake and effect of dsp 4 lesioning and antidepressant treatments
Neuropharmacology, 1996Co-Authors: Sharon C. Cheetham, J.a. Viggers, S. A. Butler, M.r. Prow, David J. HealAbstract:Abstract Nisoxetine is a potent and selective inhibitor of noradrenaline uptake into noradrenergic neurones. [3H]Nisoxetine binding to rat frontal cortical membranes was of high affinity. The binding data of both competition and saturation studies fitted a single site binding model. [3H]Nisoxetine binding was potently inhibited by the selective noradrenaline uptake inhibitors desipramine and Protriptyline. In addition, a very good correlation was obtained between the ability of 25 monoamine reuptake inhibitors and related compounds both to inhibit [3H]nisoxetine binding and to inhibit [3H]noradrenaline uptake in rat frontal cortex. DSP-4 (10–100 mg/kg, i.p.) dose-dependently depleted cortical noradrenaline concentrations (51–100%), with no significant effects on 5-HT and dopamine. These depletions, which were used as a marker of loss of noradrenergic nerve terminals, were associated with a dose-dependent decrease in the number of [3H]nisoxetine binding sites (20–97%) with no change in binding affinity. Furthermore, a good correlation was obtained between cortical noradrenaline concentrations and the number of [3H]nisoxetine binding sites. These data support the view that [3H]nisoxetine binds to a single population of homogeneous sites associated with the noradrenaline transporter complex. Using this ligand, the effects of repeated administration of both antidepressant drugs with a range of pharmacological actions and of electroconvulsive shock on noradrenaline reuptake sites were examined. The number and affinity of [3H]nisoxetine binding sites were unaltered by all treatments. It is unlikely, therefore, that antidepressant therapy would produce adaptive changes in noradrenaline uptake sites.
Mahesh J. Kulkarni - One of the best experts on this subject based on the ideXlab platform.
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Destabilization of amyloid dimer by Protriptyline.
2014Co-Authors: Sneha B. Bansode, Asis K. Jana, Kedar B. Batkulwar, Shrikant D. Warkad, Rakesh S. Joshi, Neelanjana Sengupta, Mahesh J. KulkarniAbstract:A. Evolution of monomer-monomer interaction strength over time for free dimer (broken line) and Protriptylline-bound dimer (solid line). Inset. Distributions of the interactions from multiple trajectories, and the dimer interactions with Protriptylline (in brown) B. Distributions of the asphericity for free (in broken line) and Protriptylline-bound (solid line) dimer C. Representative snapshot of most populated cluster of free, and D. Protriptylline-bound dimer [16–20 region in blue colour with 19–20 showed in line representation; Protriptyline in red colour and two Aβ peptides are in cyan and limon colour respectively] E. Residue-residue contact probabilities for free dimer, and F. Protriptylline-bound dimer G. Residue-wise Beta sheet percentages for free dimer (in red) and Protriptylline-bound dimer (in blue) H. Residue-wise helical percentages for free dimer (in red) and Pro-bound dimer (in blue).
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Protriptyline inhibits AChE activity.
2014Co-Authors: Sneha B. Bansode, Asis K. Jana, Kedar B. Batkulwar, Shrikant D. Warkad, Rakesh S. Joshi, Neelanjana Sengupta, Mahesh J. KulkarniAbstract:A. Determination of IC50 values of five drugs for AChE by using 0.05–0.8 mM concentration range of all the drugs B. Estimation of the kinetic constants by Lineweaver–Burk analysis. AChE inhibition by Protriptyline showed competitive inhibition. C. Isothermal Titration Calorimetric analysis of Protriptyline – AChE interactions. The upper panel shows the raw data in the form of heat effect during titration and the lower panel shows corresponding thermogram representing the best fit curve D. Snapshot of drug binding with catalytic subsite of AChE E. snapshot of drug binding with anionic subsite of AChE F. Distribution of Protriptyline –anionic subsite (solid line) and Protriptyline –esteratic subsite (broken line) nonbonded (nonb) interaction energy; data are averaged over last 20 ns G. Fluorescence quenching of AChE by Protriptyline H. CD spectra of binding of Protriptyline to AChE and I. CD pro analysis to study the conformational change J. Evolution of the backbone RMSD for the Protriptylline bound (solid line) and free (broken line) AChE active sites from MD trajectories K. SASA distributions of active sites for Pro-bound (solid line) and free (broken line) AChE active sites from MD trajectories L. Measurement of AChE activity after treatment of neuro2a cells with 25 µM and 60 µM Protriptyline for 15 h.
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Cell viability in neuro2a cells.
2014Co-Authors: Sneha B. Bansode, Asis K. Jana, Kedar B. Batkulwar, Shrikant D. Warkad, Rakesh S. Joshi, Neelanjana Sengupta, Mahesh J. KulkarniAbstract:Effect of various concentrations of Protriptyline (25–500 µM) on cell viability was assessed by MTT assay. Cells were 90% viable up to 150 µM Protriptyline concentration.
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Protriptyline Does Not Affect Other Proteases.
2014Co-Authors: Sneha B. Bansode, Asis K. Jana, Kedar B. Batkulwar, Shrikant D. Warkad, Rakesh S. Joshi, Neelanjana Sengupta, Mahesh J. KulkarniAbstract:Effect of Protriptyline on A. Trypsin B. ADAM 17activity. Specific synthetic substrate BApNA and fluorogenic peptide was used for analyzing activity on trypsin and ADAM 17, respectively. Trypsin activity was unaffected, while ADMA 17 showed weak inhibition in presence of Protriptyline.
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Protriptyline as MTDL.
2014Co-Authors: Sneha B. Bansode, Asis K. Jana, Kedar B. Batkulwar, Shrikant D. Warkad, Rakesh S. Joshi, Neelanjana Sengupta, Mahesh J. KulkarniAbstract:The scheme represents that Protriptyline (at the center) is able to inhibit key targets of AD pathogenesis such as AChE, BACE-1, Amyloid aggregation and glycation induced amyloid aggregation.
Ioannis Papoutsis - One of the best experts on this subject based on the ideXlab platform.
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a fully validated method for the simultaneous determination of 11 antidepressant drugs in whole blood by gas chromatography mass spectrometry
Journal of Pharmaceutical and Biomedical Analysis, 2012Co-Authors: Ioannis Papoutsis, Alaa Khraiwesh, Panagiota Nikolaou, Constantinos Pistos, Chara Spiliopoulou, Sotirios AthanaselisAbstract:Antidepressant drugs are widely used for the treatment of depression and other psychiatric disorders and as a result they are involved in numerous clinical and forensic cases. The aim of this study was the development, optimization and validation of a simple, specific and sensitive GC/MS method for the simultaneous determination of 11 antidepressant drugs and 4 of their metabolites (amitriptyline, citalopram, clomipramine, fluoxetine, fluvoxamine, maprotiline, desmethyl-maprotiline, mirtazapine, desmethyl-mirtazapine, nortriptyline, paroxetine, sertraline, desmethyl-sertraline, venlafaxine and desmethyl-venlafaxine) in whole blood. The combination of solid-phase extraction with derivatization using heptafluorobutyric anhydride efficiently reduced matrix effect and improved sensitivity of the method. In this assay, Protriptyline was used as internal standard. Absolute recovery values for all analytes were ranged from 79.2 to 102.6%. LODs and LOQs were found to be between 0.30-1.50 μg/L and 1.00-5.00 μg/L, respectively. The calibration curves were linear (R(2)≥0.990) within the range of 5.00-1000 μg/L for all analytes. Accuracy expressed as the % E(r) was found to be between -12.3 and 12.2%. Precision expressed as the % RSD was found to be less than 11.7% for all antidepressants. The developed method proved to be suitable for routine work and it was used to successfully analyze more than 2500 clinical and forensic blood samples.
