Le but du travail est d'étudier la structure supramoléculaire de mélanges de tensioactif hydrophile, n-octyl-beta-glucoside (C8G1), et d'un extractant d'ions métalliques hydrophobe, le tributyl-n-phosphate (TBP), en présence d'eau, d'huile et de sels. Les systèmes classiques d'extraction ionique (composés d'une phase aqueuse, d'huile et d'extractant dont le but est d'extraire un soluté de la phase polaire sont passés en revue. L'aspect colloïdal et les transitions de phases que l'on retrouve dans ces systèmes sont souvent décrits singulièrement. Nous avons transposé l'approche « diagramme de phases » issue de la physico-chimie des systèmes moléculaires organisés à ces systèmes d'extractant afin d'orienter globalement l'analyse de ces systèmes complexes. La discussion est basée sur des considérations géométriques. Un modèle thermodynamique a été développé en considérant les contraintes d'empilement des ces extractants dans le film moléculaire formant les micelles inverses d'extractant dans l'huile. Ce modèle a permis de prédire la solubilité de l'eau au sein de ces micelles inverses ainsi que leurs tailles obtenues expérimentalement. Dans une deuxième partie, le comportement physico-chimique des phases aqueuses et organiques composées respectivement d'eau/C8G1 et de TBP/huile/eau ont été étudiées, en s'intéressant particulièrement aux effets de sels, par des techniques de diffusion de rayons X aux petits angles, diffusion dynamique de la lumière et de spectroscopie UV-visible. Dans la dernière partie la description complète de la microémulsion en faisant varier la balance hydrophile-hydrophobe du mélange C8G1 et TBP a été obtenue en combinant des mesures de diffusion de neutrons aux petits angles et d'analyse chimique (Karl-Fischer, Carbone Organique Total, ICP-OES…). Le comportement co-surfactant du TBP a été déterminé par comparaison aux co-surfactants classiques que sont les n-alcools (4<n<8). Les compositions de films moléculaires mixtes de C8G1/TBP et de C8G1/n-hexanol, obtenues expérimentalement, ont été confirmées par un modèle basé sur des paramètres géométriques moléculaires. Nous avons tenté d'exploiter les propriétés interfaciales de ces molécules pour le contrôle des cinétiques d'extraction liquide-liquide d'ion et la séparation d'ion « sans solvant » par flottation. / The presented work describes the supramolecular structure of mixtures of a hydrophilic surfactant n-octyl-beta-glucoside (C8G1), and the hydrophobic metal ion extractant tributylphosphate (TBP) in n-dodecane/water as well as in the presence of salts.In the first part, basic solvent extraction system, composed of water, oil and extractant, will be introduced. The focus, however, lies on the extraction of multivalent metal ions from the aqueous phase. During this extraction process and in the following thermodynamic equilibrium, aggregation and phase transition in supramolecular assemblies occur, which are already described in literature. Notably, these reports rest on individual studies and specific conclusions, while a general concept is still missing. We therefore suggest the use of generalized phase diagrams to present the physico-chemical behaviour of (amphiphilic) extractant systems. These phase diagrams facilitated the development of a thermodynamic model based on molecular geometry and packing of the extractant molecules in the oil phase. As a result, we are now in the position to predict size and water content of extractant aggregates and, thus, verify the experimental results by calculation.Consequently, the second part presents a systematic study of the aqueous and organic phase of water/C8G1 and water/oil/TBP mixtures. The focus lies on understanding the interaction between metal ions and both amphiphilic molecules by means of small angle x-ray scattering (SAXS), dynamic light scattering (DLS) and UV-Vis spectroscopy. We confirmed the assumption that extraction of metal ions is driven by TBP, while C8G1 remains passive. In the third and last part, microemulsions of C8G1, TBP, water (and salt) and n-dodecane are characterized by small angle neutron scattering (SANS), and chemical analytics (Karl Fischer, total organic carbon, ICP-OES,...). The co-surfactant behaviour of TBP was highlighted by comparison to the classical n-alcohol (4<n<8) co-surfactants. The compositions of the C8G1/TBP and C8G1/n-hexanol interfacial mixed films obtained experimentally were confirmed by the prediction of a model based on the molecular geometrical parameters. We furthermore exploit the interfacial properties of these molecules to control the kinetics of liquid-liquid extraction and attempt a “solvent free” ion separation using flotation.

Orientador: Anselmo Gomes de Oliveira / Resumo: O celecoxibe (CEL) é um inibidor específico de ciclooxigenase 2 e vem sendo estudado também como inibidor da atividade angiogênica em razão de sua propriedade de inibir o fator de crescimento endotelial vascular (VEGF). Devido às suas características físico-químicas, o CEL possui baixa solubilidade em água e alta permeabilidade, sendo classificado como fármaco pertencente à classe 2 do Sistema de Classificação Biofarmacêutica. Alguns anti-inflamatórios não esteróides têm sido utilizados por via tópica no tratamento de grande parte das doenças do segmento anterior dos olhos, mas também apresentam bom prognóstico para o tratamento de doenças do segmento posterior dos olhos, tais como a retinopatia diabética (RD), degeneração macular relacionada à idade (DMRI) e oclusão venosa retinal (OVR). Na maioria dos casos as concentrações locais dos fármacos no segmento posterior dos olhos não conseguem atender às necessidades quantitativas e temporais dos estímulos dessas doenças quando administrados pela via oral, ocular tópica ou parenteral sistêmica. Assim, o objetivo deste projeto foi desenvolver e caracterizar nanoemulsões (NEs) biocompatíveis visando à administração intraocular do CEL. Os sistemas nanoemulsionados contêm Fosfatidilcolina de Soja (FS) e Tween®20 (Tw) como tensoativos, Captex®200 como fase oleosa e tampão fosfato de potássio pH 7,2 como fase aquosa. As NEs foram desenvolvidas e sua nanoestrutura foi caracterizada através do diâmetro médio de gotículas onde as NEs vaz... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Celecoxib (CEL) is a specific inhibitor of cyclooxygenase 2 and has also been studied as an inhibitor of angiogenic activity because of its property of inhibiting vascular endothelial growth factor (VEGF). Due to its physico-chemical characteristics, CEL has low solubility in water and high permeability being classified as a drug belonging to class 2 of the Biopharmaceutical Classification System. Some anti-inflammatory drugs have been used topically to treat most of the anterior segment eye diseases, but also have a good prognosis for the treatment of diseases of the posterior segment of the eye such as diabetic retinopathy (DR), age-related macular degeneration (AMD) and retinal venous occlusion (RVO). In most cases the local concentrations of the drugs in the posterior segment of the eye fail to reach the quantitative and temporal needs of the stimuli of these diseases when administered by the oral, topical ocular and systemic parenteral rout. The aim of this project was to develop and characterize biocompatible nanoemulsions (NEs) capable of increasing the apparent solubility of CEL for intraocular administration. Nanoemulsified systems contain Soy Phosphatidylcholine (FS) and Tween®20 (Tw) as surfactants, Captex®200 as oily phase and potassium phosphate buffer pH 7.2 as the aqueous phase. The NEs were developed and their nanostructure was characterized by the mean diameter of droplets where the empty NEs had an average diameter of the order of 40 nm with a zeta potential... (Complete abstract click electronic access below) / Doutor

Les chromophores classiques ne sont pas toujours efficaces en absorption à deux photons. Leur faible efficacité nécessite l'utilisation de fortes puissances laser et de grandes concentrations en colorants. Dans ce sens, la microscopie à deux photons in vivo requière le développement de nouvelles stratégies de marquage utilisant des chromophores spécialement dédiés à la microscopie à deux photons. Dans le cadre de collaborations avec des chimistes spécialisés dans la synthèse de molécules à forte section efficace d'absorption à deux photons, différents chromophores ont été synthétisés. Ces molécules organiques sont souvent hydrophobes et ne sont pas utilisables directement pour les applications en biologie. Le travail effectuer ici a consisté à encapsuler ces molécules dans des micelles de copolymères biocompatibles, les Pluronic. Les Pluronic sont des matériaux pouvant s'auto assembler en milieu aqueux sous forme de micelles et permettent de solubiliser des composés hydrophobes. Cette stratégie est déjà utilisé pour permettre de transporter différents composés hydrophobes dans les organismes vivants et a été utilisée ici pour transporter des chromophores ultrasensibles à deux photons dans le sang de manière à imager la vascularisation in vivo. / Classic fluorescent dyes are not necessary efficient in two-photon absorption. Their low two-photon absorption efficiency often requires high laser power and important dye concentrations. Therefore, new dyes and other administration strategies need to be developed specifically for intravital two-photon microscopy. In collaboration with chemists, specialized in the synthesis of molecules with a high two-photon absorption cross-section, different dyes have been synthesized. Most of these dyes are hydrophobic and not directly suitable for biological applications. The work presented in this thesis consisted of encapsulating hydrophobic molecules in biocompatible Pluronic block copolymers. In water, Pluronic unimers with hydrophobic and hydrophilic blocks self-assembled in hydrophilic micelles forming a hydrophobic core around the molecules. This strategy has been used already for the transport and delivery of different hydrophobic molecules in living organism. In the present study, this strategy has been transposed to transport ultra sensitive two-photon dyes in the blood plasma for deep vascular imaging in vivo.

Made available in DSpace on 2014-12-17T15:42:08Z (GMT). No. of bitstreams: 1 FabianoESG_TESE.pdf: 2562039 bytes, checksum: f41fc74bb604ad5b4eb0383a80628c68 (MD5) Previous issue date: 2010-03-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Among the new drugs launched into the market since 1980, up to 30% of them belong to the class of natural products or they have semisynthetic origin. Between 40-70% of the new chemical entities (or lead compounds) possess poor water solubility, which may impair their commercial use. An alternative for administration of poorly water-soluble drugs is their vehiculation into drug delivery systems like micelles, microemulsions, nanoparticles, liposomes, and cyclodextrin systems. In this work, microemulsion-based drug delivery systems were obtained using pharmaceutically acceptable components: a mixture Tween 80 and Span 20 in ratio 3:1 as surfactant, isopropyl mirystate or oleic acid as oil, bidistilled water, and ethanol, in some formulations, as cosurfactants. Self-Microemulsifying Drug Delivery Systems (SMEDDS) were also obtained using propylene glycol or sorbitol as cosurfactant. All formulations were characterized for rheological behavior, droplet size and electrical conductivity. The bioactive natural product trans-dehydrocrotonin, as well some extracts and fractions from Croton cajucara Benth (Euphorbiaceae), Anacardium occidentale L. (Anacardiaceae) e Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae) specimens, were satisfactorily solubilized into microemulsions formulations. Meanwhile, two other natural products from Croton cajucara, trans-crotonin and acetyl aleuritolic acid, showed poor solubility in these formulations. The evaluation of the antioxidant capacity, by DPPH method, of plant extracts loaded into microemulsions evidenced the antioxidant activity of Phyllanthus amarus and Anacardium occidentale extracts. For Phyllanthus amarus extract, the use of microemulsions duplicated its antioxidant efficiency. A hydroalcoholic extract from Croton cajucara incorporated into a SMEDDS formulation showed bacteriostatic activity against colonies of Bacillus cereus and Escherichia coli bacteria. Additionally, Molecular Dynamics simulations were performed using micellar systems, for drug delivery systems, containing sugar-based surfactants, N-dodecylamino-1-deoxylactitol and N-dodecyl-D-lactosylamine. The computational simulations indicated that micellization process for N-dodecylamino-1- deoxylactitol is more favorable than N-dodecyl-D-lactosylamine system. / Dos novos f?rmacos lan?ados no mercado a partir de 1980, cerca de 30% apresentam origem natural ou semissint?tica. Entre 40 e 70% destes novos prot?tipos de f?rmacos (naturais ou sint?ticos) apresentam baixa solubilidade aquosa, o que pode inviabilizar a sua utiliza??o comercial. Uma das alternativas encontrada pela ind?stria farmac?utica foi a veicula??o dessas subst?ncias a partir de ve?culos ou sistemas de libera??o de f?rmacos, tais como: micelas, microemuls?es, lipossomos, nanopart?culas e ciclodextrinas. Neste trabalho, sistemas microemulsionados biologicamente compat?veis foram obtidos utilizando a mistura Tween 80 e Span 20, na propor??o 3:1, como tensoativo, miristato de isopropila ou ?cido ol?ico como fase oleosa, ?gua bidestilada, e em alguns sistemas, etanol como cotensoativo. Tamb?m foram obtidos sistemas auto-microemulsificantes (SMEDDS) utilizando propilenoglicol ou sorbitol como cotensoativo. As microemuls?es obtidas foram caracterizadas quanto ao comportamento reol?gico, tamanho das got?culas e condutividade el?trica. O produto natural bioativo trans-desidrocrotonina (DCTN), bem como extratos e fra??es das esp?cies vegetais Croton cajucara Benth (Euphorbiaceae), Anacardium occidentale L. (Anacardiaceae) e Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae), foram solubilizados satisfatoriamente nos sistemas microemulsionados obtidos, enquanto que outros produtos tamb?m isolados da esp?cie Croton cajucara, trans-crotonina e ?cido acetilaleurit?lico, n?o apresentaram resultados satisfat?rios em termos de solubilidade. A avalia??o da propriedade antioxidante, pelo m?todo do DPPH, dos extratos vegetais incorporados nos sistemas microemulsionados obtidos evidenciou a capacidade antioxidante dos extratos de Phyllanthus amarus e Anacardium occidentale, bem como a atua??o dos sistemas microemulsionados, que para o caso do extrato etan?lico de Phyllanthus amarus dobrou a sua atividade antioxidante quando solubilizado em microemuls?es. O extrato hidroalco?lico de Croton cajucara incorporado em um sistema auto-microemulsificante mostrou atividade bacteriost?tica frente a col?nias de bact?rias Bacillus cereus e Escherichia coli. Adicionalmente, foi realizado um estudo de simula??o computacional por Din?mica Molecular de sistemas micelares para uso farmacol?gico contendo tensoativos derivados de a??cares, N-dodecilamino-1-deoxilactitol e N-dodecil- -lactosilamina, que indicou que o processo de miceliza??o do primeiro sistema ? mais favor?vel que o segundo.

Made available in DSpace on 2014-12-17T15:01:49Z (GMT). No. of bitstreams: 1 ErikaASG_TESE_partes_autorizadas.pdf: 3587859 bytes, checksum: 8731a4ebad1b8f6f11b36c879b4a1a76 (MD5) Previous issue date: 2009-12-30 / The WAT is the temperature at the beginning of the appearance of wax crystals. At this temperature the first wax crystals are formed by the cooling systems paraffin / solvents. Paraffins are composed of a mixture of saturated hydrocarbons of high molecular weight. The removal of petroleum from wells and the production lines means a surcharge on produced oil, thus solubilize these deposits formed due to modifications of thermodynamics has been a constant challenge for companies of oil exploration. This study combines the paraffin solubilization by microemulsion systems, the determination of WAT systems paraffin / solvent and performance of surfactant in reducing the crystallization. We used the methods: rheological and the photoelectric signal, validating the latter which was developed to optimize the data obtained due to sensitivity of the equipment used. Methods developed for description of wax precipitation are often in poor agreement with the experimental data, they tend to underestimate the amount of wax at temperatures below the turbidity point. The Won method and the Ideal solution method were applied to the WAT data obtained in solvent systems, best represented by the second interaction of Won method using the solvents naphtha, hexane and LCO. It was observed that the results obtained by WAT photoelectric signal when compared with the viscosity occur in advance, demonstrating the greatest sensitivity of the method developed. The ionic surfactant reduced the viscosity of the solvent systems as it acted modifying the crystalline structure and, consequently, the pour point. The curves show that the WAT experimental data is, in general, closer to the modeling performed by the method of Won than to the one performed by the ideal solution method, because this method underestimates the curve predicting the onset of paraffin hydrocarbons crystallization temperature. This occurs because the actual temperature measured was the crystallization temperature and the method proposes the fusion temperature measurement. / A TIAC ? a temperatura de in?cio do aparecimento dos cristais de parafina. Nesta temperatura os primeiros cristais de parafina s?o formados, pelo resfriamento de sistemas parafina/solventes. As parafinas s?o compostas de uma mistura de hidrocarbonetos saturados de alto peso molecular. A remo??o de parafinas dos po?os e das linhas de produ??o significa um custo adicional ao petr?leo produzido, portanto solubilizar estes dep?sitos formados decorrentes das modifica??es termodin?micas tem sido um desafio constante das empresas exploradoras de petr?leo. Este estudo alia a solubiliza??o paraf?nica por sistemas microemulsionados, ? determina??o da TIAC dos sistemas parafina/solvente e a atua??o do tensoativo na redu??o da cristaliza??o. Utilizaram-se os m?todos: reol?gico e o do sinal fotoel?trico, validando este ?ltimo o qual foi desenvolvido visando aperfei?oar os dados obtidos devido a sensibilidade do equipamento utilizado. M?todos desenvolvidos para descri??o da precipita??o da cera est?o freq?entemente em pobre concord?ncia com os dados experimentais; eles tendem a subestimar a quantidade de cera ?s temperaturas abaixo do ponto de turbidez. Foram aplicados os m?todos de Won e o da solu??o ideal aos dados de TIAC da parafina obtidos em sistemas com solventes, sendo melhor representado pela segunda intera??o do m?todo de Won com os solventes: nafta, hexano e LCO. Foi observado que os resultados de TIAC obtidos pelo sinal fotoel?trico quando comparados com a viscosidade, ocorrem antecipadamente, demonstrando a maior sensibilidade do m?todo desenvolvido. O tensoativo i?nico reduziu a viscosidade dos sistemas paraf?nicos, pois ele atuou modificando a estrutura cristalina, conseq?entemente o ponto de fluidez. As curvas que representam os dados experimentais da TIAC est?o, de maneira geral, mais pr?ximas da modelagem realizada pelo m?todo de Won do que da solu??o ideal, pois este m?todo subestima a curva de predi??o do in?cio da temperatura de cristaliza??o da parafina com os hidrocarbonetos. Isto ocorre porque a temperatura real medida foi a de cristaliza??o, e a proposta pelos m?todos ? a de fus?o

Micelles (MIs) and microemulsions (MEs) are classified as stabilized systems by surfactants and are very similar with respect to their structure and physico-chemical properties. As for the applicability, they have been deployed by being able to carry drugs which have a limited systemic bioavailability by oral route. The formation of these systems is mainly dependent on the types of components used, making it important to study its influence on the structure. The goal of this study was to obtain and characterize micellar and microemulsion systems (containing essential oil of Citrus sinensis (L.) Osbeck as oil phase) stabilized by a nonionic surfactant (Tween 80) and short-chain cosurfactant (alcohol ethyl) which may be used as a delivery system for nifedipine (NFD a model drug) seeking to verify the influence of the phases and the interaction of the drug in the structure of these systems. Ternary and pseudoternary phase diagrams for MIs and MEs, respectively, and were obtained from the formation regions, formulations were selected for physico-chemical characterization and incorporation of NFD. The macro and microscopic aspects were evaluated using polarized light microscopy (MLP), measures pH, electrical conductivity and surface tension. The average droplet size was measured by dynamic light scattering (DLS) and small angle x-ray scattering (SAXS). The results demonstrated that such systems are stable, optically isotropic and transparent in the absence and presence of drug. The droplet size decreases with increasing amount of surfactant to MIs and the mixture surfactant/cosurfactant to the MEs. The influence of the cosurfactant in MIs was negligible. The increase of the amount of oily phase in MEs caused an increase in the droplet size. The presence of NFD no influence on the structure of MIs, but for the MEs increased droplet size, suggesting that the NFD is the internal phase of the MEs. The modeling by SAXS curves for MIs and MEs most diluted were made and showed the interaction between the NFD and systems, confirming the previous results. Studies by Fourier Transformed Infra Red (FTIR) confirmed the interaction between MIs and MEs with the stratum corneum (EC) , which allows the use of these systems as permeation enhancers of NFD. / As micelas (MIs) e as microemulsões (MEs) são classificadas como sistemas estabilizados por tensoativos e se assemelham bastante com relação a sua estrutura e propriedades físico-químicas. Quanto a sua aplicabilidade, elas têm sido destacadas por serem capazes de veicular fármacos que possuem uma biodisponibilidade sistêmica limitada por via oral. A formação destes sistemas é dependente principalmente dos tipos de componentes utilizados, tornando-se relevante o estudo da sua influência na estrutura. O objetivo do presente trabalho foi a obtenção e caracterização de sistemas micelares e microemulsionados (contendo óleo essencial de Citrus sinensis (L.) Osbeck como fase oleosa), estabilizados por um tensoativo não iônico (Tween 80) e um cotensoativo de cadeia curta (álcool etílico), que possam ser utilizados como sistema de liberação para a nifedipina (NFD, um fármaco modelo), buscando verificar a influência das fases e a interação do fármaco na estrutura desses sistemas. Diagramas de fase ternário e pseudoternário para MIs e MEs, respectivamente, foram obtidos e a partir das regiões de formação, formulações foram selecionadas para caracterização físico-química e incorporação da NFD. Os aspectos macro e microscópicos foram avaliados utilizando microscopia de luz polarizada (MLP), medidas de pH, condutividade elétrica e tensão superficial. O tamanho médio de gotículas foi avaliado por espalhamento dinâmico de luz (DLS) e espalhamento de raios-x a baixos ângulos (SAXS). Os resultados demonstraram que esses sistemas são estáveis, isotrópicos e opticamente transparentes na ausência e presença de fármaco. O tamanho das gotículas diminuiu com o aumento da quantidade de tensoativo para as MIs e de mistura de tensoativo/cotensoativo para as MEs. A influência do cotensoativo nas MIs foi praticamente desprezível. O aumento da quantidade de fase oleosa nas MEs ocasionou um aumento do tamanho das gotículas. A presença da NFD não exerceu influência na estrutura das MIs, entretanto para as MEs aumentou o tamanho de gotículas, sugerindo que a NFD se encontra na fase interna das MEs. Os modelamentos das curvas de SAXS para as MIs e MEs mais diluídas foram realizados e mostraram a interação existente entre a NFD e os sistemas, corroborando com os resultados anteriores. Estudos por espectrofotometria de absorção na região do infravermelho com transformada de Fourier (FTIR) comprovaram a interação das MIs e das MEs com o estrato córneo (EC), o que possibilita o uso destes sistemas como promotores de permeação da NFD.