De nos jours, l’encapsulation est une technique très répandue dans le domaine de la parfumerie. En effet, elle permet une libération contrôlée du parfum et une protection des molécules de parfumerie qui peuvent s’oxyder avec le temps. L’objectif de cette thèse a été de mettre au point un nouveau concept de capsules fondé sur la formulation d’émulsions doubles huile-dans-eau-dans-huile et de polymériser la phase aqueuse intermédiaire. Les phases huiles, intérieure et extérieure, sont respectivement constituées du parfum et d’un solvant de parfumerie. La phase aqueuse est, elle, composée de monomères hydrophiles dont la polymérisation radicalaire permet l’obtention d’une matrice polymère plus ou moins diffusive vis-à-vis du parfum. L’intérêt de ce nouveau principe d’encapsulation est de séparer la polymérisation et les molécules de parfumerie qui peuvent être réactives en polymérisation radicalaire en les localisant dans des compartiments distincts et ainsi éviter toute interaction. Cette stratégie qui combine la Science des Emulsions, des Polymères et des Parfums et la Formulation a permis l’élaboration de capsules robustes possédant des propriétés de libération progressive par diffusion et de libération provoquée par application d'une contrainte mécanique sans altérer l'intégrité des capsules. Elles se comportent alors comme des micro-éponges capables de se déformer et de reprendre leur forme initiale. Dans ce schéma général, les propriétés peuvent être modulées plus finement par le choix et les concentrations des réactifs lors de la synthèse. / Nowadays, encapsulation is a widespread technology in fragrance applications. Indeed, it allows control of the fragrance release as well as protection of the fragrance molecules with respect to oxidation. The objective of this PhD is the development of a new concept of encapsulation based on the formulation of double oil-in-water-in-oil emulsion and the polymerization of the intermediate aqueous phase. The two, internal and external, oil phases, , are respectively the fragrance and perfume solvent while the aqueous phase is composed of hydrophilic monomers leading to a more or less fragrance-diffusive polymer matrix after their radical polymerization. The main advantage of this encapsulation principle is to locate the polymerization and the possibly reactive fragrance’s molecules in separate compartments. This strategy which combines the Sciences of Emulsion, Polymers and Fragrance but also the Formulation allows obtaining robust capsules exhibiting both diffusive properties and a triggered release under a mechanical stress. These capsules behaves as micrometric sponges that can deform and restore their initial state.. In this general scheme, the capsules' properties can be tuned by an appropriate choice of the polymerization reactants and their concentrations.

Chan Yuen Lai. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2002-2003, design report." / Includes bibliographical references. / Chapter 00_ --- FOREWORD: I BEGAN CREATING MY TIME CAPSULE BOXES / Chapter 01_ --- INVENTORY OF BOXES / Chapter 02_ --- "THE ARCHIVE GALLERY, AS AN INVENTED PROGRAM" / Chapter 03_ --- HABITATION / MAN AND HIS ENVIRONMENT / TOURISTIC EXPERIENCE / DEAN MACCANNELL / "ADVENTURER, TRAVELLER, TOURIST" / CHRISTIAN NORBERG-SCHULZ / RELPH EDWARD / INSIDENESS AND OUTSIDENESS / "THE ONE, THE THING, THE PLACE" / AUTHENTICITY VS PEUSDO-EVENT / THE HOME / Chapter 04_ --- THE SITE / TOPOLOGY VS GEOGRAPHY / TIME AND MOVEMENT / ANDY WARHOL / DAN GRAHAM / UMBERTO ECO / ENCODING AND DECODING / AS SIGN AND AS MIRROR / TIME CAPSULE / "REGISTRATION, RETENTION, RECALL OF MEMORY" / WALTER BENJAMIN / CITY AND MEMORY / THE METAPHOR / Chapter 05_ --- THE STATEMENT / OUR WORLD. REALITY VS VIRTUAL ITY. LABYRINTH. MIRROR. METAPHOR. CUBE. PLANE. LINE. POINT. MODEL. ARCHITECTURE. THESIS / GRID. LABYRINTH. TIME. BODY. MIRROR / Chapter 06_ --- LABYRINTH AND MIRROR / THESEUS AND MINOTAUR / NARCISSUS / RACHEL WHITEREAD / SARAH SZE / JOSEPH CORNELL / MEMORY BOXES / WORLD AND SELF / ITALO CALVINO / LABYRINTHINE CHARACTER / ZAIRA AND ITS PAST / NETWORK / MEDIATION / MIRROR REFLECTIVITY / THE BIG STONE FEDORA AND THE LITTLE FEDORAS IN THE GLASS GLOBES / IMAGES OF CONTAINMENT / ENCLOSURE / Chapter 07_ --- THE PROGRAM / THE ARCHIVE GALLERY / "START OF THE JOURNEY, COLLECTION OF THE BOX" / "THE THING, THE BOX, THE LETTER" / STORAGE OF THE BOX / "RETRIEVAL OF THE BOX, THE ARTIST'S CONVERSATION" / "FROM THE BOX TO THE INSTALLATION AND SO ON, THE CYCLE" / Chapter 08_ --- MODELS / DRAWINGS / SKETCHES / SNAPSHOTS / ENCAPSULATED / Chapter 09_ --- CREDITS / Chapter 10_ --- DEDICATIONS: THIS THESIS IS SOMEWHERE SOMETIME WITH SOMEONE

Bacterial capsules are important virulence factors for a number of different pathogens, including Escherichia coli, Neisseria meningitidis, Haemophilus influenzae, and Pasteurella multocida. Capsular polysaccharides (CPSs) synthesized via the ATP-binding cassette (ABC) transporter-dependent pathway protect these bacteria from complement-mediated killing and phagocytosis, and consist of long polysaccharide chains attached to the cell surface via a phospholipid. CPSs are synthesized on the cytoplasmic face of the inner membrane before transport to the cell surface. While the enzymes that synthesize the polysaccharide have been studied in detail, very little is known about the structure and biosynthesis of the phospholipid terminus. To determine the structure of the reducing terminal glycolipid, CPS from E. coli K1, K5, and N. meningitidis group B was purified using a novel strategy and its structure was determined by mass spectrometry, nuclear magnetic resonance and chemical methods. All three polysaccharides possess terminal lyso-phosphatidylglycerol, which is connected to the CPS repeat unit by a linker consisting of multiple 3-deoxy-D-manno-octulosonic acid (Kdo) residues, forming an alternating β-2,4/β-2,7-linked structure. In addition to describing its structure, the biosynthesis of the glycolipid terminus was also investigated. KpsC and KpsS are conserved proteins encoded in the capsule loci from different bacteria with ABC transporter-dependent capsule assembly pathways but have no previously assigned function. An in vitro assay was developed to characterize KpsSC activities, leading to the finding that they are the Kdo transferases responsible for synthesis of the poly-Kdo linker. This research has contributed significantly to the understanding of the structure and biosynthesis of capsular polysaccharides.

Stability studies were undertaken at ambient (25ºC/60%RH) and accelerated conditions (40ºC/75%RH) to determine the effect of changing of hard gelatin capsule supplier on a phenytoin sodium (100 mg) capsule formulation. Three hard gelatin capsule suppliers: RP Scherer (Supplier A), Capsugel (supplier B) and Associated Caps (Supplier C) were used in the study. Capsules were analyzed just after filling of the capsules (T0), after 1 month (T1), after 2 months (T2) and after 3 months (T3) after being stored in securitainers under the above-mentioned conditions. The moisture content of the empty shells as well as the capsule contents were analysed at each time-point. The capsule disintegration time was recorded at each time point. Multi-point dissolution testing was performed at each time point to determine the release of the active substance in each case. Based on the achieved results, the best capsule shell supplier was recommended, and other suggestions were made to improve the capsule formulation.

Cette thèse a pour objectif de comprendre les mécanismes physiques régissant la formation de capsules submillimétriques à coeur aqueux possédant une membrane fine d'hydrogel et ainsi de mieux maitriser ce procédé. Des bigouttes sont d'abord formées dans l'air par fragmentation d'un jet cylindrique composé d'un coeur aqueux enveloppé par une solution d'alginate. La coque est ensuite gélifiée après immersion dans une solution de calcium. L'étude du co-Écoulement au sein de l'injecteur a montré l'existence d'une instabilité élastique qui est amplifiée en présence de cations, du fait du caractère polyélectrolyte de l'alginate. Nous avons montré que cette instabilité était à l'origine d'un battement du jet composé en sortie d'extrusion. En provoquant un décentrage du coeur, l'instabilité induit une relaxation asymétrique du profil de vitesse, ce qui crée un couple qui courbe le jet. Nous avons mis en évidence cet effet en produisant des jets courbés à partir d'une pointe biseautée. La fragmentation du jet est ensuite contrôlée par une perturbation harmonique des débits d'injection. Nous observons une décroissance de la vitesse d'onde à la surface du jet pilotée par la tension de surface. La viscosité élevée des solutions d'alginate entraine une amplification de fluctuations de cette vitesse donnant lieu à des coalescences au sein du jet. L'ajout de tensioactifs peut exacerber cet effet en induisant une tension de surface dynamique à la surface du jet. Finalement, nous parvenons à produire des capsules submillimétriques de taille contrôlée, monodisperses, possédant une membrane fine, avec un taux d'encapsulation supérieur à 99%. Ces capsules trouvent des applications dans le domaine des biotechnologies comme nouvel outil pour la culture cellulaire. / The purpose of this work is to understand physical mechanisms that control the formation of aqueous-Core submillimetric capsules with a thin hydrogel membrane. This comprehension will allow a better control of the process. Compound drops are first formed in the air by the break-Up of a cylindrical jet composed of an aqueous core surrounded by an alginate solution. The shell is then solidified after immersion in a gelling calcium solution. The study of the co-Flow inside the injector showed the existence of an elastic instability which is amplified in the presence of cations, due to the polyelectrolyte property of alginate. We showed that this instability causes the flapping of the compound jet out of the injector. The instability induces a displacement of the core fluid position which leads to an asymmetric velocity relaxation that creates a torque and finally bends the jet. We produced curved jets with a beveled capillary to demonstrate this effect. The jet break-Up is controlled by a harmonic perturbation of the injection flow rates. We measured a decrease of the wave speed on the jet surface which is controlled by the surface tension. The alginate solution high viscosity causes an amplification of speed fluctuations that induces coalescence inside the jet. This amplification is enhanced by the addition of surfactants which create a dynamic surface tension at the jet interface. Finally, we managed to produce submillimetric and monodisperse capsules with a thin membrane, an encapsulation yield above 99% and a size that we can tune. These capsules can be used in biotechnology applications as a new tool for cell culture.

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Reproduction de : Thèse d'exercice : Médecine. Hépato-gastroentérologie : Nantes : 2008. / Bibliogr.

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Cápsulas gelatinosas são formas farmacêuticas empregadas para a veiculação de fármacos por via oral. Há diversas vantagens em sua utilização como a facilidade de deglutição, mascaramento do sabor e odor de fármacos e rápida disponibilização de seu conteúdo no trato gastrointestinal. Atualmente, as cápsulas são as principais formas farmacêuticas nos estabelecimentos magistrais. Como formas de liberação imediata, seu comportamento após a deglutição deve permitir a rápida liberação do(s) fármaco(s). Desta forma, fatores como a escolha correta de excipientes, observando-se a compatibilidade entre estes e o fármaco, deve ser baseada nas características físico-químicas de ambos para a obtenção de um produto eficaz. As etapas de preparo não são menos relevantes e merecem atenção, como a pesagem, a mistura e o enchimento. O objetivo deste trabalho foi discutir o tema cápsulas, salientando fatores acerca de seu emprego como forma farmacêutica, elaboração de formulações, produção e controle, visando a adequada aplicabilidade no setor magistral. / Gelatin capsules are pharmaceutical forms employed in oral drug delivery. There are many advantages on its use like easy deglutition, smell and tast masking and fast availability of its content in gastrointestinal tract. Nowadays, the capsules are the main drug delivery forms used on magistral pharmacies. As immediate drug delivery forms its behavior after deglutition should promote a fast availability of the drug(s). Thus, the right choice of the excipients, observing the compatibility between these and the drug, should be based on physicochemical caracteristhics of the compounds to achieve an adequate product. The production steps are not less relevant and deserve an appropriate attention, Iike weighing, mixture and filling. The goal of this work was discussing the theme capsules, exploring factors around its employing as drug delivery form, formulations development, production and control, seeking a suitable applicability on magistral field.