Current Issue : April-June Volume : 2024 Issue Number : 2 Articles : 5 Articles
The profile of and dynamic concentration changes in tyrosine, phenylalanine, and tryptophan metabolites in blood are of great interest since they could be considered potential biomarkers of different disorders. Some aromatic metabolites, such as 4-hydroxyphenyllactic, 4-hydroxyphenylacetic, phenyllactic, and 4-hydroxybenzoic acids have previously demonstrated their diagnostic significance in critically ill patients and patients with post-COVID-19 syndrome. In this study, a sensitive method, including serum protein precipitation with methanol and ultra-high-pressure liquid chromatographytandem mass spectrometry (UPLC-MS/MS) detection, was developed and validated for six phenyland five indole-containing acids in human serum. The liquid–liquid extraction was also examined, but it demonstrated unsatisfactory results based on analyte recoveries and the matrix effect. However, the recoveries for all analytes reached 100% and matrix effects were not observed using protein precipitation. This made it possible to use deionized water as a blank matrix. The lower limits of quantitation (LLOQs) were from 0.02 to 0.25 μmol/L. The validated method was used for the analysis of serum samples of healthy volunteers (n = 48) to reveal the reference values of the target analytes. The concentrations of the most clinically significant metabolite 4-hydroxyphenyllactic acid, which were revealed using UPLC-MS/MS and a previously developed gas chromatography-mass spectrometry method, were completely comparable. The proposed UPLC-MS/MS protocol can be used in the routine clinical practice of medical centers....
Thymoquinone (TQ) is the primary component of Nigella sativa L. (NS) oil, which is renowned for its potent hepatoprotective effects attributed to its antioxidant, anti-fibrotic, antiinflammatory, anti-carcinogenic, and both anti- and pro-apoptotic properties. The aim of this work was to establish a method of measuring TQ in serum in order to investigate the pharmacokinetics of TQ prior to a targeted therapeutic application. In the first step, a gas chromatography–mass spectrometry method for the detection and quantification of TQ in an oily matrix was established and validated according to European Medicines Agency (EMA) criteria. For the assessment of the clinical application, TQ concentrations in 19 oil preparations were determined. Second, two serum samples were spiked with TQ to determine the TQ concentration after deproteinization using toluene. Third, one healthy volunteer ingested 1 g and another one 3 g of a highly concentrated NS oil 30 and 60 min prior to blood sampling for the determination of serum TQ level. After the successful establishment and validation of the measurement method, the highest concentration of TQ (36.56 g/L) was found for a bottled NS oil product (No. 1). Since a capsule is more suitable for oral administration, the product with the third highest TQ concentration (No. 3: 24.39 g/L) was used for all further tests. In the serum samples spiked with TQ, the TQ concentration was reliably detectable in a range between 5 and 10 μg/mL. After oral intake of NS oil (No. 3), however, TQ and/or its derivatives were not detectable in human serum. This discrepancy in detecting TQ after spiking serum or following oral ingestion may be attributed to the instability of TQ in biomatrices as well as its strong protein binding properties. A pharmacokinetics study was therefore not viable. Studies on isotopically labeled TQ in an animal model are necessary to study the pharmacokinetics of TQ using alternative modalities....
High exercise loading causes intricate and ambiguous proteomic and metabolic changes. This study aims to describe the dataset on protein and metabolite contents in plasma samples collected from highly trained athletes across different sports disciplines. The proteomic and metabolomic analyses of the plasma samples of highly trained athletes engaged in sports disciplines of different intensities were carried out using HPLC-MS/MS. The results are reported as two datasets (proteomic data in a derived mgf-file and metabolomic data in processed format), each containing the findings obtained by analyzing 93 mass spectra. Variations in the protein and metabolite contents of the biological samples are observed, depending on the intensity of training load for different sports disciplines. Mass spectrometric proteomic and metabolomic studies can be used for classifying different athlete phenotypes according to the intensity of sports discipline and for the assessment of the efficiency of the recovery period....
The objective of the present report was to develop and validate a simple, selective, and reproducible high-performance liquid chromatography method with UV detection suitable for routine therapeutic drug monitoring of the most commonly used antiepileptic drugs and some of their metabolites. Simple precipitation of plasma proteins with acetonitrile was used for sample preparation. 10,11-dihydrocarbamazepine was used as an internal standard. Chromatographic separation of the analytes was achieved by gradient elution on a Phenyl–Hexyl column at 40 ◦C, using methanol and potassium phosphate buffer (25 mM; pH 5.1) as a mobile phase. The method was validated according to the FDA guidelines for bioanalytical method validation. It showed to be selective, accurate, precise, and linear over the concentration ranges of 1–50 mg/L for phenobarbital, phenytoin, levetiracetam, rufinamide, zonisamide, and lacosamide; 0.5–50 mg/L for lamotrigine, primidone, carbamazepine and 10-monohydroxycarbazepine; 0.2–10 mg/L for carbamazepine metabolites: 10,11-trans-dihydroxy-10,11-dihydrocarbamazepine and carbamazepine-10,11-epoxide; 0.1–10 mg/L for oxcarbazepine; 2–100 mg/L for felbamate and 3–150 mg/L for ethosuximide. The suitability of the validated method for routine therapeutic drug monitoring was confirmed by quantification of the analytes in plasma samples from patients with epilepsy on combination antiepileptic therapy....
Systemic antifungal agents are essential for high-risk patients undergoing immunosuppressive therapy or cancer chemotherapy because of the rapid increase in opportunistic fungal infections. Therapeutic drug monitoring is crucial to ensuring the efficacy and safety of antifungal agents owing to their pharmacokinetic variability. In the present study, we developed and validated a quantitative method for the simultaneous detection of seven commonly used antifungal drugs (amphotericin B, isavuconazole, voriconazole, fluconazole, posaconazole, caspofungin, and micafungin) using liquid chromatography-tandem mass spectrometry. Methanol (containing 0.1% formic acid) was used for protein precipitation and only 50 μL of serum was required for the analysis. Chromatographic separation was conducted using a Waters Acquity UPLC C8 column, and one stable isotope-labeled agent and two analogs were used as internal standards. The calibration curves ranged from 0.1 to 50 μg/mL for all agents, and the correlation coefficient (R2) for all calibration curves was above 0.9835. The intra-day precision (1.2–11.2%), inter-day precision (2.4–13.2%), and mean bias values (−10.9 to 13.6%) were within an acceptable range of ±15%. Successful implementation of the developed method in clinical practice would facilitate the effective monitoring of these antifungal agents....
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