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Développement de méthodes analytiques pour la détection et la quantification de traces de produits pharmaceutiques dans les eaux du fleuve Saint LaurentGarcia Ac, Araceli 09 1900 (has links)
Le présent projet vise à documenter la nécessité d’augmenter notre connaissance
de la présence des contaminants organiques tels que les médicaments dans
l’environnement et d’évaluer leur devenir environnemental. On a étudié la présence de
composés pharmaceutiques dans différents échantillons d'eau. On a focalisé nos efforts
spécialement sur les échantillons d'eau de l'usine d'épuration de la Ville de Montréal et
ses effluents, les eaux de surface avoisinantes et l’eau du robinet dans la région de
Montréal. Pour ce faire, on a tout d’abord développé deux méthodes analytiques
automatisées basées sur la chromatographie liquide avec extraction en phase solide
(SPE) couplée à la chromatographie liquide couplée à la spectrométrie de masse en
tandem (LC-MS/MS).
On a également étudié les performances des trois techniques d'ionisation à pression
atmosphérique (API), pour ensuite les utiliser dans la méthode analytique développée.
On a démontré que l'ionisation par électronébulisation (ESI) est une méthode
d'ionisation plus efficace pour l'analyse des contaminants pharmaceutiques dans des
échantillons de matrices très complexes comme les eaux usées.
Une première méthode analytique SPE couplée à la LC-MS/MS a été développée et
validée pour l'étude des échantillons complexes provenant de l'usine d'épuration de la
Ville de Montréal et des eaux de surface près de l'usine. Cinq médicaments de
prescription ont été étudiés: le bézafibrate (un régulateur de lipides), le
cyclophosphamide et le méthotrexate (deux agents anticancéreux), l'orlistat (un agent
anti-obésité) et l’énalapril (utilisé dans le traitement de l'hypertension). La plupart de
ces drogues sont excrétées par le corps humain et rejetées dans les eaux usées
domestiques en faisant par la suite leur chemin vers les usines municipales de traitement
des eaux usées. On a pu démontrer qu'il y a un faible taux d’élimination à l'usine
d'épuration pour le bézafibrate et l'énalapril. Ces deux composés ont aussi été détectés
dans les eaux de surface sur un site à proximité immédiate de la décharge de l’effluent
de la station d'épuration.
i
En observant la nécessité de l'amélioration des limites de détection de la première
méthode analytique, une deuxième méthode a été développée. Pour la deuxième
méthode, un total de 14 contaminants organiques, incluant trois agents anti-infectieux
(clarithromycin, sulfaméthoxazole et triméthoprime), un anticonvulsant
(carbamazépine) et son produit de dégradation (10,11-dihydrocarbamazépine), l'agent
antihypertensif (enalapril), deux antinéoplastiques utilisés en chimiothérapie
(cyclophosphamide et méthotrexate), des herbicides (atrazine, cyanazine, et simazine)
et deux produits de transformation de l’atrazine (deséthylatrazine et
déisopropylatrazine) ainsi qu’un agent antiseptique (triclocarban). Ces produits ont été
quantifiés dans les eaux de surface ainsi que dans l’eau du robinet. L'amélioration des
limites de détection pour cette méthode a été possible grâce à la charge d'un volume
d'échantillon supérieur à celui utilisé dans la première méthode (10 mL vs 1 mL).
D'autres techniques de confirmation, telles que les spectres des ions produits utilisant
une pente d’énergie de collision inverse dans un spectromètre de masse à triple
quadripôle et la mesure des masses exactes par spectrométrie de masse à temps d’envol,
ont été explorées. L'utilisation d'un analyseur de masse à temps d’envol a permis la
confirmation de 6 des 14 analytes.
Finalement, étant donné leur haute toxicité et pour évaluer leur persistance et leur
transformation au niveau du traitement des eaux potables, la cinétique d'oxydation du
cyclophosphamide et de méthotrexate avec l'ozone moléculaire et des radicaux OH a été
étudiée. Les constantes de dégradation avec l'ozone moléculaire ont été calculées et la
qualité de l'eau après traitement a pu être évaluée. Le rendement du processus
d'ozonation a été amélioré pour la cyclophosphamide dans les eaux naturelles, en raison
de la combinaison de réactions directes et indirectes. Cette étude a montré que l'ozone
est très efficace pour oxyder le méthotrexate mais que le cyclophosphamide serait trop
lent à s’oxyder pour un traitement efficace aux conditions usuelles de traitement de
l’eau potable. / This project aims to document the need to increase our knowledge of organic
contaminants such as pharmaceuticals in the environment and to assess their
environmental fate. We studied the presence of pharmaceutical compounds in different
water samples. We studied their presence in wastewater samples from the treatment
plant of the City of Montreal, effluents, surface and tap water. To do this we developed
two analytical methods based on solid phase extraction (SPE) coupled to liquid
chromatography -tandem mass spectrometry (LC-MS/MS).
.
The performance of three atmospheric pressure ionization (API) techniques was also
studied for their subsequent use in the developed method. It was demonstrated that
electrospray ionization (ESI) is a more effective ionization method for the analysis of pharmaceutical contaminants in samples as complex as wastewaters.
A first analytical LC-MS/MS method, was developed and validated for the investigation
of samples from the wastewater treatment plant and surface waters near the plant of
Montreal. Five prescription drugs were studied: bezafibrate (lipid regulator),
cyclophosphamide, and methotrexate (two anticancer agents), orlistat (an anti-obesity
agent) and enalapril used in the treatment of hypertension. Most of these drugs are
excreted by the human body in high percentages and released into domestic
wastewaters, making their way to the municipal wastewater treatment plants. It was
demonstrated that there is a low rate of elimination at the wastewater treatment plant for bezafibrate and enalapril. These two compounds were also detected in surface waters on a site close to the discharge of the treatment plant effluents.
For this first analytical method we observed the necessity of improvement of the
detection limits of the method. A second method was then developed to improve the
detection limits and to study a total of 14 organic contaminants, including three antiinfective agents (clarithromycin, sulfamethoxazole and trimethoprim), an anticonvulsant (carbamazepine) and its degradation product 10,11-dihydrocarbamazepine, the iii
antihypertensive agent (enalapril), two antineoplastic (methotrexate and
cyclophosphamide), herbicides (atrazine, cyanazine, and simazine) and two
transformation products of atrazine (desethylatrazine and déisopropylatrazine) and an antiseptic agent (triclocarban). These products were quantified in surface water and tap water. The improvement of the detection limits of this method was possible due to the loading of a greater sample volume than that used in the first method (10 mL vs 1 mL).
Other confirmation techniques, such as the data-dependent reverse energy ramp scan on
a triple quadrupole and accurate mass measurements on a time-of-flight mass
spectrometer were explored. Using time-of-flight mass spectrometer determinations
allowed the confirmation of six of the 14 analytes.
Finally, due to their toxic properties, the oxidation kinetics of cyclophosphamide and
methotrexate with molecular ozone and OH radicals was studied in bench scale. The
degradation constants with molecular ozone were calculated and the water quality after
treatment was assessed. The overall process performance was improved for
cyclophosphamide in natural waters, due to the combination of direct and indirect
reactions. The study showed that ozone is very effective for the oxidation of
methotrexate, but cyclophosphamide is too slowly oxidized for an effective drinking
water treatment under usual conditions.
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Développement de méthodes analytiques pour la détection et la quantification de traces de produits pharmaceutiques dans les eaux du fleuve Saint LaurentGarcía Ac, Araceli 09 1900 (has links)
No description available.
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Analyse de traces de micropolluants dans l'eau et le lait maternel en vue d'évaluer leur impact sur la santé / Quantification of traces of micropollutants in water and breast milk in assessment impact on human healthCariot, Axelle 26 November 2012 (has links)
L'exposition humaine au bisphénol A et aux nonylphénols constitue un problème majeur de santé publique, en conséquence du caractère ubiquitaire de ces molécules et de leur toxicité en tant que perturbateur endocrinien. Leurs dérivés chlorés, formés par chloration lors de l'étape de désinfection de l'eau potable, présentent un effet perturbateur endocrinien jusqu'à 100 fois plus important que les composés parents. Au cours de ce travail nous avons développé des méthodes de dosage sensibles et reproductibles par LC-MS/MS de ces polluants dans l'eau. Le choix de l'isomère 353NP a été discuté et retenu comme substance de référence des nonylphénols. Le bisphénol A et le 353NP ont été retrouvés dans l'eau de surface (en entrée) et dans l'eau traitée (en sortie) de 8 usines de traitement d'eau potable, à des concentrations comprises entre 2,0 et 29,7 ng.L-1 et entre <4,1 et 124,9 ng.L-1 respectivement. Par ailleurs, aucun dérivé chloré n'a été détecté. Des dosages du bisphénol A et de ses dérivés chlorés réalisés dans 14 eaux du robinet et 4 eaux embouteillées ont montré leur présence dans ces eaux de boisson. Pour évaluer l'imprégnation de la population au bisphénol A et ses dérivés chlorés, nous avons mis au point un dosage ultrasensible de ces molécules par SPE-UPLC-MS/MS dans le lait maternel, validé selon les recommandations internationales. Ces composés ont été retrouvés dans le colostrum de 21 mères avec des concentrations comprises entre <0,40 et 6,12 ng.mL-1. Ces résultats prouvent qu'il existe une origine hydrique de la contamination chez l'homme par le bisphénol A, comme pour ses dérivés chlorés. / Bisphenol A and nonylphenols are widespread industrial chemicals which over the past decade have demonstrated their toxicity as endocrine disruptors. Residual chlorine present in drinking water may react with these compounds to form chlorinated derivatives, which have demonstrated a heightened level of estrogenic activity. In this work, we have comprehensively validated accurate and reproducible methods of quantification measuring these target compounds in water using LC-MS/MS. We have discussed and selected 353NP as the reference material for the analysis of nonylphenols. Bisphenol A and 353NP were found in both surface and treated water samples extracted from eight French drinking water treatment plants, at a level ranging from 2.0 to 29.7 ng.L-1 and from <4.1 to 124.9 ng.L-1, respectively. Neither chlorinated BPA nor chlorinated 353NP was detected. Quantification of bisphenol A and its chlorinated derivatives in 14 tap water samples and 4 bottled water samples showed that those pollutants are present in drinking water. Exposure to bisphenol A and its chlorinated derivatives in the population was investigated through breast milk. We developed a method using on-line SPE-UPLC-MS/MS to quantify these chemicals in breast milk according to internationally accepted guidelines. The target compounds were found in the colostrum of 21 women at concentrations ranging from <0.40 to 6.12 ng.mL-1. Drinking water may consequently constitute a source of human exposure to bisphenol A and its chlorinated derivatives.
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Exposition fœtale à différentes familles de xénobiotiques en Bretagne : analyse de la matrice méconium / Fetal exposure to different families of xenobiotics in Brittany, France : analysis of meconium matrixMeyer, Marie 22 December 2014 (has links)
Le méconium constitue les premières selles du nourrisson. Cette matrice complexe est analysée dans le cadre du projet « PENEW » (Pregnancy Environment and NEWborn malformations) afin de déterminer si le degré d'exposition fœtale aux xénobiotiques joue un rôle dans la survenue de malformations congénitales. Le but de cette étude était le développement analytique pour la détection et la quantification dans le méconium d’une quarantaine de composés de familles différentes (composés organiques volatils, pesticides, éthers de glycol et les métabolites associés). Trois techniques analytiques différentes et une préparation d’échantillon spécifiques ont été développées pour la détection et la quantification de ces composés dans le méconium. L’application des ces méthodes à 246 échantillons de méconium a montré une exposition fœtale à plusieurs des substances recherchées. / Meconium is the earliest stool of newborns. This complex matrix was analyzed through the "PENEW" project (Pregnancy and Newborn malformations Environment) to determine if the degree of fetal exposure to xenobiotics has an influence in the occurrence of birth defects. The objective of this thesis was developed analytical methods for the detection and quantification of several different families of compounds (volatile organic compounds, pesticides, glycol ethers and their metabolites) in meconium. Three different analytical methods and a specific sample preparation have been developed for the detection and quantification of these compounds in the meconium. The application of these methods to 246 meconium samples showed a fetal exposure to several target compounds.
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Detektion av hydrolyserad β-laktamantibiotika i plasma med Matrix-Assisted Laser Desorption Ionization – Time of Flight Mass Spectrometry och Liquid Chromatography tandem Mass Spectrometry / Detection of hydrolyzed β-lactam antibiotics in plasma by Matrix-Assisted Desorption Laser Ionization – Time of Flight Mass Spectrometry and Liquid Chromatography tandem Mass SpectrometryThenstedt, Niklas January 2020 (has links)
Introduktion Antibiotikaresistens är ett globalt växande problem. Till gruppen β-laktamantibiotika hör piperacillin-tazobaktam och cefotaxim som båda verkar genom att försvaga cellväggen med kovalenta bindningar till peptidoglykanlagret som lyserar cellen. E. coli och K. pneumoniae tillhör gruppen Enterobacteriaceae, som är en del av den humana tarmfloran och ofta förekommande vid urinvägsinfektion och sepsis. Utvidgat Spektrum β-Laktamas (ESBL) är ett enzym som finns hos Enterobacteriaceae och som hydrolyserar β-laktamantibiotika. Matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) är en kvalitativ analysteknik för detektion av kemiska föreningar i avseende på massa och laddning. Kännedom om antibiotikametaboliters molekylvikt vid hydrolys möjliggör detektion. Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) är en högsensitiv kvantifieringsmetod som separerar molekyler i avseende på polaritet för vidare detektion i avseende på massa och laddning. Syfte Syftet med denna studie var att vidareutveckla en snabb och effektiv metod för att påvisa nedbrytning av piperacillin-tazobaktam och cefotaxim i blodplasma med LC-MS/MS. Material och Metod Tiofaldigt sjunkande koncentrationer av piperacillin-tazobaktam från 2000 till 2 µg/ml, och cefotaxim med koncentrationerna 500 till 0,5 µg/ml analyserades med MALDI-TOF MS, dels intakt men även med bakterierna E. coli och K. pneumoniae med uttryck av olika resistensmekanismer. Vid optimerade koncentrationer spikades plasmaprover med nedbrutet antibiotika som sedan kvantifierades med LC-MS/MS. Resultat Lägsta detektionsgräns med MALDI-TOF MS för intakt och hydrolyserat piperacillin-tazobaktam var 20/2,5 µg/ml. För cefotaxim var lägsta gränsen 5 µg/ml. Med kliniskt relevanta blodkoncentrationer gick hydrolys inte att detektera för. Med tre bakteriekolonier/50 µl kunde dock hydrolys detekteras och kvantifieras med LC-MS/MS. Slutsats Detektion av β-laktamantibiotika är möjligt med både MALDI-TOF MS och LC-MS/MS. För att påvisa hydrolys krävdes större mängder bakterier än förväntat med LC-MS/MS. / Introduction Antibiotic resistance is a global growing problem. Piperacillin-tazobactam and cefotaxime are parts of the group β-lactam antibiotics. The common feature is to inhibit the cell wall synthesis by covalent bindings to the peptidoglycan layer and thereby causing lysis of the bacterial cell. E. coli and K. pneumoniae are members of the Enterobacteriaceae which is a part of the human normal flora but also are commonly associated with urinary tract infections which sometimes develops into to sepsis. Extended Spectrum β-Lactamases (ESBLs) are enzymes with hydrolytic abilities acting on β-lactam antibiotics, expressed by Enterobacteriaceae. The qualitative, Matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) can be used to detect chemical compounds in the ratio of mass to charge in accordance to their molecular weight. Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) is a highly sensitive two-step method of quantification which first separate molecules by their polarity attraction force and then by the ratio of mass to charge. Aim The aim of this study was to develop a fast and efficient method to determine degradation of piperacillin-tazobactam and cefotaxime in blood plasma by LC-MS/MS. Method Tenfold dilution of piperacillin-tazobactam in concentrations of 2000 to 2 µg/ml, and cefotaxime in concentrations of 500 to 0,5 µg/ml where analyzed by MALDI-TOF MS, intact and also with the bacteria E. coli and K. pneumoniae with different expression of antibiotic resistance. Optimized concentrations where fixed in blood plasma and then quantified by LC-MS/MS. Result The detection limit by using MALDI TOF MS of hydrolyzed as well as non-hydrolyzed piperacillin-tazobactam was 20/2,5 µg/ml. The detection limit in cefotaxime was 5 µg/ml. Hydrolysis could not be detected in clinically fixed blood concentrations. Detection and quantification of hydrolysis by LC-MS/MS was possible in a concentration of three bacteria colonies/50 µl. Conclusion It is possible to detect hydrolysis in both MALDI TOF MS and LC-MS/MS. A larger amount of bacteria than expected was needed to demonstrate hydrolysis In LC-MS/MS.
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Optimering av vätskekromatografiska parametrar vid kvantifiering av läkemedel i serum med LC-MS/MS för klinisk diagnostik / Optimizing Chromatographic Parameters for Quantification of Pharmaceuticals in Serum with LC-MS/MS for Clinical UseEdlund, Sofie January 2021 (has links)
Vid Klinisk kemi och farmakologi, Specialkemi, vid Skånes universitetssjukhus, Lund, utförs kvantifiering med LC-MS/MS av antipsykotiska och antidepressiva läkemedelskoncentrationer i serum med acetonitril (ACN) som mobilfas. ACN är på grund av sin höga elueringsstyrka ett av de vanligaste organiska lösningsmedlen vid reversed phase (RP) kromatografi, men uppvisar samtidigt en hög toxicitet med risk för stora leveransproblem. I syfte att reducera mängden ACN undersöktes därför möjligheten till ett mobilfasbyte till metanol (MeOH). Ordinarie metod jämfördes med tre nyutvecklade metoder med MeOH-baserad mobilfas. I en av metoderna ändrades endast mobilfas och elueringsgradient, medan två av metoderna även använde andra sorters RP-kolonner med anpassade elueringsgradienter. Samtliga analyter uppvisade godkänd separation och retention vid eluering med MeOH, men stor fluktuation från referensmetod sågs vid kvantifieringen av flera analyter, däribland olanzapin, desmetylolaznapin och mirtazapin. Liknande avvikelser med avseende på regression och kvantifieringsdifferens observerades vid eluering med andra sorters RP-kolonner. Detta indikerar att vidare optimering av andra vätskekromatografiska och masspektrometriska parametrar bör utföras innan metoderna kan valideras. / The quantification of antipsychotics and antidepressants in human serum with LC-MS/MS is usually performed with acetonitrile (ACN) as mobile phase. ACN is one of the most common organic solvents in reversed phase (RP) chromatography thanks to its high elution strength but is also highly toxic and can at times suffer from major delivery problems. The present study investigated the possibility of replacing ACN with methanol (MeOH) as primary organic solvent with the purpose of reducing the total ACN-usage. Three newly developed methods for chromatographic analysis of antipsychotic and antidepressant drugs using MeOH as organic solvent as part of the mobile phase were compared to the routine method in regard to analyte separation and retention, as well as the relative quantification of substance. In one of the methods only the mobile phase and elution gradient was changed whereas different types of RP columns were applied in addition to the changed mobile phase in the other two. All substances showed acceptable separation and retention when eluted with MeOH but displayed large fluctuations in the quantification of the analyzed substances, more specifically olanzapine, desmethylolanzapine and mirtazapine, in comparison to the reference method. Similar deviations in terms of regression and quantification bias were observed when analytes were eluted with MeOH through other types of RP columns. This indicates that further optimization of other parameters relating to the chromatography and mass spectrometer should be performed before validation.
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A novel method for the measurement of plasma metanephrines using online solid phase extraction-liquid chromatography tandem mass spectrometryAdaway, Joanne E., Peitzsch, Mirko, Keevil, Brian G. 19 September 2019 (has links)
Background: Measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine is useful in the diagnosis of phaeochromocytomas, but many assays require a large volume of plasma due to poor assay sensitivity, and often require lengthy sample preparation. Our aim was to develop a method for measurement of plasma metanephrines using a small sample volume with minimal hands-on preparation. Methods: Samples were deproteinised using 10 K spin filters prior to online solid phase extraction using a Waters Acquity UPLC Online SPE Manager (Waters, Manchester, UK) coupled to a Waters Xevo TQ-S mass spectrometer (Waters, Manchester, UK). The assay was validated and results compared to a previously published method. Results: We achieved a limit of quantification of 37.5 pmol/L for metanephrine and 3-methoxytyramine and 75 pmol/L for normetanephrine using only 150 mL of sample. The assay was linear up to 30,000 pmol/L for all analytes and in a method comparison study results showed good agreement with a previously published LC-MS/MS assay. Conclusions: We have developed a simple method for measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine using only 150 mL of sample. There is minimal hands-on sample preparation required and the assay is suitable for routine use in a clinical laboratory.
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Development of novel analytical methods for vitamin D metabolites analysis in biological matrices based on mass spectrometry – Derivatization strategies and LC-MS/MS method development.Alexandridou, Anastasia 12 December 2024 (has links)
Vitamin-D-Mangel und -Unterversorgung haben sich zu einem großen Problem für die öffentliche Gesundheit entwickelt, das vor allem auf eine unzureichende Sonnenlichtexposition und eine begrenzte Zufuhr dieses essenziellen Nährstoffs über die Nahrung zurückzuführen ist. Diese "Pandemie" hat zu einem bemerkenswerten Anstieg der Nachfrage nach der Bestimmung des zirkulierenden 25-Hydroxyvitamin-D-Spiegels (25(OH)D) geführt. Die meisten Studien fokussieren sich in erster Linie auf 25(OH)D und betrachten es als Biomarker für den Vitamin-D-Status. Es besteht jedoch ein wachsendes Interesse an der gleichzeitigen Messung mehrerer klinisch bedeutsamer Vitamin-D-Metaboliten wie dem nativen Vitamin D, 25(OH)D-Epimeren, 1,25-Dihydroxyvitamin D und 24,25-Dihydroxyvitamin D. Die Flüssigchromatographie/Tandem-Massenspektrometrie (LC-MS/MS) gilt als "Goldstandard" für die Bestimmung des Vitamin-D-Spiegels und ermöglicht die gleichzeitige Analyse mehrerer Analyten, die für das Verständnis der physiologischen Rolle von Vitamin D und seiner klinischen Auswirkungen unerlässlich sind. In der vorliegenden Doktorarbeit soll verschiedene Aspekte der Vitamin-D-Landschaft erforschen, umfassende Einblicke geben und Herausforderungen innerhalb des Forschungsthemas besprechen. Zunächst lag der Schwerpunkt auf dem Vergleich mehrerer Derivatisierungsreagenzien für die Vitamin-D-Analyse und der Frage, wie sie sich auf die Nachweisempfindlichkeit der Methode und die chromatographische Trennung der getesteten Vitamin-D-Metaboliten auswirken. Ein zweiter Schwerpunkt lag auf der Untersuchung der Stabilität der Derivatisierungsprodukte in Serumextrakten. Der letzte Versuch war die Entwicklung einer LC-MS/MS-Methode, die die Ergebnisse der vorangegangenen Untersuchungen nutzen sollte. Als Ergebnis wurde eine neue Methode vorgestellt, die meines Wissens zum ersten Mal FMP-TS für die chemische Derivatisierung von Vitamin-D-Metaboliten verwendet. / Vitamin D deficiency has emerged as a significant public health concern, attributed largely to insufficient exposure to sunlight and limited dietary sources rich in this essential nutrient. This “pandemic” has led to a notable increase in the demand for assessing circulating levels of 25-hydroxyvitamin D (25(OH)D). Most studies have primarily focused on 25(OH)D, considered it as the vitamin D status biomarker. However, there is a growing interest in simultaneously measuring multiple clinically significant vitamin D metabolites such as the native vitamin D, 25(OH)D epimer, 1,25-dihydroxyvitamin D, 24,25-dihydroxyvitamin D and others. Thus, there is an urgent need to develop analytical methods which will be able to separate and quantify the metabolites of interest accurately and precisely. Liquid chromatography/tandem mass spectrometry (LC-MS/MS) stands out as the “gold standard” technique for vitamin D analysis. Its versatility enables simultaneous analysis of multiple analytes, thereby facilitating the generation of comprehensive vitamin D profiles essential for understanding its physiological role and clinical implications. The present doctoral thesis is designed to explore diverse aspects of vitamin D landscape, providing comprehensive insights and addressing challenges within the research topic. Initially there was a focus on comparing multiple derivatization reagents for vitamin D analysis and discovering how they impact the method’s detection sensitivity and the chromatographic separation of the tested vitamin D metabolites. Moreover, there was a second focal point on examining the stability of the derivatization products in serum extracts. The final attempt was the development of an LC-MS/MS method that would utilize the outcomes of the investigations conducted before. As a result, a new method was introduced utilizing FMP-TS for the chemical derivatization of vitamin D metabolites, a reagent which has not been reported before for vitamin D analysis.
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Biology and Detection of Pregnanes During Late Gestation in the MareWynn, Michelle Arelia Ann 01 January 2017 (has links)
Progesterone in the mare declines to almost undetectable concentrations in late gestation. It’s metabolized into several pregnanes, some circulating at very high concentrations. Although the function of many pregnanes remains unclear, 5α-dihydroprogesterone and allopregnanolone are bioactive. Measurements of pregnanes in late gestation are typically by immunoassay, although results are confounded by cross-reactivity with related pregnanes. Conversely, liquid chromatography tandem mass spectrometry (LC-MS/MS) allows differentiation of individual pregnanes. The purposes of these studies were: 1) to evaluate the ability of a 5α-reductase inhibitor, dutasteride, to alter pregnane metabolism and pregnancy outcome, 2) to evaluate changes in target pregnanes in late gestation by LC-MS/MS in mares with ascending placentitis, and 3) compare immunoassay and LC-MS/MS detection of pregnanes in late gestation. Our findings suggest that dutasteride significantly altered pregnane metabolism without effects on pregnancy outcome. Pregnane measurement by LC-MS/MS resulted in a significant (p<0.05) differences in assay results, while correlation was observed between immunoassay measurements and actual progesterone concentrations by LC-MS/MS. These studies demonstrate the complexity of pregnane metabolism in late gestation in the mare and the necessity of LC-MS/MS to detect specific changes that immunoassays cannot differentiate.
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An investigation into the metabolic activation of novel chloromethylindolines by isoforms of cytochrome P450 : targeting drug metabolising enzymes in cancer : analysis of the role and function of selected cytochrome P450 oxidising novel cancer prodrugsAlandas, Mohammed Nasser January 2012 (has links)
Introduction: Cytochromes P450 (CYPs) are the major family of enzymes responsible for detoxification and metabolism of a wide range of both endogenous and xenobiotics chemicals in living organisms. The use of CYPs to activate prodrugs to cytotoxins selectively in tumours has been explored including AQ4N, Phortress and Aminoflavone. CYP1A1, CYP1B1, CYP2W1, and CYP4F11 have been identified as expressed in tumour tissue and surrounding stroma at high frequency compared to most normal tissues. Aim is to investigate the differential metabolism of novel chloromethylindoline by high frequency expressed CYPs in tumours. This differential may be exploited to elicit a selective chemotherapeutic effect by metabolising inert small molecules to potent cytotoxins within the tumour environment. Materials and Methods: Sensitive and specific LC/MS/MS techniques have been developed to investigate the metabolism of chloromethylindolines. Recombinant enzymes and transfected cell lines were used to investigate the metabolic profiles with a focus on production of the cytotoxic derivatives of chloromethylindolines. Results: Detailed metabolic studies show that (1-(Chloromethyl)-1,2-dihydropyrrolo [3,2-e]indol-3(6H)-yl)(5-methoxy-1H-indol-2-yl) methanone (ICT2700) and other chloromethylindolines are converted by CYP1A1 mediated hydroxylation at the C-5 position leading to highly potent metabolites. In vitro cytotoxicity studies showed differentials of up to 1000-fold was achieved between CYP1A1 activated compared to the non-metabolised parent molecules. The reactivity of metabolites of ICT2700 was also explored using glutathione as a nucleophile. The metabolites were identified by a combination of LC/MS and LC MS/MS techniques. Investigations using mouse and human liver microsomes show that a large number of metabolites are created though none were shown to be associated with a potential anticancer effect. Studies focused on CYP2W1 show that this isoform metabolised ICT2706 to a cytotoxic species and a pharmacokinetic study showed a good distribution of ICT2706 into mouse tissues including tumour. However metabolism of ICT2726 by CYP2W1 resulted only in a non-toxic metabolite profile and may have potential as a biomarker for functional CYP2W1 in tissues. Preliminary studies show that palmitic acid hydroxylation is a useful marker of functional CYP4F11. Summary and conclusion: The in vitro results show that the chloromethylindolines are a novel class of agent with potential as prodrugs that following specific hydroxylation by CYP1A1 and CYP2W1 are converted to ultra-potent cytotoxins. Other metabolites are also evident which are not cytotoxic. Studies in vivo show that selected chloromethylindolines possess a good pharmacokinetic profile and show potential as prodrug anticancer agents that require activation by CYP1A1 or CYP2W1. The methods, results, progress and suggestions for future work are presented in this thesis.
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