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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Depolymèrization enzymatique d’Hydroxypropyl Methyl Cellulose (HPMC) pour la conception des nouveaux copolymères à blocs . / Enzymatic depolymerization of Hydroxypropyl Methylcellulose (HPMC) to desing novel biobased block copolymers.

Caceres Najarro, Marleny 16 December 2015 (has links)
Parmi les bio-polymères issus des ressources renouvelables, les polysaccharides fournissent une alternative intéressante aux polymères de synthèse. Dans ce contexte, l’objectif de ce travail de thèse est basé sur la conception des copolymères amphiphiles pour la préparation de nouveaux biomatériaux. Ainsi, l’hydroxypropylméthylcellulose (HPMC) a été étudiée en raison de ses propriétés remarquables, dont la biocompatibilité, la biodégradabilité, la rétention d'eau et la gélification thermoréversible. Ces propriétés sont utiles pour de nombreuses applications telles que le relargage de médicament, la préparation des membranes et la formation de biomatériaux. L'hydrolyse enzymatique avec des endo cellulases issues de Trichoderma reesei a été étudiée pour produire des fragments d'HPMC ayant une masse molaire (Mw) entre 6000 et 30000 g mol-1. Les paramètres de l’activité enzymatique ont été étudiés en fonction de : la nature de substrat, le temps de réaction et la concentration de l'enzyme. Les polymères obtenus ont été comparés à ceux produits par hydrolyse acide. Il a été constaté que la structure des polymères issus d’un procédé d’hydrolyse, varie en termes de degré de substitution pour un même Mw. Cet effet donne lieu à différentes propriétés de gélification thermoréversible. Des copolymères amphiphiles tels que HPMC-b-poly (propylène glycol) et HPMC-b-PLA ont été préparés par amination réductrice et par couplage click thiol-ene, respectivement. Les propriétés d’agrégation ont été caractérisées par la diffusion de la lumière (DLS), le microscope électronique en transmission (TEM) et par la séparation de phase obtenue par la mesure du point de trouble. / Following the concept of bio-refinery, we propose to produce small fragments of biopolymers that can be used further as building blocks to prepare novel polymeric architectures. In the case of polysaccharides, enzymatic hydrolysis enables to form reducing end groups after each cleavage on the polymer chain. Reaction by reductive amination affords the possibility to introduce polysaccharides fragments in a large variety of materials going from amphiphilic copolymers to more sophisticated devices. Hydroxypropyl methylcellulose (HPMC) was used in this work because of its remarkable properties including biocompatibility, biodegradability, water retention and thermoreversible gelation beneficial for many applications such as drug delivery, film and biomaterial formation. Enzymatic hydrolysis using endo cellulases from Trichoderma reesei was investigated to produce a library of HPMC fragments with molecular weight (Mw) from 6000 to 30000 g mol-1. Mw control was carried out by varying the procedure conditions including the nature of starting HPMC, reaction time and enzyme concentration. The obtained polymers were compared to those produced by acidic hydrolysis.According to the preparation conditions, the structure of short chain polymers regarding substitution degrees varied for the same Mw giving rise to different clouding temperature and thermoreversible gelation properties. Amphiphilic block copolymers HPMC-b-poly(propylene glycol) and HPMC-b-PLA were prepared by reductive amination and by the thiol-ene click reaction, respectively. Self-assembly properties of these novel block copolymer were characterized by dynamic light scattering (DLS), transmission electron microscope (TEM), and clouding point temperature.
12

Reologie viskózních modifikovaných past na bázi portlandského cementu určených ke tváření extruzí / A rheology of high viscosity portland cement pastes applied on extrusion technology

Tihlařík, Petr Unknown Date (has links)
The aim of this doctoral thesis is to verify a possibilities of fibercement extrusion. A mixture for extrusion is typical for its high toughness and high fiber content, as the fiber content may be several times higher than when utilizing other production methods. The technology of a twin shaft kneader makes it possible to produce homogenous mixture for extrusion with low water/cement ratio. With use of auger moulder a mixture of high toughness is formed to final shape. The extreme shear and pressure stress is applied in the process. Therefore high requirements are posed on the equipment.
13

Fonctionnalisation et caractérisatin de films bioactifs à base d'HPMC : influence de l'introduction d'antioxydants sur les propriétés des films et la conservation des aliments / Functionalization and Characterization of Bioactive Films Based on HPMC : Influence of Antioxidants Inclusion on Films Properties and Food Preservation

Akhtar, Muhammad Javeed 13 September 2012 (has links)
La fonctionnalisation d'emballages biodégradables avec des antioxydants naturels est l'une des techniques prometteuses pour améliorer la conservation des aliments, diminuer la quantité de conservateurs chimiques utilises, protéger la dégradation aromatique des produits et ainsi conserver une meilleure qualité globale. Le contrôle du relargage de ces composés actifs de l'emballage vers l'aliment permet d'étendre l'efficacité de la fonctionnalisation en libérant progressivement les antioxydants à la surface de l'aliment. L'objectif global de ce travail était de fonctionnaliser le polymère HPMC afin de produire un film d'emballage coloré à activité antioxydante et d'évaluer son aptitude à servir d'emballage actif. Tout d'abord, des films d'HPMC contenant différents colorants synthétiques comme le bleu, le vert, le jaune, le rouge et le blanc ont été testés afin de déterminer la couleur la plus adaptée pour le contrôle de la photo-oxydation de produits gras. Ensuite, la couleur rouge synthétique, montrant un maximum de contrôle contre la photo-oxydation, a été remplacée par des composés actifs naturels de même couleur. Ces composés provenaient soit d'un mélange d'extraits de betterave et de carottes pourpres, d'un mélange de bétalaïnes soit d'un mélange d'anthocyanes. Le mode d'incorporation de ces composés actifs dans la matrice d'HPMC, leurs effets sur les propriétés thermiques, mécaniques, barrière et structurales des films ont été étudiés. Les résultats ont montré que l'intégration de ces différents composés actifs naturels a permis d'améliorer les propriétés des films. Les composés actifs utilisés ont la capacité de contrôler le photo-vieillissement de la matrice polymérique et que l'HPMC est un bon candidat pour incorporer ces molécules et permettre le contrôle de la dégradation de produits alimentaires riches en lipides / Biodegradable packaging functionalized with natural antioxidants is one of the promising techniques to enhance foods shelf-life, lower use of preservatives in food formations, higher protection of flavours and higher food qualities. Controlled release of these bioactive compounds from packaging to food surface provides longer food stability by continuously librating antioxidants at food surface. The overall objective of the present work was to functionalize the HPMC polymer as colored antioxidant packaging and investigate its suitability as active packaging for unsaturated lipids. Firstly, HPMC films containing different synthetic colours like blue, green, yellow, red and white were tested to chose a suitable color having control against photo-oxidation. Secondly, red synthetic color (showing maximum control against pho-oxidation) was replaced by natural active red compounds including "natural red color" (beetroot extract + purple carrot extract), betalains and anthocyanins to produce bioactive food packaging. Mode of incorporation of these active compounds in HPMC matrix and also their potential effects on thermal, mechanical, barrier and structural properties of films were investigated. Controlled release kinetics, antioxidant capacity and light stability of bioactive compounds in HPMC films were also investigated. The overall results showed that successful incorporation of different natural active compounds have capability to improve film properties. The active compounds under discussion have ability to control photo ageing of polymer matrix and HPMC has the capability for being a suitable carrier for antioxidant active packaging for some food products
14

Développement du système mixte hydroxypropyl-betacyclodextrine/ liposome en vue de l’encapsulation des constituants des huiles essentielles / Development of drug-in-cyclodextrin-in-liposomes as carrier system for encapsulation of monoterpenes essential oils

Gharib, Riham 13 December 2016 (has links)
L'objectif principal de notre étude a été la mise au point des formulations liposomiales encapsulant des monoterpènes (MT) et phénylpropènes (PP). Le manuscrit contient deux axes principaux. Le premier a porté sur l'interaction de l'HP-ß-CD, de MT et PP avec des membranes lipidiques. L'HP-ß-CD interagit avec les têtes polaires et les chaînes acyles des phospholipides et montre un effet fluidifiant sur les liposomes formés de DPPC et de Lipoid S100. De plus, l'HP-ß-CD présent dans le compartiment aqueux des liposomes les protège durant la lyophilisation. Les MT et PP interagissent avec la tête et les chaînes alkyles de DPPC entrainant sa fluidification. D'autre part, les composés les plus hydrophobes de la série, ont été plus actifs contre E. coli. Le deuxième axe a été orienté vers la préparation des liposomes conventionnels et du système mixte CD/liposome (ACL). La technique de double encapsulation (ACL2) a été appliquée. Les préparations sont faites à partir de Phospholipon 90H ou Lipoid S100 par la méthode d'injection éthanolique. Les vésicules ont été caractérisées pour la taille, pdI, le potentiel zêta, la morphologie, le rendement et la cinétique de libération de la molécule. L'anéthol (Ane) est utilisé comme un système modèle. ACL et ACL2 ont permis d'améliorer le rendement d'encapsulation de l'Ane et de ralentir sa libération. Les liposomes composés de Lipoid S100 ont montré une meilleure photostabilité et rendement d'encapsulation. Le Lipoid S100 a été ainsi utilisé pour la préparation à grande échelle. Les vésicules obtenues à petite et grande échelle, ont présenté les caractéristiques proches ce qui témoigne d'une bonne reproductibilité de ces procédés / The main objective of this work was the development of liposomal formulations encapsulating monoterpenes (MT) and phenylpropene (PP). The manuscript contains two main axes: the first axis was oriented to the interaction of HP-ß-CD, MTs and PPs with lipid membranes. The HP-ß-CD interacts with the polar heads and acyl chains of phospholipids and showed a fluidizing effect on liposomes formed with DPPC or Lipoid S100. In addition, the incorporation of HP-ß-CD in the internal aqueous compartment of the liposomes protected them during lyophilization. The studied monoterpenes interact with the choline head group and the alkyl chains of DPPC membrane raising the bilayer’s fluidity. In addition, the most hydrophobic compounds of the series, were more active against E. coli. The second axis was oriented towards the preparation of conventional liposomes and drug-in-cyclodextrin-in-liposomes (ACL). The double loaded technique (double loaded liposomes, ACL2) was applied. Phospholipon 90H or Lipoid S100 were used to prepare liposomes by the ethanol injection method. Vesicles were characterized in terms of size, pdI, zeta potential, morphology, loading rate and drug release kinetics. Anethole (Ane) is used as a model system. Compared to conventional liposomes, ACL and ACL2 improve the loading rate of Ane and reduce Ane release. Liposomes prepared with Lipoid S100 showed the best photostability and loading rate. Lipoid S100 is used to prepare liposomes at large scale by membrane contactor and by pilot scale. The characteristics of the vesicles obtained at laboratory and large scale confirmed the reproducibility of the two methods of preparation
15

Desenvolvimento e caracterização de matrizes poliméricas como veículo de componentes ativos do extrato etanólico da película de amendoim / Development and characterization of polymer matrices as a vehicle for active components of the ethanol extract of peanut skin

Tedesco, Marcela Perozzi 02 March 2015 (has links)
A película de amendoim é um resíduo da indústria de alimentos. Esse resíduo é rico em compostos fenólicos como resveratrol e procianidinas e apresenta elevada atividade antioxidante e atividade farmacológica. Apesar de suas atividades farmacológicas, compostos fenólicos apresentam baixa biodisponibilidade devido à glucuronidação catalisada pelas enzimas UDP-glucuronosyltransferases (UGTs), que acontece na primeira passagem no intestino e/ou fígado, dificultando a utilização dos compostos fenólicos como agentes terapêuticos. Filmes de desintegração oral permitem que o princípio ativo seja absorvido no epitélio bucal diretamente pela circulação sistêmica podendo melhorar a biodisponibilidade desses compostos naturais. Nesse contexto, o objetivo desse trabalho foi desenvolver um filme de desintegração oral à base de gelatina e hidroxipropilmetilcelulose (GEL:HPMC) incorporado com extrato de película de amendoim como um carreador de compostos bioativos. O extrato de película de amendoim foi produzido utilizando-se etanol (70%) como solvente (razão sólidos/solvente de 1:20) à temperatura ambiente sob agitação mecânica (10 minutos), sendo realizada três extrações consecutivas. O extrato foi liofilizado para ser caracterizado em relação à atividade antioxidante, fenólicos totais e aflatoxinas. Os filmes de desintegração oral com diferentes concentrações de gelatina e hidroxipropilmetilcelulose (GEL:HPMC) foram produzidos por casting (2g de macromoléculas/100 g de solução filmogênica e 0,4g de sorbitol/100g de solução filmogênica). O extrato de película de amendoim foi incorporado líquido e concentrado nas concentrações de 10, 20 e 30g/100g de solução filmogênica. Os filmes foram caracterizados em relação à propriedades mecânicas, ângulo de contato, tempo de desintegração, mucoadesividade, pH de superfície, microscopia eletrônica de varredura e espectroscopia de infravermelho. O extrato (liofilizado) apresentou concentração fenólica igual a 718,57 mg de equivalente em ácido gálico/g e EC50 igual a 146,07 ± 8.37 µg/mL e 0,37 ng B₁/g. Os filmes sem adição de extrato, independente da formulação, apresentaram homogeneidade e, de um modo geral, os filmes à base de hidroxipropilmetilcelulose apresentaram melhores propriedades mecânicas, hidrofilicidade superior, tempo de desintegração reduzido e mucoadesividade superior em relação aos filmes com gelatina em sua composição. Comportamento similar foi observado para os filmes de desintegração oral com adição de extrato. Entretanto, filmes com adição de extrato e altas concentrações de gelatina (100:0, 75:25) apresentaram formação de complexos insolúveis entre taninos e proteínas, aparentes visualmente. Em função dos resultados obtidos, os filmes à base de hidroxipropilmetilcelulose (0:100) e com 20% de extrato de película de amendoim apresentaram propriedades mecânicas superiores (tensão na ruptura = 26,63 MPa, elongação = 4,97% e módulo elástico = 1284,82 MPa) e menor tempo de desintegração (17,87 segundos) em relação as demais formulações, sendo esta considerada a formulação otimizada como potencial aplicação para filmes de desintegração oral. / Peanut skin is a food industry byproduct which is rich in phenolic compounds, such as resveratrol and procyanidins. Moreover, it has high antioxidant and pharmacological properties. Despite these activities, phenolic compounds have low oral bioavailability due to glucuronidation catalyzed by the enzyme UDP-glucuronosyltransferases (UGTs). This catalyze occurs in the first-pass metabolism (gut and/or liver) difficulting the use of phenolic compounds as therapeutic agents. For oral disintegrating films the active ingredient is directly absorbed into systemic circulation by oral epithelium improving the bioavailability of these natural compounds. The aim of this study was to develop oral disintegrating film composed of gelatin and hydroxypropyl methylcellulose (GEL: HPMC) added of peanut skin extract as a vehicle for bioactive compounds. The peanut skin extract was produced using ethanol (70%) as solvent (solid/solvent ratio 1:20) at room temperature under mechanical stirring (10 minutes) with three consecutive extractions. The extract was lyophilized to be characterized by antioxidant activity, total phenolic and aflatoxins. The oral disintegrating films were produced by casting (2g macromolecules/100 g filmogenic solution and 0.4g of sorbitol/100g of filmogenic solution) with different concentrations of gelatin and hydroxypropylmethylcellulose (GEL: HPMC). The peanut skin extract was added to films liquid and concentrated at concentrations of 10, 20 and 30g / 100g of filmogenic solution. The films were characterized by mechanical properties, contact angle, disintegrating time, mucoadesivity, surface pH, scanning electron microscopy and infrared spectroscopy. The extract (lyophilized) showed phenolic concentration of 718.57 mg of gallic acid equivalent/g, EC50 of 146.07 ± 8.37 µg/mL and 0.37 ng B₁/g. Films without extract, regardless of formulation were homogeneous. In general, hydroxypropyl methylcellulose films exhibited better mechanical properties, higher hydrophilicity and mucoadesivity and reduced disintegration time compared to films with gelatin in its composition. Similar behavior was observed for oral disintegrating films with addition of extract. Films formulation with high gelatin content (100: 0, 75:25) added of extract showed insoluble complexes formed between proteins and tannins. Hydroxypropyl methylcellulose films (0: 100) added of peanut skin extract (20%) showed superior mechanical properties (tensile strength = 26.63 MPa, elongation = 4.97% and elastic modulus = 1284.82 MPa) and lower disintegration time (17.87 seconds) compared with other formulations, which is considered the optimized formulation as a potential application for oral disintegrating films.
16

Estabilidade de emulsões na presença da biomassa da microalga Arthrospira platensis e do polímero hidroxipropil metilcelulose / Stability of emulsions using the biomass of Arthrospira platensis <microalgae and hydroxypropyl methylcellulose polymer

Shimada, Robson Takeshi 02 June 2017 (has links)
Arthrospira platensis ou Spirulina é uma microalga com alto valor nutricional. Foram preparados extratos de Spirulina, caracterizados e aplicados como estabilizadores de emulsão de óleo de girassol comercial em água (O/A) (10% v/v) na ausência e na presença de quatro tipos de hidroxipropil metilcelulose (HPMC). Os extratos brutos de Spirulina foram preparados em tampões a pH 6 (EB6) e pH 8 (EB8) por sonicação para promover a lise celular e a libertação de proteínas e fosfolípides; Parte dos extratos foi centrifugada (EC6 ou EC8). Independentemente das condições de extração, todos os extratos apresentados apresentaram valores de potencial-&#950 médio variando de - (16 ± 2) mV a - (20 ± 2) mV, tamanho médio variando de (108 ± 52) nm a (306 ± 68) nm e atividade interfacial. As emulsões O/A preparadas com extratos de Spirulina (10 g / L) exibiram partículas com potencial- médio variando de - (16 ± 2) mV a - (27 ± 4) mV, tamanho médio variando de ~ 70 nm (EB6 ou EB8) a ~ 700 nm (EC6 ou EC8). No entanto, o EB6 levou a emulsões ligeiramente mais estáveis do que as outras. A combinação de EB6 (10 g / L) e HPMC (1,0 % m/m) levou a um aumento substancial na estabilidade da emulsão, embora os valores de potencial- diminuíram uma ordem de grandeza. Em particular, a HPMC com a maior massa molar e o maior grau de substituição de grupos metila conduziu a i) camada interfacial mais robusta resultante da formação de complexos entre cadeias HPMC e proteínas EB6 e (ii) meio contínuo mais viscoso. / Arthrospira platensis or Spirulina is a microalga with a high nutritional value. Extracts of Spirulina were prepared, characterized and applied as oil in water (O/W) (10 % v/v) emulsion stabilizers in the absence and presence of four types of hydroxypropyl methylcellulose (HPMC). The emulsions were prepared with edible sunflower oil. Crude extracts of Spirulina were prepared in buffers at pH 6 (CE6-Crude extract pH6) and pH 8 (CE8-Crude extract pH8) by sonication to promote cell lysis and protein and phospholipids release; part of the extracts was centrifuged (CCE6 or CCE8). Regardless of the extraction conditions, all extracts presented mean -potential ranging from (16 ± 2) mV to (20 ± 2) mV, mean diameter ranging from (108 ± 52) nm to (306 ± 68) nm and interfacial activity. The emulsions prepared with Spirulina extracts (10 g/L) displayed particles with mean -potential ranging from (16 ± 2) mV to (27 ± 4) mV, mean diameter ranging from ~ 70 nm (CCE6 or CCE8) to ~ 700 nm (CE6 or CE8). However, CE6 led to emulsions slightly more stable than the others did. The combination of CE6 (10 g/L) HPMC (1.0 wt %) led to substantial increase in the emulsion stability, although the -potential values decreased one order of magnitude. Particularly, the HPMC with the highest molecular weight and highest methyl substitution degree led to the most (i) robust interfacial layer resulting from the complex formation between HPMC chains and CE6 proteins and (ii) viscous continuous medium.
17

Obtenção de fração enriquecida em isoflavonas de Trifolium pratense L e avaliação da permeação cutânea de formononetina e biochanina A incorporadas em hidrogel de HPMC contendo ciclodextrinas

Dias, Paula Hollweg January 2017 (has links)
A formononetina e a biochanina A são as isoflavonas majoritárias nas partes aéreas de Trifolium pratense L. (trevo-vermelho) relacionadas com as principais atividades farmacológicas da planta. São chamadas de fitoestrógenos, pois possuem estrutura similar ao do 17-β-estradiol, e são capazes de se ligar aos receptores estrogênicos (ERβ e ERα). As isoflavonas agliconas são moléculas de baixa hidrossolubilidade, o que pode limitar sua aplicação em produtos para pele e a expressão de sua atividade biológica. O presente trabalho tem como objetivo obter uma fração enriquecida em isoflavonas de T. pratense e avaliar a permeação cutânea das agliconas formononetina e biochanina A individualmente e associadas. Adicionalmente, o efeito de promoção da permeação cutânea em pele de orelha suina também foi objeto do estudo. A fração foi preparada por maceração e após precipitação das isoflavonas agliconas por evaporação do etanol, o precipitado foi separado por filtração e purificado por cromatografia em coluna de poliamida. O produto foi seco e apresentou concentração de isoflavonas de 2,8 mg/g de formononetina e 2,7 mg/g de biochanina A. No entanto, essa concentração ainda não foi suficiente para posterior incorporação em uma formulação visando testes de permeação cutanea. Neste contexto, os estudos de permeação em pele de orelha de suíno (Franz cells) foram realizados com as isoflavonas majoritárias de referência incorporadas à hidrogéis de hidroxipropilmetilcellulose (HPMC). Para avaliar o teor de isoflavonas nas formulações e nas diferentes camadas da pele foi desenvolvido método bioanalítico utilizando cromatografia líquida de alta eficiência, o qual mostrou-se linear, específico, exato, preciso e robusto. Os hidrogéis foram desenvolvidos utilizando como polímero HPMC (3,5%, m/v) e as isoflavonas (0,1%) foram incorporadas à essa base, individualmente ou associadas, em presença ou ausência de hidroxipropil-β-ciclodextrina (HPβCD) ou metil-β-ciclodextrina (MβCD). Os resultados obtidos na avaliação da permeação cutânea revelaram que as isoflavonas permearam mais quando incorporadas individualmente na base especialmente a formononetina. A biochanina A apresentou maior capacidade de permeação do que a formononetina, alcançando concentrações na epiderme de 0,5 ug/cm2 e na derme de 1,5 μg/cm2, representando cerca de 2,7 vezes mais comparando com a concentração de formononetina (respectivamente, 0,2 μg/cm2 e 0,4 μg/cm2). uso de ciclodextrinas aumentou significativamente a permeação da formononetina, tanto na epiderme quanto na derme. Para a biochanina A, apenas a retenção na epiderme foi aumentada com a presença de ciclodextrinas. A HPβCD foi a ciclodextrina que apresentou os melhores resultados de promoção da permeação da formononetina na derme e epiderme, proporcionando um aumento de 113%. Para a biochanina A, as duas ciclodextrinas aumentaram a sua concentração na epiderme na mesma proporção (37%). Quando as duas isoflavonas foram incorporadas em misturas 1:1 no hidrogel, a formononetina apresentou menor retenção, tanto na epiderme (0,1 μg/cm2) quanto na derme (0,4 μg/cm2). Contrariamente, a biochanina A apresentou retenção semelhante àquela apresentada quando foi incorporada isoladamente no hidrogel, caracterizando-se como uma molécula mais permeável e não sofrendo interferência da formononetina na sua permeação e retenção. Não foi observado efeito significativo da presença das ciclodextrinas na promoção da permeação cutânea das isoflavonas nas misturas, exceto para a formononetina, na epiderme. O conjunto dos resultados demonstrou que a formononetina e biochanina A são capazes de permear a pele sendo majoritariamente retidas na epiderme e na derme, revelando o seu potencial uso em preparações cosméticas destinadas à prevenção do envelhecimento cutâneo. As ciclodextrinas apresentaram acentuado efeito promotor da permeação cutânea apenas para a formononetina, que apresenta menor permeabilidade. / The main isoflavones present Trifolium pratense L. (red clover) aereal parts are the isoflavones formononetin and biochanin A, related to its pharmacological activities. These compounds are known as phytoestrogens due to its similarity to the structure of 17-β-estradiol, being able to bind to the estrogen receptor (ERβ and ERα). Aglicones of isoflavones display low water solubility limiting its incorporation in products for the skin and expression of its biological activity. The present work aims to develop a isoflavones-enriched fraction of T. pratense and to evaluate the skin permeation of the aglicones formononetin and biochanin A individually, and in association. Moreover the promoter effect of cyclodextrins on their skin permeation will also be evaluated. The enriched-fraction was prepared by maceration in ethanol 40% (v/v). The ethanol was evaporated and the dispersion was filtered. The supernatant was purified using a column chromatography packet with polyamide. The final product was dried and presented a concentration of 2.8 mg/g of formononetin and 2.7 mg/g of biochanin A. However, these amounts of isoflavones were not enough for subsequent incorporation into a formulation to proceed the cutaneous permeation tests. In this context, the permeation studies were performed using the chemical reference formononetin and biochanin A, incorporated into the hydroxypropyl methylcellulose (HPMC) hydrogels for the permeation studies on porcine ear skin (Franz cells). To evaluate the isoflavone concentration in the formulations and in the different skin layers, a bioanalytical method was validated using high performance liquid chromatography (HPLC), which showed linearity, specificity, accuracy, precision and robusteness. Hydrogels were developed using HPMC (Methocel® K4M) polymer (3.5%, m/v) and the isoflavones were incorporated into this base individually or in combination, in the presence or absence of hydroxypropyl-β-cyclodextrin (HPβCD) or methyl-β-cyclodextrin (MβCD). The results obtained in the cutaneous permeation tests showed higher permeation values when the isoflavones were individually incorporated into the formulations especially for formononetin. Biochanin A showed higher permeation capacity when compared to formononetin, reaching 0.5 μg/cm2 in the epidermis and 1.5 μg/cm2 in the dermis, representing about 2.7 times the concentration of formononetin (0.2 μg/cm2 and 0.4 μg/cm2). The use of cyclodextrins increased significantly the permeation values of formononetin, both in the epidermis and in the dermis. For biochanin A only the retention in the epidermis was increased. HPβCD was the cyclodextrin that showed the best results for formononetin as permeation promoter, providing an increasing in the epidermis and dermis of 113%. Both cyclodextrins improved the biochanin A permeation in the same proportion in the epidermis (37%). When the isoflavones were incorporated into hydrogels together (1:1 ratio), formononetin showed less retention in both skin layers (0.1 μg/cm2 in the epidermis and 0.4 μg/cm2 in the dermis) and biochanin A remained with similar performance when added alone. In the presence of cyclodextrins, no significant effect was observed in the promotion of skin permeation of isoflavones in mixtures, except for formononetin, in the epidermis. Taken together, the results indicated that formononetin and biochanin A present skin permeation being mostly retained in the epidermis and dermis, revealing its potential use in cosmetic products preparations for preventing skin aging. Cyclodextrins presented a marked skin permeation promoting effect only on formononetin, which molecule presents lower permeability.
18

Desenvolvimento de um sistema terapêutico micro-/nanoestruturado contendo 5-fluorouracil para administração pulmonar

Zatta, Kelly Cristine January 2016 (has links)
A inexistência de um agente terapêutico único satisfatório para o tratamento do melanoma metastático e a potencialidade do quimioterápico 5FU (5-fluorouracil) motivou esta pesquisa, a qual teve por objetivo o desenvolvimento tecnológico de sistemas carreadores micro-/ e nanoestruturados contendo 5FU a fim de aumentar sua eficácia terapêutica e reduzir a toxicidade por meio da administração pulmonar. Duas formulações pulverulentas foram desenvolvidas com polímeros naturais, sulfato de condroitina e hidroxipropil-metil-celulose, denominadas 5FU-MS e 5FU-NS, utilizando as técnicas de aspersão e atomização vibracional piezoelétrica, respectivamente. Ambas as formulações foram avaliadas quanto às características físicas e químicas, perfil toxicológico in vivo (C. elegans e em ratos Wistar), e penetração e biodisponibilidade no tecido pulmonar pela quantificação da fração livre de fármaco por microdiálise pulmonar. A análise físico-química revelou a obtenção de partículas micrométricas para 5FU-MS e submicrométricas para 5FU-NS, com diâmetros médios de partícula de 2,546 ± 0,07 m e 0,652 ± 0,03 m, e fração respirável (FR%) de 55,12 ± 2,98 e 76,84 ± 0,07, respectivamente. Ambas demonstraram características e propriedades adequadas para administração pulmonar, com capacidade de deposição nas porções média e profunda. A toxicidade das formulações avaliada em C. elegans considerou o percentual de morte, desenvolvimento, DL50 e produção de ROS para os nematodos sob tratamento agudo e crônico. Os resultados evidenciaram redução significativa da toxicidade proporcionada pela redução da taxa de morte e maior desenvolvimento dos grupos tratados com as formulações 5FU-MS e 5FU-NS em comparação ao fármaco livre, sugerindo perfis de segurança satisfatórios para administração. Além disso, 5FU-MS revelou-se um agente pró-oxidante, representando um diferencial promissor deste sistema, podendo alcançar maior sensibilização das células tumorais com menores doses. A toxicidade pulmonar aguda foi avaliada pela análise de LDH e proteínas totais no fluido de lavagem bronco-alveolar (BALF) após a administração combinada das formulações 5FU-MS e 5FU-NS para administração como um sistema terapêutico único (5FU-MS/NS), e análise de dano tecidual pulmonar em ratos. Os resultados da análise bioquímica e histológica indicaram o baixo potencial de indução de lesão tecidual a partir da administração pulmonar combinada das formulações, em relação ao fármaco livre. A análise do perfil farmacocinético por microdiálise pulmonar evidenciou o êxito no desenvolvimento dos sistemas carreadores, tornando possível duplicar o t1/2 do 5FU e aumentar significativamente a biodisponibilidade no tecido pulmonar. Os resultados obtidos indicam a eficiência das formulações 5FU-MS e 5FU-NS em alcançar os benefícios terapêuticos do fármaco 5FU com menores doses e maiores intervalos de administração. Este trabalho de tese apresenta uma abordagem promissora na terapia de neoplasias com recorrência de metástase pulmonar. / The absence of a single therapeutic agent suitable for the treatment of metastatic melanoma and the potential of 5FU chemotherapy (5-fluorouracil) motivated this study, which aimed the development of carrier systems based on micro-/ and nanostructures containing 5FU to increase the therapeutic efficacy and reduce toxicity of this drug by pulmonary administration. Two different formulations of dry powders were developed with natural polymers, chondroitin sulfate and hydroxypropyl-methyl-cellulose, denomined 5FU-MS and 5FU-NS, using the spray-drying and vibrational piezoelectric atomization techniques, respectively. Both formulations were evaluated in terms of physico-chemical characteristics, in vivo toxicological behaviors (C. elegans and in Wistar rats), bioavailability and penetration in the lung tissue by quantifying of drug free fraction by lung microdialysis. The physicochemical analysis showed that were obtained as micrometric (5FU-MS) and submicron particles (5FU-NS), with average diameters of particle 2.546 ± 0.07 m and 0.652 ± 0.03 m, and respirable fraction (FR%) of 55.12 ± 2.98 and 76.84 ± 0.07, respectively. Both showed suitable characteristics and properties for pulmonary delivery, with deposition capacity in the middle and deep lung portions. The toxicity of the formulations evaluated in C. elegans considered the death rate, body development, DL50 and production of ROS to nematodes under acute and chronic treatment. The results showed significant reduction of toxicity, reducing the death rate and greater development of the groups treated with 5FU-MS and 5FU-NS formulations compared to the free drug, suggesting satisfactory safety profile for administration. In addition, 5FU-MS proved to be a pro-oxidant agent, representing a promising differential of this system which can achieve greater sensitization of tumoral cells with lower doses. Acute pulmonary toxicity was evaluated by analyzing LDH, and total protein in the bronchoalveolar lavage fluid (BALF) after combined administration of 5FU-MS formulations and 5FU-NS for administration as a single therapeutic system (5FU-MS/NS) and analysis of lung tissue damage in rats. The results of biochemical and histological analysis indicated the low potential to induce tissue damage from the pulmonary administration of combined formulations, compared to free drug. Analysis of the pharmacokinetic profile for pulmonary microdialysis showed the successful development of carrier systems, making it possible to double the t1/2 of 5FU and significantly increase bioavailability in lung tissue. The results indicate the effectiveness of the formulations 5FU-MS and 5FU-NS in achieving the therapeutic benefits of the drug 5FU at lower doses and higher dosing intervals. This thesis work presents a promising approach to cancer therapy with lung metastasis recurrence.
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Klampą reguliuojančių medžiagų įtaka emulsijų sedimentaciniam ir agregatiniam stabilumui / The influence of viscosity regulators on sedimentation and aggregation stability of emulsions

Lelevičienė, Kristina 18 June 2014 (has links)
Palyginus klampos modifikatorių savybes nustatyta, kad didėjant hidroksipropilkrakmolo fosfato koncentracijai brinkimo laikas reikšmingai ilgėja, todėl siekiant sumažinti laiko sąnaudas tikslingiau rinktis akrilato/stearato-20 itakonato kopolimerą, kuris yra skystame būvyje arba polietilenglikolio hidroksipropil hidroksietil etilceliuliozės polimerą, kuris lyginant su modifikuotu krakmolu išbrinksta reikšmingai greičiau. Sudarant emulsijų receptūras pastebėta, kad glicerolis klampos modifikatorių brinkimo laikui įtakos neturi, tačiau produktui įtakos turi brinkinimo temperatūra ir pagaminimo metodas: norint pagaminti didelės klampos produktą reiktų tirštiklį brinkinti 25±2oC temperatūroje ir homogenizuoti aparatu „Unguator“. Sudarant emulsinių pagrindų sudėtis, pastebėta, kad klampos modifikatorių pakanka 0,2-2%, išskyrus hidroksipropilkrakmolo fosfato, kurio, norit pasiekti 8,45 ±0,02 Pa*s klampą, reikėjo 6%. Centrifugavimo testo metu nustatyta, kad stresinėmis sąlygomis didžiausiu stabilumu pasižymi emulsijos, pagamintos naudojant klampą reguliuojančias medžiagas, kadangi tyrime nagrinėjami emulsiniai pagrindai testo metu neišsisluoksniavo ir išliko stabilūs 14 dienų. Mikroskopinio tyrimo metu nustatytas monodispersiškiausias pagrindas su 6% hidroksipropilkrakmolo fosfatu, skirtumas tarp maksimaliųjų ir minimaliųjų dalelių yra 1,1 μm. Analizuojant emulsinių pagrindų tekstūrą nustatyta, kad kiečiausias ir lipniausias pagrindas gautas naudojant, akrilato/stearato-20... [toliau žr. visą tekstą] / While comparing the properties of viscosity modifiers it was established that with an increase in concentration of hydroxypropyl starch phosphate the time of swelling extends on condition p<0,05, because of that to reduce the time its beter to choose acrylates/steareth-20 itaconate copolymer, which is in liquid state or polyethylene glycol hydroxy propyl hydroxyethyl ethyl cellulose polymer, which swells noticeably faster. It was observed that glycerol does not make an impact on the time thickeners swel, but the product is influenced by the temperature of swelling and the production method. To produce high-viscosity product viscosity modifiers should be soak in water at room temperature and homogenized device called "Unguator". It was observed that in order to reach 8.45 ± 0.02 Pa*s viscosity you would need 6 % of hydroxypropyl starch phosphate, while others viscosity regulators would make it with percentage 0,2-2%. Emulsion bases together with viscosity modifiers, which were used in the research, prevent droplet aggregation after formation and remained stable for 14 days and didn‘t split into layers during the centrifuge test (thereby increasing long-term stability). In microskopic test it was revealed that the smallest difference in the particle size of emulsions is the base 6% hydroxypropyl starch phosphate (1,1 μm). For the purposes of analyzing the texture is established that the hardest and the most viscous base was produced using an acrylates/steareth-20 itaconate... [to full text]
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Visualization, design, and scaling of drop generation in coflow processes

Manuela Duxenneuner Unknown Date (has links)
No description available.

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