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Obtenção de nanoemulsões O/A à base de óleo de semente de uva e oliva aditivadas de metoxicinamato de octila e estudo do potencial antioxidante e fotoprotetor das emulsões; Attainment of O/W nano-emulsion with grape seed oil and olive oil added of octylmethoxycinnamate and study of the antioxidant potential and the sun protection of the emulsions

Pereira, Gabriela Garrastazu
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/12/2008 PT
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A nanotecnologia é um fenômeno que se aplica a praticamente todos os etores da ciência, sendo que na área cosmética o elevado investimento neste campo tem reforçado a idéia de que os produtos nanotecnológicos proporcionam vantagens reais aos consumidores. A crescente exigência do consumidor e os avanços no conhecimento sobre a obtenção e estabilidade dos sistemas dispersos viabilizam o desenvolvimento de veículos diferenciados como, por exemplo, nanoemulsões, que além da inerente estabilidade, apresentam aspecto sensorial agradável, alta capacidade de espalhabilidade e hidratação. Existem dois métodos de obtenção das nanoemulsões: empregando baixa ou alta energia de emulsificação. O uso de óleos vegetais em produtos cosméticos tem sido intensamente valorizado, baseando-se no conceito de que são seguros e biocompatíveis. Podem ser utilizados em cosméticos com sua funcionalidade potencializada, sendo estes ricos em ácidos graxos essenciais, Ômega 3, Ômega 6, Ômega 9, fitosteróis, vitamina C e polifenóis (antocianinas). Alguns óleos vegetais têm poder antioxidante comprovado, previnem as oxidações biológicas e reduzem a formação de radicais livres responsáveis pelo dano celular, grande vilão do envelhecimento e das doenças crônico-degenerativas...

Separation and preconcentration of dioxin in blood samples by nano-baskets of calixarene and inclusion emulsion membranes

Mokhtari,Bahram; Pourabdollah,Kobra
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 EN
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Inclusion-separation and preconcentration of dioxin from blood samples were reported by the inclusion-facilitated emulsion liquid membrane process. The novelty of this study is the application of nano-baskets of calixarene as well as emulsion liquid membranes in the selective and efficient preconcentration of dioxin. For this aim, inclusion-extraction parameters of four p-tert-calix[4]arene derivatives sulfonamide moieties previously synthesized were investigated. Analysis by a gas chromatograph revealed that under the optimized operating condition, the preconcentration of dioxin was improved and the method achieved lower limit of detections.

Inclusion separation of alkali metals in emulsion liquid membranes by nanobaskets of calix[4]crown-3

Mokhtari,B.; Pourabdollah,K.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2012 EN
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Nano-assisted inclusion separation of alkali metals from basic solutions was reported by an inclusion-facilitated emulsion liquid membrane process. The novelty of this study is application of nanobaskets of calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this purpose, two diacids, p-tert-butylcalix[4]arene-1,2-crown-3 in the cone and the 1,2alternate conformation, as well as another diacid, p-tert-butylcalix[4]arene-1,2-thiacrown-3 in the cone conformation, were synthesized. Their inclusion-extraction parameters were optimized, including the calixcrown scaffold (04, 4 wt%) as the carrier/demulsifier, commercial kerosene as the diluent in the membrane, sulphonic acid (0.2 M) and ammonium carbonate (0.4 M) as the strip and the feed phases; the phase and the treat ratios were 0.8 and 0.3, mixing speed (300 rpm), and initial solute concentration (100 mg/L). The selectivity of the membrane was examined for more than ten interfering cations was examined and the results reveled that, under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%.

An injectable hybrid nanoparticle-in-oil-in-water submicron emulsion for improved delivery of poorly soluble drugs

Wang, Shuo; Wang, Hua; Liang, Wenquan; Huang, Yongzhuo
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em 13/04/2012 EN
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36.4%
Poor drugability problems are commonly seen in a class of chemical entities with poor solubility in water and oil, and moreover, physicochemical instability of these compounds poses extra challenges in design of dosage forms. Such problems contribute a significant high failure rate in new drug development. A hybrid nanoparicle-in-oil-in-water (N/O/W) submicron emulsion was proposed for improved delivery of poorly soluble and unstable drugs (e.g., dihydroartemisinin (DHA)). DHA is known for its potent antimalarial effect and antitumor activity. However, its insolubility and instability impose big challenges for formulations, and so far, no injectable dosage forms are clinically available yet. Therefore, an injectable DHA N/O/W system was developed. Unlike other widely-explored systems (e.g., liposomes, micelles, and emulsions), in which low drug load and only short-term storage are often found, the hybrid submicron emulsion possesses three-fold higher drug-loading capacity than the conventional O/W emulsion. Of note, it can be manufactured into a freeze-drying form and can render its storage up to 6 months even in room temperature. The in vivo studies demonstrated that the PK profiles were significantly improved, and this injectable system was effective in suppressing tumor growth. The strategy provides a useful solution to effective delivery of such a class of drugs.

Clindamycin 1% Nano-emulsion Gel Formulation for the Treatment of Acne Vulgaris: Results of a Randomized, Active Controlled, Multicentre, Phase IV Clinical Trial

Bhavsar, Bhavik; Choksi, Bimal; Sanmukhani, Jayesh; Dogra, Alka; Haq, Rizwan; Mehta, Sudhanshu; Mukherjee, Santanu; Subramanian, V; Sheikh, Shafiq; Mittal, Ravindra
Fonte: JCDR Research and Publications (P) Limited Publicador: JCDR Research and Publications (P) Limited
Tipo: Artigo de Revista Científica
EN
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46.39%
Background: Acne vulgaris of the face is a common dermatological disease with a significant impact on the quality of life, psychosocial development as well as self-esteem of the patients. Nano emulsion gel formulations are said to have various advantages over the conventional formulations.

Core-shell-structured silica/polyacrylate particles prepared by Pickering emulsion: influence of the nucleation model on particle interfacial organization and emulsion stability

Ji, Jing; Shu, Shi; Wang, Feng; Li, Zhilin; Liu, Jingjun; Song, Ye; Jia, Yi
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em 29/09/2014 EN
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36.59%
This work reports a new evidence of the versatility of silica sol as a stabilizer for Pickering emulsions. The organization of silica particles at the oil-water interface is a function of the nucleation model. The present results show that nucleation model, together with monomer hydrophobicity, can be used as a trigger to modify the packing density of silica particles at the oil-water interface: Less hydrophobic methylmethacrylate, more wettable with silica particles, favors the formation of core-shell-structured composite when the composite particles are prepared by miniemulsion polymerization in which monomers are fed in batch (droplet nucleation). By contrast, hydrophobic butylacrylate promotes the encapsulating efficiency of silica when monomers are fed dropwise (homogeneous nucleation). The morphologies of polyacrylate-nano-SiO2 composites prepared from different feed ratio of methylmethacrylate/butylacrylate (with different hydrophobicity) and by different feed processes are characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. The results from SEM and TEM show that the morphologies of the as-prepared polyacrylate/nano-SiO2 composite can be a core-shell structure or a bare acrylic sphere. The stability of resulting emulsions composed of these composite particles is strongly dependent on the surface coverage of silica particles. The emulsion stability is improved by densely silica-packed composite particles.

Oral Administration of Nano-Emulsion Curcumin in Mice Suppresses Inflammatory-Induced NFκB Signaling and Macrophage Migration

Young, Nicholas A.; Bruss, Michael S.; Gardner, Mark; Willis, William L.; Mo, Xiaokui; Valiente, Giancarlo R.; Cao, Yu; Liu, Zhongfa; Jarjour, Wael N.; Wu, Lai-Chu
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 04/11/2014 EN
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46.39%
Despite the widespread use of curcumin for centuries in Eastern medicine as an anti-inflammatory agent, its molecular actions and therapeutic viability have only recently been explored. While curcumin does have potential therapeutic efficacy, both solubility and bioavailability must be improved before it can be more successfully translated to clinical care. We have previously reported a novel formulation of nano-emulsion curcumin (NEC) that achieves significantly greater plasma concentrations in mice after oral administration. Here, we confirm the immunosuppressive effects of NEC in vivo and further examine its molecular mechanisms to better understand therapeutic potential. Using transgenic mice harboring an NFκB-luciferase reporter gene, we demonstrate a novel application of this in vivo inflammatory model to test the efficacy of NEC administration by bioluminescent imaging and show that LPS-induced NFκB activity was suppressed with NEC compared to an equivalent amount of curcumin in aqueous suspension. Administration of NEC by oral gavage resulted in a reduction of blood monocytes, decreased levels of both TLR4 and RAGE expression, and inhibited secretion of MCP-1. Mechanistically, curcumin blocked LPS-induced phosphorylation of the p65 subunit of NFκB and IκBα in murine macrophages. In a mouse model of peritonitis...

Droplet size and stability of nano-emulsions produced by the temperature phase inversion method

Ee, S.; Duan, X.; Liew, C.; Nguyen, Q.
Fonte: Elsevier Science Sa Publicador: Elsevier Science Sa
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
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36.36%
We studied the formation and stability of n-decane in water nano-emulsions produced by the phase inversion temperature (PIT) emulsification method using polyoxyethylene lauryl ether as surfactant. The results obtained indicate that the droplet size and size distribution are strongly dependent on the methods of heating and cooling, and on the final temperature to which the mixture is cooled after phase inversion. Importantly, there exists an optimum storage temperature, at which the nano-emulsions are most stable, and develop ultra-small droplet sizes, ranging from 35 nm to 54 nm, with low polydispersity indices (0.2). This optimum temperature is about 20 °C below the PIT, and dependent on the surfactant concentration. Any departure in temperature from the optimum would result in increases in droplet sizes, polydispersity and instability by Ostwald ripening. Furthermore, nano-emulsions destabilized after a long period of storage at different temperatures can be rejuvenated simply by equilibration for a few minutes at the optimum temperature.; Sher Lin Eea, Xiumei Duana, Jeffery Liewa and Q. Dzuy Nguyen; http://www.elsevier.com/wps/find/journaldescription.cws_home/601273/description#description

The influence of surfactant mixing ratio on nano-emulsion formation by the pit method

Izquierdo, P.; Feng, Jin; Esquena, Jordi; Tadros, Tharwat F.; Dederen, Joseph C.; García, María José; Azemar Sazatornil, Nuria; Solans, Conxita
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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56.73%
7 pages, 6 figures, 2 tables.-- PMID: 15797437 [PubMed].-- Available online Dec 23, 2004.; The formation of O/W nano-emulsions by the PIT emulsification method in water/mixed nonionic surfactant/oil systems has been studied. The hydrophilic–lipophilic properties of the surfactant were varied by mixing polyoxyethylene 4-lauryl ether (View the MathML source) and polyoxyethylene 6-lauryl ether (View the MathML source). Emulsification was performed in samples with constant oil concentration (20 wt%) by fast cooling from the corresponding HLB temperature to 25 °C. Nano-emulsions with droplet radius 60–70 nm and 25–30 nm were obtained at total surfactant concentrations of 4 and 8 wt%, respectively. Moreover, droplet size remained practically unchanged, independent of the surfactant mixing ratio, XC12E6. At 4 wt% surfactant concentration, the polydispersity and instability of nano-emulsions increased with the increase in XC12E6. However, at 8 wt% surfactant concentration, nano-emulsions with low polydispersity and high stability were obtained in a wide range of surfactant mixing ratios. Phase behavior studies showed that at 4 wt% surfactant concentration, three-liquid phases (W + D + O) coexist at the starting emulsification temperature. Furthermore...

Ceramic particles obtained using W/O nano-emulsions as reaction media

Porras, M.; Martínez, A.; Solans, Conxita; González, Carlos; Gutiérrez, José M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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46.41%
6 pages, 7 figures.-- Printed version published Dec 1, 2005.; Monodisperse ceramic particles can be produced from water-in-oil (W/O) nano-emulsions by hydrolysis and condensation of ceramic alkoxides into aqueous droplets, thereby yielding nanoparticles of controlled size and shape. This study addressed both the formation of W/O nano-emulsions and the resultant ceramic particles obtained in reaction media. Nano-emulsions were prepared by adding water or catalyst aqueous solution to a mixture of decane and surfactants. Droplet size was determined by dynamic light scattering, with mean sizes ranging from 30 to 120 nm. Higher water concentrations resulted in larger droplets. Ceramic nanoparticles were prepared by adding ceramic alkoxides in W/O nano-emulsions. Tetraethyl orthosilicate and tetraisopropyl orthotitanate were used to obtain silica and titania nanoparticles, respectively. Ceramic nanoparticles were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS). Particles with average size from 30 to 230 nm were obtained. Particle sizes correlated with droplet sizes of those nano-emulsions were used as reaction media.; Peer reviewed

A study on the influence of emulsion droplet size on the skin penetration of tetracaine

Izquierdo, P.; Wiechers, J. W.; Escribano, E.; García-Celma, M. J.; Tadros, Tharwat F.; Esquena, Jordi; Dederen, Joseph C.; Solans, Conxita
Fonte: S. Karger AG Publicador: S. Karger AG
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
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46.65%
8 pages, 4 figures.-- PMID: 17641530 [PubMed].; [Objectives/Aims] The influence of emulsion droplet size on the skin penetration of a model drug, tetracaine, was studied. For this purpose, in vitro dermal and transdermal delivery of tetracaine from 6 emulsions (3 macro-emulsions with droplet sizes > 1μm and 3 nano-emulsions with droplet sizes < 100 nm) were tested.; [Methods] Two approaches were used: in the first one, the composition of the emulsions was kept constant, while in the second one, the surfactant concentration in the aqueous phase was kept constant by varying the overall surfactant concentration.; [Results] The results from emulsions differing only in droplet size did not provide statistically significant evidence for the anticipated increase in transdermal or dermal delivery (after 24 h) when reducing emulsion droplet size. The same results were obtained when the surfactant concentration in the aqueous phase was kept constant, indicating that there is no influence of emulsion droplet size on the skin penetration of tetracaine within the droplet size range studied.; [Conclusion] This is in contrast to what has been reported in various publications that claim penetration to increase with reducing droplet size. It should be noted that the results reported so far are based on emulsions that apart from droplet size also differed in composition and/or system components.; The authors acknowledge financial support by Uniqema...

Nano-emulsions

Solans, Conxita; Izquierdo, P.; Nolla Anguera, Jordi; Azemar Sazatornil, Nuria; García-Celma, M. J.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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56.98%
9 pages, 5 figures.-- Printed version published Oct 2005.; The formation, properties and applications of nano-emulsions (also referred to as miniemulsions, ultrafine emulsions, submicron emulsions) are reviewed and summarized. Nano-emulsion droplet sizes fall typically in the range of 20–200 nm and show narrow size distributions. Although most of the publications on either oil-in-water (O/W) or water-in-oil (W/O) nano-emulsions report their formation by dispersion or high-energy emulsification methods, an increased interest is observed in the study of nano-emulsion formation by condensation or low-energy emulsification methods (based on the phase transitions that take place during the emulsification process). Phase behaviour studies have shown that the size of the droplets is governed by the surfactant phase structure (bicontinuous microemulsion or lamellar) at the inversion point induced by either temperature or composition. Studies on nano-emulsion formation by the phase inversion temperature (PIT) method have shown a relation between minimum droplet size and complete solubilization of the oil in a microemulsion bicontinuous phase independently of whether the initial phase equilibria is single or multiphase. Due to their small droplet size nano-emulsions possess stability against sedimentation or creaming with Ostwald ripening forming the main mechanism of nano-emulsion breakdown. The main application of nano-emulsions is the preparation of nanoparticles using a polymerizable monomer as the disperse phase (the so-called miniemulsion polymerization method) where nano-emulsion droplets act as nanoreactors. Novel complex polymeric materials as well as hybrid organic/inorganic materials...

Optimization of nano-emulsion preparation by low-energy methods in an ionic surfactant system

Solé, Isabel; Maestro, Alicia; González Azón, Carmen; Solans, Conxita; Gutiérrez, José M.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 314425 bytes; application/pdf
ENG
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46.82%
7 pages, 8 figures, 3 tables.-- PMID: 16981744 [PubMed].-- Printed version Sep 26, 2006.; The low-energy emulsification method Emulsion Inversion Point (EIP) was used to prepare O/W nano-emulsions in the W/potassium oleate−oleic acid−C12E10/hexadecane ionic system. This method had not practically been used in ionic systems up to now. The resulting droplet sizes, much smaller than those obtained with the high-energy emulsification methods, depend on the composition (formulation variables) and preparation variables (addition and mixing rate). Phase diagrams, rheology measurements, and experimental designs applied to nano-emulsion droplet sizes obtained were combined to study the formation of these nano-emulsions. To obtain small droplet sizes, it is necessary to cross a direct cubic liquid crystal phase along the emulsification path, and it is also crucial to remain in this phase long enough to incorporate all of the oil into the liquid crystal. When nano-emulsion forms, the oil is already intimately mixed with all of the components, and it only has to be redistributed. Results show that the smaller droplet sizes are obtained when the liquid crystal zone is wide and extends to high water content, because in this case, during the emulsification process...

Formation of water-in-oil (W/O) nano-emulsions in a water/mixed non-ionic surfactant/oil systems prepared by a low-energy emulsification method

Usón, N.; Garcia, María José; Solans, Conxita
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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46.64%
7 pages, 7 figures.-- Printed version published Dec 1, 2004.-- Issue title: "In honour of the 250th volume of Colloid and Surfaces A and the 25th Anniversary of the International Association of Colloid and Interface Scientists (IACIS)".; W/O nano-emulsion formation by a low-energy emulsification method is described for the first time. The nano-emulsions have been formed in water/mixed Cremophor EL:Cremophor WO7 surfactant/isopropyl myristate systems at Cremophor EL:Cremophor WO7 ratios between 1:2 and 1:9, by slow addition of isopropyl myristate to surfactant/water mixtures. Phase behaviour studies have showed that the compositions giving rise to W/O nano-emulsions belong to multiphase regions, one of the phases being a lamellar liquid crystalline phase. The droplet size of the nano-emulsions at a fixed oil concentration of 85% and mixed surfactants/water ratio of 70/30 ranged from 60 to 160 nm as Cremophor EL:Cremophor WO7 ratio increased from 1:8 to 1:2. These nano-emulsions showed high kinetic stability. No phase separation was observed during 5 months in nano-emulsions of the water/Cremophor EL:Cremophor WO7 1:8/isopropyl myristate system with 85% oil concentration, although droplet size experienced an increase with time.; The authors acknowledge financial support by CICYT (Grant PN2002-04514-C03-03) and DURSI (Grant 2001 SGR-00357).; Peer reviewed

Studies of formation of W/O nano-emulsions

Porras, M.; Solans, Conxita; González, C.; Martínez, A.; Guinart, A.; Gutiérrez, José M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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56.75%
4 pages, 4 figures.-- Printed version published Nov 30, 2004.-- Issue title: "1st International Meeting on Applied Physics" (Badajoz, Spain, Oct 13-18, 2003).; In this work, formation of water-in-oil nano-emulsions in water/mixed nonionic surfactant/oil system has been studied by a condensation method. Several mixtures of Span 20, Span 80, Tween 20 and Tween 80 were studied. It has been proved that mixtures of surfactants can provide better performance than pure surfactants. The appropriate ratio between two surfactants was studied. The existence of microemulsion, nano-emulsion and emulsion regions was investigated studying samples stability by evolution of backscattering with time multiple light scattering technique. These studies allowed to determine zones where nano-emulsions can be formed. Droplet sizes were measured by dynamic light scattering (DLS). Mean sizes between 30 and 120 nm were obtained; the higher the water concentration, the higher the size. On the other hand, nano-emulsions stability was studied by dynamic light scattering. The results showed the evolution with time of the average radius droplet. For low water concentration, nano-emulsions breakdown could be attributed to Ostwald ripening; and for high water concentration...

Formation and stability of nano-emulsions

Tadros, Tharwat F.; Izquierdo, P.; Esquena, Jordi; Solans, Conxita
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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16 pages, 18 figures, 3 tables.-- PMID: 15072948 [PubMed].-- Available online Dec 16, 2003.-- Issue title: "Emulsions, From Fundamentals to Practical Applications" (3rd World Congress on Emulsions, Lyon, France, Sep 2002).; This review describes the principles of formation and stability of nano-emulsions. It starts with an introduction highlighting the main advantages of nano-emulsions over macroemulsions for personal care and cosmetic formulations. It also describes the main problems with lack of progress on nano-emulsions. The second section deals with the mechanism of emulsification and the dynamic light scattering technique for measurement of the droplet size of nano-emulsions. This is followed by a section on methods of emulsification and the role of surfactants. Three methods are described for nano-emulsion preparation, namely high energy emulsification (using homogenisers), low energy emulsification whereby water is added to an oil solution of the surfactant and the principle of the phase inversion temperature (PIT). A section is devoted to steric stabilisation and the role of the adsorbed layer thickness. The problem of Ostwald ripening (which is the main instability process of nano-emulsions) is described in some detail. The methods that can be applied to reduce Ostwald ripening are briefly described. This involves the addition of a second less soluble oil phase such as squalene and/or addition of a strongly adsorbed and water insoluble polymeric surfactant. The last part of the review gives some examples of nano-emulsions that are prepared by the PIT method as well as using high pressure homogeniser. A comparison of the two methods is given and the rate of Ostwald ripening is measured in both cases. The effect of changing the alkyl chain length and branching of the oil was investigated using decane...

Nano-emulsions preparation by low energy methods in an ionic surfactant system

Solé, Isabel; Maestro, Alicia; Pey, C. M.; González Azón, Carmen; Solans, Conxita; Gutiérrez, José M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
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46.73%
6 pages, 1 table, 9 figures.-- Printed version published Oct 5, 2006.-- Issue title: Papers from "Formula IV: Frontiers in Formulation Science", an International conference organised by the RSC, held in London, July 4-7th 2005.; The emulsion inversion point method was used to form nano-emulsions in the ionic system water/oleic acid–potassium oleate–C12E10/hexadecane. Potassium hydroxide solutions were added to oleic acid–C12E10/hexadecane solutions at constant temperature (25 °C) in order to obtain nano-emulsions at 80% water concentration, with a stoichiometric relation of oleic acid and KOH at this point. So, the ionic surfactant (the potassium oleate) was formed along the emulsification path. The influence of the phases present during the emulsification process on nano-emulsion droplet size was analized. The results show that the smallest droplet size is obtained when along the emulsification path and near the nano-emulsion region the equilibrium is achieved with all the oil dissolved in a phase, in this case in a cubic liquid crystalline phase. It has also been found that the most probable breakdown mechanism of the nano-emulsions formed is Ostwald Ripening.; This work was funded under Spanish MCYT Project No. PPQ2002-04514-C03-02.; Peer reviewed

Optimization of nano-emulsions prepared by low-energy emulsification methods at constant temperature using a factorial design study

Pey, C. M.; Maestro, Alicia; Solé, Isabel; González Azón, Carmen; Solans, Conxita; Gutiérrez, José M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
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36.65%
7 pages, 6 figures, 5 tables.-- Printed version published Oct 5, 2006.-- Issue title: Papers from "Formula IV: Frontiers in Formulation Science", an International conference organised by the RSC, held in London, July 4-7th 2005.; The aim of this work is the study and optimization of composition and preparation method of nano-emulsions O/W by addition of one of the components at constant temperature. Experimental design techniques have been used to carry out this study. A factorial design has been done in order to investigate the effect of formulation and preparation variables over emulsion properties. The conclusion of this study is that emulsion droplet size and polydispersity change with composition and preparation method. These variables have been optimized using a central composite design obtaining response surfaces that describe this preparation method of nano-emulsions.; This work was funded under Spanish MCYT Project No. PPQ2002-04514-C03-02.; Peer reviewed

Nanocomposite polymer beads for cell detection

Jacinto, João Paulo Palma
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2015 ENG
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46.59%
Circulating tumor cells (CTCs) may induce metastases when detached from the primary tumor. The numbers of these cells in blood offers a valuable prognostic indication. Magnetoresistive sensing is an attractive option for CTC counting. In this technique, cells are labeled with nancomposite polymer beads that provide the magnetic signal. Bead properties such as size and magnetic content must be optimized in order to be used as a detection tool in a magnetoresistive platform. Another important component of the platform is the magnet required for proper sensing. Both components are addressed in this work. Nanocomposite polymer beads were produced by nano-emulsion and membrane emulsification. Formulations of the oil phase comprising a mixture of aromatic monomers and iron oxide were employed. The effect of emulsifier (surfactant) concentration on bead size was studied. Formulations of polydimethilsiloxane (PDMS) with different viscosities were also prepared with nano-emulsion method resulting in colloidal beads. Polycaprolactone (PCL) beads were also synthetized by the membrane emulsification method. The beads were characterized by different techiques such as dynamic light scattering (DLS), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Additionally...

Design of an interstitial structure for a grape seed oil emulsion by design of experiments and surface response

Chaparro-Mercado,M.C.; García-Ochoa,F.; Hernández-Sánchez,H.; Alamilla-Beltrán,L.; Quintanilla-Carvajal,M.X.; Cornejo-Mazón,M.; Pedroza-Islas,R.; Gutierrez-López,G.F.
Fonte: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería Publicador: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2012 EN
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56.74%
An interstitial structure was designed to prepare a mini (nano) - emulsion of grape seed oil; the interface was composed of surface active molecules (biopolymers and surfactants ) to produce the mini (nano) - emulsion by interfacial deposition of oil by displacement of acetone from the dispersed phase. Design of Experiments of mixes and Respond Surface was used to determine the best formulations for the system: F1, Surfactants: Tween 20, T, (0.68%), Dimodan, D, (0.331 7%) and Panodan, P, (0.0013%) and F2, Polymers system: Gum Arabic, GA, (0.029%), Maltodextrin, MD, (0.115%) and whey protein concentrate,WPC, (0.187%). The proposed formulation was prepared considering the lowest value of surface tension for surfactants and the highest value for the polymers system. A leptokurtic size distribution was obtained for the interstitial structure, prepared with a stirring rate of 10000 rpm and resulting in an average diameter of 0.1815 and a Z -potential of -18.23 mV. The emulsion was prepared using this structure and resulting average size and Z-potential values were 0.188 μm and -18.55 mV respectively. These results were not significantly different from those of the interstitial structure and therefore, it was concluded that the final composition of the emulsion and preparation procedure were adequate.