Positron emission tomography (PET) is a quantitative and non-invasive investigative tool, which permits the identification of pivotal biomarkers and their role in disease onset, transformation and progression. Quantitative detection of these disease biomarkers has qualified PET as a pioneering approach to rapid diagnosis. The tool is a powerful approach to patient diagnosis and investigation of inter- and intra- patient disease heterogeneity thereby supporting patient stratification and forging a truly personalised medicine approach. The sensitivity of PET is complemented by use of highly selective radiopharmaceuticals; this has fuelled the popularity of radiolabelled affinity peptides and proteins (APPs). Inspired by the high selectivity and affinity of biological protein-protein interactions, APP-based radiotracers are an increasingly popular class of radiotracer. Monoclonal antibodies (mAbs) are an important category of APP-based radiotracer; their prevalence in the field is attributed to their high target selectivity and affinity characteristics, which, will likely, uphold their popularity in the field. Yet, advancements in protein engineering has transformed the landscape of APP-based radiotracers, indicated by a preference for small radiolabelled APPs which exhibit rapid pharmacokinetics whilst retaining high target specificity and affinity. Their fast pharmacokinetics is matched by the half-life of 18F which has been defined as an ideal PET radionuclide. 18F APP radiolabelling hasn't yet met its full potential due to its inherent challenges; many approaches have been adopted, ranging from non-site specific radiolabelling with amine reactive prosthetic groups to site-specific methods including oxime bond formation. The radiochemistry of 18F APP radiolabelling is diverse and evolving; yet ideal goals are apparent including site-specificity, fast reaction kinetics, mild labelling conditions and applicability to automation. Automation is challenging for multi-step 18F APP radiolabelling methods, but is a key developmental step. Automation helps with conformance to good manufacturing practice (GMP) by enhancing process robustness, consistency and reliability. It also permits the radiosynthesis of clinically relevant radiotracer doses. The development of an automated generic platform, or a method that adopts a general approach, for APP radiolabelling with 18F would assist in [18F]APPs meeting their potential in PET and, importantly, aid their translation from bench-to-bedside.

Ce projet s'inscrit dans le développement d'une nouvelle stratégie de radiomarquage au fluor-18 de motifs perfluorés incorporés dans des sondes chimiques (EF3, EF5) visant à détecter et quantifier l'hypoxie tumorale de manière non invasive par tomographie par émis-sion de positrons. La méthode sélectionnée s'est portée sur des précurseurs soufrés (dithioester, dithiocétal) ou azotés qui, mis en présence d'un agent de perfluoration et d'un oxydant adéquats, génèrent un groupement trifluorométhyle ou difluorométhyle par fluorodésulfurisation oxydative. Cette méthode est efficace sur des composés comportant une fonction phtalimide. Des travaux antérieurs ayant validé cette stratégie pour le groupement CF3, notre tra-vail a tout d'abord consisté à synthétiser des précurseurs adéquats pour le radiomarquage du motif C2F5. Les premiers essais de radiomarquage ont également pu être effectués. Enfin, la dernière partie de notre travail s'est attachée à valoriser les résultats de synthèse obtenus en série fluorée. Deux procédures ont été envisagées: marquage au niveau du CF3 (précurseur difluo-ré) et marquage au niveau du CF2 (précurseurs dithiocétal et oximes trifluorés). La synthèse du précurseur difluoré (Beta-phtalimido-alpha,alpha-difluoro-dithioester) nous a amené à développer une nouvelle voie d'accès à l'alpha,alpha-difluoro-beta-alanine (3 étapes), ainsi que la première synthèse de 3,3-difluoro-azétidine-2-ones N-protégées non substituées en position C4 (3 étapes). Nous avons également mis au point une nouvelle méthode de synthèse de dithioesters au départ de thio-w-lactames. Le précurseur difluoré a été obtenu en 7 étapes avec un rendement global de 7%. Les précurseurs trifluorés ont pu être obtenus facilement à partir de la trifluoromé-thylcétone correspondante (3 étapes au total). Ces produits ont été obtenus avec des rende-ments globaux de 56 à 84 %. Les radiosynthèses effectuées ne nous ont pas permis d'atteindre le composé penta-fluoré voulu. Nous avons pu identifier des produits marqués tétrafluorés, mais sommes resté impuissant à introduire le dernier atome de fluor. Enfin, nous avons étendu les résultats de synthèse obtenus en série fluorée. Nous avons ainsi développé une nouvelle voie de synthèse pratique et efficace pour la préparation d'w-amino-dithioesters non fluorés, protégés sous formes de dérivés N-benzoyle ou N-p-nitrophényle, au départ de γ-, δ-, and ε-lactames. Cette méthode a ensuite pu être étendue au départ d'un lactame. / The aim of this study was to develop a new strategy for the fluorine-18 radiolabelling of perfluorinated groups incorporated in chemical probes (EF3, EF5), in order to assess non-invasively tumoral hypoxia by means of positron emission tomography. This technique uses sulfur (dithioesters and dithioketals) and nitrogen precursor-which, in combination with the right perfluorination agent and the right oxidant, lead to trifluoromethyl or difluoromethyl groups via oxidative fluorination. This strategy has proved efficient on aliphatic compounds bearing a phtalimide group. Since previous studies have already validated this approach for the CF3 group, we first aimed at synthesizing adequate precursors for the radiolabelling of the C2F5 moiety. First attempts of radiolabelling have also been carried out. Finally, the last part of our work was devoted to highlighting the synthesis results obtained for fluorinated compounds. Two strategies have been considered: labelling at the CF3 level (difluorinated precur-sor) and labelling at the CF2 level (trifluorinated dithioketal and oxime precursors). The synthesis of the difluorinated precursor (Beta-phtalimido-alpha,alpha-difluoro-dithioester) brought us to develop a new way to access alpha,alpha-difluoro-beta-alanine (3 steps), and the first synthesis of N-protected 3,3-difluoro-azetidin-2-ones bearing no subtituents in C4 position. We also developped a new synthesis of dithioesters, starting from thiolactams. The difluorinated precursor was obtained in 7 steps, with an overall yield of 7%. The trifluorinated precursors could be easily obtained from the corresponding trifluoromethylketone (3 steps in total). These compounds were produced with overall yields ranging from 56 to 84%. The radiosynthesis performed did not allow us to gain acces to the targetted penta-fluorinated compound. With sulfur precursors, we have been able to identify labelled tetra-fluorinated compounds, but our attempts to introduce the last fluorine atom were unsuccesful. In the end, we have expanded the scope of the dithioester synthesis developped for fluorinated compounds to non-fluorinated products. We thus disclosed a novel and practical route for preparing w-amino dithioesters, protected as N-benzoyl or N-p-nitro-phenyl and trifluoroacetyl derivatives, starting from γ-, δ-, and ε-lactams. It was subsequently possible to apply this method to lactam precursors.

Thèse d'exercice : Médecine. Médecine nucléaire : Université de Nantes : 2005. / Bibliogr. f. 127-135 [103 réf.].

Gemcitabine (dFdC) is an effective chemotherapeutic nucleoside analogue for treatment of cancers and solid tumors. Gemcitabine’s chemotherapeutic effect is limited by its rapid intracellular deamination by cytidine deaminase into the inactive uracil derivative. Herein, I designed and synthesized two sets of gemcitabine analogues: i) a 4-N-alkyl gemcitabine analogue containing a β-keto sulfonate moiety, and ii) clickable analogues possessing silicon-fluoride acceptor building blocks. Both of these sets of analogues undergo efficient fluorination, including fluorination protocols compatible with 18F labeling. The synthesis of the 4-N-alkyl gemcitabine analogue bearing β-keto sulfonate moiety began with reaction of 4-N-tosylgemcitabine with 1-amino-10-undecene, followed by a series of oxidation and sulfonation steps which yielded the β-keto sulfonate analogues. The coupling of gemcitabine with carboxylic acids using peptide coupling conditions afforded 4-N-alkanoyl analogues with a terminal alkyne or azido moiety. Click reaction of these 4-N-alkanoyl analogues with dialkylsilyl building blocks gave 4-N-alkanoylsilanegemcitabine analogue. Reaction of 4-N-tosylgemcitabine with vii functionalized azidoalkyl amines provided 4-N-alkylgemcitabine with a terminal azido group. Coupling of the latter with dialkylsilyl building block provided 4-N-alkylsilanegemcitabine. Fluorination of 4-N-alkyl gemcitabine analogues with β-keto sulfonate moieties and of the trisubstituted silane derivatives with KF and 18-Crown-6 (CH3CN/75°C/0.5-1h), gave the corresponding fluorinated 4-N-alkyl and alkanoyl gemcitabine analogues under conditions that are compatible with protocols for positron emission tomography (PET) 18F labeling. The [18F] 4-N-alkyl and alkanoyl silane gemcitabine analogues were successfully synthesized on microscale and macroscale radiochemical protocols. The biodistribution of [18F] 4-N-alkyl gemcitabine analogue was analyzed via PET imaging. The cytotoxicity activity of the silane gemcitabine analogues were studied in cancer L1210 and HEK293 cell lines and their cellular uptake were investigated using HPLC analysis and fluorescence microscopy. Reduction of ribono-1,4-lactones and gulono-1,4-lactone as well as ribono-1,5-lactone and glucono-1,5-lactones with LTBH (1.2 equiv.) in CH2Cl2 at 0 °C for 30 min provided the corresponding pentose or hexose hemiacetals in chemoselective fashion and in high yields. Commonly used in carbohydrate chemistry protecting groups such as trityl, benzyl, silyl, acetals and to some extent acyls are compatible with this reduction.

Histone deacetylase (HDAC) inhibitors (HDACIs) have long been studied and shown promises in the treatment of various neurodegenerative disorders including Huntington’s disease (HD). Based on many demonstrated potentials of HDACIs in mitigating various diseases, we evaluated the utility of [18F]FAHA, a radiolabeled derivative of suberoylanilide hydroxamic acid (SAHA), as a PET imaging agent for characterizing HDAC activity in a non-human primate model and a R6/2 transgenic mouse model of HD. We were aiming at HD as a potential first application, and therefore also examined the expression of HDAC and acetyl histone (AH) in brains of HD patients. This thesis describes that [18F]FAHA was metabolized rapidly to [18F]FACE in both blood plasma and brain. Kinetic analysis indicated that peripherally generated [18F]FACE contributed to the total brain activity. We therefore used a dual-input function model to analyze the kinetics of tracer accumulation and inhibition by SAHA in rhesus monkeys. Parametric images demonstrated the inhibition of HDAC activity in the brain by SAHA in a dose-dependent manner. Huntington’s mice (R6/2) showed a gradual increase of [18F]FAHA accumulation in all organs including the brain with age. In human tissue we found significant losses of acetyl histons expression from cells in the caudate nucleus and Purkinje cells of the cerebellum in HD, while the level of HDAC 5 was increased in these cells. The data obtained in rhesus monkeys indicated that PET imaging with [18F]FAHA could be used as a pharmacodynamic biomarker of the inhibition of class IIa HDACs by HDACIs in the brain and facilitate the development and clinical translation of novel class-IIa HDACIs.

No / Background: Vascular calcification is an active cell-mediated process that is a hallmark of atherosclerosis. Whilst macro-calcification confers stability to plaque, micro-calcification is a key feature of high-risk atheroma associated with major adverse cardiovascular events. Positron emission tomography combined with computed tomography (PET/CT) imaging of atherosclerosis using 18F-sodium fluoride (18F-NaF) has the potential to identify active micro-calcification and thus high-risk plaque. The precise molecular mechanism of 18F-NaF binding has however not been validated. The aim of this study was to provide a comprehensive model describing the binding characteristics, pharmacodynamics and pharmacokinetics of 18F-NaF. Methods: Patients undergoing carotid endarterectomy were studied. 18F-NaF binding was analysed using a combination of electron microscopy, autoradiography, gamma scintigraphy, histology and immunohistochemistry, pre-clinical microPET/microCT and dynamic clinical PET/CT. Results: 18F-NaF was shown to bind to calcium within plaque with high affinity. Binding was selective and specific. 18F-NaF PET was able to identify on-going nascent micro-calcification far beyond the resolution of clinical and pre-clinical CT systems. Furthermore, 18F-NaF was able to distinguish between areas of macro and micro-calcification. Conclusions: 18F-NaF PET/CT is the only currently available clinical imaging platform that can detect micro-calcification in active unstable atherosclerosis. The use of 18F-NaF will foster new approaches to developing treatments targeting unstable plaque and vascular calcification.

No Brasil e no mundo a medicina nuclear vem ganhando destaque com as técnicas diagnósticas que permitem o estudo metabólico de doenças, alterando significativamente o gerenciamento dos pacientes. Essa tecnologia inovadora vem trazendo expectativas tanto para os setores especializados como para a sociedade. Nesse trabalho foi estudada a utilização do radiofármaco 18F-FDG na região metropolitana de São Paulo e nas áreas adjacentes, bem como a estrutura do mercado atual e das dificuldades a serem superadas com o aumento da demanda do 18F-FDG. A pesquisa contou com uma análise do mercado de radiofármacos internacional e das principais alterações que vem ocorrendo nessa área no Brasil nos últimos anos. Foram realizadas entrevistas com profissionais atuantes na área de medicina nuclear e coleta de dados através de questionário enviado para os centros consumidores do radiofármaco na região coberta pela pesquisa. As entrevistas expressaram as opiniões dos entrevistados sobre as transformações nesse setor e as tendências futuras e os dados coletados no questionário serviram de complementação a utilização do radiofármaco nos equipamentos do tipo Single Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET) e Positron Emission Tomography / Computer Tomography (PET/CT). O maior uso do 18F-FDG tem sido para o diagnóstico oncológico nos equipamentos do tipo PET e PET/CT. Essa utilização deverá crescer nos próximos anos, podendo se expandir para outras especialidades como neurologia e cardiologia. Apesar de restrita atualmente as cidades de São Paulo e Rio de Janeiro deverá haver uma expansão dessa modalidade diagnóstica nos outros Estados do país que começam a estruturar produção do radioisótopo. A recente alteração na constituição que permite a produção e comercialização de radioisótopos de meia-vida curta também deverá aumentar o interesse da iniciativa privada nesse mercado, que internacionalmente possui projeções otimistas de crescimento. Existe também uma expectativa que a aprovação dos planos de saúde para a cobertura dos exames utilizando 18F-FDG no PET impulsione esse mercado ainda mais, repetindo a experiência internacional. Os recentes investimentos realizados pelo IPEN para aumentar a produção do 18F-FDG deverá garantir a oferta com confiabilidade, para a região Sudeste e Sul do país. / Nuclear Medicine in Brazil and worldwide has developed distinction with diagnosis techniques that allow metabolic research of the disease, changing in a significant fashion the patients outcome. This innovative technology leads expectations from specific fields up to society itself. This research studied the use of 18F-FDG radiopharmaceutical in the metropolitan region of São Paulo and adjacent areas, as well as the recent trade structure and the difficulties that should be overcome with the increase of the 18F-FDG demand. This research counted on the analysis of the international radiopharmaceutical trade and the main changes that have been happening in this area in Brazil during the past few years. Interviews were performed with professionals within the area of nuclear medicine and data has been collected through questionnaire sent to the consuming centers of the radiopharmaceutical in the region covered in this research. The interviews expressed the opinions of the interviewees concerning transformations in this field and future tendencies and the information obtained from the survey was the basis of complementation of the use of radiopharmaceutical on equipments such as Single Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET) and Positron Emission Tomography / Computer Tomography (PET/CT). The major use of 18F-FDG has been used for oncology diagnosis with equipments such as PET and PEC/CT. This use shall grow in the next years, maybe expanding to other specialties such as neurology and cardiology. Although nowadays restricted to the cities of São Paulo and Rio de Janeiro, there is a possibility of expansion to other diagnosis modalities in other states of the country that are starting to structure the production of the radioisotope. The recent change in the constitution permitting the production and commerce of short half-life radioisotopes also contributes to the increase the interest of private funding of this sector in which internationally holds optimistic projections of increase. There is also the expectancy that approving health care plans coverage of these exams using 18F-FDG with PET to boast more this sector, repeating international experience. Recent investments made by IPEN to increase the production of 18F-FDG shall guarantee the offer of confidentiality for the Southeast and Southern regions of the country.

Hemisynthèse stéréosélective d’acides aminés hétérosubstitués sur la chaîne latérale.Applications au radio-fluoromarquage pour l’imagerie de peptides.Ce travail de thèse, qui a été réalisé à l’Institut de Chimie Moléculaire de l’Université de Bourgogne et en collaboration avec l’Institut de Neuroscience Cognitives et Intégrative d’Aquitaine, porte sur la mise au point de nouvelles méthodes de synthèse d’acides aminés hétérosubstitués sur la chaine latérale par des groupements phosphorés ou silylés, ainsi que sur leurs applications. Dans une première partie, la synthèse d’acides aminés silylés sur la chaine latérale est réalisée sans racémisation par réaction de Wittig entre un sel de phosphonium, dérivé d’acide L-aspartique, avec un aldéhyde aromatique porteur du groupement silylé. Ces acides aminés ont été utilisés en synthèse peptidique pour donner des di- et tripeptides silylés par réaction avec des dérivés d’alanine et de phénylalanine. Il a été montré que les acides aminés et peptides silylés pouvaient être fluorés par réaction avec des fluorures, et que dans le cas de dérivés di-t-butylsilylés, les composés fluorés obtenus se révèlent d’une très grande stabilité à pH physiologique. L’étude de la fluoration des peptides di-t-butylsilylés par K18F/K222 a permis d’obtenir les dérivés radiomarqués avec des rendements radiochimiques et des activités molaires atteignant respectivement 39% et 410 GBq.mmol-1. Dans la seconde partie, la synthèse d’acides aminés et peptides hétérosubstitués ou fonctionnalisés sur la chaine latérale, a été mise au point. Le principe de cette synthèse repose sur une cycloaddition [3+2] entre un acide aminé porteur d’un groupement azido avec un alcyne disubstitué. Alors que la réaction par catalyse avec un sel de cuivre ou un complexe de ruthénium ne conduit pas aux produits recherchés, la cycloaddition a été mise au point sous microondes en utilisant le glycérol comme solvant. Dans ces conditions, 13 nouveaux acides aminés porteurs d’un noyau triazole en position γ, et des substituants silylés, phosphorés, amines, amides …ont été préparés sans racémisation et ce avec des rendements atteignant 89%. Les méthodologies mises au point dans ce travail de thèse offrent de nouvelles voies pour la synthèse de dérivés acides aminés silylés ou phosphorés utiles pour la chimie de coordination, la catalyse asymétrique et pour le radiomarquage par les ions fluorure 18F-.Mots clés : Phosphoniums, acides aminés, silanes ; [18F]-radiofluoration, triazoles. / Stereoselective hemisynthesis of lateral chain heterosubstituted aminoacids.Applications on radiofluorolabeling for peptide imaging.This thesis work, which was carried out at the Institute of Molecular Chemistry of the University of Burgundy and in collaboration with the Institute of Cognitive and Integrative Neurosciences of Aquitaine, focuses on the development of new methods for the synthesis of side chain heterosubstituted amino acids including phosphine containing or silyl groups, as well as on their applications. In a first part, the synthesis of side chain silylated amino acids is achieved without racemization using a key Wittig reaction between a phosphonium salt, derived from L-aspartic acid, and an aromatic aldehyde bearing the silyl group. These aminoacids have been used in peptide synthesis to give silylated di- and tripeptides by reaction with alanine and phenylalanine derivatives. It has been shown that the silylated aminoacids and peptides can be fluorinated by reaction with fluorides, and that in the case of di-t-butylsilyl derivatives, the fluorinated compounds obtained are found to be very stable at physiological pH. The study of the fluorination of di-t-butylsilyl peptides by K18F / K222 allowed to obtain radiolabelled derivatives with radiochemical yields and molar activities reaching 39% and 410 GBq.mol-1, respectively. In the second part, the synthesis of aminoacids and peptides heterosubstituted or functionalized on the side chain, was developed. The principle of this synthesis is based on a [3 + 2] cycloaddition between an aminoacid bearing an azido group with disubstituted alkyne. While the reaction catalyzed using a copper salt or a ruthenium complex does not lead to the desired products, the cycloaddition was developed under microwave irradiation using glycerol as a solvent. Under these conditions, 13 new amino acids carrying a triazole ring at the γ position, and bearing silyles, phosphines, amines, amides.. substituents were prepared without racemization and with yields up to 89%. The methodologies developed in this thesis offer new efficient ways for the synthesis of silyl or phosphorus amino acid derivatives, useful for coordination chemistry, asymmetric catalysis and radiolabeling by the fluoride ion18F-.Key words: Phosphoniums, aminoacids, silanes, [18F]-radiofluorination, triazoles

No Brasil e no mundo a medicina nuclear vem ganhando destaque com as técnicas diagnósticas que permitem o estudo metabólico de doenças, alterando significativamente o gerenciamento dos pacientes. Essa tecnologia inovadora vem trazendo expectativas tanto para os setores especializados como para a sociedade. Nesse trabalho foi estudada a utilização do radiofármaco 18F-FDG na região metropolitana de São Paulo e nas áreas adjacentes, bem como a estrutura do mercado atual e das dificuldades a serem superadas com o aumento da demanda do 18F-FDG. A pesquisa contou com uma análise do mercado de radiofármacos internacional e das principais alterações que vem ocorrendo nessa área no Brasil nos últimos anos. Foram realizadas entrevistas com profissionais atuantes na área de medicina nuclear e coleta de dados através de questionário enviado para os centros consumidores do radiofármaco na região coberta pela pesquisa. As entrevistas expressaram as opiniões dos entrevistados sobre as transformações nesse setor e as tendências futuras e os dados coletados no questionário serviram de complementação a utilização do radiofármaco nos equipamentos do tipo Single Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET) e Positron Emission Tomography / Computer Tomography (PET/CT). O maior uso do 18F-FDG tem sido para o diagnóstico oncológico nos equipamentos do tipo PET e PET/CT. Essa utilização deverá crescer nos próximos anos, podendo se expandir para outras especialidades como neurologia e cardiologia. Apesar de restrita atualmente as cidades de São Paulo e Rio de Janeiro deverá haver uma expansão dessa modalidade diagnóstica nos outros Estados do país que começam a estruturar produção do radioisótopo. A recente alteração na constituição que permite a produção e comercialização de radioisótopos de meia-vida curta também deverá aumentar o interesse da iniciativa privada nesse mercado, que internacionalmente possui projeções otimistas de crescimento. Existe também uma expectativa que a aprovação dos planos de saúde para a cobertura dos exames utilizando 18F-FDG no PET impulsione esse mercado ainda mais, repetindo a experiência internacional. Os recentes investimentos realizados pelo IPEN para aumentar a produção do 18F-FDG deverá garantir a oferta com confiabilidade, para a região Sudeste e Sul do país. / Nuclear Medicine in Brazil and worldwide has developed distinction with diagnosis techniques that allow metabolic research of the disease, changing in a significant fashion the patients outcome. This innovative technology leads expectations from specific fields up to society itself. This research studied the use of 18F-FDG radiopharmaceutical in the metropolitan region of São Paulo and adjacent areas, as well as the recent trade structure and the difficulties that should be overcome with the increase of the 18F-FDG demand. This research counted on the analysis of the international radiopharmaceutical trade and the main changes that have been happening in this area in Brazil during the past few years. Interviews were performed with professionals within the area of nuclear medicine and data has been collected through questionnaire sent to the consuming centers of the radiopharmaceutical in the region covered in this research. The interviews expressed the opinions of the interviewees concerning transformations in this field and future tendencies and the information obtained from the survey was the basis of complementation of the use of radiopharmaceutical on equipments such as Single Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET) and Positron Emission Tomography / Computer Tomography (PET/CT). The major use of 18F-FDG has been used for oncology diagnosis with equipments such as PET and PEC/CT. This use shall grow in the next years, maybe expanding to other specialties such as neurology and cardiology. Although nowadays restricted to the cities of São Paulo and Rio de Janeiro, there is a possibility of expansion to other diagnosis modalities in other states of the country that are starting to structure the production of the radioisotope. The recent change in the constitution permitting the production and commerce of short half-life radioisotopes also contributes to the increase the interest of private funding of this sector in which internationally holds optimistic projections of increase. There is also the expectancy that approving health care plans coverage of these exams using 18F-FDG with PET to boast more this sector, repeating international experience. Recent investments made by IPEN to increase the production of 18F-FDG shall guarantee the offer of confidentiality for the Southeast and Southern regions of the country.

No description available.