Metabolites In Biological Fluids Research Articles

In Vitro and In Vivo Analysis of Fentanyl and Fentalog Metabolites using Hyphenated Chromatographic Techniques: A Review.

Fentanyl and fentanyl analogues (also called fentalogs) are used as medical prescriptions to treat pain for a long time. Apart from their pharmaceutical applications, they are misused immensely, causing the opioid crisis. Fentanyl and its analogues are produced in clandestine laboratories and sold over dark Web markets to different parts of the world, leading to a rise in the death rate due to drug overdose. This is because the users are unaware of the lethal effects of the newer forms of fentalogs. Unlike other drugs, these fentalogs cannot be detected easily, as very little data are available, and this is one of the major reasons for the risk of life-threatening poisoning or deaths. Hence, rigorous studies of these drugs and their possible metabolites are required. It is also necessary to develop techniques for the detection of minute traces of metabolites in biological fluids. This Review provides an overview of the application of hyphenated chromatographic techniques used to analyze multiple novel fentalogs, using in vivo and in vitro methods. The article focuses on the metabolites formed in phase I and phase II processes in biological specimens obtained in recent cases of drug abuse and overdose deaths that could be useful for the detection and differentiation of multiple fentalogs.

Anabolic treatments in bovines: quantification of plasma protein markers of dexamethasone administration.

The aim of this study was to profile plasma proteome responses in bulls experimentally treated with dexamethasone at anabolic dosage. Illicit use of active substances in animal husbandry remains a matter of concern in Europe. Corticosteroids are probably one of the most widespread growth promoter family illegally used in beef cattle and veal calves. Testing for corticosteroids relies on detection of drug residues or their metabolites in biological fluids or tissues. Their indirect detection by mapping altered physiological parameters may overcome limits linked to route of administration, dosage, biotransformation and elimination kinetics that can lower residual drug concentration, hampering official controls. A set of 11 proteins proposed in literature as potential markers of anabolic treatments with dexamethasone, was quantified in bovine plasma by targeted proteomics based on liquid chromatography-high resolution tandem mass spectrometry. Among investigated proteins, sex hormone-binding globulin (SHBG), histidine-rich glycoprotein (HRG) and paraoxonase-1 (PON1) were found to be biomarkers of treatment. To investigate further such biomarkers, an additional group of veal calves was experimentally treated with dexamethasone at anabolic. These animals also demonstrated a significant alteration in SHBG, HRG and PON1 concentration, suggesting that quantification of plasma markers have the potential to detect animals illegally exposed to dexamethasone.

Detection of Metabolite-Protein Interactions in Complex Biological Samples by High-Resolution Relaxometry: Toward Interactomics by NMR.

Metabolomics, the systematic investigation of metabolites in biological fluids, cells, or tissues, reveals essential information about metabolism and diseases. Metabolites have functional roles in a myriad of biological processes, as substrates and products of enzymatic reactions but also as cofactors and regulators of large numbers of biochemical mechanisms. These functions involve interactions of metabolites with macromolecules. Yet, methods to systematically investigate these interactions are still scarce to date. In particular, there is a need for techniques suited to identify and characterize weak metabolite-macromolecule interactions directly in complex media such as biological fluids. Here, we introduce a method to investigate weak interactions between metabolites and macromolecules in biological fluids. Our approach is based on high-resolution NMR relaxometry and does not require any invasive procedure or separation step. We show that we can detect interactions between small and large molecules in human blood serum and quantify the size of the complex. Our work opens the way for investigations of metabolite (or other small molecules)-protein interactions in biological fluids for interactomics or pharmaceutical applications.

A review on bioanalytical method development and pre-method validation concepts using SPE and LLE process by LC-MS/MS method

The review article provides guidance for the development of a Bio-Analytical Method intended for the estimation of drugs in biological fluids. The development of a suitable analytical method for the identification, isolation and quantification of different drugs and or their metabolites from biological fluids is an essential and challenging component of pharmacokinetic studies. The uses of detection techniques that are highly sensitive and specific for the quantification of drugs and or metabolites in biological fluids are preferred. To collect the information on physiochemical, pharmacokinetic, chromatographic and extraction procedures of the drug/Metabolites from available sources, e.g. Medline, Journals, Analytical abstract, Physician Desk Reference, Library etc. Summarize the physiochemical, pharmacokinetic properties, chromatographic and extraction procedures. Select the equipment according to the availability and sensitivity. Select the initial chromatographic conditions and also identify the extraction. The selection of Internal standard should be similar to the analyte. Prepare the required solutions and stock dilutions at the required concentration. Tune the instrument with suitable solutions and optimize parameters for Q1/Q3 ions. Condition the system and column with the selected mobile phase. Perform pre-method validation experiments. Select the best weighing factors for the standards. Compile all the chromatograms and raw data and archive since the development of a Bio-Analytical method for a given drug is so essential to start with, this guidance for approaching and conclude for a suitable method that later can be validated. It is important to note that this is intended to identify minimal criteria for producing consistent and comparable data. This procedure is applicable to the methods that are to be developed for the estimation of drugs and metabolites from biological fluids using any chromatographic devices in the Bio- Analytical Department.

Narrative review of metabolomics in cardiovascular disease

Cardiovascular diseases are accompanied by disorders in the cardiac metabolism. Furthermore, comorbidities often associated with cardiovascular disease can alter systemic and myocardial metabolism contributing to worsening of cardiac performance and health status. Biomarkers such as natriuretic peptides or troponins already support diagnosis, prognosis and treatment of patients with cardiovascular diseases and are represented in international guidelines. However, as cardiovascular diseases affect various pathophysiological pathways, a single biomarker approach cannot be regarded as ideal to reveal optimal clinical application. Emerging metabolomics technology allows the measurement of hundreds of metabolites in biological fluids or biopsies and thus to characterize each patient by its own metabolic fingerprint, improving our understanding of complex diseases, significantly altering the management of cardiovascular diseases and possibly personalizing medicine. This review outlines current knowledge, perspectives as well as limitations of metabolomics for diagnosis, prognosis and treatment of cardiovascular diseases such as heart failure, atherosclerosis, ischemic and non-ischemic cardiomyopathy. Furthermore, an ongoing research project tackling current inconsistencies as well as clinical applications of metabolomics will be discussed. Taken together, the application of metabolomics will enable us to gain more insights into pathophysiological interactions of metabolites and disease states as well as improving therapies of patients with cardiovascular diseases in the future.

Synthesis and sorptive properties of molecularly imprinted polymer for simultaneous isolation of catecholamines and their metabolites from biological fluids

Simultaneous quantitative analysis of catecholamines (CAs) and their respective acid metabolites in biological fluids can become a powerful tool for diagnosis and treatment of various diseases. However, selective sample preparation procedure is necessary to isolate the aforementioned analytes from the matrix. Therefore, we propose a synthetic strategy for the preparation of a molecularly imprinted sorbent with binding sites for both CAs and their respective acid metabolites. The synthesis combines noncovalent and semicovalent imprinting methods. Methylenebisacrylamide, 4-vynilbenzyl-N,N,N-trimethylammonium (3,4-dimethoxyphenyl)acetate, and 3-phenylpropylacrylate were used as the cross-linker, functional monomer 1/“dummy” template 1, and functional monomer 2/“dummy” template 2 under precipitation polymerization conditions, respectively. The polymer was characterized using Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. The binding properties were studied by constructing adsorption isotherms and conducting competitive binding tests. The performance of the molecularly imprinted polymers (MIPs) toward CAs and the acids was described by good imprinting factors (3.1–5.6), fast-binding equilibrium, and the ability to differentiate nonmethylated CAs from methylated ones. The MIP was used to simultaneously isolate the analytes from human plasma under dispersive solid-phase extraction conditions with subsequent detection using optimized UHPLC/MS/MS procedure. As a result, no major interferences were detected which suggests that the impurities were well separated from the analytes.

Disposition of Phytocannabinoids, Their Acidic Precursors and Their Metabolites in Biological Matrices of Healthy Individuals Treated with Vaporized Medical Cannabis

Inhalation by vaporization is a useful application mode for medical cannabis. In this study, we present the disposition of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), their acidic precursors, and their metabolites in serum, oral fluid, and urine together with the acute pharmacological effects in 14 healthy individuals treated with vaporized medical cannabis. THC and CBD peaked firstly in serum and then in oral fluid, with higher concentrations in the first biological matrices and consequent higher area under the curve AUCs. Acidic precursors Δ-9-tetrahydrocannabinolic acid A (THCA) and cannabidiolic acid (CBDA) showed a similar time course profile but lower concentrations due to the fact that vaporization partly decarboxylated these compounds. All THC and CBD metabolites showed a later onset with respect to the parent compounds in the absorption phase and a slower decrease to baseline. In agreement with serum kinetics, THC-COOH-GLUC and 7-COOH-CBD were the significantly most excreted THC and CBD metabolites. The administration of vaporized medical cannabis induced prototypical effects associated with the administration of cannabis or THC in humans, with a kinetic trend overlapping that of parent compounds and metabolites in serum. The pharmacokinetics of cannabinoids, their precursors, and their metabolites in biological fluids of individuals treated with vaporized medical cannabis preparations showed a high interindividual variability as in the case of oral medical cannabis decoction and oil. Inhaled medical cannabis was absorbed into the organism earlier than decoction and oil. Cannabinoids reached higher systemic concentrations, also due to the fact that the acid precursors decarboxylated to parent cannabinoids at high temperatures, and consequently, the physiological and subjective effects occurred earlier and resulted with higher intensity. No serious adverse effects were observed.

A Review of Analytical Methods for the Determination of Tibolone: Pharmacokinetics and Pharmaceutical Formulations Analysis and Application in Doping Control

Background:: Tibolone is a synthetic steroid commercialized by Organon under the brand name Livial (Org OD14), which is used in hormone therapy for menopause management and treatment of postmenopausal osteoporosis. Tibolone is defined as a selective tissue estrogenic activity regulator (STEAR) demonstrating tissue-specific effects on several organs such as brain, breast, urogenital tract, endometrium, bone and cardiovascular system. Aims:: This work aims to (1) present an overview of important published literature on existing methods for the analysis of tibolone and/or its metabolites in pharmaceutical formulations and biological fluids and (2) to conduct a critical comparison of the analytical methods used in doping control, pharmacokinetics and pharmaceutical formulations analysis of tibolone and its metabolites. Results and conclusions: : The major analytical method described for the analysis of tibolone in pharmaceutical formulations is High Pressure Liquid Chromatography (HPLC) coupled with ultraviolet (UV) detection, while Liquid Chromatography (LC) or Gas Chromatography (GC) used in combination with Mass Spectrometry (MS) or tandem mass spectrometry (MS/MS) is employed for the analysis of tibolone and/or its metabolites in biological fluids.

Liquid Chromatographic Methods for COVID-19 Drugs, Hydroxychloroquine and Chloroquine.

COVID-19 has been a threat throughout the world since December 2019. In attempts to discover an urgent treatment regime for COVID-19, hydroxychloroquine (HCQ) and chloroquine (CQ) have been on solidarity clinical trial. However, many countries have pulled HCQ and CQ from their COVID-19 treatment regimens recently, some countries still continue using them for patients who have previously started HCQ and CQ and they may complete their course under the supervision of a doctor. HCQ and CQ are 4-aminoquinoline drugs and it is safe to use them for autoimmune diseases, rheumatoid arthritis, systemic lupus erythematosus and malaria as well. Determination of CQ, HCQ and their metabolites in biologic fluids and in pharmaceuticals has great importance, especially for pharmacokinetics, pharmacodynamics and epidemiological studies. In this review, liquid chromatographic methods developed in the last 10 years were summarized focusing on sample preparation and detection methods for HCQ and CQ determination in biological fluids and pharmaceutical preparations. It is hoped that this article could be helpful to facilitate the use of these drugs in clinical trials or drug research studies as it provides comprehensive information on the reported analytical methods.

Serological biomarkers of zearalenone exposure in beef heifers receiving anti-mycotoxin additive

The inclusion of anti-mycotoxin additives (AMA) in the diet of production animals has been widely used to avoid mycotoxin exposure. In order to confirm the efficacy of such productsin vivo, measurement of mycotoxins and/or their metabolites in biological fluids is preconized. This study aimed at determining the serological biomarkers of zearalenone (ZEN), α-zearalenol, β-zearalenol, α-zearalanol, β-zearalanol (β-ZAL) and zearalanone, to evaluate the efficacy of an AMA in beef heifers. The trial lasted 37 days: 11 days of adaptation, 21 days of actual experiment, and 5 days of regression. Twenty-four heifers were randomly assigned to receive one of the following treatments (n=6/group): (T1) basal diet (control); (T2) basal diet + 5 mg/kg of ZEN; (T3) basal diet + 5 mg/kg of ZEN + 2.5 kg/t of AMA; and (T4) basal diet + 5 mg/kg of ZEN + 5.0 kg/t of AMA. Blood sampling was performed on different days after the diet was given. The samples were centrifuged to obtain the blood serum, and then analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). β-ZAL was detected above the limit of quantification both in the unconjugated (>0.60 ng/ml) and conjugated (>0.90 ng/ml) forms. The remaining metabolites presented concentrations under the limit of detection. In the efficacy evaluation of the AMA, there was no significant difference (P>0.05) between the treatments with and without additive at the tested levels of inclusion. Thus, β-ZAL may be employed as a biomarker of ZEN exposure via diet to evaluate the efficacy of an AMA through serological parameters. The technique applied in this study proved to be an adequate alternative forin vivo confirmation of the efficacy of products in adsorbing the toxin.

Mass spectrometry in the diagnosis of thyroid disease and in the study of thyroid hormone metabolism.

The importance of thyroid hormones in the regulation of development, growth, and energy metabolism is well known. Over the last decades, mass spectrometry has been extensively used to investigate thyroid hormone metabolism and to discover and characterize new molecules involved in thyroid hormones production, such as thyrotropin-releasing hormone. In the earlier period, the quantification methods, usually based on gas chromatography-mass spectrometry, were complicated and time consuming. They were mainly focused on basic research, and were not suitable for clinical diagnostics on a routine basis. The development of the modern mass spectrometers, mainly coupled to liquid chromatography, enabled simpler sample preparation procedures, and the accurate quantification of thyroid hormones, of their precursors, and of their metabolites in biological fluids, tissues, and cells became feasible. Nowadays, molecules of physiological and pathological interest can be assayed also for diagnostic purposes on a routine basis, and mass spectrometry is slowly entering the clinical laboratory. This review takes stock of the advancements in the field of thyroid metabolism that were carried out with mass spectrometry, with special focus on the use of this technique for the quantification of molecules involved in thyroid diseases.

Disposition of cannabinoids and their metabolites in serum, oral fluid, sweat patch and urine from healthy individuals treated with pharmaceutical preparations of medical cannabis.

Recently, several countries authorized the use of cannabis flowering tops (dried inflorescences) with a standardized amount of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD) and their acidic precursors [Δ-9-tetrahydrocannabinolic acid A (THCA-A) and cannabidiolic acid (CBDA)] to treat neurogenic pain. We studied the acute pharmacological effects and disposition of cannabinoids and their metabolites in serum, oral fluid, sweat patch and urine of 13 healthy individuals treated with medical cannabis decoction and oil. Cannabinoids and their metabolites were quantified by ultrahigh performance tandem mass spectrometry. Even if the oil contained a significantly higher amount of THC, the absorption of THC and its metabolites were similar in both herbal preparations. Conversely, whereas oil contained a significantly higher amount of CBD and a lower amount of CBDA, absorption was significantly higher after decoction intake. Only cannabinoids present in both herbal preparations (THC, CBD, THCA-A and CBDA) were found in oral fluid, due to the higher acidity compared with that of serum. THC metabolites urinary excretion was always higher after decoction administration. Decoction induced greater feeling of hunger and drowsiness than oil preparation. Pharmacokinetics of cannabinoids, their precursors and their metabolites in biological fluids of individuals treated with cannabis decoction and oil showed a high interindividual variability. The aqueous preparation was generally better absorbed than the oil, even if it contained a minor amount of THC, THCA-A and CBD.

Metabolomics profiles associated with diabetic retinopathy in type 2 diabetes patients.

Diabetic retinopathy (DR) is a common complication of diabetes, and it is the consequence of microvascular retinal changes due to high glucose levels over a long time. Metabolomics profiling is a rapidly evolving method used to identify the metabolites in biological fluids and investigate disease progression. In this study, we used a targeted metabolomics approach to quantify the serum metabolites in type 2 diabetes (T2D) patients. Diabetes patients were divided into three groups based on the status of their complications: non-DR (NDR, n = 143), non-proliferative DR (NPDR, n = 123), and proliferative DR (PDR, n = 51) groups. Multiple logistic regression analysis and multiple testing corrections were performed to identify the significant differences in the metabolomics profiles of the different analysis groups. The concentrations of 62 metabolites of the NDR versus DR group, 53 metabolites of the NDR versus NPDR group, and 30 metabolites of the NDR versus PDR group were found to be significantly different. Finally, sixteen metabolites were selected as specific metabolites common to NPDR and PDR. Among them, three metabolites including total DMA, tryptophan, and kynurenine were potential makers of DR progression in T2D patients. Additionally, several metabolites such as carnitines, several amino acids, and phosphatidylcholines also showed a marker potential. The metabolite signatures identified in this study will provide insight into the mechanisms underlying DR development and progression in T2D patients in future studies.

Chloroquine Phosphate Metabolism and Gender-based Phenotypic Analysis in Healthy Subjects’ Urine Following Oral Administration

Background: Chloroquine, 4-N-(7-chloroquinolin-4-yl)-1-N,-N-diethylpentane-1,4-diamine has promising activity against corona virus disease 2019 (COVID-19) and as such, it is imperative to thoroughly understand and determine the rate at which individual body systems metabolizes the drug. Chloroquine a known antimalarial drug belongs to the chemical class of 4-aminoquinolines.
 Objectives: The study aimed to analyze Chloroquine and its metabolite in biological fluids of healthy subjects by simple thin layer chromatography (TLC), which is an efficient, and inexpensive method for quantifying Chloroquine and its metabolites.
 Methods: A total of 30 healthy volunteers participated in the study by ingesting 500 mg of chloroquine, and the results were compared with side effects experienced by these subjects. Two brands of Chloroquine phosphate were used for the analysis and the urine were collected pre and post-drug administration and the intensities of the spots observed were compared with the reference standard stock solution. The same or greater intensity of sample spot indicates poor metabolizer, less intensity when compared to the stock spot indicates intermediate metabolizer while a much lesser intensity indicates an extensive metabolizer.
 Results: There was a statistically significant difference between the brands of chloroquine used at P<0.05. 30% of the volunteers were assigned poor metabolizer phenotype, 50% were assigned extensive metabolizer phenotype, and 20% assigned Intermediate metabolizer phenotype based on the intensity of spots observed. The majority of the poor metabolizers were females while the majority of the extensive metabolizers were males.
 Conclusion: Gender differences plays a vital the role in metabolism, therefore outine implementation of phenotype determination before therapy will therefore greatly improve the goal of therapy and quality of life. implementation of phenotype determination before therapy will, therefore, greatly improve the goal of therapy and quality of life.

Certain Indicators of Diclofenac Sodium Pharmacokinetics in Patients with Rheumatoid Arthritis Considering Comorbide States

Introduction: Much attention is paid to pharmacokinetic (FK) researches for studying the processes ofsupply, distribution, biotransformation and excretion of medications at the present time, as well as identifyinglinks between medical substances concentration and (or) its metabolites in biological fluids and tissues, andits pharmacological effect. In the treatment of rheumatoid arthritis (RA), non-steroidal anti-inflammatorydrugs (NSAID) are widely used for a symptom therapy, where Diclofenac Sodium (DS) is most commonlyprescribed. Duration of anti-inflammatory effect, effectiveness of NSAID in whole are directly dependent onthe level of effective concentration of medications and circulation duration in blood in free form.The Aim of the present research work is to study in a comparative aspect certain indicators of DiclofenacSodium pharmacokinetics in patients with rheumatoid arthritis with gastric microbiocenosis disorders(gastric dysbiosis) and without disorders (without dysbiosis).Materials and Method: 38 patients at the age from 18 to 60 years were examined, with I-II-III degree ofdisease activity. In addition to the general clinical examination, an immune-enzyme method and urease testwere carried out to determine Helicobacter Pylori and highly effective liquid chromatography to determineDiclofenac pharmacokinetics.Results: Conducted researches and analysis of their results indicate that in conditions of rheumatoid arthritis,particularly, in the presence of comorbid states, there is a decrease in the metabolism rate and an extension ofNSAID half-excretion period, which increases the risk of side effects, especially to the gastrointestinal tract,and significantly affects the disease course and the results of the treatment.Conclusion: In conditions of rheumatoid arthritis with comorbid states, there is more frequent occurrenceof the NSAID side effects. Research conducted and analysis of their results indicate that in conditionsof rheumatoid arthritis, particularly at comorbid states, there are reasonable changes in the NSAIDpharmacokinetics. The decreasing of metabolic rate and the extension of the NSAID half-excretion increasesthe risk of side effects, especially on the side of the GIT, which significantly affects the disease course andresults of the treatment. This circumstance dictates the need to take these results into account in the treatmentof the studied pathology and in the development of a personalized approach to the treatment of rheumatoidarthritis

Current status of bioanalysis of etoposide and related compounds

Etoposide (VP16 or VP16-213) which was approved by the United States FDA for testicular cancer in 1983, is one of the most effective anticancer agents in the treatment of testicular teratoma, Hodgkin's and non-Hodgkin's lymphomas, small-cell lung cancer, and a variety of other malignancies. Development of bioanalytical methods for VP16 and its metabolites is critical for pharmacokinetic and metabolic studies as well as for mechanisms of action studies. In this review, the current status of the bioanalysis of VP16 and its metabolites are discussed. Recent progress in mechanism of action and metabolism studies is also presented. A number of HPLC methods employing UV, fluorescence, or electrochemical detection are available for the bioanalysis of VP16 and its metabolites. Most of these HPLC methods are sensitive and reliable enough for determining the parent drugs and their metabolites in biological fluids. In addition to radioimmunoassay, enzyme-linked immunosorbent assay (ELISA) for VP16, which is the most sensitive assay method to date, has been developed based on modern immunoassay technology. The primary pharmacological and pharmacokinetic data of GL331, a new derivative of epipodophyllotoxin discovered and developed in author's laboratory, which has shown superior antitumor activity to that of VP16, are also discussed.

Undetectable Free Aromatic Amino Acids in Nails of Breast Carcinoma: Biomarker Discovery by a Novel Metabolite Purification VTGE System.

Background: Metabolic reprogramming in breast cancer is depicted as a crucial change in the tumor microenvironment. Besides the molecular understanding of metabolic heterogeneity, appreciable attention is drawn to characterizing metabolite profiles in tumor tissue and derived biological fluids and tissue materials. Several findings reported on the metabolic alterations of free aromatic amino acids (FAAAs) and other metabolites in biological fluids. Furthermore, there is a significant gap in the development of a suitable method for the purification and analysis of metabolite biomarkers in nails of cancer patients.Methods: To address the metabolite alterations, specifically FAAA levels in nails, fingernail clippings of breast cancer patients (N = 10) and healthy subjects (N-12) were used for extraction and purification of metabolites. Here, we reported a novel and specifically designed vertical tube gel electrophoresis (VTGE) system that helped in the purification of metabolites in the range of 100–1,000 Da from nail materials. Here, the VTGE system uses 15% polyacrylamide under non-denaturing and non-reducing conditions, which makes eluted metabolites directly compatible with LC-HRMS and other analytical techniques. Qualitative and quantitative determination of FAAAs in nail lysates was done in positive ESI mode of the Agilent LC-HRMS platform.Results: The analysis on collected data of nail metabolites clearly suggested that FAAAs including tryptophan, tyrosine, phenylalanine, and histidine were undetectable in nail lysates of breast cancer over healthy subjects. This is a first report that showed highly reduced levels of FAAAs in nails of breast cancer patients. Furthermore, the present observation is in consonance with previous findings that showed cancer cachexia and high amino acid catabolism in breast cancer patients that drive metabolite-led cancer growth and proliferation.Conclusion: This paper provides a proof of concept for a novel and specifically developed VTGE process that showed first evidence on the undetectable level of FAAAs in nails of breast cancer patients as metabolite biomarkers. Here, the authors propose the potential use of a VTGE-assisted process to achieve metabolomic discovery in nails of breast cancer and other tumor types.

Reviewing the Analytical Methodologies to Determine the Occurrence of Citrinin and its Major Metabolite, Dihydrocitrinone, in Human Biological Fluids.

Until now, the available data regarding citrinin (CIT) levels in food and the consumption of contaminated foods are insufficient to allow a reliable estimate of intake. Therefore, biomonitoring configuring analysis of parent compound and/or metabolites in biological fluids, such as urine or blood, is being increasingly applied in the assessment of human exposure to CIT and its metabolite, dihydrocitrinone (DH-CIT). Most studies report urinary levels lower for the parent compound when compared with DH-CIT. A high variability either in the mean levels or in the inter-individual ratios of CIT/DH-CIT between the reported studies has been found. Levels of DH-CIT in urine were reported as being comprised between three to seventeen times higher than the parent mycotoxin. In order to comply with this objective, sensitive analytical methodologies for determining biomarkers of exposure are required. Recent development of powerful analytical techniques, namely liquid chromatography coupled to mass spectrometry (LC-MS/MS) and ultra-high-performance liquid chromatography (UHPLC-MS/MS) have facilitated biomonitoring studies, mainly in urine samples. In the present work, evidence on human exposure to CIT through its occurrence and its metabolite, in biological fluids, urine and blood/plasma, in different countries, is reviewed. The analytical methodologies usually employed to evaluate trace quantities of these two molecules, are also presented. In this sense, relevant data on sampling (size and pre-treatment), extraction, cleanup and detection and quantification techniques and respective chromatographic conditions, as well as the analytical performance, are evidenced.

Participation of Undergraduate Students in a Controlled Feeding Study with Metabolomics Analysis to Enhance Learning of Metabolism

Metabolomics, the large-scale study of metabolites in biological fluids and tissues, offers the ability to observe metabolic changes in a broad context. Traditionally, nutritional metabolism educat...

Distribution of quetiapine and metabolites in biological fluids and tissues

Quetiapine is an atypical antipsychotic drug, frequently found in post-mortem samples. The quantitative determination of active metabolites may help in the interpretation of the potential toxic effects of the parent drug and its role in death. A fully validated LC–MS/MS method was developed for the identification and quantification of quetiapine and two main metabolites (N-desalkylquetiapine and 7-hydroxyquetiapine) in blood, biological fluids and tissues. Then, the distribution of analytes in different matrices was evaluated. LODs of 0.9, 0.3 and 0.3ng/mL were calculated for quetiapine, N-desalkylquetiapine and 7-hydroxyquetiapine respectively; while a LOQ at the concentration of 10.0ng/mL was defined for the three analytes. 13 post-mortem positive real cases have been included in the experiment. The results revealed that quetiapine and N-desalkylquetiapine might undergo a significant post-mortem redistribution, while 7-hydroxyquetiapine is less affected by this factor. N-desalkylquetiapine could be found in blood in relatively high concentrations in comparison to those of quetiapine; therefore, it should be always advisable to measure both the analytes. The analysis of tissues could provide additional data on potential intoxication with quetiapine.