In the present work, a new generation opaque polymer pigment with multihollow structure was synthesized by suspension polymerization of &ldquo / Water-in-Oil-in-Water&rdquo / (W/O/W) emulsion system. Oil phase was methyl methacrylate and ethylene glycol dimethacrylate monomer mixture at 1:1 weight ratio. The dimension and distribution of hollows inside polymer particles are dependent on the size of water droplets which are encapsulated in micelles. For Water-in-Oil (W/O) assembly, a hydrophobic surfactant and hydrophilic co-surfactant (Span 80-Tween 80) combination with a hydrophilic/lipophilic balance (HLB) value between 5-8 was used. The effects of surfactant and co-surfactant composition on the stability of the W/O emulsion and also on the size of water droplets were studied. In addition, the effect of the ultrasonication on the average size of water droplets was investigated. The hollow size distribution which may possibly give the maximum scattering efficiency was predicted by a mathematical model based on the Mie scattering. The optimum size distribution for W/O emulsion was obtained at the monomer/surfactant/water ratio of 75.5/9.4/15.1 after ultrasonication for 30 seconds at 80 W power. The W/O/W emulsion was prepared by dispersing the W/O emulsion in aqueous solution of hydrophilic Triton X-405. The influence of surfactant concentration and mechanical mixing on monomer droplets was investigated by size measurement and optical microscopy. After stabilizing with 1 %w/w polyvinylpyrrolidone (PVP) solution, the W/O/W emulsion was polymerized at 55 &deg / C for 20 h. The surface morphology of synthesized polymer pigments was analyzed by scanning electron microscopy (SEM) and the inner hollow structure was confirmed by transmission electron microscopy (TEM). The analysis indicated that multihollow opaque polymer pigments were successfully synthesized. The opacity, the L*a*b* color, and the gloss properties of polymer pigments were examined by spectrophotometer and glossmeter. The opacity values were assessed by contrast ratio measurements, and the synthesized polymer pigments provided up to 97.3 % opacity (50 %v/v solid content). In addition, the pigments exhibited low gloss values, and yielded matt films.

In this thesis, mechanisms for enhancing the stability of whey protein emulsions using two approaches were investigated. First, the physicochemical and emulsifying properties of whey protein isolate (WPI), and its two main proteins, alpha-lactalbumin (ALA) and beta-lactoglobulin (β-LG), were investigated in response to changes in pH and temperature pre-treatments. Solvent conditions which inhibit protein aggregation, such as pHs away from the isoelectric point, were found to form stable emulsions. In contrast, thermal treatments were found to negatively affect emulsion stability, where the most stable emulsions for WPI, ALA and β-LG were formed at room temperature (i.e. 25°C) at pH 7.0. It was also determined that emulsions formed using WPI, ALA and β-LG were stabilized by electrostatically repulsive forces which prevent flocculation and creaming. Secondly, the use of tailored protein-polysaccharide interactions involving WPI and carrageenan (CG) were explored as a means of enhancing emulsion stability. Carrageenan (CG) partakes in electrostatic attraction with WPI when acidified, leading to the formation of coupled gel networks. CG was selected for its anionic properties and for its well-characterized structure in that kappa-, iota- and lambda-type CG contain 1-, 2- and 3-sulfated groups per disaccharide repeating unit respectively. WPI-CG mixtures formed gel networks once acidified, where WPI-kappa-CG and WPI-iota-CG mixtures formed stiff networks, whereas WPI-lambda-CG formed a weak fluid network. WPI-CG complexes were found to be surface active, causing changes to the interfacial tension and interfacial rheology at pHs corresponding to where electrostatic attraction occurs upon acidification. Electrostatically coupled gel networks were formed in an emulsion, where oil droplets became entrapped within the biopolymer matrix. WPI-CG mixtures were sensitive to WPI-CG mixing ratio as stiffer gels were formed at higher CG content. Furthermore, WPI-iota-CG gels were stiffer than those made with WPI-kappa-CG gels presumably due to the higher number of sulfated groups lending greater opportunities for iota-CG to form bonds with neighboring polymers compared to kappa-CG.

Tyrimo tikslas – sumodeliuoti a/v emulsinę sistemą su linų sėmenų aliejumi ir biofarmaciniu tyrimu in vitro nustatyti sistemos sudėties ir vaisto formos įtaką modelinės hidrofilinės medžiagos išsiskyrimui iš a/v emulsinės sistemos. Tyrimo uždaviniai: nustatyti linų sėmenų aliejui reikalingą HLB skaičių ir sumodeliuoti a/v emulsinę sistemą; sumodeliuoti a/v emulsinę sistemą, kai aliejinė fazė – linų sėmenų aliejus ir ištirti fizikocheminius rodiklius; nustatyti modeliuojamos emulsinės sistemos stabilumą po 1 mėnesio pagal įvertintus fizikocheminius rodiklius; įterpti modelinę medžiagą – askorbo rūgštį į sumodeliuotą emulsinę sistemą ir ištirti askorbo rūgšties išsiskyrimą iš emulsinės sistemos tyrimu in vitro per pusiau pralaidžią membraną. Atlikus tyrimus nustatyta, kad linų sėmenų aliejui reikalingas HLB skaičius a/v emulsijai yra 7,51. Tirtos emulsinės sistemos, kurių aliejinė fazė: 20%, 30%, 50% ir 60% linų sėmenų aliejus, vandeninė terpė: išgrynintas vanduo, 0,5% ir 1% chitozano tirpalas ir 20% nuo aliejinės fazės emulsiklių spano 80 ir tvino 80 mišinys. Nustatyta, kad linų sėmenų aliejus ir chitozano tirpalas didina emulsijų klampumą, o chitozano tirpalas didina emulsijų rūgštingumą taip stabilizuodamas emulsijas ir suteikdamas dermatologiniams preparatams pageidaujamą rūgštinę pH reikšmę bei užlaikantis emulsijų išsisluoksniavimą. Sumodeliuota ir atrinkta a/v emulsinė sistema, kurios aliejinė fazė 50 proc. linų sėmenų aliejus, o vandeninė terpė 1 proc. chitozano... [toliau žr. visą tekstą] / Purpose of the research – design oil-in-water emulsion system with linseed oil and in vitro biopharmaceutical research determine system composition and drug form influence on hydrophilic agent release from o/w emulsion system. Task of the research: determine linseed oil required HLB value and design o/w emulsion system; design o/w emulsion system, when oil phase – linseed oil and study physico – chemical properties; establish emulsion system stability after 1 month by physico – chemical properties; incorporate ascorbic acid in emulsion system and investigate ascorbic acid release from emulsion system research in vitro through semi – permeable membrane. Studies showed that the required HLB of linseed oil for o/w emulsion is 7,51. Investigated emulsion systems, which oil phase was 20%, 30%, 50% and 60% linseed oil, aqueous phase – purified water, 0,5% and 1% chitosan solution also emulsifiers span 80 and tween 80 concentration was 20% by weight of the oil phase. It is established that linseed oil and chitosan solution also increase emulsions viscosity and delay emulsions creaming. Also chitosan solution increase emulsions acidity, stabilizes them and provide desired acid pH for dermatological preparations. Desighed and selected o/w emulsion system, which oil phase is 50% linseed oil, aqueous phase 1% chitosan solution according to microstucture, viscosity and pH value. This emulsion stayed stable during 1 month storage. Studies also showed that hydrophilic agent – ascorbic... [to full text]

Even though edible oils undergo refining processes to remove undesirable components, commercial oils still contain small amounts of minor components that can contribute to either prooxidant and antioxidant pathways which ultimately affect the quality of the oils. The objective of this research was to determine the role of free fatty acids and mono- and diacylglycerols on the oxidative stability of oil-in-water emulsions. Free fatty acids acted as a strong prooxidants in stripped soybean oil-in-water emulsions. Concentrations as low as 0.1% of the lipid accelerated lipid oxidation rate by both shortening the lag phase of lipid hydroperoxide and hexanal formation. The results showed that the most likely mechanisms for the prooxidant activity of free fatty acids is through their ability to increase the negatively charge on emulsion droplets that in turn could attract the cationic transition metals to the emulsion droplet surface where they can interact with lipid and thus promote oxidation. The prooxidant activity of free fatty acids was dependent on fatty acid type with lipid oxidation rates being in the order of linolenic < linoleic < oleic. Surprisingly, an increase in the degree of unsaturation of the free fatty viii acids lowered the ability of the free fatty acids to promote oxidation which may be due to their differences in geometric shape thus influencing their ability to access the emulsion droplet interface and increase the negative charge. Overall, free fatty acids are strong prooxidants in oil-in-water emulsions. This prooxidant activity is dependent not only on their concentration but also on the molecular structure of the fatty acid. Addition of mono- and diacylglycerols in oil-in-water emulsions showed an antioxidative effect in both non-stripped and stripped soybean oil. Addition of 1-monooleoylglycerol only had a small impact on the oxidative stability of non-stripped soybean oil-in-water emulsions but did inhibit lipid oxidation in emulsions prepared with stripped soybean. Much stronger antioxidant activity was observed upon the addition of 1,2-dioleoyl-sn-glycerol to both non-stripped and stripped soybean oil-in-water emulsions. Both lipid hydroperoxide and hexanal formation decreased with increasing 1,2-dioleoyl-sn-glycerol concentrations with 2.5% 1,2-dioleoyl-sn-glycerol almost completely preventing hydroperoxide and hexanal production over the course of the study. Overall, these results suggest that diacylglycerols could be an effective antioxidant in oil-in-water emulsions which possibility due to their ability to form a liquid crystal phase which could form a physical barrier that decreases interactions between unsaturated fatty acids in the emulsion droplet core and prooxidants or oxygen in the aqueous phase of the emulsion. However, the antioxidant mechanism of diacylglycerols is not currently understood and needs further investigation.

Phospholipids, such as phosphatidylserine (PS) have been shown to work synergistically with tocopherols to extend the shelf life of oil-in-water emulsions. However, the high cost of PS prevents it from being used as a food additive. This work investigated the potential use of a high PS enzyme-modified lecithin to be used along with α-tocopherol to extend the lag phase of oil-in-water emulsions stabilized using Tween 20. Phospholipase D from Streptomyces sp. and L-serine were used to modify lecithin to increase PS concentration. Enzyme activity was optimized as a function of pH and temperature using a high PC soybean lecithin. The high PS modified lecithin was examined for its ability to enhance the activity of α-tocopherol in Tween 20-stabilized oil-in-water emulsions. The modification was also performed in high PC sunflower lecithin and egg lecithin which were later analyzed for their efficiency in controlling lipid oxidation. α-Tocopherol (3.0 µmol/kg emulsion) alone increased the lag phase of hydroperoxide and hexanal lag phases by 3 and 4 days compared to the control. Authentic PS (15.0 µmol/kg emulsion) increased hydroperoxide and hexanal lag phases by 1 and 3 days, respectively, whereas high PS soy lecithin increased hydroperoxide and hexanal lag phases by 3 and 4 days, respectively. The addition of high PS sunflower and egg lecithin did not have any considerable effects on lag phases compared to the control. Authentic PS (15.0 µmol/kg emulsion) and a-tocopherol (3.0 µmol/kg emulsion) decreased lipid oxidation by increasing the hydroperoxide and hexanal lag phase to 6 and 9 days. The combination of phospholipase D modified high PS lecithins (15.0 µmol/kg emulsion) and a-tocopherol (3.0 µmol/kg emulsion) were able to synergistically increase the antioxidant activity of a-tocopherol increasing the hydroperoxide and hexanal lag phase by 6 and 9 days for soy, 5 days, and 7 days for sunflower and 4 and 6 days for egg lecithin, respectively. This resulted in synergistic antioxidant activity (interaction index > 1.0) except for a-tocopherol and high PS Egg lecithin which showed an additive effect. This research shows that the combination of enzyme-modified high PS lecithin and α-tocopherol could be an effective and commercially viable clean label antioxidant strategy to control lipid oxidation in emulsions.

Magister Pharmaceuticae - MPharm / Background: Tenofovir disoproxil fumarate (TDF) and Zidovudine (AZT) are both nucleotide and nucleoside analogue reverse transcriptase inhibitors (NtRTIs and NRTIs), respectively. They are used for the management and prevention of the Human Immunodeficiency Virus (HIV) infection. These drugs are faced with oral delivery challenges such as low intestinal permeability and extensive first pass liver metabolism for TDF and AZT, respectively. Their use may also be limited by dose-dependent adverse effects, which may result in treatment failure when patients become non-compliant and non-adherent to their prescribed antiretroviral (ARV) regimen. Non-compliance and non-adherence to ARV regimen may lead to drug resistance and a need for change in regimen, which can be very expensive, not only financially but in terms of morbidity and mortality. To solve such issues, a new drug can be formulated, or an existing drug can be modified. The development and formulation of a new drug is time consuming and expensive, especially with no available data and a high probability of failure. Modifying existing drugs is a cheaper, less time-consuming option with lower probability of failure. Such modification can be achieved via non-covalent interactions using various methods such as preparation of nano-particulates with polymeric micelles (a non-covalent interaction). Polymeric micelles offer a variety of polymers to choose from for drug modification purposes. Purpose: The aim of this study was to formulate polymeric nanoparticles of TDF and AZT using different ratios of poly-lactic-co-glycolic acid (PLGA), characterize the formulated nanoparticles (using the following analyses: particle size, zeta potential, encapsulation efficiency, hot stage microscopy, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy and scanning electron microscopy), analyze for stability during storage (2-8˚C) and determine the release rate of the active pharmaceutical ingredients in the formulated nanoparticles. Methods: Nanoparticles were prepared using a modified version of the double emulsion (water-in-oil-in-water) solvent evaporation and diffusion method. Two ratios of PLGA (50:50 and 85:15) were used to prepare four formulations (two each of TDF and AZT). Thereafter, the physicochemical and pharmaceutical properties of the formulations were assessed by characterizing the nanoparticles for particle size, zeta potential, polydispersity index, percentage yield, release profile and particle morphology, using the suggested analytical techniques. Results: For TDF-PLGA 85:15, TDF-PLGA 50:50, AZT-PLGA 85:15 and AZT-PLGA 50:50, nanoparticles of 160.4±1.7 nm,154.3±3.1 nm,127.0±2.32 nm and 153.2±4.3 nm, respectively, were recovered after washing. The polydispersity index (PDI) values were ≤0.418±0.004 after washing, indicating that the formulations were monodispersed. The zeta potential of the particles was -5.72±1 mV, -19.1 mV, -12.2±0.6 mV and -15.3±0.5 mV for TDF-PLGA 85:15, TDF-PLGA 50:50, AZT-PLGA 85:15 and AZT-PLGA 50:50 respectively after washing. The highest percentage yield was calculated to be 79.14% and the highest encapsulation efficiency obtained was 73.82% for AZT-PLGA 50:50, while the particle morphology showed spherical nanoparticles with signs of coalescence and aggregation for all formulated nanoparticles. The release profiles were biphasic; that is, an initial burst which indicated the presence of surface API followed by sustained release. Comparing the release profiles of AZT and TDF at pH 1.2 and 7.4, it was indicative that more AZT was released at pH 1.2 while more TDF was released at pH 7.4. On computing the release data further into various mathematical models, the Weibull model was found to be the best fit. The loaded nanoparticles showed an increase in stability after washing; however, they showed signs of gradual decrease in stability after 10 days of storage at 2-8°C. Conclusions: Relatively small, spherical and smooth nanoparticles were formulated. The nanoparticle release profile was indicative of sustained release; however, there was no conclusive indication that 48 hours duration was sufficient to release all encapsulated drug. Further studies with an increased API or polymer ratio in the formulation needs to be performed to determine if the encapsulation efficiency can be improved and in-vivo studies are required for a better understanding of the API release from formulations as well as its absorption in the body.

In the present work, the flow behavior of an oil-in-water emulsion around and inside the measurement chamber of an in-line optical sensor probe is studied. The emulsion consists of a metalworking fluid, with oil droplets diameter ranging from 100 nanometers to 100 micrometers. The design of the UV-Vis light spectrometer probe is in accordance with the concept proposed in the research project named EPM (Emulsion Process Monitor in Metalworking Processes), carried out within the scope of the BRAGECRIM program between the University of São Paulo and the University of Bremen. This study is based on the numerical simulation of the interactions between the emulsion and the measurement system using computational fluid dynamic techniques, and is aimed at evaluating the effects of the probe geometry, its position relative to the flow field, and fluid properties on the expected spectrometer readings. Such effects are correlated with changes in droplet concentration and or droplet size segregation inside the measurement chamber of the optical probe, which can cause changes in the scattered light intensity readings. Segregation effects due to flow disturbances around the probe can be neglected under normal measurement conditions, with the probe facing the slit area inlet against the flow stream. Based on the simulation results, even if the probe is misplaced, the effect on the measurements is still insignificant. In-situ measurements carried out in a laboratory set up installed in the injection tube of a drilling machine support the simulation results, since no segregation effect related to the measurement system was observed. In addition to the study, the possibility of bacteria attachment on the internal glass walls of the probe was evaluated and it was found that when the flow velocity is large enough to produce a wall shear stress of about 3-5 Pa the bacterial contamination may be avoided. Changes in the probe geometry are proposed in order to attain an isokinetic condition for the flow around and inside the probe, resulting in a higher wall shear stress for lower inlet flow velocities. An additional study was performed using a tracking particle model to understand the relevance of the individual particles behavior under different flow conditions. The results do not indicate any significant effect on the measurements inside the probe, although additional studies should be carried out in this topic by considering a population balance model for the oil droplets. / O presente trabalho tem como objetivo o estudo do comportamento do escoamento de uma emulsão do tipo óleo - em água que flui no interior de câmara/duto de medição e que tem como obstáculo em seu caminho uma sonda de um sensor óptico, sensor óptico este que deve avaliar em tempo real a estabilidade da emulsão onde está inserido. A emulsão é constituída por um fluido de corte para usinagem, com gotículas de óleo de diâmetro variando de 100 nanômetros para 100 micrometros. A sonda utilizada junto ao espectrômetro de luz UV- Vis está de acordo com o conceito proposto no projeto de pesquisa chamado EPM (Emulsion Process Monitor in Metalworking Fluid), realizado no âmbito do programa BRAGECRIM entre a Universidade de São Paulo e a Universidade de Bremen. Este estudo baseia-se na simulação numérica das interações entre a emulsão e o sistema de medição proposto, utilizando técnicas de Fluido Dinâmica Computacional (CFD), e tem por objetivo avaliar os efeitos da geometria da sonda, a sua posição em relação ao campo do escoamento, e propriedades do fluido, em especial as propriedades a serem medidas pelo espectrômetro. Tais efeitos estão correlacionadas com alterações na concentração de gotas e a segregação ou o tamanho das gotas dentro da câmara de medição da sonda óptica, o que pode causar mudanças nas leituras de intensidade de luz difusa. Efeitos de segregação devido a perturbações do escoamento em torno da sonda podem ser negligenciados, em condições normais de medição, com a sonda voltada para frente e sua área de entrada contra a corrente do escoamento. Com base nos resultados de simulação, mesmo que a sonda seja deslocada, o efeito sobre as medições ainda é insignificante. Medições foram efetuadas em laboratório e também foram realizadas medições in-situ utilizando um adaptador de medição acoplado diretamente no tubo de injeção de fluido de corte da máquina de perfuração, estes testes foram feitos para de validar os resultados obtidos por simulação, uma vez que não se observou qualquer efeito de segregação relacionada com o sistema de medição. Além disso, foi acrescentada ao estudo, a possibilidade de fixação de bactérias nas paredes de vidro internas da sonda e verificou-se que quando a velocidade de escoamento é suficientemente grande para produzir uma tensão de cisalhamento de cerca de 3-5 Pa a fixação de bacteriana pode ser evitado. Aproveitando os resultados do estudo para prevenção de contaminação por bactéria, mudanças na geometria da sonda foram propostas a fim de atingir uma condição isocinética para o escoamento ao redor e dentro da sonda, resultando em uma maior tensão de cisalhamento para baixas velocidades de fluxo de entrada. Por fim um estudo adicional foi realizado utilizando um modelo de rastreamento de partículas para compreender a relevância do comportamento individual de cada partícula no escoamento da emulsão. Os resultados não indicam qualquer efeito significativo sobre as medições no interior da sonda, embora estudos adicionais devem ser realizados neste tópico, considerando um modelo de balanço populacional para as gotículas de óleo.

High pressure applications are alternatives to conventional methods in food processing. They provide interesting modifications in food structures which leads to new product formulations. The aim of this study is to identify the effects of two different treatments, high hydrostatic pressure (HHP) and high dynamic pressure (HDP) on stability and rheological properties of model oil-in-water emulsions. Microfluidization was selected among the HDP homogenization techniques. The performance of each process was analyzed in terms of rheological modifications and emulsion stability improvements compared to the coarse emulsions which were prepared with colloid mill homogenization. Stability of emulsions was determined comparatively by using an analytical photo-centrifuge device employing a novel analysis technology. Whey protein isolate (WPI) was used as an emulsifier in combination with a food polysaccharide as a stabilizer. The polysaccharides used were xanthan gum, guar gum and locust bean gum which are widely used stabilizing ingredients in food industry. The effective disruption of oil droplets and the degradation of polysaccharides by the shear forces under high pressure in HDP microfluidization yielded finer emulsions with lower viscosities. The finer emulsions obtained with this homogenization technique led to distinctive improvements in emulsion stability. On the other hand, the improvements in stability by HHP treatment were due to the thickening of the emulsions mainly induced by protein unfolding. The corresponding increases in viscosity were intensified in emulsion formulations with higher oil content. Apart from these, HHP treatment was found to be relatively more contributing to the enhancements in viscoelastic properties.

Made available in DSpace on 2014-12-17T15:01:28Z (GMT). No. of bitstreams: 1 RaniereDV_DISSERT.pdf: 2210959 bytes, checksum: 50b0d022488541db247d404d8e3dc596 (MD5) Previous issue date: 2012-02-10 / The treatment of oil produced water and its implications are continually under investigation and several questions are related to this subject. In the Northeast Region Brazil, the onshore reservoirs are, in its majority, mature oil fields with high production of water. As this oil produced water has high levels of oil, it cannot be directly discarded into the environment because it represents a risk for contamination of soil, water, and groundwater, or even may cause harm to living bodies. Currently, polyelectrolytes that promote the coalescence of the oil droplets are used to remove the dispersed oil phase, enhancing the effectiveness of the flotation process. The non-biodegradability and high cost of polyelectrolytes are limiting factors for its application. On this context, it is necessary to develop studies for the search of more environmentally friendly products to apply in the flotation process. In this work it is proposed the modeling of the flotation process, in a glass column, using surfactants derived from vegetal oils to replace the polyelectrolytes, as well as to obtain a model that represents the experimental data. In addition, it was made a comparative study between the models described in the literature and the one developed in this research. The obtained results showed that the developed model presented high correlation coefficients when fitting the experimental data (R2 > 0.98), thus proving its efficiency in modeling the experimental data. / O tratamento da ?gua produzida (AP) e suas implica??es s?o continuamente estudadas e v?rias perguntas s?o direcionadas a esta ?rea. No Nordeste do Brasil os reservat?rios em terra (ONSHORE) s?o, em sua maioria, po?os maduros, com alta produ??o de ?gua, e como esta ?gua possui altos teores de ?leo, n?o pode ser descartada simplesmente, pois s?o um risco para o ambiente pela contamina??o do solo, ?guas subterr?neas ou mesmo animais e plantas. Atualmente, s?o utilizados polieletr?litos que facilitam a coalesc?ncia das gotas de ?leo dispersas nesta ?gua para assim aumentar a efici?ncia do seu processo de tratamento que ? a flota??o. Estes polieletr?litos al?m de serem de alto custo n?o s?o biodegrad?veis o que limita sua aplica??o. Diante deste contexto, surge a necessidade de estudar produtos menos agressivos ao meio ambiente que viabilizem este tratamento. Este trabalho prop?s a modelagem do processo de flota??o em coluna utilizando tensoativos de origem vegetal em substitui??o aos polieletr?litos, bem como obter uma correla??o que represente os dados experimentais. Al?m disto, foi realizado um estudo comparativo entre modelos apresentados na literatura e o desenvolvido neste trabalho. Os resultados mostraram que o modelo desenvolvido obteve coeficientes de correla??o R2, em rela??o aos dados experimentais, acima de 0,98, comprovando sua efici?ncia na modelagem dos dados experimentais.