Radiolabeled somatostatin analogues based on octreotide have proven useful in the management of somatostatin receptor subtype 2 (sstr2)-positive tumours in clinical trials. The aim was to compare the potency and evaluate the combination of 111In- and 177Lu-DOTATOC with a double-deleted version of vaccinia virus (ddVV), an oncolytic virus for inhibiting the growth of sstr2-expressing human embryonic kidney (HEK-293) cells or MC-38 murine colon cancer cells grown as monolayers or as spheroids. Cytotoxicity studies were carried out using ddVV, 111In-DOTATOC and 177Lu-DOTATOC, individually or in combination on MC-38 spheroids, HEK-293 cells and spheroids. HEK-293 cell growth in spheroids was reduced to 17.2 ± 4.9% and 26.5 ± 6.3 % with 111In-DOTATOC and 177Lu-DOTATOC alone and 13.1 ± 7.1% and 0% in combination, respectively. MC-38 spheroids showed greater toxicity in combination treatment. Combination of ddVV with 111In- or 177Lu-DOTATOC is only advantageous in monolayer culture. No advantage was observed in spheroid models.

The introduction of high fructose corn syrup into the diet has been proposed to be the cause of many illnesses related to the metabolic syndrome. Fructose and its metabolites can be metabolized into cytotoxic reactive dicarbonyls that can cause damage to macromolecules leading to deleterious consequences. Dihydroxyacetone, a fructose metabolite, was studied in this thesis. Its ability to autoxidize and cause protein carbonylation under standard (pH 7.4, 37°C) and oxidative stress conditions (Fentons reagent) was investigated. Dihydroxyacetone was able to form significant amounts of dicarbonyls and protein carbonylation. Several selected natural polyphenols were chosen for an in vitro toxicological study involving rat hepatocytes. The chosen dietary polyphenols were rutin, gallic acid, methylgallate, ethylgallate, propylgallate and curcumin. In this thesis, the polyphenols were found to be able to significantly protect against the deleterious effects of glyoxal and methylglyoxal. In summary, these polyphenols could be candidates for future in vivo studies.

The introduction of high fructose corn syrup into the diet has been proposed to be the cause of many illnesses related to the metabolic syndrome. Fructose and its metabolites can be metabolized into cytotoxic reactive dicarbonyls that can cause damage to macromolecules leading to deleterious consequences. Dihydroxyacetone, a fructose metabolite, was studied in this thesis. Its ability to autoxidize and cause protein carbonylation under standard (pH 7.4, 37°C) and oxidative stress conditions (Fentons reagent) was investigated. Dihydroxyacetone was able to form significant amounts of dicarbonyls and protein carbonylation. Several selected natural polyphenols were chosen for an in vitro toxicological study involving rat hepatocytes. The chosen dietary polyphenols were rutin, gallic acid, methylgallate, ethylgallate, propylgallate and curcumin. In this thesis, the polyphenols were found to be able to significantly protect against the deleterious effects of glyoxal and methylglyoxal. In summary, these polyphenols could be candidates for future in vivo studies.

Background: In many countries, a significant proportion of medicines traded and consumed are of poor or variable quality. Meanwhile, failures in appropriately framing and responding to the problem have led to a proliferation of public health and governance challenges. Objective: To examine the issues exacerbating the trade and consumption of medicines of poor or variable quality, as well as present locally relevant strategies. Methods: Analytic triangulation was applied to the synthesis of publicly available documents. Results: Where economic and regulatory environments are less structured, supply chain security strategies that fixate on ‘counterfeits’ often fail in limiting the prevalence of poor quality medicines. In addition to a multivariate drug quality classification chart, three quality frameworks are presented for examining appropriate policy strategies in mediating drug quality. Conclusion: These tools can assist stakeholders in determining more locally relevant and context-specific strategies, while interrogating the proposition for greater transparency vis-à-vis drug quality.

Objectives: The objectives of the research were to determine which intravenous (IV) antibiotics were cost-effective in Diabetic Foot Infections (DFIs) and to assess the impact of MRSA prevalence on clinical outcome. Methods: A Cost-effectiveness analysis (CEA) was performed on IV antibiotics used to treat moderate to severe DFIs in hospitalized patients. MRSA prevalence was taken into account by calculating an ‘Adjusted cure rate’ and re-analysing the CEA. Results: In the original CEA, imipenem/cilastatin was the cost-effective agent. When MRSA prevalence was taken into account imipenem/cilastatin, moxifloxacin, cefoxitin and ertapenem were cost-effective antibiotics. Conclusion: MRSA prevalence adjustments changed the results of the CEA and included classes of IV antibiotics that are seen being using in practice, such as fluoroquinolones and cephalosporins. These methods could potentially have an impact on the evaluation of clinical cure rates and resistance when evaluating the literature.

Background: In many countries, a significant proportion of medicines traded and consumed are of poor or variable quality. Meanwhile, failures in appropriately framing and responding to the problem have led to a proliferation of public health and governance challenges. Objective: To examine the issues exacerbating the trade and consumption of medicines of poor or variable quality, as well as present locally relevant strategies. Methods: Analytic triangulation was applied to the synthesis of publicly available documents. Results: Where economic and regulatory environments are less structured, supply chain security strategies that fixate on ‘counterfeits’ often fail in limiting the prevalence of poor quality medicines. In addition to a multivariate drug quality classification chart, three quality frameworks are presented for examining appropriate policy strategies in mediating drug quality. Conclusion: These tools can assist stakeholders in determining more locally relevant and context-specific strategies, while interrogating the proposition for greater transparency vis-à-vis drug quality.

Objectives: The objectives of the research were to determine which intravenous (IV) antibiotics were cost-effective in Diabetic Foot Infections (DFIs) and to assess the impact of MRSA prevalence on clinical outcome. Methods: A Cost-effectiveness analysis (CEA) was performed on IV antibiotics used to treat moderate to severe DFIs in hospitalized patients. MRSA prevalence was taken into account by calculating an ‘Adjusted cure rate’ and re-analysing the CEA. Results: In the original CEA, imipenem/cilastatin was the cost-effective agent. When MRSA prevalence was taken into account imipenem/cilastatin, moxifloxacin, cefoxitin and ertapenem were cost-effective antibiotics. Conclusion: MRSA prevalence adjustments changed the results of the CEA and included classes of IV antibiotics that are seen being using in practice, such as fluoroquinolones and cephalosporins. These methods could potentially have an impact on the evaluation of clinical cure rates and resistance when evaluating the literature.

Radiolabeled somatostatin analogues based on octreotide have proven useful in the management of somatostatin receptor subtype 2 (sstr2)-positive tumours in clinical trials. The aim was to compare the potency and evaluate the combination of 111In- and 177Lu-DOTATOC with a double-deleted version of vaccinia virus (ddVV), an oncolytic virus for inhibiting the growth of sstr2-expressing human embryonic kidney (HEK-293) cells or MC-38 murine colon cancer cells grown as monolayers or as spheroids. Cytotoxicity studies were carried out using ddVV, 111In-DOTATOC and 177Lu-DOTATOC, individually or in combination on MC-38 spheroids, HEK-293 cells and spheroids. HEK-293 cell growth in spheroids was reduced to 17.2 ± 4.9% and 26.5 ± 6.3 % with 111In-DOTATOC and 177Lu-DOTATOC alone and 13.1 ± 7.1% and 0% in combination, respectively. MC-38 spheroids showed greater toxicity in combination treatment. Combination of ddVV with 111In- or 177Lu-DOTATOC is only advantageous in monolayer culture. No advantage was observed in spheroid models.

Les isoenzymes du CYP450 sont grandement impliquées dans le métabolisme oxydatif des médicaments et des variations dans leur activité (interactions médicamenteuses, polymorphismes génétiques) peuvent occasionner des changements importants dans les concentrations plasmatiques et tissulaires des médicaments. Le foie régit de façon prédominante les concentrations plasmatiques des médicaments en raison d’une forte concentration des CYP450s dans cet organe. En moyenne, l’élimination d’un médicament par métabolisme représente environ 75% des mécanismes de clairance par rapport à 20% par voie rénale et 10% par la bile sous forme inchangée. Les CYP450s contribuent à environ 75% du métabolisme des médicaments. Il est ainsi logique de s’attarder au comportement et facteurs influençant l’expression et l’activité des CYP450s. L’abondance et la variété des CYP450s exprimés diffèrent entre le foie et les tissus extra-hépatiques. Le rôle de ces isoenzymes dans le devenir extra-hépatique des composés endogènes et exogènes demeure peu étudié malgré leur implication et association reconnue dans certains échecs thérapeutiques, interactions médicamenteuses ou toxicités tissulaires. Le ventricule de cœur humain exprime (ARNmessager) de façon variable certaines isoenzymes dont le CYP1A1, 2B6, 2C8, 2C9, 2D6, 2E1, 2J2, 3A5 et 4A11. La participation de ces isoenzymes exprimées dans la paroi ventriculaire cardiaque dans le métabolisme des médicaments reste à ce jour inconnue. Établir l’existence d’une participation active de certains CYP450s, étudier leur profil métabolique et leur contribution dans la clairance locale tout en déterminant les facteurs responsables de leur variabilité en terme d’activité et d’expression (ARNm) dans le tissu ventriculaire cardiaque humain représente l’objectif principal des travaux de recherche présentés dans cette thèse. Le premier volet fût le développement de cocktails médicamenteux afin d’optimiser la quantité de résultats à travers l’usage unique d’un tissu avec des substrats sélectifs jumelés à des méthodes analytiques ultra-sensibles et spécifiques (manuscrit 1). Parmi les 9 composés testés, les substrats ébastine et chlorzoxazone, substrats-cibles reconnus des isoenzymes CYP2J2 et CYP2E1 respectivement, ont démontré des activités menant à l’étude approfondie de leur profil métabolique généré par la fraction microsomale de ventricules de cœurs humains explantés (MCH). Ces travaux ont démontré une cinétique préférentielle et de très haute affinité par les MCH envers la voie d’hydroxylation de l’ébastine décrite par un modèle Michaelis-Menten. Jumelé à des essais d’inhibition, un lien fût établi, pour la toute première fois, entre l’hydroxylation de l’ébastine et l’isoenzyme CYP2J2 (manuscrit 2). L’hydroxylation de l’ébastine par les MCH fût aussi reconnue comme étant hautement variable entre des individus adressés à une transplantation cardiaque présentant des cardiomyopathies potentiellement mortelles n’étant plus maîtrisées par les thérapies ou traitements standards. L’objectif de ce dernier volet était d’étudier des facteurs (extrinsèques et intrinsèques, dont le polymorphisme du CYP2J2*7) connus chez ces patients et leur implication dans la variabilité de l’expression du CYP2J2 (ARNm) et de son activité enzymatique, déduite par l’étude du comportement métabolique du marqueur ébastine suite à une analyse des paramètres de cinétique enzymatique (Km, Vmax, CLint). Il a été démontré que le sexe, le côté gauche du ventricule, la prise d’amiodarone et le diagnostic clinique d’ischémie sont associés à la variabilité d’expression (ARNm) et d’activité (Km, Vmax, CLint) du CYP2J2 et expliquent environ 20% de la variabilité observée entre les individus. Il s’agit des premiers travaux expliquant une portion de la variabilité associée à l’expression (ARNm) et l’activité du CYP2J2 dans le ventricule du cœur humain (manuscrit 3). Finalement, nos résultats suggèrent que la capacité métabolique du CYP2J2 au sein des MCH est réelle et importante et pourrait participer aux fluctuations locales des concentrations de médicaments. L’extrapolation des résultats obtenus in vitro à l’échelle in vivo (organe entier) a permis de mettre en perspective la contribution métabolique du CYP2J2 dans le contexte locale physiologique du tissu ventriculaire cardiaque étudié. Nos résultats appuient la proposition que la concentration libre plasmatique ne reflète pas nécessairement la concentration tissulaire efficace puisque des mécanismes locaux de métabolisme enzymatique (CYP2J2) peuvent grandement faire varier la concentration libre au site d’action intracellulaire. Les résultats obtenus répondent à un besoin en recherche de comprendre le comportement et l’ampleur de la participation de différentes isoenzymes du CYP450 connues s’exprimant dans le cœur humain envers le métabolisme de médicaments s’y distribuant et ultimement prédire leurs concentrations intracellulaires. / CYP450 isoenzymes are greatly involved in oxidative drug metabolism and changes in their activity (drug interactions, genetic polymorphisms) can cause significant changes in plasma and tissue concentrations of the drugs. The liver predominantly governs plasma concentrations of drugs because of a high concentration of CYP450s. On average, the elimination of a drug through metabolism accounts for about 75% of clearance mechanisms compared to 20% via renal excretion and 10% via the bile excretion. The CYP450s contribute to about 75% of drug metabolism. It is thus logical to study factors influencing the expression and activity of CYP450s. Abundance and variety of expressed CYP450s differ between the liver and extrahepatic tissues. The role of these enzymes endogenous and drugs concentrations in the extrahepatic tissues is poorly studied despite their involvement and association recognized in some treatment failures, drug interactions or tissue toxicity. The ventricles of the human heart express (messenger RNA) variably some isoenzymes including CYP1A1, 2B6, 2C8, 2C9, 2D6, 2E1, 2J2, 3A5 and 4A11. The participation of these isoenzymes expressed in the cardiac ventricular wall in drug metabolism remains unknown to this day. Establishing the existence of an active participation of some CYP450s, their metabolic profile and contribution to the local clearance and determining factors responsible for variability in activity and expression (mRNA) in the cardiac ventricular tissue human is the main objective of the research presented in this thesis. The first module was the development of drug cocktails to maximize the amount of results through the use of low amount of heart tissue with selective substrates matched with highly sensitive and specific analytical methods (manuscript 1). Of the nine compounds tested 2 substrates, ebastine and chlorzoxazone, probe of CYP2E1 and CYP2J2 respectively, have demonstrated activities leading to a thorough study of their metabolic profile generated by the microsomal fraction of the ventricles of explanted human hearts (MCH). This work demonstrated preferential kinetics, described by a Michaelis-Menten model, and very high affinity towards the MCH hydroxylation pathway for ebastine. Combined with inhibition assays, a link was established, for the first time, between the hydroxylation of ebastine and the isoenzyme CYP2J2 (manuscript 2). Hydroxylation of ebastine by MCH was also recognized as being highly variable between individuals that went through a heart transplant with life-threatening cardiomyopathies that are no longer controlled by standard therapies or treatments. The aim of this last part was to study factors (extrinsic and intrinsic, such as polymorphism of CYP2J2 * 7) known in these patients and their involvement in the variability of expression (mRNA) and enzymatic activity of CYP2J2 studied through the analysis of the enzyme kinetic profile of ebastine (Km, Vmax, CLint). It has been shown that gender, the left ventricle, use of amiodarone and clinical diagnosis of ischemia were associated with the variability of expression (mRNA) and activity (Km, Vmax, CLint) of CYP2J2 and those factors account for about 20% of the observed variability between individuals. This is the first work to explain a portion of the variability associated with the expression (mRNA) and activity of CYP2J2 in the ventricle of the human heart (manuscript 3). Overall, our results suggested that the metabolic capacity of CYP2J2 by MCH is real and important and could participate in local fluctuations of drug levels. The extrapolation of in vitro results to in vivo scale (whole body) helped to put into perspective the contribution of CYP2J2 in the local physiological context of the cardiac ventricular tissue studied. Our results support the proposal that the free plasma concentration does not necessarily reflect the effective tissue concentration as local mechanisms, in this case enzymatic metabolism by CYP2J2, could greatly provoke variation in free intracellular concentration at the site of action. The results obtained meet a need in research to understand the behavior and extent of participation of various CYP450 isoenzymes known to be expressed in the human heart on the local metabolism of drugs that are distributed locally and ultimately developing tools to predict the intracellular drug concentrations in the physiological context.

La technique du laser femtoseconde (fs) a été précédemment utilisée pour la production de nanoparticules d'or dans un environnement aqueux biologiquement compatible. Au cours de ce travail de maîtrise, cette méthode a été investiguée en vue d'une application pour la fabrication de nanocristaux de médicament en utilisant le paclitaxel comme modèle. Deux procédés distincts de cette technologie à savoir l'ablation et la fragmentation ont été étudiés. L'influence de la puissance du laser, de point de focalisation, et de la durée du traitement sur la distribution de taille des particules obtenues ainsi que leur intégrité chimique a été évaluée. Les paramètres ont ainsi été optimisés pour la fabrication des nanoparticules. L’évaluation morphologique et chimique a été réalisée par microscopie électronique et spectroscopie infrarouge respectivement. L'état cristallin des nanoparticules de paclitaxel a été caractérisé par calorimétrie differentielle et diffraction des rayons X. L'optimisation du procédé de production de nanoparticules par laser fs a permis d'obtenir des nanocristaux de taille moyenne (400 nm, polydispersité ≤ 0,3). Cependant une dégradation non négligeable a été observée. La cristallinité du médicament a été maintenue durant la procédure de réduction de taille, mais le paclitaxel anhydre a été transformé en une forme hydratée. Les résultats de cette étude suggèrent que le laser fs peut générer des nanocristaux de principe actif. Cependant cette technique peut se révéler problématique pour des médicaments sensibles à la dégradation. Grâce à sa facilité d'utilisation et la possibilité de travailler avec des quantités restreintes de produit, le laser fs pourrait représenter une alternative valable pour la production de nanoparticules de médicaments peu solubles lors des phases initiales de développement préclinique. Mots-clés: paclitaxel, nanocristaux, laser femtoseconde, ablation, fragmentation / Femtosecond (fs) laser ablation and fragmentation, a novel technique based upon the breakdown of material using laser energy was previously used for the production of fine gold nanoparticles in suspension. This technique has been newly investigated for the fabrication of paclitaxel nanocrystals in aqueous solution. In this work, we report the fabrication and characterization of paclitaxel nanocrystals generated by fs laser technology. Two distinct methods of this technology have been explored: ablation and fragmentation. The influence of the laser power, focusing position and treatment time on the particle size, size distribution and chemical integrity of the drug has been studied. Morphology and chemical composition of the finest paclitaxel nanocrystal formulation was studied by scanning electron microscopy and Fourier-transform infrared spectroscopy respectively. Differential scanning calorimetry and X-ray diffraction analyses were employed to evaluate the polymorphic state of the paclitaxel nanocrystals. Optimal laser fabrication parameters have been established for the fabrication of uniformly small sized paclitaxel nanocrystals. Those optimal conditions generated finely-sized paclitaxel nanoparticles (400 nm, PDI ≤ 0.3) with a considerable degradation. The drug remained crystalline upon nanonization at high power, though the anhydrous crystals were converted to a partially hydrated form. These findings suggest that drug nanocrystals could be produced using the fs laser technology; however, this technique may be inappropriate for drugs sensitive to degradation. Moreover, the simple fabrication of drug nanocrystals using the fs laser fragmentation presents a great asset for the intial phases of preclinical development of many poorly soluble drug candidates, which are not as sensitive as paclitaxel. Keywords: paclitaxel, nanocrystals, femtosecond, ablation, fragmentation