Application of a molecular networking approach using LC-HRMS combined with the MetWork webserver for clinical and forensic toxicology.

Backgrounds And Aims: In toxicology, LC-HRMS for untargeted screening yields a great deal of high quality spectral data. However, there we lack tools to visualize/organize the MS data. We applied molecular networking (MN) to untargeted screening interpretation.

Quantitation of 10 antibiotics in plasma: Sulfosalicylic acid combined with 2D-LC-MS/MS is a robust assay for beta-lactam therapeutic drug monitoring.

Therapeutic drug monitoring (TDM) of antibiotics is particularly important in populations with high pharmacokinetic variabilities, such as critically ill patients, leading to unpredictable plasma concentrations and clinical outcomes. Here, we i) describe an original method for the simultaneous quantification of ten antibiotics (cefepime, ceftazidime, ampicillin, piperacillin/tazobactam, cefotaxime, amoxicillin, cloxacillin, oxacillin, linezolid) using 5-sulfosalicylic acid dihydrate (SSA) solution for protein precipitation together with 2D-LC-MS/MS, and ii) evaluate its impact in a one-year retrospective study. The method involved simple dilution with an aqueous mix of deuterated internal standards and plasma protein precipitation with SSA.

[Tonic water and quinine-a bicentennial booming cocktail].

Objectives Of The Study: During the SARS-CoV-2 pandemic, the media has often mentioned the presence of quinine in tonic water. Media accounts of quinine's antiviral effect as well as press reports about quinine-based compounds, such as hydroxychloroquine, have sparked renewed public interest in drinking tonic water, which could perhaps result in an increase in allergic phenomena. On the 200th anniversary of the discovery of quinine, our main objective was to analyze hypersensitivity reactions, related to the consumption of beverages containing quinine, described in the literature.

False positive amphetamines and 3,4-methylenedioxymethamphetamine immunoassays in the presence of metoprolol-two cases reported in clinical toxicology.

Amphetamines, frequently used recreational drugs with high risk of toxicity, are commonly included in urine drug screens. This screening is based on enzyme immunoassay, which is a quick and easy-to-perform technique, but may lack specificity resulting from cross-reactivity with other compounds, causing false positive results. We present two cases of presumed false positive MULTIGENT® amphetamine/methamphetamine and MULTIGENT® ecstasy (Abbott®) immunoassays with the beta-blocker metoprolol.

Off-line solid phase extraction and liquid chromatography-tandem mass spectrometry method for the quantitation of brivaracetam acid metabolites: Method validation and application to in vitro metabolism assays.

Brivaracetam (BRV) is a new high affinity synaptic vesicle protein 2A ligand recently approved for adults with partial-onset seizures. As a support to in vitro metabolism assays, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method coupled to off-line solid phase extraction (SPE) was developed to quantify BRV acid metabolites, that is, BRV-AC (carboxylic derivative derived from BRV hydrolysis) and BRV-OHAC (corresponding to hydroxylated BRV-AC). The method was validated for various incubates (liver and kidney tissue homogenates and blood, all from humans) and applied to in vitro metabolism assays.

Diagnosis of Heroin Overdose in an 8-Year-Old Boy: Reliable Contribution of Toxicological Investigations.

Toxicological investigations are often required by clinicians in comatose patients with suspected poisoning. However, the usefulness of toxicological analyses to support a diagnosis of acute poisoning is debated among clinicians and the interpretation of laboratory tests is challenging given the wide diversity of analytical techniques available. We report the case of an 8-year-old boy who was admitted to an intensive care unit with severe respiratory depression and neurological impairment.

[Sample preparation and bioanalysis in mass spectrometry].

The quantitative analysis of compounds of clinical interest of low molecular weight (<1000 Da) in biological fluids is currently in most cases performed by liquid chromatography-mass spectrometry (LC-MS). Analysis of these compounds in biological fluids (plasma, urine, saliva, hair..

Generic on-line solid phase extraction sample preparation strategies for the analysis of drugs in biological matrices by LC-MS/MS.

In the present work we investigate the integration of a single hardware platform (Prospekt-2) allowing on-line SPE with pre-/post-trapping dilution and direct injection of plasma extracts, and also compare the benefits and challenges of the different approaches for pharmaceutical drugs with heterogeneous physicochemical properties. In the first part, the generic use of on-line SPE with direct plasma injection or after protein precipitation was investigated for the quantitative analysis of talinolol. In the second part, pre-trapping and post-trapping dilution for on-line SPE is discussed for generic method development on an oxadiazole and its major metabolite.

Development, validation and clinical application of a LC-MS/MS method for the simultaneous quantification of hydroxychloroquine and its active metabolites in human whole blood.

A rapid, sensitive and specific method using liquid chromatography coupled to tandem mass spectrometry was developed for the simultaneous quantification of hydroxychloroquine (HCQ) and its three major metabolites in human whole blood. The assay, using a sample volume of 100μL, was linear in a dynamic 25-2000ng/mL range (R(2)>0.99) for all four compounds and suitable for the determination of elevated HCQ concentrations up to 20,000ng/mL, after appropriate sample dilution.

Are empty methadone bottles empty? An analytic study.

Background: Methadone maintenance treatment is the most widely prescribed treatment for opiate dependence with proven benefits for patients. In naïve users or in case of recreational misuse, methadone can be a source of potentially lethal intoxications, resulting in fatal overdoses. A few cases of infantile intoxications have been described in the literature, some of which resulted in death.

False hyperlactatemia in life-threatening ethylene glycol poisoning.

Ethylene glycol poisoning is rare, but prompt diagnosis is crucial, in order to initiate specific treatments. Herein, we report the case of a patient who was admitted to ICU for coma and extreme metabolic acidosis with unexpected hyperlactatemia on initial ICU blood gas analyzer. Ethylene glycol poisoning was diagnosed, and hyperlactatemia was ruled out on a blood sample sent to the biochemistry department.

Rugged and accurate quantitation of colchicine in human plasma to support colchicine poisoning monitoring by using turbulent-flow LC-MS/MS analysis.

Background: Colchicine is a common drug used in inflammatory diseases. The narrow therapeutic index requires fast and reliable techniques for its quantitation. An online, automated sample preparation using TurboFlow™ technology combined with triple-stage quadrupole MS detection was applied to identify colchicine in human plasma and follow intoxications.

[Passive cocaine inhalation by a 25-month-old child].

Cocaine and its principal metabolite were isolated from the urine, confirmed by urine chromatographic analysis, in a 25-month-old girl who had unsteady gait and a third fever seizure. She was premature, had intrauterine growth restriction (IUGR), and a psychomotor delay. The hair examination confirmed prolonged cocaine exposure.

Simultaneous quantitation of histamine and its major metabolite 1-methylhistamine in brain dialysates by using precolumn derivatization prior to HILIC-MS/MS analysis.

In nonclinical drug development targeting the central nervous system (CNS), the quantitative determination of extracellular brain concentrations of neurotransmitters is a key challenge. In some CNS disorders, the monitoring of the modified profile of neurotransmitter release such as that of histamine may explain the mechanism of action of the drug candidate. Microdialysis is a commonly used method for sampling extracellular levels of neurotransmitters/drug candidates in small laboratory animals.

Quantitation of polar analytes using column-switching: application to oxycodone and three metabolites in human plasma.

We present herein a sensitive and selective assay for the determination of oxycodone and its main metabolites, oxymorphone, noroxycodone and noroxymorphone in human plasma, using column-switching and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Sample preparation comprised protein precipitation with perchloric acid. After neutralization, the supernatant was injected without any evaporation step onto a polymeric, pH-resistant cartridge (HySphere Resin GP 10-12 microm) for sample clean-up (Prospekt II).

Method development aspects for the quantitation of pharmaceutical compounds in human plasma with a matrix-assisted laser desorption/ionization source in the multiple reaction monitoring mode.

The present work investigates various method development aspects for the quantitative analysis of pharmaceutical compounds in human plasma using matrix-assisted laser desorption/ionization and multiple reaction monitoring (MALDI-MRM). Talinolol was selected as a model analyte. Liquid-liquid extraction (LLE) and protein precipitation were evaluated regarding sensitivity and throughput for the MALDI-MRM technique and its applicability without and with chromatographic separation.

Determination of talinolol in human plasma using automated on-line solid phase extraction combined with atmospheric pressure chemical ionization tandem mass spectrometry.

A specific LC-MS/MS assay was developed for the automated determination of talinolol in human plasma, using on-line solid phase extraction system (prospekt 2) combined with atmospheric pressure chemical ionization (APCI) tandem mass spectrometry. The method involved simple precipitation of plasma proteins with perchloric acid (contained propranolol) as the internal standard (IS) and injection of the supernatant onto a C8 End Capped (10 mmx2 mm) cartridge without any evaporation step. Using the back-flush mode, the analytes were transferred onto an analytical column (XTerra C18, 50 mmx4.

Triple quadrupole linear ion trap mass spectrometer for the analysis of small molecules and macromolecules.

Recently, linear ion traps (LITs) have been combined with quadrupole (Q), time-of-flight (TOF) and Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS). LITs can be used either as ion accumulation devices or as commercially available, stand-alone mass spectrometers with MSn capabilities. The combination of triple quadrupole MS with LIT technology in the form of an instrument of configuration QqLIT, using axial ejection, is particularly interesting, because this instrument retains the classical triple quadrupole scan functions such as selected reaction monitoring (SRM), product ion (PI), neutral loss (NL) and precursor ion (PC) while also providing access to sensitive ion trap experiments.

Quantitative high-throughput analysis of drugs in biological matrices by mass spectrometry.

To support pharmacokinetic and drug metabolism studies, LC-MS/MS plays more and more an essential role for the quantitation of drugs and their metabolites in biological matrices. With the new challenges encountered in drug discovery and drug development, new strategies are put in place to achieve high-throughput analysis, using serial and parallel approaches. To speed-up method development and validation, generic approaches with the direct injection of biological fluids is highly desirable.

Gas chromatography-combustion-isotope ratio mass spectrometry analysis of 19-norsteroids: application to the detection of a nandrolone metabolite in urine.

Determination of whether the major metabolite of nandrolone in urine, 19-norandrosterone (19-NA), is exogenous or endogenous in origin is one of the most exciting challenges for antidoping laboratories. Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) can be used to differentiate these two origins by carbon isotopic ratio analysis. A complete method for purification of 19-NA in urine has been established.

Detection of exogenous intake of natural corticosteroids by gas chromatography/combustion/isotope ratio mass spectrometry: application to misuse in sport.

A detailed procedure for the analysis of exogenous hydrocortisone and cortisone in urine by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is proposed. As urinary levels of hydrocortisone are rather low for GC/C/IRMS analysis, the focus is on the main corticosteroid metabolites, tetrahydrocortisone (THE) and tetrahydrocortisol (THF). Following different solid phase extraction purifications, THE and THF are oxidized to 5beta-androstanetrione before analysis by GC/C/IRMS.