Cellulose nanofibrils for one-step stabilization of multiple emulsions (W/O/W) based on soybean oil.

PubMed

Carrillo, Carlos A; Nypelö, Tiina E; Rojas, Orlando J

2015-05-01

Cellulose nanofibrils (CNF) were incorporated in water-in-oil (W/O) microemulsions and emulsions, as well as water-in-oil-in-water (W/O/W) multiple emulsions using soybean oil. The addition of CNF to the aqueous phase expanded the composition range to obtain W/O/W emulsions. CNF also increased the viscosity of the continuous phase and reduced the drop size both of which increased the stability and effective viscosity of the emulsions. The effects of oil type and polarity on the properties of the W/O/W emulsions were tested with limonene and octane, which compared to soybean oil produced a smaller emulsion drop size, and thus a higher emulsion viscosity. Overall, CNF are a feasible alternative to conventional polysaccharides as stability enhancers for normal and multiple emulsions that exhibit strong shear thinning behavior. Copyright © 2014 Elsevier Inc. All rights reserved.

A quality by design approach to optimization of emulsions for electrospinning using factorial and D-optimal designs.

PubMed

Badawi, Mariam A; El-Khordagui, Labiba K

2014-07-16

Emulsion electrospinning is a multifactorial process used to generate nanofibers loaded with hydrophilic drugs or macromolecules for diverse biomedical applications. Emulsion electrospinnability is greatly impacted by the emulsion pharmaceutical attributes. The aim of this study was to apply a quality by design (QbD) approach based on design of experiments as a risk-based proactive approach to achieve predictable critical quality attributes (CQAs) in w/o emulsions for electrospinning. Polycaprolactone (PCL)-thickened w/o emulsions containing doxycycline HCl were formulated using a Span 60/sodium lauryl sulfate (SLS) emulsifier blend. The identified emulsion CQAs (stability, viscosity and conductivity) were linked with electrospinnability using a 3(3) factorial design to optimize emulsion composition for phase stability and a D-optimal design to optimize stable emulsions for viscosity and conductivity after shifting the design space. The three independent variables, emulsifier blend composition, organic:aqueous phase ratio and polymer concentration, had a significant effect (p<0.05) on emulsion CQAs, the emulsifier blend composition exerting prominent main and interaction effects. Scanning electron microscopy (SEM) of emulsion-electrospun NFs and desirability functions allowed modeling of emulsion CQAs to predict electrospinnable formulations. A QbD approach successfully built quality in electrospinnable emulsions, allowing development of hydrophilic drug-loaded nanofibers with desired morphological characteristics. Copyright © 2014 Elsevier B.V. All rights reserved.

Encapsulation of Polymethoxyflavones in Citrus Oil Emulsion-Based Delivery Systems.

PubMed

Yang, Ying; Zhao, Chengying; Chen, Jingjing; Tian, Guifang; McClements, David Julian; Xiao, Hang; Zheng, Jinkai

2017-03-01

The purpose of this work was to elucidate the effects of citrus oil type on polymethoxyflavone (PMF) solubility and on the physicochemical properties of PMF-loaded emulsion-based delivery systems. Citrus oils were extracted from mandarin, orange, sweet orange, and bergamot. The major constituents were determined by GC/MS: sweet orange oil (97.4% d-limonene); mandarin oil (72.4% d-limonene); orange oil (67.2% d-limonene); and bergamot oil (34.6% linalyl acetate and 25.3% d-limonene). PMF-loaded emulsions were fabricated using 10% oil phase (containing 0.1% w/v nobiletin or tangeretin) and 90% aqueous phase (containing 1% w/v Tween 80) using high-pressure homogenization. Delivery systems prepared using mandarin oil had the largest mean droplet diameters (386 or 400 nm), followed by orange oil (338 or 390 nm), bergamot oil (129 or 133 nm), and sweet orange oil (122 or 126 nm) for nobiletin- or tangeretin-loaded emulsions, respectively. The optical clarity of the emulsions increased with decreasing droplet size due to reduced light scattering. The viscosities of the emulsions (with or without PMFs) were similar (1.3 to 1.4 mPa·s), despite appreciable differences in oil phase viscosity. The loading capacity and encapsulation efficiency of the emulsions depended on carrier oil type, with bergamot oil giving the highest loading capacity. In summary, differences in the composition and physical characteristics of citrus oils led to PMF-loaded emulsions with different encapsulation and physicochemical characteristics. These results will facilitate the rational design of emulsion-based delivery systems for encapsulation of PMFs and other nutraceuticals in functional foods and beverages.

Different magnesium release profiles from W/O/W emulsions based on crystallized oils.

PubMed

Herzi, Sameh; Essafi, Wafa

2018-01-01

Water-in-oil-in-water (W/O/W) double emulsions based on crystallized oils were prepared and the release kinetics of magnesium ions from the internal to the external aqueous phase was investigated at T=4°C, for different crystallized lipophilic matrices. All the emulsions were formulated using the same surface-active species, namely polyglycerol polyricinoleate (oil-soluble) and sodium caseinate (water-soluble). The external aqueous phase was a lactose or glucose solution at approximately the same osmotic pressure as that of the inner droplets, in order to avoid osmotic water transfer phenomena. We investigated two types of crystallized lipophilic systems: one based on blends of cocoa butter and miglyol oil, exploring a solid fat content from 0 to 90% and the other system based on milk fat fractions for which the solid fat content varies between 54 and 86%. For double emulsions based on cocoa butter/miglyol oil, the rate of magnesium release was gradually lowered by increasing the % of fat crystals i.e. cocoa butter, in agreement with a diffusion/permeation mechanism. However for double emulsions based on milk fat fractions, the rate of magnesium release was independent of the % of fat crystals and remains the one at t=0. This difference in diffusion patterns, although the solid content is of the same order, suggests a different distribution of fat crystals within the double globules: a continuous fat network acting as a physical barrier for the diffusion of magnesium for double emulsions based on cocoa butter/miglyol oil and double globule/water interfacial distribution for milk fat fractions based double emulsions, through the formation of a crystalline shell allowing an effective protection of the double globules against diffusion of magnesium to the external aqueous phase. Copyright © 2017 Elsevier Inc. All rights reserved.

Investigation of in vitro Hydrophilic and Hydrophobic Dual Drug Release from Polymeric Films Produced by Sodium alginate-MaterBi® Drying Emulsions.

PubMed

Setti, Chiara; Suarato, Giulia; Perotto, Giovanni; Athanassiou, Athanassia; Bayer, Ilker S

2018-06-18

Emulsions are known to be effective carriers of hydrophobic drugs, and particularly injectable emulsions have been successfully implemented for in vivo controlled drug release. Recently, high internal phase emulsions have also been used to produce porous polymeric templates for pharmaceutical applications. However, emulsions containing dissolved biopolymers both in the oil and water phases are very scarce. In this study, we demonstrate such an emulsion, in which the oil phase contains a hydrophobic biodegradable polymer, MaterBi ® , and the water phase is aqueous sodium alginate dispersion. The two phases were emulsified simply by ultrasonic processing without any surfactants. The emulsions were stable for several days and were dried into composite solid films with varying MaterBi ® /alginate fractions. The films were loaded with two model drugs, a hydrophilic eosin-based cutaneous antiseptic and the hydrophobic curcumin. Drug release capacity of the films was investigated in detail, and controlled release of each model drug was achieved either by tuning the polymer fraction in the films during emulsification or by crosslinking sodium alginate fraction of the films by calcium salt solution immersion. The emulsions can be formulated to carry either a single model drug or both drugs depending on the desired application. Films demonstrate excellent cell biocompatibility against human dermal fibroblast, adult cells. Copyright © 2018. Published by Elsevier B.V.

Stability and Oil Migration of Oil-in-Water Emulsions Emulsified by Phase-Separating Biopolymer Mixtures.

PubMed

Yang, Nan; Mao, Peng; Lv, Ruihe; Zhang, Ke; Fang, Yapeng; Nishinari, Katsuyoshi; Phillips, Glyn O

2016-08-01

Oil-in-water (O/W) emulsions with varying concentration of oil phase, medium-chain triglyceride (MCT), were prepared using phase-separating gum arabic (GA)/sugar beet pectin (SBP) mixture as an emulsifier. Stability of the emulsions including emulsion phase separation, droplet size change, and oil migration were investigated by means of visual observation, droplet size analysis, oil partition analysis, backscattering of light, and interfacial tension measurement. It was found that in the emulsions prepared with 4.0% GA/1.0% SBP, when the concentration of MCT was greater than 2.0%, emulsion phase separation was not observed and the emulsions were stable with droplet size unchanged during storage. This result proves the emulsification ability of phase-separating biopolymer mixtures and their potential usage as emulsifiers to prepare O/W emulsion. However, when the concentration of MCT was equal or less than 2.0%, emulsion phase separation occurred after preparation resulting in an upper SBP-rich phase and a lower GA-rich phase. The droplet size increased in the upper phase whereas decreased slightly in the lower phase with time, compared to the freshly prepared emulsions. During storage, the oil droplets exhibited a complex migration process: first moving to the SBP-rich phase, then to the GA-rich phase and finally gathering at the interface between the two phases. The mechanisms of the emulsion stability and oil migration in the phase-separated emulsions were discussed. © 2016 Institute of Food Technologists®

Elucidation of stabilizing oil-in-water Pickering emulsion with different modified maize starch-based nanoparticles.

PubMed

Ye, Fan; Miao, Ming; Jiang, Bo; Campanella, Osvaldo H; Jin, Zhengyu; Zhang, Tao

2017-08-15

The aim of present study was to study the medium-chain triacylglycerol-in-water (O/W) Pickering emulsion stabilized using different modified starch-based nanoparticles (octenylsuccinylation treated soluble starch nanoparticle, OSA-SSNP, and insoluble starch nanoparticle, ISNP). The major factors for affecting the system stability, rheological behaviour and microstructure of the emulsions were also investigated. The parameters of the O/W emulsions stabilized by OSA-SSNP or ISNP were selected as follows: 3.0% of starch nanoparticles concentration, 50% of MCT fraction and 7.0 of system pH. The rheological properties indicated that both emulsions displayed shear-thinning behaviour as a non-Newtonian fluid. For OSA-SSNP, the viscosities of the emulsion were higher than those of ISNP throughout shear rate range for the same condition. The plot of droplet size distribution for emulsion stabilized OSA-SSNP appeared as a single narrow peak, whereas a broader droplet size distribution with bimodal pattern was observed for emulsion stabilized ISNP. The microscopy results showed that both OSA-SSNP and ISNP were adsorbed at oil-water interface to form a barrier film and retard the phase separation. When emulsion was stored for 30d, no phase separation was detected for O/W emulsion, revealing high stability of emulsion stabilized by both OSA-SSNP and ISNP. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stochastic Rotation Dynamics simulations of wetting multi-phase flows

NASA Astrophysics Data System (ADS)

Hiller, Thomas; Sanchez de La Lama, Marta; Brinkmann, Martin

2016-06-01

Multi-color Stochastic Rotation Dynamics (SRDmc) has been introduced by Inoue et al. [1,2] as a particle based simulation method to study the flow of emulsion droplets in non-wetting microchannels. In this work, we extend the multi-color method to also account for different wetting conditions. This is achieved by assigning the color information not only to fluid particles but also to virtual wall particles that are required to enforce proper no-slip boundary conditions. To extend the scope of the original SRDmc algorithm to e.g. immiscible two-phase flow with viscosity contrast we implement an angular momentum conserving scheme (SRD+mc). We perform extensive benchmark simulations to show that a mono-phase SRDmc fluid exhibits bulk properties identical to a standard SRD fluid and that SRDmc fluids are applicable to a wide range of immiscible two-phase flows. To quantify the adhesion of a SRD+mc fluid in contact to the walls we measure the apparent contact angle from sessile droplets in mechanical equilibrium. For a further verification of our wettability implementation we compare the dewetting of a liquid film from a wetting stripe to experimental and numerical studies of interfacial morphologies on chemically structured surfaces.

Tocopherol and tocotrienol homologs in parenteral lipid emulsions

PubMed Central

Xu, Zhidong; Harvey, Kevin A; Pavlina, Thomas M; Zaloga, Gary P; Siddiqui, Rafat A

2015-01-01

Parenteral lipid emulsions, which are made of oils from plant and fish sources, contain different types of tocopherols and tocotrienols (vitamin E homologs). The amount and types of vitamin E homologs in various lipid emulsions vary considerably and are not completely known. The objective of this analysis was to develop a quantitative method to determine levels of all vitamin E homologs in various lipid emulsions. An HPLC system was used to measure vitamin E homologs using a Pinnacle DB Silica normal phase column and an isocratic, n-hexane:1,4 dioxane (98:2) mobile phase. An optimized protocol was used to report vitamin E homolog concentrations in soybean oil-based (Intralipid®, Ivelip®, Lipofundin® N, Liposyn® III, and Liposyn® II), medium- and long-chain fatty acid-based (Lipofundin®, MCT and Structolipid®), olive oil-based (ClinOleic®), and fish oil-based (Omegaven®) and mixture of these oils-based (SMOFlipid®, Lipidem®) commercial parenteral lipid emulsions. Total content of all vitamin E homologs varied greatly between different emulsions, ranging from 57.9 to 383.9 µg/mL. Tocopherols (α, β, γ, δ) were the predominant vitamin E homologs for all emulsions, with tocotrienol content < 0.3%. In all of the soybean emulsions, except for Lipofundin® N, the predominant vitamin E homolog was γ-tocopherol, which ranged from 57–156 µg/mL. ClinOleic® predominantly contained α-tocopherol (32 µg/mL), whereas α-tocopherol content in Omegaven® was higher than most of the other lipid emulsions (230 µg/mL). Practical applications The information on the types and quantity of vitamin E homologs in various lipid emulsions will be extremely useful to physicians and healthcare personnel in selecting appropriate lipid emulsions that are exclusively used in patients with inadequate gastrointestinal function, including hospitalized and critically ill patients. Some emulsions may require vitamin E supplementation in order to meet minimal human requirements. PMID:25685054

Hierarchically porous materials from layer-by-layer photopolymerization of high internal phase emulsions.

PubMed

Sušec, Maja; Ligon, Samuel Clark; Stampfl, Jürgen; Liska, Robert; Krajnc, Peter

2013-06-13

A combination of high internal phase emulsion (HIPE) templating and additive manufacturing technology (AMT) is applied for creating hierarchical porosity within an acrylate and acrylate/thiol-based polymer network. The photopolymerizable formulation is optimized to produce emulsions with a volume fraction of droplet phase greater than 80 vol%. Kinetic stability of the emulsions is sufficient enough to withstand in-mold curing or computer-controlled layer-by-layer stereolithography without phase separation. By including macroscale cellular cavities within the build file, a level of controlled porosity is created simultaneous to the formation of the porous microstructure of the polyHIPE. The hybrid HIPE-AMT technique thus provides hierarchically porous materials with mechanical properties tailored by the addition of thiol chain transfer agent. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-dimensional molecular mapping of a multiple emulsion by means of CARS microscopy.

PubMed

Meyer, Tobias; Akimov, Denis; Tarcea, Nicolae; Chatzipapadopoulos, Susana; Muschiolik, Gerald; Kobow, Jens; Schmitt, Michael; Popp, Jürgen

2008-02-07

Multiple emulsions consisting of water droplets dispersed in an oil phase containing emulsifier which is emulsified in an outer water phase (W/O/W) are of great interest in pharmacology for developing new drugs, in the nutrition sciences for designing functional food, and in biology as model systems for cell organelles such as liposomes. In the food industry multiple emulsions with high sugar content in the aqueous phase can be used for the production of sweets, because the high sugar content prevents deterioration. However, for these emulsions the refractive indexes of oil and aqueous phase are very similar. This seriously impedes the analysis of these emulsions, e.g., for process monitoring, because microscopic techniques based on transmission or reflection do not provide sufficient contrast. We have characterized the inner dispersed phase of concentrated W/O/W emulsions with the same refractive index of the three phases by micro Raman spectroscopy and investigated the composition and molecular distribution in water-oil-water emulsions by means of three-dimensional laser scanning CARS (coherent anti-Stokes Raman scattering) microscopy. CARS microscopy has been used to study water droplets dispersed in oil droplets at different Raman resonances to visualize different molecular species. Water droplets with a diameter of about 700 nm could clearly be visualized. The advantages of CARS microscopy for studying this particular system are emphasized by comparing this microscopic technique with conventional confocal reflection and transmission microscopies.

Adsorption of the Three-phase Emulsion on Various Solid Surfaces.

PubMed

Enomoto, Yasutaka; Imai, Yoko; Tajima, Kazuo

2017-07-01

The present study investigates the adsorption of the three-phase emulsion on various solid/water interfaces. Vesicles can be used as emulsifiers in the three-phase emulsions and act as an independent phase unlike the surfactant used in conventional emulsions; therefore, it is expected that the three-phase emulsion formed by the adhesion of vesicles to the oil/water interface will adsorb on various solid/water interfaces. The cationic three-phase emulsion was prepared to encourage emulsion adsorption on negatively charged solid substrates in water. The emulsifier polyoxyethylene-(10) hydrogenated castor oil was rendered cationic by mixing with the surfactant cetyltrimethylammonium bromide and then used to prepare the cationic three-phase emulsion of hexadecane-in-water. Three solid substrates (silicon, glass, and copper) were dipped in the cationic emulsion and the emulsion was found to adsorb on the solid substrates while maintaining its structure. The amount of hexadecane adsorbed on the various surfaces was investigated by gas chromatography and found to increase with increasing hexadecane concentration in the emulsion and eventually plateaued just like molecular adsorption. The maximum surface coverage of the emulsion on the substrates was approximately 80%. However, even the equivalent nonionic three-phase emulsion was found to adsorb on the three solid surfaces. This was attributed to a novel mechanism of irreversible adhesion via the van der Waals attractive force.

Boosting the bioavailability of hydrophobic nutrients, vitamins, and nutraceuticals in natural products using excipient emulsions.

PubMed

McClements, David Julian; Saliva-Trujillo, Laura; Zhang, Ruojie; Zhang, Zipei; Zou, Liqiang; Yao, Mingfei; Xiao, Hang

2016-10-01

Many highly hydrophobic bioactives, such as non-polar nutrients, nutraceuticals, and vitamins, have a relatively low or variable oral bioavailability. The poor bioavailability profile of these bioactives may be due to limited bioaccessibility, poor absorption, and/or chemical transformation within the gastrointestinal tract (GIT). The bioavailability of hydrophobic bioactives can be improved using specially designed oil-in-water emulsions consisting of lipid droplets dispersed within an aqueous phase. The bioactives may be isolated from their natural environment and then incorporated into the lipid phase of emulsion-based delivery systems. Alternatively, the bioactives may be left in their natural environment (e.g., fruits or vegetables), and then ingested with emulsion-based excipient systems. An excipient emulsion may have no inherent health benefits itself, but it boosts the biological activity of bioactive ingredients co-ingested with it by altering their bioaccessibility, absorption, and/or chemical transformation. This review discusses the design and fabrication of excipient emulsions, and gives some examples of recent research that demonstrates their potential efficacy for improving the bioavailability of hydrophobic bioactives. The concept of excipient emulsions could be used to formulate emulsion-based food products (such as excipient sauces, dressings, dips, creams, or yogurts) specifically designed to increase the bioavailability of bioactive agents in natural foods, such as fruits and vegetables. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fabrication, characterisation and stability of oil-in-water emulsions stabilised by solid lipid particles: the role of particle characteristics and emulsion microstructure upon Pickering functionality.

PubMed

Zafeiri, I; Smith, P; Norton, I T; Spyropoulos, F

2017-07-19

The quest to identify and use bio-based particles with a Pickering stabilisation potential for food applications has lately been particularly substantial and includes, among other candidates, lipid-based particles. The present study investigates the ability of solid lipid particles to stabilise oil-in-water (o/w) emulsions against coalescence. Results obtained showed that emulsion stability could be achieved when low amounts (0.8 wt/wt%) of a surface active species (e.g. Tween 80 or NaCas) were used in particles' fabrication. Triple staining of the o/w emulsions enabled the visualisation of emulsion droplets' surface via confocal microscopy. This revealed an interfacial location of the lipid particles, hence confirming stabilisation via a Pickering mechanism. Emulsion droplet size was controlled by varying several formulation parameters, such as the type of the lipid and surface active component, the processing route and the polarity of the dispersed phase. Differential scanning calorimetry (DSC) was employed as the analytical tool to quantify the amount of crystalline material available to stabilise the emulsion droplets at different intervals during the experimental timeframe. Dissolution of lipid particles in the oil phase was observed and evolved distinctly between a wax and a triglyceride, and in the presence of a non-ionic surfactant and a protein. Yet, this behaviour did not result in emulsion destabilisation. Moreover, emulsion's thermal stability was found to be determined by the behaviour of lipid particles under temperature effects.

Characteristics of Nano-emulsion for Cold Thermal Storage

NASA Astrophysics Data System (ADS)

Fumoto, Koji; Kawaji, Masahiro; Kawanami, Tsuyoshi

Phase change emulsion (PCE) is novel kind of heat storage and heat transfer fluids. It has characteristics as follows; greater apparent specific heat and higher heat transfer abilities in the phase change temperature range than conventional single phase heat transfer fluid. In this paper, a phase change emulsion, which has droplet diameter distribution of nanometer, were prepared. The Nano-emulsion was formed by low energy emulsification methods, as known the phase inversion temperature (PIT) method. Physical properties, such as viscosity, diameter and its distribution of emulsion were investigated. Especially, the relationships between preparation method and the concentration of surfactant have been discussed in detail. The results show that the viscosity of the Nano-emulsion is lower than the micro-emulsion, which was made by same mixing ratio of surfactant and concentration of phase change material. In addition, the Nano-emulsion clarified that stability was higher than microemulsions.

Application of edible paraffin oil for cationic dye removal from water using emulsion liquid membrane.

PubMed

Zereshki, Sina; Daraei, Parisa; Shokri, Amin

2018-05-18

Using an emulsion liquid membrane based on edible oils is investigated for removing cationic dyes from aqueous solutions. There is a great potential for using edible oils in food industry extraction processes. The parameters affecting the stability of the emulsion and the extraction rate were studied. These parameters were the emulsification time, the stirring speed, the surfactant concentration, the internal phase concentration, the feed phase concentration, the volume ratio of internal phase to organic phase and the treat ratio. In order to stabilize the emulsion without using a carrier, edible paraffin oil and heptane are used at an 80:20 ratio. The optimum conditions for the extraction of methylene blue (MB), crystal violet and methyl violet (CV and MV) cationic dyes using edible paraffin oil as an environment friendly solvent are represented. A removal percentage of 95% was achieved for a mixture of dyes. The optimum concentration of sodium hydroxide in the internal phase, which results a stabile emulsion with a high stripping efficiency of 96%, was 0.04 M. An excellent membrane recovery was observed and the extraction of dyes did not decrease up to seven run cycles. Copyright © 2018 Elsevier B.V. All rights reserved.

Study of O/W micro- and nano-emulsions based on propylene glycol diester as a vehicle for geranic acid.

PubMed

Jaworska, Małgorzata; Sikora, Elżbieta; Ogonowski, Jan; Konieczna, Monika

2015-01-01

Nano- and microemulsions containing as the oil phase caprylic/capric propylene glycol diesters (Crodamol PC) were investigated as potential vehicle for controlled release of geranic acid. The influence of emulsifiers and co-surfactants on stability of the emulsions was investigated. Different kind of polysorbates (ethoxylated esters of sorbitan and fatty acids) were applied as the emulsifiers. The short-chain alcohols (ethanol, 1-propanol, 1-butanol) were used as co-surfactants. The emulsions were prepared at ambient temperature (25°C), by the phase inversion composition method (PIC). The stable O/W high dispersed emulsion systems based on Crodamol PC, of mean droplets size less than 200 nm, were prepared. Microemulsions stabilized by the mixture of Polisorbat 80 and 1-butanol were characterized by the largest degree of dispersion (137 nm) and the lowest PDI value (0.094), at surfactant/co-surfactant: oil weight ratio 90:10. The stable nano-emulsion (mean droplet size of 33 nm) was obtained for surfactant: oil (S:O) weight ratio 90:10, without co-surfactant addition. This nano-emulsion was chosen to release studies. The obtained results showed that the prepared stable nano-emulsion can be used as a carrier for controlled release of geranic acid. The active substance release from the nano-emulsion and the oil solution, after 24 hours was 22%.

Effect of layer-by-layer coatings and localization of antioxidant on oxidative stability of a model encapsulated bioactive compound in oil-in-water emulsions.

PubMed

Pan, Yuanjie; Nitin, N

2015-11-01

Oxidation of encapsulated bioactives in emulsions is one of the key challenges that limit shelf-life of many emulsion containing products. This study seeks to quantify the role of layer-by-layer coatings and localization of antioxidant molecules at the emulsion interface in influencing oxidation of the encapsulated bioactives. Oxidative barrier properties of the emulsions were simulated by measuring the rate of reaction of peroxyl radicals generated in the aqueous phase with the encapsulated radical sensitive dye in the lipid core of the emulsions. The results of peroxyl radical permeation were compared to the stability of encapsulated retinol (model bioactive) in emulsions. To evaluate the role of layer-by-layer coatings in influencing oxidative barrier properties, radical permeation rates and retinol stability were evaluated in emulsion formulations of SDS emulsion and SDS emulsion with one or two layers of polymers (ϵ-polylysine and dextran sulfate) coated at the interface. To localize antioxidant molecules to the interface, gallic acid (GA) was chemically conjugated with ϵ-polylysine and subsequently deposited on SDS emulsion based on electrostatic interactions. Emulsion formulations with localized GA molecules at the interface were compared with SDS emulsion with GA molecules in the bulk aqueous phase. The results of this study demonstrate the advantage of localization of antioxidant at the interface and the limited impact of short chain polymer coatings at the interface of emulsions in reducing permeation of radicals and oxidation of a model encapsulated bioactive in oil-in-water emulsions. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of phase inversion on the formation and stability of one-step multiple emulsions.

PubMed

Morais, Jacqueline M; Rocha-Filho, Pedro A; Burgess, Diane J

2009-07-21

A novel method of preparation of water-in-oil-in-micelle-containing water (W/O/W(m)) multiple emulsions using the one-step emulsification method is reported. These multiple emulsions were normal (not temporary) and stable over a 60 day test period. Previously, reported multiple emulsion by the one-step method were abnormal systems that formed at the inversion point of simple emulsion (where there is an incompatibility in the Ostwald and Bancroft theories, and typically these are O/W/O systems). Pseudoternary phase diagrams and bidimensional process-composition (phase inversion) maps were constructed to assist in process and composition optimization. The surfactants used were PEG40 hydrogenated castor oil and sorbitan oleate, and mineral and vegetables oils were investigated. Physicochemical characterization studies showed experimentally, for the first time, the significance of the ultralow surface tension point on multiple emulsion formation by one-step via phase inversion processes. Although the significance of ultralow surface tension has been speculated previously, to the best of our knowledge, this is the first experimental confirmation. The multiple emulsion system reported here was dependent not only upon the emulsification temperature, but also upon the component ratios, therefore both the emulsion phase inversion and the phase inversion temperature were considered to fully explain their formation. Accordingly, it is hypothesized that the formation of these normal multiple emulsions is not a result of a temporary incompatibility (at the inversion point) during simple emulsion preparation, as previously reported. Rather, these normal W/O/W(m) emulsions are a result of the simultaneous occurrence of catastrophic and transitional phase inversion processes. The formation of the primary emulsions (W/O) is in accordance with the Ostwald theory ,and the formation of the multiple emulsions (W/O/W(m)) is in agreement with the Bancroft theory.

Dynamic Model of Basic Oxygen Steelmaking Process Based on Multi-zone Reaction Kinetics: Model Derivation and Validation

NASA Astrophysics Data System (ADS)

Rout, Bapin Kumar; Brooks, Geoff; Rhamdhani, M. Akbar; Li, Zushu; Schrama, Frank N. H.; Sun, Jianjun

2018-04-01

A multi-zone kinetic model coupled with a dynamic slag generation model was developed for the simulation of hot metal and slag composition during the basic oxygen furnace (BOF) operation. The three reaction zones (i) jet impact zone, (ii) slag-bulk metal zone, (iii) slag-metal-gas emulsion zone were considered for the calculation of overall refining kinetics. In the rate equations, the transient rate parameters were mathematically described as a function of process variables. A micro and macroscopic rate calculation methodology (micro-kinetics and macro-kinetics) were developed to estimate the total refining contributed by the recirculating metal droplets through the slag-metal emulsion zone. The micro-kinetics involves developing the rate equation for individual droplets in the emulsion. The mathematical models for the size distribution of initial droplets, kinetics of simultaneous refining of elements, the residence time in the emulsion, and dynamic interfacial area change were established in the micro-kinetic model. In the macro-kinetics calculation, a droplet generation model was employed and the total amount of refining by emulsion was calculated by summing the refining from the entire population of returning droplets. A dynamic FetO generation model based on oxygen mass balance was developed and coupled with the multi-zone kinetic model. The effect of post-combustion on the evolution of slag and metal composition was investigated. The model was applied to a 200-ton top blowing converter and the simulated value of metal and slag was found to be in good agreement with the measured data. The post-combustion ratio was found to be an important factor in controlling FetO content in the slag and the kinetics of Mn and P in a BOF process.

Non-destructive monitoring of creaming of oil-in-water emulsion-based formulations using magnetic resonance imaging.

PubMed

Onuki, Yoshinori; Horita, Akihiro; Kuribayashi, Hideto; Okuno, Yoshihide; Obata, Yasuko; Takayama, Kozo

2014-07-01

A non-destructive method for monitoring creaming of emulsion-based formulations is in great demand because it allows us to understand fully their instability mechanisms. This study was aimed at demonstrating the usefulness of magnetic resonance (MR) techniques, including MR imaging (MRI) and MR spectroscopy (MRS), for evaluating the physicochemical stability of emulsion-based formulations. Emulsions that are applicable as the base of practical skin creams were used as test samples. Substantial creaming was developed by centrifugation, which was then monitored by MRI. The creaming oil droplet layer and aqueous phase were clearly distinguished by quantitative MRI by measuring T1 and the apparent diffusion coefficient. Components in a selected volume in the emulsions could be analyzed using MRS. Then, model emulsions having different hydrophilic-lipophilic balance (HLB) values were tested, and the optimal HLB value for a stable dispersion was determined. In addition, the MRI examination enables the detection of creaming occurring in a polyethylene tube, which is commonly used for commercial products, without losing any image quality. These findings strongly indicate that MR techniques are powerful tools to evaluate the physicochemical stability of emulsion-based formulations. This study will make a great contribution to the development and quality control of emulsion-based formulations.

Phase behavior and formation of o/w nano-emulsion in vegetable oil/ mixture of polyglycerol polyricinoleate and polyglycerin fatty acid ester/water systems.

PubMed

Wakisaka, Satoshi; Nakanishi, Masami; Gohtani, Shoichi

2014-01-01

It is reported that mixing polyglycerol polyricinoleate (PGPR) and polyglycerol laurilester has a great emulsifying capacity, and consequently fine oil-in-water (o/w) emulsions can be formed. However, the role of PGPR is not clear. The objective of this research is to investigate the phase behavior of vegetable oil/mixture of PGPR and polyglycerol fatty acid ester/water systems, and to clarify the role of PGPR in making a fine emulsion. Phase diagrams were constructed to elucidate the optimal process for preparing fine emulsions. In all the systems examined in this study, the phases, including the liquid crystal phase (L(c)) and sponge phase (L(3)), spread widely in the phase diagrams. We examined droplet size of the emulsions prepared from each phase and found that o/w nano-emulsions with droplet sizes as small as 50 nm were formed by emulsifying either from a single L(3) phase or a two-phase region, L(c) + L(3). These results indicate that a sponge phase L(3) or liquid crystal phase L(c) or both is necessary to form an o/w nano-emulsion whose average droplet diameter is less than 50 nm for PGPR and polyglycerin fatty acid ester mixtures used as surfactant.

Effect of High Pressure Homogenization on the Physicochemical Properties of Natural Plant-based Model Emulsion Applicable for Dairy Products

PubMed Central

Park, Sung Hee; Min, Sang-Gi; Jo, Yeon-Ji; Chun, Ji-Yeon

2015-01-01

In the dairy industry, natural plant-based powders are widely used to develop flavor and functionality. However, most of these ingredients are water-insoluble; therefore, emulsification is essential. In this study, the efficacy of high pressure homogenization (HPH) on natural plant (chocolate or vanilla)-based model emulsions was investigated. The particle size, electrical conductivity, Brix, pH, and color were analyzed after HPH. HPH significantly decreased the particle size of chocolate-based emulsions as a function of elevated pressures (20-100 MPa). HPH decreased the mean particle size of chocolate-based emulsions from 29.01 μm to 5.12 μm, and that of vanilla-based emulsions from 4.18 μm to 2.44 μm. Electrical conductivity increased as a function of the elevated pressures after HPH, for both chocolate- and vanilla-based model emulsions. HPH at 100 MPa increased the electrical conductivity of chocolate-based model emulsions from 0.570 S/m to 0.680 S/m, and that of vanilla-based model emulsions from 0.573 S/m to 0.601 S/m. Increased electrical conductivity would be attributed to colloidal phase modification and dispersion of oil globules. Brix of both chocolate- and vanilla-based model emulsions gradually increased as a function of the HPH pressure. Thus, HPH increased the solubility of plant-based powders by decreasing the particle size. This study demonstrated the potential use of HPH for enhancing the emulsification process and stability of the natural plant powders for applications with dairy products. PMID:26761891

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor)

2017-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, water, or a water-based lubricant. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Coencapsulation of (-)-Epigallocatechin-3-gallate and Quercetin in Particle-Stabilized W/O/W Emulsion Gels: Controlled Release and Bioaccessibility.

PubMed

Chen, Xing; McClements, David Julian; Wang, Jian; Zou, Liqiang; Deng, Sumeng; Liu, Wei; Yan, Chi; Zhu, Yuqing; Cheng, Ce; Liu, Chengmei

2018-04-11

Particle-stabilized W 1 /O/W 2 emulsion gels were fabricated using a two-step procedure: ( i) a W 1 /O emulsion was formed containing saccharose (for osmotic stress balance) and gelatin (as a gelling agent) in the aqueous phase and polyglycerol polyricinoleate (a lipophilic surfactant) in the oil phase; ( ii) this W 1 /O emulsion was then homogenized with another water phase (W 2 ) containing wheat gliadin nanoparticles (hydrophilic emulsifier). The gliadin nanoparticles in the external aqueous phase aggregated at pH 5.5, which led to the formation of particle-stabilized W 1 /O/W 2 emulsion gels with good stability to phase separation. These emulsion gels were then used to coencapsulate a hydrophilic bioactive (epigallocatechin-3-gallate, EGCG) in the internal aqueous phase (encapsulation efficiency = 65.5%) and a hydrophobic bioactive (quercetin) in the oil phase (encapsulation efficiency = 97.2%). The emulsion gels improved EGCG chemical stability and quercetin solubility under simulated gastrointestinal conditions, which led to a 2- and 4-fold increase in their effective bioaccessibility, respectively.

Particle self-assembly at ionic liquid-based interfaces.

PubMed

Frost, Denzil S; Nofen, Elizabeth M; Dai, Lenore L

2014-04-01

This review presents an overview of the nature of ionic liquid (IL)-based interfaces and self-assembled particle morphologies of IL-in-water, oil- and water-in-IL, and novel IL-in-IL Pickering emulsions with emphasis on their unique phenomena, by means of experimental and computational studies. In IL-in-water Pickering emulsions, particles formed monolayers at ionic liquid-water interfaces and were close-packed on fully covered emulsion droplets or aggregated on partially covered droplets. Interestingly, other than equilibrating at the ionic liquid-water interfaces, microparticles with certain surface chemistries were extracted into the ionic liquid phase with a high efficiency. These experimental findings were supported by potential of mean force calculations, which showed large energy drops as hydrophobic particles crossed the interface into the IL phase. In the oil- and water-in-IL Pickering emulsions, microparticles with acidic surface chemistries formed monolayer bridges between the internal phase droplets rather than residing at the oil/water-ionic liquid interfaces, a significant deviation from traditional Pickering emulsion morphology. Molecular dynamics simulations revealed aspects of the mechanism behind this bridging phenomenon, including the role of the droplet phase, surface chemistry, and inter-particle film. Novel IL-in-IL Pickering emulsions exhibited an array of self-assembled morphologies including the previously observed particle absorption and bridging phenomena. The appearance of these morphologies depended on the particle surface chemistry as well as the ILs used. The incorporation of particle self-assembly with ionic liquid science allows for new applications at the intersection of these two fields, and have the potential to be numerous due to the tunability of the ionic liquids and particles incorporated, as well as the particle morphology by combining certain groups of particle surface chemistry, IL type (protic or aprotic), and whether oil or water is incorporated. © 2013.

Analysis of emulsion stability in acrylic dispersions

NASA Astrophysics Data System (ADS)

Ahuja, Suresh

2012-02-01

Emulsions either micro or nano permit transport or solubilization of hydrophobic substances within a water-based phase. Different methods have been introduced at laboratory and industrial scales: mechanical stirring, high-pressure homogenization, or ultrasonics. In digital imaging, toners may be formed by aggregating a colorant with a latex polymer formed by batch or semi-continuous emulsion polymerization. Latex emulsions are prepared by making a monomer emulsion with monomer like Beta-carboxy ethyl acrylate (β-CEA) and stirring at high speed with an anionic surfactant like branched sodium dodecyl benzene sulfonates , aqueous solution until an emulsion is formed. Initiator for emulsion polymerization is 2-2'- azobis isobutyramide dehydrate with chain transfer agent are used to make the latex. If the latex emulsion is unstable, the resulting latexes produce a toner with larger particle size, broader particle size distribution with relatively higher latex sedimentation, and broader molecular weight distribution. Oswald ripening and coalescence cause droplet size to increase and can result in destabilization of emulsions. Shear thinning and elasticity of emulsions are applied to determine emulsion stability.

Experimental and modeling studies showing the effect of lipid type and level on flavor release from milk-based liquid emulsions.

PubMed

Roberts, Deborah D; Pollien, Philippe; Watzke, Brigitte

2003-01-01

The purpose of this work was to study two key parameters of the lipid phase that influence flavor release-lipid level and lipid type-and to relate the results to a mass balance partition coefficient-based mathematical model. Release of 10 volatile compounds from milk-based emulsions at 10, 25, and 50 degrees C was monitored by 1-min headspace sampling with a solid-phase microextraction fiber, followed by GC-MS analysis. As compared to the observations for milk fat, changing to a lipophilic lipid (medium-chain triglycerides, MCT) and adding a monoglyceride-based surfactant did not influence the volatiles release. However, increasing the solid fat content was found to increase the release. At 25 degrees C, and even more so at 10 degrees C, concurrent with an increase in their solid fat content, hydrogenated palm fat emulsions showed increased flavor release over that observed for emulsions made with coconut oil, coconut oil with surfactant, milk fat, and MCT. However, at 50 degrees C, when hydrogenated palm fat emulsions had zero solid fat content, there was no difference in flavor release from that observed for milk fat emulsions. Varying milk fat at nine levels between 0 and 4.5% showed a systematic dependence of the release on the lipid level, dependent on compound lipophilicity. Close correlations were found between the experimental and model predictions with lipid level and percent liquid lipid as variables.

Tunable volatile release from organogel-emulsions based on the self-assembly of β-sitosterol and γ-oryzanol.

PubMed

Chen, Xiao-Wei; Chen, Ya-Jun; Wang, Jin-Mei; Guo, Jian; Yin, Shou-Wei; Yang, Xiao-Quan

2017-04-15

A current challenge in the area of food emulsion is the design of microstructure that provides controlled release of volatile compounds during storage and consumption. Here, a new strategy addressed this problem at the fundamental level by describing the design of organogel-based emulsion from the self-assembly of β-sitosterol and γ-oryzanol that are capable of tuning volatile release. The results showed that the release rate (v 0 ), maximum headspace concentrations (C max ) and partition coefficients (k a / e ) above structured emulsions were significantly lower than unstructured emulsions and controlled release doing undergo tunable though the self-assembled interface and core fine microstructure from internal phase under dynamic and static condition. This result provides an understanding of how emulsions can behave as delivery system to better design novel food products with enhanced sensorial and nutritional attributes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on preparation and formation mechanism of n-alkanol/water emulsion using alpha-cyclodextrin.

PubMed

Hashizaki, Kaname; Kageyama, Takashi; Inoue, Motoki; Taguchi, Hiroyuki; Ueda, Haruhisa; Saito, Yoshihiro

2007-11-01

Surfactants are usually used for the preparation of emulsions; however, some have an adverse effect on the human body such as skin irritation, hemolysis, and protein denaturation, etc. In this study, we examined the preparation and formation mechanism of n-alkanol/water emulsions using alpha-cyclodextrin (alpha-CD) as an emulsifier. Emulsions were prepared by mixing oil and water phases for 4 min at 2500 rpm using a vortex mixer. The mechanism of emulsification was investigated with some physico-chemical techniques. From phase diagrams of n-alkanol/alpha-CD/water systems, the emulsion phase extended as the chain length of n-alkanols and the amount of alpha-CD added increased. Furthermore, the emulsion was not formed in the region where the n-alkanol/alpha-CD complex didn't precipitate; however, the emulsion was formed in the region where the complex precipitated. In addition, it was clear that the emulsions have a yield stress value and correspond to the Maxwell model from rheological measurement. Our experiments clearly showed that the stable emulsions are formed because the precipitated complexes form a dense film at the oil-water interface and prevent aggregation among dispersed phases. Furthermore, it is suggested that the creation of a three-dimensional network structure formed by precipitated complexes in the continuous phase contributes to the stabilization of the emulsion. Thus, we concluded that the n-alkanol/water emulsions using alpha-cyclodextrin were a kind of the Pickering emulsion.

Direct technique for monitoring lipid oxidation in water-in-oil emulsions based on micro-calorimetry.

PubMed

Dridi, Wafa; Toutain, Jean; Sommier, Alain; Essafi, Wafa; Leal-Calderon, Fernando; Cansell, Maud

2017-09-01

An experimental device based on the measurement of the heat flux dissipated during chemical reactions, previously validated for monitoring lipid oxidation in plant oils, was extended to follow lipid oxidation in water-in-oil emulsions. Firstly, validation of the approach was performed by correlating conjugated diene concentrations measured by spectrophotometry and the heat flux dissipated by oxidation reactions and measured directly in water-in-oil emulsions, in isothermal conditions at 60°C. Secondly, several emulsions based on plant oils differing in their n-3 fatty acid content were compared. The oxidability parameter derived from the enthalpy curves reflected the α-linolenic acid proportion in the oils. On the whole, the micro-calorimetry technique provides a sensitive method to assess lipid oxidation in water-in-oil emulsions without requiring any phase extraction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-body coalescence in Pickering emulsions

NASA Astrophysics Data System (ADS)

Wu, Tong; Wang, Haitao; Jing, Benxin; Liu, Fang; Burns, Peter C.; Na, Chongzheng

2015-01-01

Particle-stabilized Pickering emulsions have shown unusual behaviours such as the formation of non-spherical droplets and the sudden halt of coalescence between individual droplets. Here we report another unusual behaviour of Pickering emulsions—the simultaneous coalescence of multiple droplets in a single event. Using latex particles, silica particles and carbon nanotubes as model stabilizers, we show that multi-body coalescence can occur in both water-in-oil and oil-in-water emulsions. The number of droplets involved in the nth coalscence event equals four times the corresponding number of the tetrahedral sequence in close packing. Furthermore, coalescence is promoted by repulsive latex and silica particles but inhibited by attractive carbon nanotubes. The revelation of multi-body coalescence is expected to help better understand Pickering emulsions in natural systems and improve their designs in engineering applications.

Preparation of stable food-grade double emulsions with a hybrid premix membrane emulsification system.

PubMed

Eisinaite, Viktorija; Juraite, Dovile; Schroën, Karin; Leskauskaite, Daiva

2016-09-01

In this study we demonstrate that food-grade double emulsions can be successfully prepared using a hybrid premix emulsification system. A coarse emulsion containing beetroot juice as inner water phase, sunflower oil as oil phase and 0.5% or 1.0% whey protein isolate solution as outer water phase was prepared using a rotor stator system. This emulsion was further refined, using a bed of glass beads (diameter 71μm), through which the emulsion was pushed at different applied pressure (200-500kPa) and number of passes (1-5). All applied pressures lead to much smaller droplets while the juice remained encapsulated (>98%). The viscosity of the emulsions increased due to swelling of the internal water phase, and this implies that it is possible to encapsulate the components efficiently at relatively low internal water phase fraction at which the emulsions can be handled easily, while allowing them to obtain their final viscosity later. Copyright © 2016 Elsevier Ltd. All rights reserved.

Factors influencing the stability and type of hydroxyapatite stabilized Pickering emulsion.

PubMed

Zhang, Ming; Wang, Ai-Juan; Li, Jun-Ming; Song, Na; Song, Yang; He, Rui

2017-01-01

Hydroxyapatite (HAp) nanoparticle stabilized Pickering emulsion was fabricated with poly(l-lactic acid) dissolved in dichloromethane (CH 2 Cl 2 ) solution as oil phase and HAp aqueous dispersion as aqueous phase. Pickering emulsion was cured via in situ solvent evaporation method. Effect of PLLA concentrations, pH value, HAp concentrations, oil-water ratio, emulsification rates and times were studied on emulsion stability and emulsion type, etc. The results indicated emulsion stability increased with the increase of HAp concentration, emulsification rate and time; it is very stable when pH value of aqueous phase was adjusted to 10. Stable W/O and O/W emulsions were fabricated successfully using as-received HAp particles as stabilizer by adjusting the fabricating parameters. The interaction between HAp and PLLA played an important role to stabilize Pickering emulsions. SEM results indicated that both microsphere and porous materials were fabricated using emulsion stabilized by unmodified HAp nanoparticles, implying that both W/O and O/W emulsion type were obtained. Copyright © 2016 Elsevier B.V. All rights reserved.

Food emulsions as delivery systems for flavor compounds: A review.

PubMed

Mao, Like; Roos, Yrjö H; Biliaderis, Costas G; Miao, Song

2017-10-13

Food flavor is an important attribute of quality food, and it largely determines consumer food preference. Many food products exist as emulsions or experience emulsification during processing, and therefore, a good understanding of flavor release from emulsions is essential to design food with desirable flavor characteristics. Emulsions are biphasic systems, where flavor compounds are partitioning into different phases, and the releases can be modulated through different ways. Emulsion ingredients, such as oils, emulsifiers, thickening agents, can interact with flavor compounds, thus modifying the thermodynamic behavior of flavor compounds. Emulsion structures, including droplet size and size distribution, viscosity, interface thickness, etc., can influence flavor component partition and their diffusion in the emulsions, resulting in different release kinetics. When emulsions are consumed in the mouth, both emulsion ingredients and structures undergo significant changes, resulting in different flavor perception. Special design of emulsion structures in the water phase, oil phase, and interface provides emulsions with great potential as delivery systems to control flavor release in wider applications. This review provides an overview of the current understanding of flavor release from emulsions, and how emulsions can behave as delivery systems for flavor compounds to better design novel food products with enhanced sensorial and nutritional attributes.

Instant polysaccharide-based emulsions: impact of microstructure on lipolysis.

PubMed

Torcello-Gómez, Amelia; Foster, Timothy J

2017-06-21

The development of emulsion-based products through optimisation of ingredients, reduction in energy-input during manufacture, while fulfilling healthy attributes, are major objectives within the food industry. Instant emulsions can meet these features, but comprehensive studies are necessary to investigate the effect of the initial formulation on the final microstructure and, in turn, on the in vitro lipolysis, comprising the double aim of this work. The instant emulsion is formed within 1.5-3 min after pouring the aqueous phase into the oil phase which contains a mixture of emulsifier (Tween 20), swelling particles (Sephadex) and thickeners (hydroxypropylmethylcellulose, HPMC, and guar gum, GG) under mild shearing (180 rpm). The creation of oil-in-water emulsions is monitored in situ by viscosity analysis, the final microstructure visualised by microscopy and the release of free fatty acids under simulated intestinal conditions quantified by titration. Increasing the concentration and molecular weight (M w ) of GG leads to smaller emulsion droplets due to increased bulk viscosity upon shearing. This droplet size reduction is magnified when increasing the M w of HPMC or swelling capacity of viscosifying particles. In addition, in the absence of the emulsifier Tween 20, the sole use of high-Mw HPMC is effective in emulsification due to combined increased bulk viscosity and interfacial activity. Hence, optimisation of the ingredient choice and usage level is possible when designing microstructures. Finally, emulsions with larger droplet size (>20 μm) display a slower rate and lower extent of lipolysis, while finer emulsions (droplet size ≤20 μm) exhibit maximum rate and extent profiles. This correlates with the extent of emulsion destabilisation observed under intestinal conditions.

Simple and inexpensive microfluidic devices for the generation of monodisperse multiple emulsions

NASA Astrophysics Data System (ADS)

Li, Er Qiang; Zhang, Jia Ming; Thoroddsen, Sigurdur T.

2014-01-01

Droplet-based microfluidic devices have become a preferred versatile platform for various fields in physics, chemistry and biology. Polydimethylsiloxane soft lithography, the mainstay for fabricating microfluidic devices, usually requires the usage of expensive apparatus and a complex manufacturing procedure. Here, we report the design and fabrication of simple and inexpensive microfluidic devices based on microscope glass slides and pulled glass capillaries, for generating monodisperse multiple emulsions. The advantages of our method lie in a simple manufacturing procedure, inexpensive processing equipment and flexibility in the surface modification of the designed microfluidic devices. Different types of devices have been designed and tested and the experimental results demonstrated their robustness for preparing monodisperse single, double, triple and multi-component emulsions.

Physical and material properties of an emulsion-based lipstick produced via a continuous process.

PubMed

Beri, A; Pichot, R; Norton, I T

2014-04-01

Water-in-oil emulsions in lipsticks could have the potential to improve moisturizing properties and deliver hydrophilic molecules to the lips. The aim of this work was to investigate the effect of a continuous process (scraped surface heat exchanger (SSHE) and pin stirrer (PS)) on the physical and material properties of an emulsion-based lipstick by altering the processing conditions of both the SSHE and PS. Emulsion formation was achieved using a SSHE and PS. Emulsions were analysed using nuclear magnetic resonance restricted diffusion (droplet size), texture analysis and rheology (mechanical properties). Results showed that a higher impeller rotational velocity (IRV) (1500 r.p.m.) and a lower exit temperature (52°C) produce the smallest droplets (~ 4 μm), due to greater disruptive forces and a higher viscosity of the continuous phase. The addition of a PS reduces the droplet size (14-6 μm) if the SSHE has a low IRV (500 r.p.m.), due to greater droplet disruption as the emulsion passes through the PS unit. Results also show that if the jacket temperature of a SSHE is 65°C, so that crystallization occurs in both process and post-production, droplets can be integrated into the network resulting in a stiffer wax network (G' - 0.12, in comparison to 0.02 MPa). This is due to small crystals creating a shell around water droplets which can form connections with the continuous network forming a structured network. The addition of a pin stirrer can disrupt a formed network reducing the stiffness of the emulsion (0.3-0.05 MPa). This work suggests the potential use of a continuous process in producing an emulsion-based lipstick, particularly when wax crystals are produced in the process. Future work should consider the moisturizing or lubricating properties of wax continuous emulsions and the release of hydrophilic compounds from the aqueous phase.

Cold in-place recycling using solventless emulsion - phase IV (emulsion qualification and long-term field performance).

DOT National Transportation Integrated Search

2016-05-01

This report looks into how a successful Cold In-Place solventless emulsion behaves and how the emulsion : break test developed in Phase III of this project demonstrates that behavior. Modifications to the test have been : made to improve the consiste...

Process for removing sulfate anions from waste water

DOEpatents

Nilsen, David N.; Galvan, Gloria J.; Hundley, Gary L.; Wright, John B.

1997-01-01

A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

Organic Thin Films Deposited by Emulsion-Based, Resonant Infrared, Matrix-Assisted Pulsed Laser Evaporation: Fundamentals and Applications

NASA Astrophysics Data System (ADS)

Ge, Wangyao

Thin film deposition techniques are indispensable to the development of modern technologies as thin film based optical coatings, optoelectronic devices, sensors, and biological implants are the building blocks of many complicated technologies, and their performance heavily depends on the applied deposition technique. Particularly, the emergence of novel solution-processed materials, such as soft organic molecules, inorganic compounds and colloidal nanoparticles, facilitates the development of flexible and printed electronics that are inexpensive, light weight, green and smart, and these thin film devices represent future trends for new technologies. One appealing feature of solution-processed materials is that they can be deposited into thin films using solution-processed deposition techniques that are straightforward, inexpensive, high throughput and advantageous to industrialize thin film based devices. However, solution-processed techniques rely on wet deposition, which has limitations in certain applications, such as multi-layered film deposition of similar materials and blended film deposition of dissimilar materials. These limitations cannot be addressed by traditional, vacuum-based deposition techniques because these dry approaches are often too energetic and can degrade soft materials, such as polymers, such that the performance of resulting thin film based devices is compromised. The work presented in this dissertation explores a novel thin film deposition technique, namely emulsion-based, resonant infrared, matrix-assisted pulsed laser evaporation (RIR-MAPLE), which combines characteristics of wet and dry deposition techniques for solution-processed materials. Previous studies have demonstrated the feasibility of emulsion-based RIR-MAPLE to deposit uniform and continuous organic, nanoparticle and blended films, as well as hetero-structures that otherwise are difficult to achieve. However, fundamental understanding of the growth mechanisms that govern emulsion-based RIR-MAPLE is still missing, which increases the difficulty of using rational design to improve the performance of initial RIR-MAPLE devices that have been demonstrated. As a result, it is important to study the fundamentals of emulsion-based RIR-MAPLE in order to provide insight into the long-term prospects for this thin film deposition technique. This dissertation explores the fundamental deposition mechanisms of emulsion-based RIR-MAPLE by considering the effects of the emulsion target composition (namely, the primary solvent, secondary solvent, and surfactant) on the properties of deposited polymer films. The study of primary solvent effects on hydrophobic polymer deposition helps identify the unique method of film formation for emulsion-based RIR-MAPLE, which can be described as cluster-by-cluster deposition of emulsified particles that yields two levels of ordering (i.e., within the clusters and among the clusters). The generality of this film formation mechanism is tested by applying the lessons learned to hydrophilic polymer deposition. Based on these studies, the deposition design rules to achieve smooth polymer films, which are important for different device applications, are identified according to the properties of the polymer. After discussion of the fundamental deposition mechanisms, three applications of emulsion-based RIR-MAPLE, namely thin film deposition of organic solar cells, polymer/nanoparticle hybrid solar cells, and antimicrobial/fouling-release multifunctional films, are studied. The work on organic solar cells identifies the ideal deposition mode for blended films with nanoscale domain sizes, as well as demonstrates the relationships among emulsion target composition, film properties, and corresponding device performance. The studies of polymer/nanoparticle hybrid solar cells demonstrate precise control of colloidal nanoparticle deposition, in which the integrity of nanoparticles is maintained and a distinct film morphology is achieved when co-deposited with polymers. Finally, the application of antimicrobial and fouling-release multifunctional films demonstrates the importance of blended film deposition with nanoscale phase separation, a key feature to achieving reusable bio-films that can kill bacteria when illuminated with ultraviolet light. Thus, this dissertation provides great insight to the fundamentals of emulsion-based RIR-MAPLE, serves as a valuable reference for future development, and paves the pathway for wider adoption of this unique thin film deposition technique, especially for organic solar cells.

Critical frequency for coalescence of emulsions in an AC electric field

NASA Astrophysics Data System (ADS)

Liu, Zhou; Ali, Faizi Hammad; Shum, Ho Cheung

2017-11-01

Applying an electric field to trigger the coalescence of emulsions has been applied in various applications which include crude oil recovery, emulsion stability characterization as well as pico-injection and droplet-based chemical reaction in microfluidics. In this work, we systematically investigated the responses of surfactant-stabilized emulsions to a controlled AC electric field using a customer-built chip. At a given amplitude of the AC voltage, we found a critical frequency beyond which the emulsions remain stable. When the frequency is decreased to below the critical value, emulsions coalesce immediately. Such critical frequency is found to be dependent of amplitude of the AC voltage, viscosity of the fluids, concentration and type of the surfactant as well as the electric conductivity of the droplet phase. Using a model based on the drainage of thin film, we have explored the mechanism behind and interpret this phenomenon systematically. Our work extends the understanding of the electro-coalescence of emulsions and can be beneficial for any applications involve the coalescence of droplets in an AC electric field.

Hydrophobin-nanofibrillated cellulose stabilized emulsions for encapsulation and release of BCS class II drugs.

PubMed

Paukkonen, Heli; Ukkonen, Anni; Szilvay, Geza; Yliperttula, Marjo; Laaksonen, Timo

2017-03-30

The purpose of this study was to construct biopolymer-based oil-in-water emulsion formulations for encapsulation and release of poorly water soluble model compounds naproxen and ibuprofen. Class II hydrophobin protein HFBII from Trichoderma reesei was used as a surfactant to stabilize the oil/water interfaces of the emulsion droplets in the continuous aqueous phase. Nanofibrillated cellulose (NFC) was used as a viscosity modifier to further stabilize the emulsions and encapsulate protein coated oil droplets in NFC fiber network. The potential of both native and oxidized NFC were studied for this purpose. Various emulsion formulations were prepared and the abilities of different formulations to control the drug release rate of naproxen and ibuprofen, used as model compounds, were evaluated. The optimal formulation for sustained drug release consisted of 0.01% of drug, 0.1% HFBII, 0.15% oxidized NFC, 10% soybean oil and 90% water phase. By comparison, the use of native NFC in combination with HFBII resulted in an immediate drug release for both of the compounds. The results indicate that these NFC originated biopolymers are suitable for pharmaceutical emulsion formulations. The native and oxidized NFC grades can be used as emulsion stabilizers in sustained and immediate drug release applications. Furthermore, stabilization of the emulsions was achieved with low concentrations of both HFBII and NFC, which may be an advantage when compared to surfactant concentrations of conventional excipients traditionally used in pharmaceutical emulsion formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Micro-explosion of compound drops

NASA Astrophysics Data System (ADS)

Chen, Chun-Kuei; Lin, Ta-Hui

2014-08-01

Introducing water into spray combustion systems, by either water-in-oil emulsification or supplementary water injection, is one of the major techniques for combustion improvement and NOx reduction. Plentiful researches are available on combustion of water-in-oil emulsion fuel drops. The emulsified liquid is a heterogeneous mixture of immiscible liquids. One component forms the continuous phase and the other component forms the discrete phase. The discrete phase consists of globules of the one fluid that are suspended in the continuous phase fluid. Water-in-oil emulsions are commonly considered for combustion applications because emulsions can result in micro-explosion, thereby reducing the average drop diameter to enhance liquid vaporization, and suppressing the formation of soot and NOx. However, the water addition generally does not exceed about 20% for smooth engine operations[!, 21. The combustion characteristics and micro-explosion of emulsion drop were studied by many researchers. The micro-explosion of water in fuel emulsion drops was caused by very fast growth of superheated water vapor bubbles, its superheat limits must be lower than the boiling point temperature of the fuel. These bubbles were primarily governed by the pressure difference between the superheated vapor and the liquid, and by the inertia imparted to the liquid by the motion of the bubble surface[3 6 In this study, we used a coaxial nozzle to generation the multi-component drop. The different type of water-in-oil fuel drops called the compound drops. Unlike an emulsion drop, a compound drop consists of a water core and a fuel shell, which can originate from the phase separation of emulsion[7, 81 or a water drop colliding with a fuel drop[9, 101 Burning and micro-explosion of compound drops have been found to be distinct from those of emulsion drops[9-111 Wang et al.[9 , 101 studied the combustion characteristics of collision merged alkane-water drops. The merged drops appeared in adhesive and inserted manners. The drop ignition delay time increased with increasing water content. The average burning rate of alkane-water drops decreased with increasing water content. In the burning process, hexadecane-water drops exhibited flash vaporization or flame extinction. Heterogeneous explosion was occasionally observed in drops with trapped air bubbles. The air bubbles were assumed to be the nucleation points of the heterogeneous explosions. Chen and Lin[11 studied the characteristics of water-in-dodecane compound drop with different water content, diameter of drop and environmental oxygen concentration. The vaporization rate increased with increasing environmental oxygen concentration. The compound drops micro-exploded during the burning process in a random way. The number of micro-explosions was majorly influenced by drop diameter, followed by environmental oxygen concentration. Water content had a weaker effect on micro-explosion. As available literature and research results of compound drop burning are scarce, their combustion and micro-explosion behaviors are still poorly understood. In this regard, we changed the drop nature as compound drops to study their combustion characteristics and micro-explosion phenomena.

Formulation and evaluation of carrot seed oil-based cosmetic emulsions.

PubMed

Singh, Shalini; Lohani, Alka; Mishra, Arun Kumar; Verma, Anurag

2018-05-08

The present study deals with the evaluation of antiaging potential of carrot seed oil-based cosmetic emulsions. Briefly, cosmetic emulsions composed of carrot seed oil in varying proportions (2, 4, and 6% w/v) were prepared using the hydrophile-lipophile balance (HLB) technique. Coconut oil, nonionic surfactants (Tween 80 and Span 80), and xanthan gum were used as the oil phase, emulgent, and emulsion stabilizer, respectively. The formed emulsions were evaluated for various physical, chemical, and biochemical parameters such as the zeta potential, globule size measurement, antioxidant activity, sun protection factor (SPF), skin irritation, and biochemical studies. The zeta potential values ranged from -43.2 to -48.3, indicating good stability. The polydispersity index (PDI) of various emulsion formulations ranged from 0.353 to 0.816. 1,1-Diphenyl-2-picrylhydrazyl- (DPPH) and nitric oxide-free radical scavenging activity showed the antioxidant potential of the prepared carrot seed oil emulsions. The highest SPF value (6.92) was shown by F3 having 6%w/v carrot seed oil. Histopathological data and biochemical analysis (ascorbic acid (ASC) and total protein content) suggest that these cosmetic emulsions have sufficient potential to be used as potential skin rejuvenating preparations.

Evolution of volume fractions and droplet sizes by analysis of electrical conductance curves during destabilization of oil-in-water emulsions.

PubMed

Kostoglou, M; Varka, E-M; Kalogianni, E P; Karapantsios, T D

2010-09-01

Destabilization of hexane-in-water emulsions is studied by a continuous, non-intrusive, multi-probe, electrical conductance technique. Emulsions made of different oil fractions and surfactant (C(10)E(5)) concentrations are prepared in a stirred vessel using a Rushton turbine to break and agitate droplets. During the separation of phases, electrical signals from pairs of ring electrodes mounted at different heights onto the vessel wall, are recorded. The evolution of the local water volume fractions at the locations of the electrodes is estimated from these signals. It is found that in the absence of coalescence, the water fraction evolution curve from the bottom pair of electrodes is compatible with a bidisperse oil droplet size distribution. The sizes and volume fractions of the two droplet modes are estimated using theoretical arguments. The electrically determined droplet sizes are compared to data from microscopy image analysis. Results are discussed in detail. Copyright 2010 Elsevier Inc. All rights reserved.

Pickering emulsions stabilized by a metal-organic framework (MOF) and graphene oxide (GO) for producing MOF/GO composites.

PubMed

Zhang, Fanyu; Liu, Lifei; Tan, Xiuniang; Sang, Xinxin; Zhang, Jianling; Liu, Chengcheng; Zhang, Bingxing; Han, Buxing; Yang, Guanying

2017-10-18

Herein we demonstrate the formation of a novel kind of Pickering emulsion that is stabilized by a Zr-based metal-organic framework (Zr-MOF) and graphene oxide (GO). It was found that the Zr-BDC-NO 2 and GO solids assembling at the oil/water interface can effectively stabilize the oil droplets that are dispersed in the water phase. Such a Pickering emulsion offers a facile route for fabricating Zr-MOF/GO composite materials. After removing water and oil by freeze drying from Pickering emulsions, the Zr-MOF/GO composites were obtained and their morphologies, structures and interaction properties were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectrometry, respectively. The influences of the concentration of GO and Zr-MOF on the emulsion microstructures and the properties of the MOF/GO composites were studied. Based on experimental results, the mechanisms for the emulsion formation by Zr-MOF and GO and the as-synthesized superstructures of the Zr-MOF/GO composite were proposed. It is expected that this facile and tunable route can be applied to the synthesis of different kinds of MOF-based or GO-based composite materials.

Studies on ocular and parenteral application potentials of azithromycin- loaded anionic, cationic and neutral-charged emulsions.

PubMed

Tamilvanan, Shunmugaperumal; Khanum, Ramona; Senthilkumar, Sudalimuthu Ramachandran; Muthuraman, Marimuthu; Rajasekharan, Thenrajan

2013-10-01

Ocular and parenteral application potentials of azithromycin-containing, non-phospholipid-based cationic nanosized emulsion in comparison to the phospholipid-based anionic and neutral-charged nanosized emulsions were investigated. Various physical, chemical, nonclinical toxicity and antimicrobial activity studies (mean droplet diameter, surface charge, creaming index, entrapment efficiency, accelerated, long-term and freeze-thaw cycling stabilities, TLC study, modified hen's egg chorioallantoic membrane (HET-CAM) test, in vitro hemolysis test, in vitro and in vivo myotoxicity, and in vitro antimicrobial activity) were conducted for assessing the potentials of these three types of emulsions. Following autoclave sterilization, all of these emulsions exhibited a nanometer range mean particle diameter (200 ± 29 to 434 ± 13 nm). While the anionic and cationic emulsions did show high negative (-34.2 ± 1.23 mV) and positive zeta potential (42.6 ± 1.45 mV) values, the neutral-charged emulsion did not. Even with 5 freeze-thaw cycles, the cationic emulsion remained stable whereas other two emulsions underwent phase-separation. The hen's egg chorioallantoic membrane test revealed an irritation score value that was higher for the anionic emulsion than for cationic or neutral-charged emulsion. A significantly higher % hemolysis value was also noticed for the anionic emulsion when compared to the % hemolysis value of cationic emulsion (ANOVA, P ‹ 0.05). However, all of the emulsions showed a lesser intracellular creatine kinase (CK) release/plasma CK level in comparison to the positive control (phenytoin) indicating their lesser myotoxicity at the injection site . When compared to anionic and neutral-charged emulsions, the possible controlled drug release from cationic emulsion delayed the in vitro antimicrobial action against H.influenzae and S.pneumoniae.

Effect of citronella essential oil fractions as oil phase on emulsion stability

NASA Astrophysics Data System (ADS)

Septiyanti, Melati; Meliana, Yenny; Agustian, Egi

2017-11-01

The emulsion system consists of water, oil and surfactant. In order to create stable emulsion system, the composition and formulation between water phase, surfactant and oil phase are very important. Essential oil such as citronella oil has been known as active ingredient which has ability as insect repellent. This research studied the effect of citronella oil and its fraction as oil phase on emulsion stability. The cycle stability test was conducted to check the emulsion stability and it was monitored by pH, density, viscosity, particle size, refractive index, zeta potential, physical appearance and FTIR for 4 weeks. Citronellal fraction has better stability compared to citronella oil and rhodinol fraction with slight change of physical and chemical properties before and after the cycle stability test. However, it is need further study to enhance the stability of the emulsion stability for this formulation.

Sensory and instrumental characterization of fast inverting oil-in-water emulsions for cosmetic application.

PubMed

Korać, R; Krajišnik, D; Milić, J

2016-06-01

The aim of this study was to perform short-term sensory testing and instrumental (conductivity and rheological) characterization of a fast inverted oil-in-water (o/w) emulsion base, also known as a SWOP (Switch-Oil-Phase) emulsion, and reference o/w and water-in-oil (w/o) emulsion bases under various testing conditions: in the presence of ions and at different temperatures. SWOP emulsions are known as metastable o/w emulsions, which invert into w/o emulsions on application of mechanical energy, while rubbing it onto the skin and due to their properties SWOP emulsion are especially suitable as a cosmetic vehicle in, for example, sun-protection products. Sensory testing, which included the evaluation of twenty attributes of the investigated emulsion bases, was performed by a panel of 20 healthy assessors experienced in the evaluation of cosmetic products. Rheological characterization of the investigated emulsion bases included continuous flow testing and oscillatory measurements under various testing conditions. Additionally, conductivity measurements were combined with rheological characterization to monitor stability changes of investigated emulsions. The instrumental and sensory results were analysed statistically and compared. The obtained results indicated that the investigated emulsions behaved differently in the presence of ions (originating from artificial sweat solution) and at different temperatures (under storage and application conditions). Namely, the SWOP emulsion showed similar behaviour to the reference o/w emulsion under storage conditions, but in the presence of ions and at skin temperature, the SWOP emulsion was followed by re-establishment of a stable w/o system, whereas reference o/w emulsion was irreversibly destroyed. The statistical analysis of chosen sensorial attributes indicated that the reference w/o emulsion was significantly different in comparison with the reference o/w and SWOP emulsions, mainly, standing in good agreement with the results of rheological characterization. The study showed that rheological measurements potentially could be related to certain sensory attributes and used for faster development of SWOP emulsions in the future. Finally, SWOP emulsions should be considered for further investigation as suitable vehicles in cosmetic products due to their favourable physicochemical and sensory characteristics which could be partially predicted with instrumental characterization. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Development of lamellar gel phase emulsion containing marigold oil (Calendula officinalis) as a potential modern wound dressing.

PubMed

Okuma, C H; Andrade, T A M; Caetano, G F; Finci, L I; Maciel, N R; Topan, J F; Cefali, L C; Polizello, A C M; Carlo, T; Rogerio, A P; Spadaro, A C C; Isaac, V L B; Frade, M A C; Rocha-Filho, P A

2015-04-25

Appropriate therapeutics for wound treatments can be achieved by studying the pathophysiology of tissue repair. Here we develop formulations of lamellar gel phase (LGP) emulsions containing marigold (Calendula officinalis) oil, evaluating their stability and activity on experimental wound healing in rats. LGP emulsions were developed and evaluated based on a phase ternary diagram to select the best LGP emulsion, having a good amount of anisotropic structure and stability. The selected LGP formulation was analyzed according to the intrinsic and accelerated physical stability at different temperatures. In addition, in vitro and in vivo studies were carried out on wound healing rats as a model. The LGP emulsion (15.0% marigold oil; 10.0% of blend surfactants and 75.0% of purified water [w/w/w]) demonstrated good stability and high viscosity, suggesting longer contact of the formulation with the wound. No cytotoxic activity (50-1000 μg/mL) was observed in marigold oil. In the wound healing rat model, the LGP (15 mg/mL) showed an increase in the leukocyte recruitment to the wound at least on days 2 and 7, but reduced leukocyte recruitment after 14 and 21 days, as compared to the control. Additionally, collagen production was reduced in the LGP emulsion on days 2 and 7 and further accelerated the process of re-epithelialization of the wound itself. The methodology utilized in the present study has produced a potentially useful formulation for a stable LGP emulsion-containing marigold, which was able to improve the wound healing process. Copyright © 2015 Elsevier B.V. All rights reserved.

Production of W/O/W (water-in-oil-in-water) multiple emulsions: droplet breakup and release of water.

PubMed

Schuch, Anna; Deiters, Philipp; Henne, Julius; Köhler, Karsten; Schuchmann, Heike P

2013-07-15

We investigate breakup of W/O/W double emulsion droplets at high viscosity ratios and coalescence of inner water droplets dependent on the dispersed phase content (DPC) of the inner emulsion. The rheological analyses of the inner emulsions confirm the behavior expected from literature - increasing viscosity with increasing DPC and elastic behavior for high DPC. The resulting droplet sizes seem to be influenced only by the viscosity ratio calculated using the viscosity of the inner emulsion. An influence of the elastic properties of the inner emulsions could not be observed. Moreover, breakup of double emulsion droplets seems to follow the same rules as breakup of Newtonian droplets. In the second part of the paper we focus on the release of water from double emulsions by coalescence. A direct correlation between resulting double emulsion droplet sizes and encapsulation efficiency was found for each system. The initial inner dispersed phase content has a big influence on the release rate. This can partly be explained by the influence of the dispersed phase content on collision rate. Moreover, it was found that for high internal phase concentrations inner droplets coalesce with each other. The so formed bigger inner droplets seem to increase the overall release rate. Copyright © 2013 Elsevier Inc. All rights reserved.

Nanoscale and Microscale Iron Emulsions for Treating DNAPL

NASA Technical Reports Server (NTRS)

Geiger, Cherie L.

2002-01-01

This study demonstrated the feasibility of using emulsified nanoscale and microscale iron particles to enhance dehalogenation of (Dense Non-Aqueous Phase Liquid) DNAPL free-phase. The emulsified system consisted of a surfactant-stabilized, biodegradable oil-in-water emulsion with nanoscale or microscale iron particles contained within the emulsion droplets. It was demonstrated that DNAPLs, such as trichloroethene (TCE), diffuse through the oil membrane of the emulsion particle whereupon they reach an aqueous interior and the surface of an iron particle where dehalogenation takes place. The hydrocarbon reaction by-products of the dehalogenation reaction, primarily ethene (no chlorinated products detected), diffuse out of the emulsion droplet. This study also demonstrated that an iron-emulsion system could be delivered in-situ to the DNAPL pool in a soil matrix by using a simulated push well technique. Iron emulsions degraded pure TCE at a rate comparable to the degradation of dissolved phase TCE by iron particles, while pure iron had a very low degradation rate for free-phase TCE. The iron-emulsion systems can be injected into a sand matrix where they become immobilized and are not moved by flowing water. It has been documented that surfactant micelles possess the ability to pull pooled TCE into emulsion droplets where degradation of TCE takes place.

The nature of the apolar phase influences the structure of the protein emulsifier in oil-in-water emulsions stabilized by bovine serum albumin. A front-surface fluorescence study.

PubMed

Rampon, Vincent; Brossard, Chantal; Mouhous-Riou, Nadine; Bousseau, Benoît; Llamas, Geneviève; Genot, Claude

2004-05-20

Proteins are widely used as emulsifiers in food emulsions. Model emulsions, designed to study emulsifying properties of proteins and their conformation at the interfaces often contain a hydrocarbon as apolar phase instead of natural triglycerides as found in food products. Yet, some results indicate that the protein conformation at the interface depends on the nature of the apolar phase. Front-surface fluorescence spectroscopy was used to evidence differences in the structure of bovine serum albumin (BSA) adsorbed at the interface of emulsions prepared with different apolar phases: an hydrocarbon (n-dodecane), a synthetic medium-chain triglyceride (miglyol) and a natural vegetable oil (sunflower oil). Emulsions had similar size distributions of oil droplets. Front-surface fluorescence emission spectra of tryptophanyl residues of the protein (Trp) in emulsions, creams and serums varied as a function of the nature of hydrophobic phase. In emulsions and creams, wavelength of the maximum fluorescence intensities was blue-shifted as compared to the BSA solution. The shift was larger in creams than in emulsions and in samples containing dodecane than with the other apolar phases. Fourth derivative spectra of emulsions and creams exhibited two peaks assigned, respectively, to Trp located in hydrophilic and hydrophobic environments. The peaks were slightly red-shifted in the presence of sunflower oil as compared to miglyol and dodecane and the relative intensity of the "hydrophobic peak" was higher in dodecane. The effects were greater in creams than in emulsions. Fluorescence intensity of Trp was the highest in the serums of emulsions prepared with dodecane as compared to serums issued from sunflower oil and miglyol emulsions. Thus, proportion of adsorbed protein was lower in dodecane emulsions than with the other apolar phases. These results evidence that the mean environment of Trp was more hydrophobic in emulsions and creams than in solutions due to a displacement of some of the Trp of the protein to a more hydrophobic environment. Dodecane had the greatest impact on Trp environment (more hydrophobic) followed by miglyol and then by sunflower oil. This is likely due to differences in the conformation of the protein at the hydrocarbon-water interface as compared to the triacylglycerol-water ones. In addition, sunflower oil provoked a large decrease of Trp fluorescence intensity in emulsions and creams as compared to miglyol or dodecane. This could be due to contaminant quenchers in the oil or to interactions of the unsaturated fatty chains with the protein inducing quenching of the Trp. These observations should be related to the physical properties of the apolar phase and its molecular organization and interactions with the protein at the interface.

The effects of biomacromolecules on the physical stability of W/O/W emulsions.

PubMed

Li, Jinlong; Zhu, Yunping; Teng, Chao; Xiong, Ke; Yang, Ran; Li, Xiuting

2017-02-01

The effect of bovine serum albumin (BSA), whey protein isolate (WPI), whey protein hydrolysate (WPH), sodium caseinate (SC), carboxymethylcellulose sodium (CMC), fish gelatin (FG), high methoxyl apple pectin (HMAP), low methoxyl apple pectin (LMAP), gum Arabic (GA), ι-carrageenan (CGN), and hydroxypropyl chitosan (HPCTS) on physical stability of internal or external aqueous phase of water-in-oil-in-water (W/O/W) emulsions was evaluated. WPI and CGN in the internal aqueous phase, and GA, HPCTS, and CMC in the external phase reduced the size of emulsion droplets. BSA, WPI, SC, FG, CGN, and HPCTS improved the dilution stability of W/O/W emulsions, but HMAP had a negative effect. BSA, WPI, SC, FG, LMAP, GA, CGN, HPCTS, or CMC significantly improved the thermal stability of W/O/W emulsions. Results also indicated that the addition of CGN (1.0%), HMAP (1.0%), WPH (1.0%), or HPCTS (1.0%) in internal aqueous phase significantly increased the viscosity of emulsions, however, addition to the external aqueous phase had insignificant effects. A protein-knockout experiment confirmed that proteins as biomacromolecules, were the key factor in improving physical stability of emulsions.

Adjuvanted multi-epitope vaccines protect HLA-A*1101 transgenic mice against Toxoplasma gondii

USDA-ARS?s Scientific Manuscript database

We created and tested multi-epitope DNA or protein vaccines with TLR4 ligand emulsion adjuvant (gluco glucopyranosyl lipid adjuvant in a stable emulsion (GLA-SE)) for their ability to protect against Toxoplasma gondii in HLA transgenic mice. Our constructs each included five of our best down selecte...

Physical and antimicrobial properties of thyme oil emulsions stabilized by ovalbumin and gum arabic.

PubMed

Niu, Fuge; Pan, Weichun; Su, Yujie; Yang, Yanjun

2016-12-01

Natural biopolymer stabilized oil-in-water emulsions were formulated using ovalbumin (OVA), gum arabic (GA) solutions and their complexes. The influence of interfacial structure of emulsion (OVA-GA bilayer and OVA/GA complexes emulsions) on the physical properties and antimicrobial activity of thyme oil (TO) emulsion against Escherichia coli (E. coli) was evaluated. The results revealed that the two types of emulsions with different oil phase compositions remained stable during a long storage period. The oil phase composition had an appreciable influence on the mean particle diameter and retention of the TO emulsions. The stable emulsion showed a higher minimum inhibitory concentration (MIC), and the TO emulsions showed an improved long-term antimicrobial activity compared to the pure thyme oil, especially complexes emulsion at pH 4.0. These results provided useful information for developing protection and delivery systems for essential oil using biopolymer. Copyright © 2016 Elsevier Ltd. All rights reserved.

A dual-core double emulsion platform for osmolarity-controlled microreactor triggered by coalescence of encapsulated droplets.

PubMed

Guan, Xuewei; Hou, Likai; Ren, Yukun; Deng, Xiaokang; Lang, Qi; Jia, Yankai; Hu, Qingming; Tao, Ye; Liu, Jiangwei; Jiang, Hongyuan

2016-05-01

Droplet-based microfluidics has provided a means to generate multi-core double emulsions, which are versatile platforms for microreactors in materials science, synthetic biology, and chemical engineering. To provide new opportunities for double emulsion platforms, here, we report a glass capillary microfluidic approach to first fabricate osmolarity-responsive Water-in-Oil-in-Water (W/O/W) double emulsion containing two different inner droplets/cores and to then trigger the coalescence between the encapsulated droplets precisely. To achieve this, we independently control the swelling speed and size of each droplet in the dual-core double emulsion by controlling the osmotic pressure between the inner droplets and the collection solutions. When the inner two droplets in one W/O/W double emulsion swell to the same size and reach the instability of the oil film interface between the inner droplets, core-coalescence happens and this coalescence process can be controlled precisely. This microfluidic methodology enables the generation of highly monodisperse dual-core double emulsions and the osmolarity-controlled swelling behavior provides new stimuli to trigger the coalescence between the encapsulated droplets. Such swelling-caused core-coalescence behavior in dual-core double emulsion establishes a novel microreactor for nanoliter-scale reactions, which can protect reaction materials and products from being contaminated or released.

A dual-core double emulsion platform for osmolarity-controlled microreactor triggered by coalescence of encapsulated droplets

PubMed Central

Guan, Xuewei; Hou, Likai; Ren, Yukun; Deng, Xiaokang; Lang, Qi; Jia, Yankai; Hu, Qingming; Tao, Ye; Liu, Jiangwei; Jiang, Hongyuan

2016-01-01

Droplet-based microfluidics has provided a means to generate multi-core double emulsions, which are versatile platforms for microreactors in materials science, synthetic biology, and chemical engineering. To provide new opportunities for double emulsion platforms, here, we report a glass capillary microfluidic approach to first fabricate osmolarity-responsive Water-in-Oil-in-Water (W/O/W) double emulsion containing two different inner droplets/cores and to then trigger the coalescence between the encapsulated droplets precisely. To achieve this, we independently control the swelling speed and size of each droplet in the dual-core double emulsion by controlling the osmotic pressure between the inner droplets and the collection solutions. When the inner two droplets in one W/O/W double emulsion swell to the same size and reach the instability of the oil film interface between the inner droplets, core-coalescence happens and this coalescence process can be controlled precisely. This microfluidic methodology enables the generation of highly monodisperse dual-core double emulsions and the osmolarity-controlled swelling behavior provides new stimuli to trigger the coalescence between the encapsulated droplets. Such swelling-caused core-coalescence behavior in dual-core double emulsion establishes a novel microreactor for nanoliter-scale reactions, which can protect reaction materials and products from being contaminated or released. PMID:27279935

Fat emulsions based on structured lipids (1,3-specific triglycerides): an investigation of the in vivo fate.

PubMed

Hedeman, H; Brøndsted, H; Müllertz, A; Frokjaer, S

1996-05-01

Structured lipids (1,3-specific triglycerides) are new chemical entities made by enzymatic transesterification of the fatty acids in the 1,3 positions of the triglyceride. The purpose of this study is to characterize structured lipids with either short chain fatty acids or medium chain fatty acids in the 1,3 positions with regard to their hydrophobicity, and investigate the in vivo fate in order to evaluate the potential of structured lipids as core material in fat emulsions used as parenteral drug delivery system. The lipids were characterized by employing reversed phase high performance liquid chromatography. The biodistribution of radioactively labeled emulsions was studied in rats. By employing high performance liquid chromatography a rank order of the hydrophobicities of the lipids could be given, with the triglycerides containing long chain fatty acids being the most hydrophobic and the structured lipid with short chain fatty acids in the 1,3 positions the least. When formulated as fat emulsions, the emulsion based on structured lipids with short fatty acids in the 1,3 positions was removed slower from the general blood circulation compared to emulsions based on lipids with long chain fatty acids in the 1,3 positions. The type of core material influences the in vivo circulation time of fat emulsions.

A low-cost mullite-titania composite ceramic hollow fiber microfiltration membrane for highly efficient separation of oil-in-water emulsion.

PubMed

Zhu, Li; Chen, Mingliang; Dong, Yingchao; Tang, Chuyang Y; Huang, Aisheng; Li, Lingling

2016-03-01

Oil-in-water (O/W) emulsion is considered to be difficult to treat. In this work, a low-cost multi-layer-structured mullite-titania composite ceramic hollow fiber microfiltration membrane was fabricated and utilized to efficiently remove fine oil droplets from (O/W) emulsion. In order to reduce membrane cost, coal fly ash was effectively recycled for the first time to fabricate mullite hollow fiber with finger-like and sponge-like structures, on which a much more hydrophilic TiO2 layer was further deposited. The morphology, crystalline phase, mechanical and surface properties were characterized in details. The filtration capability of the final composite membrane was assessed by the separation of a 200 mg·L(-1) synthetic (O/W) emulsion. Even with this microfiltration membrane, a TOC removal efficiency of 97% was achieved. Dilute NaOH solution backwashing was used to effectively accomplish membrane regeneration (∼96% flux recovery efficiency). This study is expected to guide an effective way to recycle waste coal fly ash not only to solve its environmental problems but also to produce a high-valued mullite hollow fiber membrane for highly efficient separation application of O/W emulsion with potential simultaneous functions of pure water production and oil resource recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-interactive Chemicals Contained in Boundary Layer-targeted Emulsions

NASA Technical Reports Server (NTRS)

Richmond, Robert Chafee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor)

2013-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Harry F., Jr. (Inventor)

2016-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Fouling reduction by ozone-enhanced backwashing process in ultrafiltration of petroleum-based oil in water emulsion

NASA Astrophysics Data System (ADS)

Aryanti, Nita; Prihatiningtyas, Indah; Kusworo, Tutuk Djoko

2017-06-01

Ultrafiltration membrane has been successfully applied for oily waste water treatment. However, one significant drawback of membrane technology is fouling which is responsible for permeate flux decline as well as reducing membrane performance. One method commonly used to reduce fouling is a backwashing process. The backwashing is carried out by a push of reversed flow from permeate side to the feed side of a membrane to remove fouling on the membrane pore and release fouling release fouling layer on the external side. However, for adsorptive fouling, the backwashing process was not effective. On the other hand, Ozone demonstrated great performance for reducing organics fouling. Hence this research was focused on backwashing process with ozone for removing fouling due to ultrafiltration of petroleum based oil emulsion. Gasoline and diesel oil were selected as dispersed phase, while as continuous phase was water added with Tween 80 as a surfactant. This research found that the Ozone backwashing was effective to improve flux recovery. In ultrafiltration of gasoline emulsion, the flux recovery after Ozone backwashing was in the range of 42-74%. For ultrafiltration of diesel oil emulsion, the permeate flux recovery was about 35-84%. In addition, foulant deposition was proposed and predicting that foulant deposition for ultrafiltration of gasoline-in-water emulsion was surfactant as the top layer and the oil was underneath the surfactant. On the other hand, for ultrafiltration of diesel oil-in-water emulsion, the oil was predicted as a top layer above the surfactant foulant.

Pickering Particles Prepared from Food Waste

PubMed Central

Gould, Joanne; Garcia-Garcia, Guillermo; Wolf, Bettina

2016-01-01

In this paper, we demonstrate the functionality and functionalisation of waste particles as an emulsifier for oil-in-water (o/w) and water-in-oil (w/o) emulsions. Ground coffee waste was chosen as a candidate waste material due to its naturally high content of lignin, a chemical component imparting emulsifying ability. The waste coffee particles readily stabilised o/w emulsions and following hydrothermal treatment adapted from the bioenergy field they also stabilised w/o emulsions. The hydrothermal treatment relocated the lignin component of the cell walls within the coffee particles onto the particle surface thereby increasing the surface hydrophobicity of the particles as demonstrated by an emulsion assay. Emulsion droplet sizes were comparable to those found in processed foods in the case of hydrophilic waste coffee particles stabilizing o/w emulsions. These emulsions were stable against coalescence for at least 12 weeks, flocculated but stable against coalescence in shear and stable to pasteurisation conditions (10 min at 80 °C). Emulsion droplet size was also insensitive to pH of the aqueous phase during preparation (pH 3–pH 9). Stable against coalescence, the water droplets in w/o emulsions prepared with hydrothermally treated waste coffee particles were considerably larger and microscopic examination showed evidence of arrested coalescence indicative of particle jamming at the surface of the emulsion droplets. Refinement of the hydrothermal treatment and broadening out to other lignin-rich plant or plant based food waste material are promising routes to bring closer the development of commercially relevant lignin based food Pickering particles applicable to emulsion based processed foods ranging from fat continuous spreads and fillings to salad dressings. PMID:28773909

Treatment methods for breaking certain oil and water emulsions

DOEpatents

Sealock, Jr., L. John; Baker, Eddie G.; Elliott, Douglas C.

1992-01-01

Disclosed are treatment methods for breaking emulsions of petroleum oil and salt water, fatty oil and water, and those resulting from liquefication of organic material. The emulsions are broken by heating to a predetermined temperature at or above about 200.degree. C. and pressurizing to a predetermined pressure above the vapor pressure of water at the predetermined temperature to produce a heated and pressurized fluid. The heated and pressurized fluid is contained in a single vessel at the predetermined temperature and pressure for a predetermined period of time to effectively separate the emulsion into substantially distinct first and second phases, the first phase comprising primarily the petroleum oil, the second phase comprising primarily the water. The first and second phases are separately withdrawn from the vessel at a withdraw temperature between about 200.degree. C. and 374.degree. C. and a withdraw pressure above the vapor pressure of water at the withdraw temperature. Where solids are present in the certain emulsions, the above described treatment may also effectively separate the certain emulsion into a substantially distinct third phase comprising primarily the solids.

Thick phase holographic gratings recorded on BB-640 and PFG-01 silver halide materials

NASA Astrophysics Data System (ADS)

Neipp, Cristian; Márquez, Andrés; Pascual, Inmaculada; Beléndez, Augusto

2003-09-01

Photographic emulsions are still widely used to record holographic optical elements. In particular, if high diffraction efficiencies are needed, phase volume holograms are preferably recorded on these emulsions. Two particular techniques producing high-quality volume phase holograms are fixation-free rehalogenating bleaching and the use of silver-halide-sensitized gelatin. In this work we compare these two particular techniques applied to three different red-sensitive emulsions: Agfa 8E75 HD, BB-640, and Slavich PFG-01 emulsions. The differences between these emulsions determine the particular experimental conditions needed to record high-quality volume holograms on them. In this work these differences are analysed, and also their influence on the experimental procedure.

Absorption enhancement of adefovir dipivoxil by incorporating MCT and ethyl oleate complex oil phase in emulsion

PubMed Central

Li, Ping; Yu, Hong-zhen; Zhang, Xin-xin; Gan, Li; Zhu, Chun-liu; Gan, Yong

2010-01-01

Aim: To improve the oral absorption of adefovir dipivoxil (ADV) by employing MCT and the esterase inhibitor ethyl oleate (EO) as a complex oil phase in emulsion. Methods: EO was used as the esterase inhibitor, and its inhibitory effect on esterase activity was assessed in rat intestinal homogenates. ADV emulsions with or without EO were prepared. The emulsions' protective effect against intestinal metabolism was evaluated in rat luminal contents, ex vivo, as well as in vivo. Results: The IC50 of EO in intestinal mucosal homogenates was 2.2 mg/mL. The emulsions exhibited significant protective effects in rat luminal contents compared to a simple suspension (98.7%, 96.3%, 95.7% vs 74.7%, P<0.01). The permeability calculated from the emulsion containing EO was significantly different (11.4×10−6 vs 7.4/8.0×10−6, P<0.05) from the simple suspension or the emulsion without EO in an ex vivo assay. A bioavailability study in vivo revealed that emulsions containing both EO and MCT as a complex oil phase demonstrated 1.6- and 1.5-fold enhancements in area under the curve (AUC0–12) values (5358 vs 3386/3618, P<0.05), respectively, when compared with emulsions containing EO or MCT as a single oil phase. Conclusion: Heterotic lipid formulations (emulsions) with an esterase inhibitor (ie, EO) may be useful in protecting ester prodrugs from intestinal metabolism and increasing their oral bioavailability. PMID:20562905

Temperature-Induced Protein Release from Water-in-Oil-in-Water Double Emulsions

PubMed Central

Rojas, Edith C.; Staton, Jennifer A.; John, Vijay T.; Papadopoulos, Kyriakos D.

2009-01-01

A model water-in-oil-in-water (W1/O/W2) double emulsion was prepared by a two-step emulsification procedure and subsequently subjected to temperature changes that caused the oil phase to freeze and thaw while the two aqueous phases remained liquid. Our previous work on individual double-emulsion globules1 demonstrated that crystallizing the oil phase (O) preserves stability, while subsequent thawing triggers coalescence of the droplets of the internal aqueous phase (W1) with the external aqueous phase (W2), termed external coalescence. Activation of this instability mechanism led to instant release of fluorescently tagged bovine serum albumin (fluorescein isothiocyanate (FITC)-BSA) from the W1 droplets and into W2. These results motivated us to apply the proposed temperature-induced globule-breakage mechanism to bulk double emulsions. As expected, no phase separation of the emulsion occurred if stored at temperatures below 18 °C (freezing point of the model oil n-hexadecane), whereas oil thawing readily caused instability. Crucial variables were identified during experimentation, and found to greatly influence the behavior of bulk double emulsions following freeze-thaw cycling. Adjustment of these variables accounted for a more efficient release of the encapsulated protein. PMID:18543998

DELIVERY OF WATER-SOLUBLE DRUGS USING ACOUSTICALLY-TRIGGERED, PERFLUOROCARBON DOUBLE EMULSIONS

PubMed Central

Fabiilli, Mario L.; Lee, James A.; Kripfgans, Oliver D.; Carson, Paul L.; Fowlkes, J. Brian

2010-01-01

Purpose Ultrasound can be used to release a therapeutic payload encapsulated within a perfluorocarbon (PFC) emulsion via acoustic droplet vaporization (ADV), a process whereby the PFC phase is vaporized and the agent is released. ADV-generated microbubbles have been previously used to selectively occlude blood vessels in vivo. The coupling of ADV-generated drug delivery and occlusion has therapeutically, synergistic potentials. Methods Micron-sized, water-in-PFC-in-water (W1/PFC/W2) emulsions were prepared in a two-step process using perfluoropentane (PFP) or perfluorohexane (PFH) as the PFC phase. Fluorescein or thrombin was contained in the W1 phase. Results Double emulsions containing fluorescein in the W1 phase displayed a 5.7±1.4 fold and 8.2±1.3 fold increase in fluorescein mass flux, as measured using a Franz diffusion cell, after ADV for the PFP and PFH emulsions, respectively. Thrombin was stably retained in four out of five double emulsions. For three out of five formulations tested, the clotting time of whole blood decreased, in a statistically significant manner (p < 0.01), when incubated with thrombin-loaded emulsions exposed to ultrasound compared to emulsions not exposed to ultrasound. Conclusions ADV can be used to spatially and temporally control the delivery of water-soluble compounds formulated in PFC double emulsions. Thrombin release could extend the duration of ADV-generated, microbubble occlusions. PMID:20872050

Lipid oxidation in base algae oil and water-in-algae oil emulsion: Impact of natural antioxidants and emulsifiers.

PubMed

Chen, Bingcan; Rao, Jiajia; Ding, Yangping; McClements, David Julian; Decker, Eric Andrew

2016-07-01

The impact of natural hydrophilic antioxidants, metal chelators, and hydrophilic antioxidant/metal chelator mixture on the oxidative stability of base algae oil and water-in-algae oil emulsion was investigated. The results showed that green tea extract and ascorbic acid had greatest protective effect against algae oil oxidation and generated four day lag phase, whereas rosmarinic acid, grape seed extract, grape seed extract polymer, deferoxamine (DFO), and ethylenediaminetetraacetic acid (EDTA) had no significant protective effect. Besides, there was no synergistic effect observed between natural antioxidants and ascorbic acid. The emulsifiers are critical to the physicochemical stability of water-in-algae oil emulsions. Polyglycerol polyricinoleate (PGPR) promoted the oxidation of emulsion. Conversely, the protective effect on algae oil oxidation was appreciated when defatted soybean lecithin (PC 75) or defatted lyso-lecithin (Lyso-PC) was added. The role of hydrophilic antioxidants in emulsion was similar to that in algae oil except EDTA which demonstrated strong antioxidative effect in emulsion. The results could provide information to build up stable food products containing polyunsaturated fatty acids (PUFA). Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of osmotic pressure and gelling in the generation of highly stable single core water-in-oil-in-water (W/O/W) nano multiple emulsions of aspirin assisted by two-stage ultrasonic cavitational emulsification.

PubMed

Tang, Siah Ying; Sivakumar, Manickam; Nashiru, Billa

2013-02-01

The present investigation focuses in investigating the effect of osmotic pressure, gelling on the mean droplet diameter, polydispersity index, droplet size stability of the developed novel Aspirin containing water-in-oil-in-water (W/O/W) nano multiple emulsion. The aspirin-loaded nano multiple emulsion formulation was successfully generated using two-stage ultrasonic cavitational emulsification which had been reported in author's previous study. The osmotic behavior of ultrasonically prepared nano multiple emulsions were also examined with different glucose concentrations both in the inner and outer aqueous phases. In addition, introducing gelatin into the formulation also observed to play an important role in preventing the interdroplet coalescence via the formation of interfacial rigid film. Detailed studies were also made on the possible mechanisms of water migration under osmotic gradient which primarily caused by the permeation of glucose. Besides, the experimental results have shown that the interfacial tension between the two immiscible phases decreases with varying the composition of organic phase. Although the W/O/W emulsion prepared with the inner/outer glucose weight ratio of 1-0.5% (w/w) showed an excellent droplet stability, the formulation containing 0.5% (w/w) glucose in the inner aqueous phase appeared to be the most stable with minimum change in the mean droplet size upon one-week storage period. Based on the optimization, nano multiple emulsion droplets with the mean droplet diameter of around 400 nm were produced using 1.25% (w/w) Span 80 and 0.5% Cremophore EL. Overall, our investigation makes a pathway in proving that the use of ultrasound cavitation is an efficient yet promising approach in the generation of stable and uniform nano multiple emulsions and could be used in the encapsulation of various active pharmaceutical ingredients in the near future. Copyright © 2012 Elsevier B.V. All rights reserved.

Preference of multi-walled carbon nanotube (MWCNT) to single-walled carbon nanotube (SWCNT) and activated carbon for preparing silica nanohybrid pickering emulsion for chemical enhanced oil recovery (C-EOR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

AfzaliTabar, M.; Alaei, M., E-mail: alaiem@ripi.ir; Ranjineh Khojasteh, R.

The aim of this research was to determine the best nano hybrid that can be used as a Pickering emulsion Chemical Enhanced Oil Recovery (C-EOR). Therefore, we have prepared different carbon structures nano hybrids with SiO{sub 2} nano particles with different weight percent using sol-gel method. The as-prepared nano materials were characterized with X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Thermal Gravimetric Analysis (TGA). Pickering emulsions of these nanohybrids were prepared at pH=7 in ambient temperature and with distilled water. Stability of the mentioned Pickering emulsions was controlled for one month. Emulsion phase morphology was investigated usingmore » optical microscopic imaging. Evaluation results demonstrated that the best sample is the 70% MWCNT/SiO{sub 2} nanohybrid. Stability of the selected nanohybrid (70% MWCNT/SiO{sub 2} nanohybrid) was investigated by alteration of salinity, pH and temperature. Results showed that the mentioned Pickering emulsion has very good stability at 0.1%, 1% salinity, moderate and high temperature (25 °C and 90 °C) and neutral and alkaline pH (7, 10) that is suitable for the oil reservoirs conditions. The effect of the related nano fluid on the wettability of carbonate rock was investigated by measuring the contact angle and interfacial tension. Results show that the nanofluid could significantly change the wettability of the carbonate rock from oil wet to water wet and can decrease the interfacial tension. Therefore, the 70% MWCNT/SiO{sub 2} nanohybrid Pickering emulsion can be used for Chemical Enhanced Oil Recovery (C-EOR).« less

Multiscale and Multifunctional Emulsions by Host–Guest Interaction-Mediated Self-Assembly

PubMed Central

2018-01-01

Emulsions are widely used in numerous fields. Therefore, there has been increasing interest in the development of new emulsification strategies toward emulsions with advanced functions. Herein we report the formation of diverse emulsions by host–guest interaction-mediated interfacial self-assembly under mild conditions. In this strategy, a hydrophilic diblock copolymer with one block containing β-cyclodextrin (β-CD) can assemble at the oil/water interface when its aqueous solution is mixed with an oil phase of benzyl alcohol (BA), by host–guest interactions between β-CD and BA. This results in significantly reduced interfacial tension and the formation of switchable emulsions with easily tunable droplet sizes. Furthermore, nanoemulsions with excellent stability are successfully prepared simply via vortexing. The self-assembled oil-in-water emulsions also show catastrophic phase inversion, which can generate stable bicontinuous phase and water-in-oil emulsions, thereby further extending phase structures that can be realized by this host–guest self-assembly approach. Moreover, the host–guest nanoemulsions are able to engineer different nanoparticles and microstructures as well as solubilize a diverse array of hydrophobic drugs and dramatically enhance their oral bioavailability. The host–guest self-assembly emulsification is facile, energetically friendly, and fully translatable to industry, therefore representing a conceptually creative approach toward advanced emulsions. PMID:29806006

Pickering emulsions based on cyclodextrins: A smart solution for antifungal azole derivatives topical delivery.

PubMed

Leclercq, Loïc; Nardello-Rataj, Véronique

2016-01-20

Surfactants are usually used for the preparation of emulsions. Potential drawbacks on the human body or on the environment can be observed for some of them(e.g. skin irritation, hemolysis, protein denaturation, etc.). However, it is possible to use biocompatible emulsifiers such as native cyclodextrins (CDs). The mixture of oil (paraffin oil or isopropyl myristate), water and native CDs results in the formation of Pickering emulsions. The emulsion properties were investigated by ternary phase diagrams elaboration, multiple light scattering, optical and transmission microscopies. The results prove that these Pickering emulsions were very stable against coalescence due to the dense film format the oil/water interface. The rheological behavior has shown that these emulsions remain compatible for topical applications. This kind of emulsions (biocompatibility, stability and surfactant free) has been used to obtain sustainable formulations for antifungal econazole derivatives delivery. Our results prove that these new formulations are at least as active as commercially available formulations.

Laboratory performance evaluation of CIR-emulsion and its comparison against CIR-foam test results from phase III.

DOT National Transportation Integrated Search

2009-12-01

Currently, no standard mix design procedure is available for CIR-emulsion in Iowa. The CIR-foam mix : design process developed during the previous phase is applied for CIR-emulsion mixtures with varying : emulsified asphalt contents. Dynamic modulus ...

Phase holograms in silver halide emulsions without a bleaching step

NASA Astrophysics Data System (ADS)

Belendez, Augusto; Madrigal, Roque F.; Pascual, Inmaculada V.; Fimia, Antonio

2000-03-01

Phase holograms in holographic emulsions are usually obtained by two bath processes (developing and bleaching). In this work we present a one step method to reach phase holograms with silver-halide emulsions. Which is based on the variation of the conditions of the typical developing processes of amplitude holograms. For this, we have used the well-known chemical developer, AAC, which is composed by ascorbic acid as a developing agent and sodium carbonate anhydrous as accelerator. Agfa 8E75 HD and BB-640 plates were used to obtain these phase gratings, whose colors are between yellow and brown. In function of the parameters of this developing method the resulting diffraction efficiency and optical density of the diffraction gratings were studied. One of these parameters studied is the influence of the grain size. In the case of Agfa plates diffraction efficiency around 18% with density < 1 has been reached, whilst with the BB-640 emulsion, whose grain is smaller than that of the Agfa, diffraction efficiency near 30% has been obtained. The resulting gratings were analyzed through X-ray spectroscopy showing the differences of the structure of the developed silver when amplitude and transmission gratings are obtained. The angular response of both (transmission and amplitude) gratings were studied, where minimal transmission is showed at the Braggs angle in phase holograms, whilst a maximal value is obtained in amplitude gratings.

Self-assembly formation of palm-based esters nano-emulsion: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Abdul Rahman, Mohd. Basyaruddin; Huan, Qiu-Yi; Tejo, Bimo A.; Basri, Mahiran; Salleh, Abu Bakar; Rahman, Raja Noor Zaliha Abdul

2009-10-01

Palm-oil esters (POEs) are unsaturated and non-ionic esters that can be prepared by enzymatic synthesis from palm oil. Their nano-emulsion properties possess great potential to act as drug carrier for transdermal drug delivery system. A ratio of 75:5:20 (water/POEs/Span20) was chosen from homogenous region in the phase diagram of our previous experimental work to undergo molecular dynamics simulation. A 15 ns molecular dynamics simulation of nano-emulsion system (water/POEs/Span20) was carried out using OPLS-AA force field. The aggregations of the oil and surfactant molecules are observed throughout the simulation. After 8 ns of simulation, the molecules start to aggregate to form one spherical micelle where the POEs molecules are surrounded by the non-ionic surfactant (Span20) molecules with an average size of 4.2 ± 0.05 nm. The size of the micelle and the ability of palm-based nano-emulsion to self-assemble suggest that this nano-emulsion can potentially use in transdermal drug delivery system.

Enhanced emulsifying properties of wood-based cellulose nanocrystals as Pickering emulsion stabilizer.

PubMed

Gong, Xiaoyu; Wang, Yixiang; Chen, Lingyun

2017-08-01

Cellulose nanocrystals are hydrophilic nanomaterials, which limits their applications as interfacial compounds. Herein, we propose using modified wood-based cellulose nanocrystals as Pickering emulsion stabilizer. Wood cellulose was consecutively oxidized and modified with phenyltrimethylammonium chloride to create hydrophobic domains comprised of phenyl groups. These modified oxidized cellulose nanocrystals (m-O-CNCs) were homogeneous/electrostatically stable in water and they can stabilize O/W Pickering emulsions. The dispersed phase volume fraction (DPVF) of the Pickering emulsion was 0.7 at around 1.5g/L, whereas the tween-20 control needed a 13-fold greater concentration to have a similar DPVR. In addition, these m-O-CNC stabilized Pickering emulsions also showed good mechanical and thermal stability against centrifugation and heat, as well as size controllability. In terms of stability, size controllability, surfactant-free status, these m-O-CNCs possess superior and enhanced emulsifying properties. Future research for these new interfacial materials have potential in applications, for personal care, cosmetic and pharmaceutic industries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of O/I1-type Emulsions and S/I1-type Dispersions Encapsulating UV-Absorbing Agents.

PubMed

Aramaki, Kenji; Kimura, Minami; Masuda, Kazuki

2015-01-01

Oil-in-cubic phase (O/I1) emulsions encapsulating the cosmetic UV absorbing agents 2-ethylhexyl 4-methoxycinnamate (EHMC), 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (octocrylene, OCR) and 1-(4-tertbutylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione (Avobenzone, TBMP) were prepared by vortex mixing accompanied by a heating-cooling process. A ternary phase diagram in a water/C12EO25/EHMC system at 25°C was constructed and the two-phase equilibrium of an oil phase and an I1 phase, which is necessary to prepare the O/I1-type emulsions, was confirmed. Also, the melting of the I1 phase into a fluid micellar solution phase was confirmed, allowing emulsification by a heating-cooling process. The O/I1-type emulsions were formulated in the ternary system as well as a quaternary system. The four-component system contained an additional cosolvent, isopropyl myristate (IPM). The use of the cosolvent allows the use of reduced amounts of EHMC, which is desirable because EHMC can cause temporary skin irritation. Formulation of the O/I1-type emulsions with other UV absorbing agents (OCR and TBMP) was also possible using the same emulsification method. When IPM was changed to tripalmitin, which has a melting point greater than room temperature, a solid-oil dispersion in I1 phase was formed. We have termed this a "solidin-cubic phase (S/I1) type dispersion". These novel emulsions have not been reported previously. The UV absorbability of the O/I1-type emulsions and S/I1-type dispersions that encapsulate the UV absorbing agents was confirmed by measurement of UV absorption spectra.

Formation of random and regular relief-phase structures on silver halide photographic emulsions by holographic methods

NASA Astrophysics Data System (ADS)

Ganzherli, N. M.; Gulyaev, S. N.; Gurin, A. S.; Kramushchenko, D. D.; Maurer, I. A.; Chernykh, D. F.

2009-07-01

The formation of diffusers and microlens rasters on silver halide emulsions by holographic methods is considered. Two techniques for converting amplitude holographic recording to relief-phase recording, selective curing and irradiation of the emulsion gelatin by short-wavelength UV radiation, are compared.

Demulsification of oil-in-water emulsions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roark, D.N.

1986-09-30

This patent describes a process of demulsifying an oil-in-water emulsion which comprises admixing with the emulsion a water-soluble polymer of monoallylamine that causes formation of and separation between an oil phase and an aqueous phase to occur. The emulsion has a pH in the range of about 5 to about 10 and the polymer has a weight average molecular weight of at least 1000 and contains at least 95% by weight of monoallylamine.

The research about microscopic structure of emulsion membrane in O/W emulsion by NMR and its influence to emulsion stability.

PubMed

Xie, Yiqiao; Chen, Jisheng; Zhang, Shu; Fan, Kaiyan; Chen, Gang; Zhuang, Zerong; Zeng, Mingying; Chen, De; Lu, Longgui; Yang, Linlin; Yang, Fan

2016-03-16

This paper discussed the influence of microstructure of emulsion membrane on O/W emulsion stability. O/W emulsions were emulsified with equal dosage of egg yolk lecithin and increasing dosage of co-emulsifier (oleic acid or HS15). The average particle size and centrifugal stability constant of emulsion, as well as interfacial tension between oil and water phase were determined. The microstructure of emulsion membrane had been studied by (1)H/(13)C NMR, meanwhile the emulsion droplets were visually presented with TEM and IFM. With increasing dosage of co-emulsifier, emulsions showed two stable states, under which the signal intensity of characteristic group (orient to lipophilic core) of egg yolk lecithin disappeared in NMR of emulsions, but that (orient to aqueous phase) of co-emulsifiers only had some reduction at the second stable state. At the two stable states, the emulsion membranes were neater in TEM and emulsion droplets were rounder in IFM. Furthermore, the average particle size of emulsions at the second stable state was bigger than that at the first stable state. Egg yolk lecithin and co-emulsifier respectively arranged into monolayer and bilayer emulsion membrane at the two stable states. The microstructure of emulsion membrane was related to the stability of emulsion. Copyright © 2016 Elsevier B.V. All rights reserved.

Phospholipid hydrolysis in a pharmaceutical emulsion assessed by physicochemical parameters and a new analytical method.

PubMed

Rabinovich-Guilatt, Laura; Dubernet, Catherine; Gaudin, Karen; Lambert, Gregory; Couvreur, Patrick; Chaminade, Pierre

2005-09-01

The aim of this work was to develop a simple high-performance liquid chromatography (HPLC) technique with evaporative light scattering detection (ELSD) for the separation and quantification of the major phospholipid (PL) and lysophospholipid (LPL) classes contained in a pharmaceutical phospholipid-based emulsion. In the established method, phosphatidylcholine (PC), phosphatidylethanolamine (PE), sphingomyeline (SM), lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) were separated with a PVA-Sil stationary phase and a binary gradient from pure chloroform to methanol:water (94:6 v/v) at 3.4%/min. The ELSD detection was enhanced using 0.1% triethylamine and formic acid in each gradient mobile phases. Factors such as stationary phase and ELSD drift tube temperature were optimized, concluding in optimal temperatures of 25 degrees C for separation and 50 degrees C for evaporation. This HPLC-ELSD method was then applied to a PL-emulsion exposed to autoclaving and accelerated thermal conditions at 50 degrees C. Hydrolysis of PC and PE followed first-order kinetics, representing only 45% of the total lipid mass after 3 months. The chemical stability was correlated to commonly measured formulation physical and physico-chemical parameters such as droplet size, emulsion pH and zeta-potential.

Determination of chloride in brazilian crude oils by ion chromatography after extraction induced by emulsion breaking.

PubMed

Robaina, Nicolle F; Feiteira, Fernanda N; Cassella, Alessandra R; Cassella, Ricardo J

2016-08-05

The present paper reports on the development of a novel extraction induced by emulsion breaking (EIEB) method for the determination of chloride in crude oils. The proposed method was based on the formation and breaking of oil-in-water emulsions with the samples and the consequential transference of the highly water-soluble chloride to the aqueous phase during emulsion breaking, which was achieved by centrifugation. The determination of chloride in the extracts was performed by ion chromatography (IC) with conductivity detection. Several parameters (oil phase:aqueous phase ratio, crude oil:mineral oil ratio, shaking time and type and concentration of surfactant) that could affect the performance of the method were evaluated. Total extraction of chloride from samples could be achieved when 1.0g of oil phase (0.5g of sample+0.5g of mineral oil) was emulsified in 5mL of a 2.5% (m/v) solution of Triton X-114. The obtained emulsion was shaken for 60min and broken by centrifugation for 5min at 5000rpm. The separated aqueous phase was collected, filtered and diluted before analysis by IC. Under these conditions, the limit of detection was 0.5μgg(-1) NaCl and the limit of quantification was 1.6μgg(-1) NaCl. We applied the method to the determination of chloride in six Brazilian crude oils and the results did not differ statistically from those obtained by the ASTM D6470 method when the paired Student-t-test, at 95% confidence level, was applied. Copyright © 2016 Elsevier B.V. All rights reserved.

Descriptive sensory profiling of double emulsions with gelled and non-gelled inner water phase.

PubMed

Oppermann, A K L; Piqueras-Fiszman, B; de Graaf, C; Scholten, E; Stieger, M

2016-07-01

The use of double emulsions (w 1 /o/w 2 ) has been acknowledged as a promising strategy to reduce oil content in several food applications. Despite the potential of double emulsions for oil reduction, their sensory properties have not been investigated. In this study, we investigated sensory perception of double emulsions by descriptive sensory profiling using a trained panel (n=11). Two sets of emulsions with either 30 or 50% dispersed phase fraction were studied. Each set differed in composition (gelled and non-gelled inner w 1 phase, gelatin as gelling agent) and fat reduction level (30 to 50%), but was similar in oil droplet size and viscosity. Fat reduction level depended on the amount of water droplets entrapped inside the oil droplets. Emulsions were evaluated on nine attributes describing taste (T), mouth-feel (MF) and after-feel (AF) perception, including thickness (MF), creaminess (MF, AF), fattiness (MF, AF), and cohesiveness (MF). The replacement of oil by small water droplets w 1 did not decrease the intensity of fat-related attributes. When inner w 1 droplets were gelled, 47wt.% of oil could be replaced while increasing the intensity of fat-related attributes. This indicates that the sensory perception of single and double emulsions with gelled and non-gelled w 1 phase is mainly determined by the total oil droplet surface area. The composition of the inner water phase (gelled or not) also influences the sensory perception of double emulsions. We conclude that fat reduction up to 47wt.% can be achieved in double emulsions while maintaining or enhancing fat-related sensory perception. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro digestion behavior of water-in-oil-in-water emulsions with gelled oil-water inner phases.

PubMed

Andrade, Jonathan; Wright, Amanda J; Corredig, Milena

2018-03-01

Double emulsions may be able to protect and release in a controlled manner bioactive compounds during digestion of food matrices. It was hypothesized that the physical state and solid content in the inner phases of water-in-oil-in-water (W 1 /O/W 2 ) emulsions may affect the overall stability and the release behavior of bioactives during in vitro digestion. Therefore, hydrophobic (phytosterols or Vitamin D 3 ) and hydrophilic (Vitamin B 12 ) molecules were incorporated in double emulsions prepared either with a liquid (soybean oil - SO) or oil-fat gel (soybean oil+trimyristin - STO) lipid phase and liquid internal aqueous phase. In addition, the impact of a gelled inner aqueous phase was studied, using high methoxyl pectin. W 1 /O/W 2 emulsions were prepared with polyglycerol polyricinoleate (PGPR) and sodium caseinate as emulsifiers. After the 30min in vitro gastric stage, all double emulsions showed no significant change in size. Lipid crystals were visible in the STO emulsions. Fat crystallization, and the formation of an oil fat gel, led to coalescence of the inner aqueous droplets. The inner aqueous droplets were no longer visible by confocal microscopy after the initial stages of 2h in vitro duodenal digestion. Fat crystals and droplets of non-spherical shape were also noted in the STO double emulsions up to 25min of in vitro duodenal stage. Overall, the STO emulsions had a higher extent of free fatty acid release and consequent bioactive transfer compared to the SO emulsions. The presence of the medium chain fatty acids (from trimyristin), in addition to the surface-to-core distribution of the hydrophobic bioactives within the oil droplet were key factors in lipid digestibility and bioactive release. The STO and SO samples did not differ in terms of the release of the hydrophilic molecule, vitamin B 12 , over time. On the other hand, there was a significant increase in the stability of the inner water phase, after gastric digestion, when this phase was gelled with high methoxyl pectin. This work demonstrated that the physical properties of the different internal phases of W 1 /O/W 2 influenced lipid digestion and bioactive transfer kinetics during in vitro digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

W/O/W multiple emulsions with diclofenac sodium.

PubMed

Lindenstruth, Kai; Müller, Bernd W

2004-11-01

The disperse oil droplets of W/O/W multiple emulsions contain small water droplets, in which drugs could be incorporated, but the structure of these emulsions is also the reason for possible instability. Due to the middle oil phase which acts as a 'semipermeable' membrane the passage of water across the oil phase can take place. However, the emulsions have been produced in a two-step-production process so not only the leakage of encapsulated drug molecules out of the inner water phase during storage but also a production-induced reduction of the encapsulation rate should be considered. The aim of this study was to ascertain how far the production-induced reduction of the encapsulation rate relates to the size of inner water droplets and to evaluate the relevance of multiple emulsions as drug carrier for diclofenac sodium. Therefore multiple emulsions were produced according to a central composite design. During the second production step it was observed that the parameters pressure and temperature have an influence on the size of the oil droplets in the W/O/W multiple emulsions. Further experiments with different W/O emulsions resulted in W/O/W multiple emulsions with different encapsulation rates of diclofenac sodium, due to the different sizes of the inner water droplets, which were obtained in the first production step.

Formulation and optimization by experimental design of eco-friendly emulsions based on d-limonene.

PubMed

Pérez-Mosqueda, Luis M; Trujillo-Cayado, Luis A; Carrillo, Francisco; Ramírez, Pablo; Muñoz, José

2015-04-01

d-Limonene is a natural occurring solvent that can replace more pollutant chemicals in agrochemical formulations. In the present work, a comprehensive study of the influence of dispersed phase mass fraction, ϕ, and of the surfactant/oil ratio, R, on the emulsion stability and droplet size distribution of d-limonene-in-water emulsions stabilized by a non-ionic triblock copolymer surfactant has been carried out. An experimental full factorial design 3(2) was conducted in order to optimize the emulsion formulation. The independent variables, ϕ and R were studied in the range 10-50 wt% and 0.02-0.1, respectively. The emulsions studied were mainly destabilized by both creaming and Ostwald ripening. Therefore, initial droplet size and an overall destabilization parameter, the so-called turbiscan stability index, were used as dependent variables. The optimal formulation, comprising minimum droplet size and maximum stability was achieved at ϕ=50 wt%; R=0.062. Furthermore, the surface response methodology allowed us to obtain the formulation yielding sub-micron emulsions by using a single step rotor/stator homogenizer process instead of most commonly used two-step emulsification methods. In addition, the optimal formulation was further improved against Ostwald ripening by adding silicone oil to the dispersed phase. The combination of these experimental findings allowed us to gain a deeper insight into the stability of these emulsions, which can be applied to the rational development of new formulations with potential application in agrochemical formulations. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and Characterization of Graphene Oxide-Polystyrene Composite Capsules with Aqueous Cargo via a Water-Oil-Water Multiple Emulsion Templating Route.

PubMed

Ali, Muthana; McCoy, Thomas M; McKinnon, Ian R; Majumder, Mainak; Tabor, Rico F

2017-05-31

Graphene oxide/polystyrene (GO/PS) nanocomposite capsules containing a two-compartment cargo have been successfully fabricated using a Pickering emulsion strategy. Highly purified GO sheets with typically micrometer-scale lateral dimensions and amphiphilic characteristics were prepared from the oxidation reaction of graphite with concomitant exfoliation of the graphite structure. These GO sheets were employed as a stabilizer for oil-in-water emulsions where the oil phase comprised toluene or olive oil. The stability and morphology of the emulsions were extensively studied as a function of different parameters including GO concentration, aqueous phase pH, ultrasonication time, effects of added electrolytes and stability to dilution. In selected conditions, the olive oil emulsions showed spontaneous formation of multiple w/o/w emulsions with high stability, whereas toluene formed simple o/w emulsions of lower overall stability. Olive oil emulsions were therefore used to prepare capsules templated from emulsion droplets by surrounding the oil phase with a GO/PS shell. The GO sheets, emulsions and composite capsules were characterized using a variety of physical and spectroscopic techniques in order to unravel the interactions responsible for capsule formation. The ability of the capsules to control the release of a model active agent in the form of a hydrophilic dye was explored, and release kinetics were monitored using UV-visible spectroscopy to obtain rate parameters. The composite capsules showed promising sustained release properties, with release rates 11× lower than the precursor GO-stabilized multiple emulsion droplets.

Organogel-emulsions with mixtures of β-sitosterol and γ-oryzanol: influence of water activity and type of oil phase on gelling capability.

PubMed

Sawalha, Hassan; den Adel, Ruud; Venema, Paul; Bot, Arjen; Flöter, Eckhard; van der Linden, Erik

2012-04-04

In this study, water-in-oil emulsions were prepared from water containing different salt concentrations dispersed in an oil phase containing a mixture of β-sitosterol and γ-oryzanol. In pure oil, the β-sitosterol and γ-oryzanol molecules self-assemble into tubular microstructures to produce a firm organogel. However, in the emulsion, the water molecules bind to the β-sitosterol molecules, forming monohydrate crystals that hinder the formation of the tubules and resulting in a weaker emulsion-gel. Addition of salt to the water phase decreases the water activity, thereby suppressing the formation of sitosterol monohydrate crystals even after prolonged storage times (∼1 year). When the emulsions were prepared with less polar oils, the tubular microstructure was promoted, which significantly increased the firmness of the emulsion-gel. The main conclusion of this study is that the formation of oryzanol and sitosterol tubular microstructure in the emulsion can be promoted by reducing the water activity and/or by using oils of low polarity.

Long-term stability of crystal-stabilized water-in-oil emulsions.

PubMed

Ghosh, Supratim; Pradhan, Mamata; Patel, Tejas; Haj-Shafiei, Samira; Rousseau, Dérick

2015-12-15

The impact of cooling rate and mixing on the long-term kinetic stability of wax-stabilized water-in-oil emulsions was investigated. Four cooling/mixing protocols were investigated: cooling from 45°C to either 25°C or 4°C with/without stirring and two cooling rates - slow (1°C/min) and fast (5°C/min). The sedimentation behaviour of the emulsions was significantly affected by cooling protocol. Stirring was critical to the stability of all emulsions, with statically-cooled (no stirring) emulsions suffering from extensive aqueous phase separation. Emulsions stirred while cooling showed sedimentation of a waxy emulsion layer leaving a clear oil layer at the top, with a smaller separation and droplet size distribution at 4°C compared to 25°C, indicating the importance of the amount of crystallized wax on emulsion stability. Light microscopy revealed that crystallized wax appeared both on the droplet surface and in the continuous phase, suggesting that stirring ensured dispersibility of the water droplets during cooling as the wax was crystallizing. Wax crystallization on the droplet surface provided stability against droplet coalescence while continuous phase wax crystals minimized inter-droplet collisions. The key novel aspect of this research is in the simplicity to tailor the spatial distribution of wax crystals, i.e., either at the droplet surface or in the continuous phase via use of a surfactant and judicious stirring and/or cooling. Knowledge gained from this research can be applied to develop strategies for long-term storage stability of crystal-stabilized W/O emulsions. Copyright © 2015 Elsevier Inc. All rights reserved.

Rheological behavior, zeta potential, and accelerated stability tests of Buriti oil (Mauritia flexuosa) emulsions containing lyotropic liquid crystals.

PubMed

Zanatta, Cinthia Fernanda; de Faria Sato, Anne Miwa Callejón; de Camargo, Flavio Bueno; Campos, Patrícia Maria Berardo Gonçalves Maia; Rocha-Filho, Pedro Alves

2010-01-01

It is well known that the Amazon region presents a huge biodiversity; therefore, countless natural resources are being employed in the production of phytocosmetics and phytomedicines. The purpose of this work was to obtain emulsions produced with Buriti oil and non-ionic surfactants. Two surfactant systems were employed (Steareth-2 associated to Ceteareth-5 and to Ceteareth-20) to produce the emulsions using phase diagram method. Emulsions were obtained by echo-planar imaging method at 75°C. Rheological behavior and zeta potential were evaluated, and accelerated stability tests were performed. All emulsions analyzed presented pseudoplastic behavior. Zeta potential values were obtained between -14.2 and -53.3 mV. The formulations did not show changes in either physical stability, pH, or rheological behavior after accelerated stability tests. Significant differences were observed only after temperature cycling test. Based on these results, the emulsions obtained could be considered as promising delivery systems.

Feasibility of Freeze-Drying Oil-in-Water Emulsion Adjuvants and Subunit Proteins to Enable Single-Vial Vaccine Drug Products.

PubMed

Iyer, Vidyashankara; Cayatte, Corinne; Marshall, Jason D; Sun, Jenny; Schneider-Ohrum, Kirsten; Maynard, Sean K; Rajani, Gaurav Manohar; Bennett, Angie Snell; Remmele, Richard L; Bishop, Steve M; McCarthy, Michael P; Muralidhara, Bilikallahalli K

2017-06-01

To generate potent vaccine responses, subunit protein antigens typically require coformulation with an adjuvant. Oil-in-water emulsions are among the most widely investigated adjuvants, based on their demonstrated ability to elicit robust antibody and cellular immune responses in the clinic. However, most emulsions cannot be readily frozen or lyophilized, on account of the risk of phase separation, and may have a deleterious effect on protein antigen stability when stored long term as a liquid coformulation. To circumvent this, current emulsion-formulated vaccines generally require a complex multivial presentation with obvious drawbacks, making a single-vial presentation for such products highly desirable. We describe the development of a stable, lyophilized squalene emulsion adjuvant through innovative formulation and process development approaches. On reconstitution, freeze-dried emulsion preparations were found to have a minimal increase in particle size of ∼20 nm and conferred immunogenicity in BALB/c mice similar in potency to freshly prepared emulsion coformulations in liquid form. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Dairy-Based Emulsions: Viscosity Affects Fat Difference Thresholds and Sweetness Perception.

PubMed

Zahn, Susann; Hoppert, Karin; Ullrich, Franziska; Rohm, Harald

2013-11-27

In complex emulsions, viscosity or viscosity-associated sensory attributes such as creaminess are important for quality assessment and product differentiation. Two sets of emulsions with fat or locust bean gum content being varied at seven levels were developed; the two emulsions at each level had similar apparent viscosity. Additionally, sugar concentration was kept constant either with respect to total emulsion, or with respect to the aqueous phase. Series of two-alternative forced choice tests were performed with one constant stimulus, and just noticeable differences were calculated using probability regression. The results show that, when viscosity was not compensated, it was easy for the subjects to (a) distinguish emulsions with different fat content when the fat content was addressed in the question, and to (b) distinguish emulsions with different fat or locust bean gum content when creaminess was addressed. For the latter descriptor, it is of minor importance whether viscosity is altered by fat content or a thickener. Weber fractions that were calculated for viscosity were approximately 0.20. The quantitative effects of viscosity on sweetness, however, depend on how product rheology was modified.

Recovery of Ni Metal from Spent Catalyst with Emulsion Liquid Membrane Using Cyanex 272 as Extractant

NASA Astrophysics Data System (ADS)

Yuliusman; Huda, M.; Ramadhan, I. T.; Farry, A. R.; Wulandari, P. T.; Alfia, R.

2018-03-01

In this study was conducted to recover nickel metal from spent nickel catalyst resulting from hydrotreating process in petroleum industry. The nickel extraction study with the emulsion liquid membrane using Cyanex 272 as an extractant to extract and separate nickel from the feed phase solution. Feed phase solution was preapred from spent catalyst using sulphuric acid. Liquid membrane consists of a kerosene as diluent, a Span 80 as surfactant, a Cyanex 272 as carrier and sulphuric acid solutions have been used as the stripping solution. The important parameters governing the permeation of nickel and their effect on the separation process have been studied. These parameters are surfactant concentration, extractant concentration feed phase pH. The optimum conditions of the emulsion membrane making process is using 0.06 M Cyanex 272, 8% w/v SPAN 80, 0.05 M H2SO4, internal phase extractant / phase volume ratio: 1/1, and stirring speed 1150 rpm for 60 Minute that can produce emulsion membrane with stability level above 90% after 4 hours. In the extraction process with optimum condition pH 6 for feed phase, ratio of phase emulsion/phase of feed: 1/2, and stirring speed 175 rpm for 15 minutes with result 81.51% nickel was extracted.

Water-in-oil Pickering emulsions stabilized by stearoylated microcrystalline cellulose.

PubMed

Pang, Bo; Liu, Huan; Liu, Peiwen; Peng, Xinwen; Zhang, Kai

2018-03-01

Hydrophobic particles with static water contact angles larger than 90° are more like to stabilize W/O Pickering emulsions. In particular, high internal phase Pickering emulsions (HIPEs) are of great interest for diverse applications. However, W/O HIPEs have rarely been realized using sustainable biopolymers. Herein, we used stearoylated microcrystalline cellulose (SMCC) to stabilize W/O Pickering emulsions and especially, W/O HIPEs. Moreover, these W/O HIPEs can be further used as platforms for the preparation of porous materials, such as porous foams. Stearoylated microcrystalline cellulose (SMCC) was prepared by modifying MCC with stearoyl chloride under heterogeneous conditions. Using SMCC as emulsifiers, W/O medium and high internal phase Pickering emulsions (MIPEs and HIPEs) with various organic solvents as continuous phases were prepared using one-step and two-step methods, respectively. Polystyrene (PS) foams were prepared after polymerization of oil phase using HIPEs as templates and their oil/water separation capacity were studied. SMCC could efficiently stabilize W/O Pickering emulsions and HIPEs could only be prepared via the two-step method. The internal phase volume fraction of the SMCC-stabilized HIPEs reached as high as 89%. Diverse internal phase volume fractions led to distinct inner structures of foams with closed or open cells. These macroporous polystyrene (PS) foams demonstrated great potential for the effective absorption of organic solvents from underwater. Copyright © 2017 Elsevier Inc. All rights reserved.

Two-step emulsification process for water-in-oil-in-water multiple emulsions stabilized by lamellar liquid crystals.

PubMed

Ito, Toshifumi; Tsuji, Yukitaka; Aramaki, Kenji; Tonooka, Noriaki

2012-01-01

Multiple emulsions, also called complex emulsions or multiphase emulsions, include water-in-oil-in-water (W/O/W)-type and oil-in-water-in-oil (O/W/O)-type emulsions. W/O/W-type multiple emulsions, obtained by utilizing lamellar liquid crystal with a layer structure showing optical anisotropy at the periphery of emulsion droplets, are superior in stability to O/W/O-type emulsions. In this study, we investigated a two-step emulsification process for a W/O/W-type multiple emulsion utilizing liquid crystal emulsification. We found that a W/O/W-type multiple emulsion containing lamellar liquid crystal can be prepared by mixing a W/O-type emulsion (prepared by primary emulsification) with a lamellar liquid crystal obtained from poly(oxyethylene) stearyl ether, cetyl alcohol, and water, and by dispersing and emulsifying the mixture in an outer aqueous phase. When poly(oxyethylene) stearyl ether and cetyl alcohol are each used in a given amount and the amount of water added is varied from 0 to 15 g (total amount of emulsion, 100 g), a W/O/W-type multiple emulsion is efficiently prepared. When the W/O/W-type multiple emulsion was held in a thermostatic bath at 25°C, the droplet size distribution showed no change 0, 30, or 60 days after preparation. Moreover, the W/O/W-type multiple emulsion strongly encapsulated Uranine in the inner aqueous phase as compared with emulsions prepared by one-step emulsification.

Oil-in-water emulsions as a delivery system for n-3 fatty acids in meat products.

PubMed

Salminen, Hanna; Herrmann, Kurt; Weiss, Jochen

2013-03-01

The oxidative and physical stabilities of oil-in-water emulsions containing n-3 fatty acids (25 wt.% oil, 2.5 wt.% whey protein, pH 3.0 or pH 6.0), and their subsequent incorporation into meat products were investigated. The physical stability of fish oil emulsions was excellent and neither coalescence nor aggregation occurred during storage. Oxidative stability was better at pH 6.0 compared to pH 3.0 likely due to antioxidative continuous phase proteins. Incorporation of fish oil emulsions into pork sausages led to an increase in oxidation compared to sausages without the added fish oil emulsion. Confocal microscopy of pork sausages with fish oil emulsions revealed that droplets had coalesced in the meat matrix over time which may have contributed to the decreased oxidative stability. Results demonstrate that although interfacial engineering of n-3 fatty acids containing oil-in-water emulsions provides physical and oxidative stability of the base-emulsion, their incorporation into complex meat matrices is a non-trivial undertaking and products may incur changes in quality over time. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comment to "The pharmacopeial evolution of Intralipid injectable emulsion in plastic containers: from a coarse to a fine emulsion".

PubMed

Ellborg, Anders; Ferreira, Denise; Mohammadnejad, Javad; Wärnheim, Torbjörn

2010-06-15

The droplet size distribution of 50 batches of multi-chamber bags containing the parenteral nutrition emulsions Intralipid (Kabiven and Kabiven Peripheral) or Structolipid (StructoKabiven and StructoKabiven Peripheral), respectively, has been investigated. The results show that the non-compounded lipid emulsions analysed are in compliance with the United States Pharmacopeia (USP) chapter 729, Method II limit for the droplet size distribution, PFAT(5)<0.05%. Copyright 2010 Elsevier B.V. All rights reserved.

Effect of antioxidant properties of lecithin emulsifier on oxidative stability of encapsulated bioactive compounds.

PubMed

Pan, Yuanjie; Tikekar, Rohan V; Nitin, N

2013-06-25

Oxidation of encapsulated bioactive compounds in emulsions is one of the key challenges that limit shelf life of emulsion containing products. Oxidation in these emulsions is triggered by permeation of free radicals generated at the emulsion interface. The objective of this study was to evaluate the role of antioxidant properties of common emulsifiers (lecithin and Tween 20) in reducing permeation of free radicals across the emulsion interface. Radical permeation rates were correlated with oxidative stability of a model bioactive compound (curcumin) encapsulated in these emulsions. Rate of permeation of peroxyl radicals from the aqueous phase to the oil phase of emulsion was inversely proportional to the antioxidant properties of emulsifiers. The rate of radical permeation was significantly higher (p<0.05) for emulsions stabilized using Tween 20 and oxidized lecithin compared to native lecithin that showed higher antioxidant activity. Free radical permeation rate correlated with stability of curcumin in emulsions and was significantly higher (p<0.05) in lecithin stabilized emulsions as compared to Tween 20 emulsions. Overall, this study demonstrates that antioxidant activity of emulsifiers significantly influences permeation of free radicals across the emulsion interface and the rate of oxidation of bioactive encapsulant. Copyright © 2013 Elsevier B.V. All rights reserved.

pH-induced inversion of water-in-oil emulsions to oil-in-water high internal phase emulsions (HIPEs) using core cross-linked star (CCS) polymer as interfacial stabilizer.

PubMed

Chen, Qijing; Deng, Xiaoyong; An, Zesheng

2014-06-01

A pH-responsive core cross-linked star (CCS) polymer containing poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) arms was used as an interfacial stabilizer for emulsions containing toluene (80 v%) and water (20 v%). In the pH range of 12.1-9.3, ordinary water-in-oil emulsions were formed. Intermediate multiple emulsions of oil-in-water-in-oil and water-in-oil-in-water were formed at pH 8.6 and 7.5, respectively. Further lowering the pH resulted in the formation of gelled high internal phase emulsions of oil-in-water type in the pH range of 6.4-0.6. The emulsion behavior was correlated with interfacial tension, conductivity and configuration of the CCS polymer at different pH. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In situ quantification of β-carotene partitioning in oil-in-water emulsions by confocal Raman microscopy.

PubMed

Wan Mohamad, W A Fahmi; Buckow, Roman; Augustin, MaryAnn; McNaughton, Don

2017-10-15

Confocal Raman microscopy (CRM) was able to quantify the β-carotene concentration in oil droplets and determine the partitioning characteristics of β-carotene within the emulsion system in situ. The results were validated by a conventional method involving solvent extraction of β-carotene separately from the total emulsion as well as the aqueous phase separated by centrifugation, and quantification by absorption spectrophotometry. CRM also enabled the localization of β-carotene in an emulsion. From the Raman image, the β-carotene partitioning between the aqueous and oil phases of palm olein-in-water emulsions stabilized by whey protein isolate (WPI) was observed. Increasing the concentration of β-carotene in an emulsion (from 0.1 to 0.3g/kg emulsion) with a fixed gross composition (10% palm olein:2% WPI) decreased the concentration of β-carotene in the oil droplet. CRM is a powerful tool for in situ analyses of components in heterogeneous systems such as emulsions. Copyright © 2017 Elsevier Ltd. All rights reserved.

The influence of emulsion structure on the Maillard reaction of ghee.

PubMed

Newton, Angela E; Fairbanks, Antony J; Golding, Matt; Andrewes, Paul; Gerrard, Juliet A

2015-04-15

Food systems, such as cream and butter, have an emulsion or emulsion-like structure. When these food emulsions are heated to high temperatures to make products such as ghee, the Maillard reaction forms a range of volatile flavour compounds. The objective of this paper was to unravel the specific influence of emulsion structure on the Maillard reaction pathways that occur during the cooking of ghee using model systems. Switching the dispersed phase from oil to water provided a means of altering the ratios of volatile compounds produced in the cooked samples. The oil-in-water emulsion generated a volatile compound profile similar to that of the fat containing two phase model matrix, whereas the water-in-oil emulsion produced a different ratio of these compounds. The ability to generate different volatile compound profiles through the use of inverted emulsion structures could point to a new avenue for control of the Maillard reaction in high temperature food systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Variation in emulsion stabilization behavior of hybrid silicone polymers with change in molecular structure: Phase diagram study.

PubMed

Mehta, Somil C; Somasundaran, P; Kulkarni, Ravi

2009-05-15

Silicone oils are widely used in cosmetics and personal care applications to improve softness and condition skin and hair. Being insoluble in water and most hydrocarbons, a common mode of delivering them is in the form of emulsions. Currently most applications use polyoxyethylene (non-ionic) modified siloxanes as emulsifiers to stabilize silicone oil emulsions. However, ionically grafted silicone polymers have not received much attention. Ionic silicones have significantly different properties than the non-ionic counterpart. Thus considerable potential exists to formulate emulsions of silicones with different water/silicone oil ratios for novel applications. In order to understand the mechanisms underlying the effects of hydrophilic modifications on the ability of hybrid silicone polymers to stabilize various emulsions, this article focuses on the phase diagram studies for silicone emulsions. The emulsifying ability of functional silicones was seen to depend on a number of factors including hydrophilicity of the polymer, nature of the functional groups, the extent of modification, and the method of emulsification. It was observed that the region of stable emulsion in a phase diagram expanded with increase in shear rate. At a given shear rate, the region of stable emulsion and the nature of emulsion (water-in-oil or oil-in-water) was observed to depend on hydrophilic-hydrophobic balance of the hybrid silicone emulsifier. At a fixed amount of modification, the non-ionically modified silicone stabilized an oil-in-water emulsion, whereas the ionic silicones stabilized inverse water-in-oil emulsions. This was attributed to the greater hydrophilicity of the polyoxyethylene modified silicones than the ionic counterparts. In general, it is postulated that with progressive increase in hydrophilicity of hybrid silicone emulsifiers, their tendency to stabilize water-in-oil emulsion decreases with corresponding increase in oil-in-water emulsion. Further, this behavior is hypothesized to depend on the nature of modifying functional groups. Thus a hybrid silicone polymer can be tailored by selecting the nature and degree of hydrophilicity to obtain a desired silicone emulsion.

The calcium phosphate coating of soy lecithin nanoemulsion with performance in stability and as an oxygen carrier

NASA Astrophysics Data System (ADS)

Han, Kyu B.

This work studied the relationship between surfactant, oil, and water, by building ternary phase diagrams, the goal of which was to identify the oil-in-water phase composition. The resulting nano-sized emulsion was coated with dicalcium phosphate by utilizing the ionic affinity between calcium ions and the emulsion surface. Since the desired function of the particle is as an oxygen carrier, the particle stability, oxygen capacity, and oxygen release rate were investigated. The first step in the process was to construct ternary phase diagrams with 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) and soy derived lecithin. The results showed that the lecithin surfactant formed an oil-in-water phase region that was 36 times greater than that of DOPA. With the desired phase composition set, the lecithin emulsion was extruded, resulting in a well-dispersed nanosized particle. A pH titration study of the emulsion found an optimized calcium phosphate coating condition at pH 8.8, at which, the calcium ion had a greater affinity for the emulsion surface than phosphate. A Hill plot was used to show calcium cooperativeness on the emulsion surface which suggested one calcium ion binds to one lecithin molecule. The lecithin emulsion particles were then coated with calcium phosphate using a layering technique that allowed for careful control of the coating thickness. The overall particle hydrodynamic radius was consistent with the growth of the calcium phosphate coating, from 8 nm to 28 nm. This observation was further supported with cryo-TEM measurements. The stability of the coated emulsion was tested in conditions that simulate practical thermal, physical, and time-dependent conditions. Throughout the tests, the coated emulsion exhibited a constant mono-dispersed particle size, while the uncoated emulsion size fluctuated greatly and exhibited increased polydispersion. The fast mixing method with the stopped-flow apparatus was employed to test the product as an oxygen carrier, and it was shown that particles with thicker calcium phosphate coatings released smaller amounts of oxygen in a given timeframe. This study proved the hypothesis by showing a fundamental understanding of emulsion science, coating the flexible emulsion surface with a biocompatible material, and a strong particle performance with regard to stability and as an oxygen carrier.

Role of continuous phase protein, (-)-epigallocatechin-3-gallate and carrier oil on β-carotene degradation in oil-in-water emulsions.

PubMed

Liu, Lei; Gao, Yanxiang; McClements, David Julian; Decker, Eric Andrew

2016-11-01

The chemical instability of β-carotene limits its utilization as a nutraceutical ingredient in foods. In this research, the effect of continuous phase alpha-lactalbumin (α-LA) and (-)-epigallocatechin-3-gallate (EGCG) on β-carotene degradation in medium chain triacylglycerol (MCT)- and corn oil-in-water emulsions was examined. EGCG significantly inhibited β-carotene degradation in both MCT and corn oil-in-water emulsions in a dose dependent manner. α-LA was not able to protect β-carotene in MCT emulsions and the combination of EGCG and α-LA had a similar effect as EGCG alone. EGCG had no effect on lipid oxidation in corn oil-in-water emulsions but can protect β-carotene. β-Carotene was more stable in corn oil emulsions stabilized by α-LA compared to emulsions stabilized by Tween 20. These results show that EGCG is effective at protecting β-carotene in different emulsion systems without negatively impacting lipid oxidation suggesting that it could be utilized to increase the incorporation of β-carotene into food emulsions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation of l-phenylalanine-imprinted solid-phase extraction sorbent by Pickering emulsion polymerization and the selective enrichment of l-phenylalanine from human urine.

PubMed

Li, Ji; Hu, Xiaoling; Guan, Ping; Zhang, Xiaoyan; Qian, Liwei; Zhang, Nan; Du, Chunbao; Song, Renyuan

2016-05-01

A novel l-phenylalanine molecularly imprinted solid-phase extraction sorbent was synthesized by the combination of Pickering emulsion polymerization and ion-pair dummy template imprinting. Compared to other polymerization methods, the molecularly imprinted polymers thus prepared exhibit a high specific surface, large pore diameter, and appropriate particle size. The key parameters for solid-phase extraction were optimized, and the result indicated that the molecularly imprinted polymer thus prepared exhibits a good recovery of 98.9% for l-phenylalanine. Under the optimized conditions of the procedure, an analytical method for l-phenylalanine was well established. By comparing the performance of the molecularly imprinted polymer and a commercial reverse-phase silica gel, the obtained molecularly imprinted polymer as an solid-phase extraction sorbent is more suitable, exhibiting high precision (relative standard deviation 3.2%, n = 4) and a low limit of detection (60.0 ± 1.9 nmol·L(-1) ) for the isolation of l-phenylalanine. Based on these results, the combination of the Pickering emulsion polymerization and ion-pair dummy template imprinting is effective for preparing selective solid-phase extraction sorbents for the separation of amino acids and organic acids from complex biological samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Early Dynamics and Stabilization Mechanisms of Oil-in-Water Emulsions Containing Colloidal Particles Modified with Short Amphiphiles: A Numerical Study.

PubMed

Cerbelaud, Manuella; Videcoq, Arnaud; Alison, Lauriane; Tervoort, Elena; Studart, André R

2017-12-19

Emulsions stabilized by mixtures of particles and amphiphilic molecules are relevant for a wide range of applications, but their dynamics and stabilization mechanisms on the colloidal level are poorly understood. Given the challenges to experimentally probe the early dynamics and mechanisms of droplet stabilization, Brownian dynamics simulations are developed here to study the behavior of oil-in-water emulsions stabilized by colloidal particles modified with short amphiphiles. Simulation parameters are based on an experimental system that consists of emulsions obtained with octane as the oil phase and a suspension of alumina colloidal particles modified with short carboxylic acids as the continuous aqueous medium. The numerical results show that attractive forces between the colloidal particles favor the formation of closely packed clusters on the droplet surface or of a percolating network of particles throughout the continuous phase, depending on the amphiphile concentration. Simulations also reveal the importance of a strong adsorption of particles at the liquid interface to prevent their depletion from the droplet surface when another droplet approaches. Strongly adsorbed particles remain immobile on the droplet surface, generating an effective steric barrier against droplet coalescence. These findings provide new insights into the early dynamics and mechanisms of stabilization of emulsions using particles and amphiphilic molecules.

Physical stability of R-(+)-Limonene emulsions stabilized by Ulva fasciata algae polysaccharide.

PubMed

Shao, Ping; Ma, Huiling; Qiu, Qiang; Jing, Weiping

2016-11-01

The physical stability of R-(+)-Limonene emulsions stabilized by Ulva fasciata polysaccharide (UFP) was investigated in this study. Emulsion physical stability was evaluated under different polysaccharide concentrations (1%-5%, wt/wt) and pH values (3.0-11.0). The stability of R-(+)-Limonene emulsions was demonstrated by droplet size distribution, rheological properties, zeta potential and visual phase separation. R-(+)-Limonene emulsions displayed monomodal droplet size distributions, high absolute values of zeta potential and good storage stability when 3% (wt/wt) UFP was used. The rheological properties and stability of R-(+)-Limonene emulsions appeared to be dependent on polysaccharide concentration. The emulsion stability was impacted by pH. Higher zeta potential (-52.6mV) and smaller mean droplet diameter (2.45μm) were achieved in neutral liquid environment (pH 7.0). Extreme acidity caused the flocculation of emulsions, which was manifested as phase separation, while emulsions were quite stable in an alkaline environment. Through comparing the stabilities of emulsions stabilized by different emulsifiers (i.e. UFP, GA and Gelatin), the result suggested that UFP was the best emulsifying agent among them. Copyright © 2016 Elsevier B.V. All rights reserved.

Grape seed and apple tannins: emulsifying and antioxidant properties.

PubMed

Figueroa-Espinoza, Maria Cruz; Zafimahova, Andrea; Alvarado, Pedro G Maldonado; Dubreucq, Eric; Poncet-Legrand, Céline

2015-07-01

Tannins are natural antioxidants found in plant-based foods and beverages, whose amphiphilic nature could be useful to both stabilize emulsions and protect unsaturated lipids from oxidation. In this paper, the use of tannins as antioxidant emulsifiers was studied. The main parameters influencing the stability of emulsions (i.e. tannins structure and concentration, aqueous phase pH, and ionic strength) were identified and optimized. Oil in water emulsions stabilized with tannins were compared with those stabilized with two commercial emulsifying agents, poly(vinyl alcohol) (PVA) and polyoxyethylene hydrogenated castor oil. In optimized conditions, the condensed tannins allowed to obtain a stability equivalent to that of PVA. Tannins presented good antioxidant activity in oil in water emulsion, as measured by the conjugated autoxidizable triene (CAT) assay. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of palmitoyl pentapeptide and Ceramide III B on the droplet size of nanoemulsion

NASA Astrophysics Data System (ADS)

Sondari, Dewi; Haryono, Agus; Harmami, Sri Budi; Randy, Ahmad

2010-05-01

The influence of the Palmitoyl Pentapeptide (PPp) and Ceramide IIIB (Cm III B) as active ingredients on the droplet size of nano-emulsion was studied using different kinds of oil (avocado oil, sweet almond oil, jojoba oil, mineral oil and squalene). The formation of nano-emulsions were prepared in water mixed non ionic surfactant/oils system using the spontaneous emulsification mechanism. The aqueous solution, which consist of water and Tween® 20 as a hydrophilic surfactant was mixed homogenously. The organic solution, which consist of oil and Span® 80 as a lipophilic surfactant was mixed homogenously in ethanol. Ethanol was used as a water miscible solvent, which can help the formation of nano-emulsion. The oil phase (containing the blend of surfactant Span® 80, ethanol, oil and active ingredient) and the aqueous phase (containing water and Tween® 20) were separately prepared at room temperatures. The oil phase was slowly added into aqueous phase under continuous mechanical agitation (18000 rpm). All samples were subsequently homogenized with Ultra-Turrax for 30 minutes. The characterizations of nano-emulsion were carried out using photo-microscope and particle size analyzer. Addition of active ingredients on the formation of nano-emulsion gave smallest droplet size compared without active ingredients addition on the formation of nano-emulsion. Squalene oil with Palmitoyl Pentapeptide (PPm) and Ceramide IIIB (Cm IIIB) gave smallest droplet size (184.0 nm) compared without Palmitoyl Pentapeptide and Ceramide IIIB (214.9 nm), however the droplets size of the emulsion prepared by the other oils still in the range of nano-emulsion (below 500 nm). The stability of nano-emulsion was observed using two methods. In one method, the stability of nano-emulsion was observed for three months at temperature of 5°C and 50°C, while in the other method, the stability nano-emulsion was observed by centrifuged at 12000 rpm for 30 minutes. Nanoemulsion with active ingredient was remained stable even when stored until three months. Coalescence process between the droplets was not occurred significantly and droplet size was still below 500 nm. Over all, the emulsion remained stable, even it was centrifuged at 12000 rpm for 30 minutes.

PHYSICAL AND CHEMICAL STABILITY ANALYSIS OF COSMETIC MULTI- PLE EMULSIONS LOADED WITH ASCORBYL PALMITATE AND SODIUM ASCORBYL PHOSPHATE SALTS.

PubMed

Khan, Hira; Akhtar, Naveed; Ali, Atif; Khan, Haji M Shoaib; Sohail, Muhammad; Naeem, Muhammad; Nawaz, Zarqa

2016-09-01

Stability of hydrophilic and lipophilic vitamin C derivatives for quenching synergistic antioxidant activities and to treat oxidative related diseases is a major issue. This study was aimed to encapsulate hydrophilic and lipophilic vitamin C derivatives (ascorbyl palmitate and sodium ascorbyl phosphate) as functional ingredients in a newly formulated multiple emulsion of the W//W type to attain the synergistic antioxidant effects and the resultant system's long term physical and chemical stability. Several multiple emulsions using the same concentration of emulsifiers but different concentrations of ascorbyl palmitate and sodium ascorbyl phosphate were developed. Three finally selected multiple emulsions (ME₁, ME₂ and ME₃) were evaluated for physical stability in terms of rheology, microscopy, conductivity, pH, and organoleptic characteristics under different storage conditions for 3 months. Chemical stability was determined by HPLC on Sykam GmbH HPLC system (Germany), equipped with a variable UV detector. Results showed that at accelerated storage conditions all the three multiple emulsions had shear thinning behavior of varying shear stress with no influence of location of functional ingredients in a carrier system. Conductivity values increased and pH values remained within the skin pH range for 3 months. Microscopic analysis showed an increase in globule size with the passage of time, especially at higher temperatures while decreased at low temperatures. Centrifugation test did not cause phase separation till the 45th day, but little effects after 2 months. Chemical stability analysis by HPLC at the end of 3 months showed that ascorbyl palmitate and sodium ascorbyl phosphate were almost stable in all multiple emulsions with no influence of their location in a carrier system. Multiple emulsions were found a stable carrier for hydrophilic and lipophilic vitamin C derivatives to enhance their desired effects. Considering that many topical formulations contain simple vitamin C it is suggested that present study may contribute to the development of more stable formulations with a combination of vitamin C derivatives to enhance their cosmetic benefits.

Multiple emulsions controlled by stimuli-responsive polymers.

PubMed

Besnard, Lucie; Marchal, Frédéric; Paredes, Jose F; Daillant, Jean; Pantoustier, Nadège; Perrin, Patrick; Guenoun, Patrick

2013-05-28

The phase inversion of water-toluene emulsions stabilized with a single thermo- and pH-sensitive copolymer occurs through the formation of multiple emulsions. At low pH and ambient temperature, oil in water emulsions are formed which transform into highly stable multiple emulsions at pHs immediately lower than the inversion border. At higher pHs, the emulsion turns into a water in oil one. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Uniform discotic wax particles via electrospray emulsification.

PubMed

Mejia, Andres F; He, Peng; Luo, Dawei; Marquez, Manuel; Cheng, Zhengdong

2009-06-01

We present a novel colloidal discotic system: the formation and self-assembling of wax microdisks with a narrow size distribution. Uniform wax emulsions are first fabricated by electrospraying of melt alpha-eicosene. The size of the emulsions can be flexibly tailored by varying the flow rate of the discontinuous phase, its electric conductivity, and the applied voltage. The process of entrainment of wax droplets, vital for obtaining uniform emulsions, is facilitated by the reduction of air-water surface tension and the density of the continuous phase. Then uniform wax discotic particles are produced via phase transition, during which the formation of a layered structure of the rotator phase of wax converts the droplets, one by one, into oblate particles. The time span for the conversion from spherical emulsions to disk particles is linearly dependent on the size of droplets in the emulsion, indicating the growth of a rotator phase from surface to the center is the limiting step in the shape transition. Using polarized light microscopy, the self-assembling of wax disks is observed by increasing disk concentration and inducing depletion attraction among disks, where several phases, such as isotropic, condensed, columnar stacking, and self-assembly of columnar rods are present sequentially during solvent evaporation of a suspension drop.

Electric field-driven, magnetically-stabilized ferro-emulsion phase contactor

DOEpatents

Scott, T.C.

1990-07-17

Methods and systems are disclosed for interfacial surface area contact between a dispersed phase liquid and a continuous phase liquid in counter-current flow for purposes such as solvent extraction. Initial droplets of a dispersed phase liquid material containing ferromagnetic particles functioning as a packing'' are introduced to a counter-current flow of the continuous phase. A high intensity pulsed electric field is applied so as to shatter the initial droplets into a ferromagnetic emulsion comprising many smaller daughter droplets having a greater combined total surface area than that of the initial droplets in contact with the continuous phase material. A magnetic field is applied to control the position of the ferromagnetic emulsion for enhanced coalescence of the daughter droplets into larger reformed droplets. 2 figs.

Electric field-driven, magnetically-stabilized ferro-emulsion phase contactor

DOEpatents

Scott, Timothy C.

1990-01-01

Methods and systems for interfacial surface area contact between a dispersed phase liquid and a continuous phase liquid in counter-current flow for purposes such as solvent extraction. Initial droplets of a dispersed phase liquid material containing ferromagnetic particles functioning as a "packing" are introduced to a counter-current flow of the continuous phase. A high intensity pulsed electric field is applied so as to shatter the initial droplets into a ferromagnetic emulsion comprising many smaller daughter droplets having a greater combined total surface area than that of the initial droplets in contact with the continuous phase material. A magnetic field is applied to control the position of the ferromagnetic emulsion for enhanced coalescence of the daughter droplets into larger reformed droplets.

Influence of surfactant on the thermal behavior of marigold oil emulsions with liquid crystal phases.

PubMed

dos Santos, Orlando David Henrique; da Rocha-Filho, Pedro Alves

2007-05-01

Vegetable oils have been largely consumed owing to the interest of pharmaceutical and cosmetic industries in using natural raw materials. The production of stable emulsions with vegetable oils challenges formulators due to its variability in composition and fatty acids constitution within batches produced. In the present work, it was studied that the influence of the size of carbon chain and the number of ethylene oxide moieties of the surfactant on the thermal behavior of eight emulsions prepared with marigold oil stabilized by liquid crystal phases. Differential scanning calorimetry (DSC) was used to determine the thermal behavior of the emulsions. The ratio of bound water was calculated, being between 29.0 and 42.0%, confirming the extension of the liquid-crystalline net in the external phase. Changing the lipophilic surfactant from Ceteth-2 to Steareth-2, there was an increase in the temperature of phase transition of the liquid crystal influencing the system stability. Calorimetric study is very useful in understanding the performance of liquid crystals with the increase of temperature and to estimate emulsions stability.

Decoupling of mass transport mechanisms in the stagewise swelling of multiple emulsions.

PubMed

Bahtz, Jana; Gunes, Deniz Z; Hughes, Eric; Pokorny, Lea; Riesch, Francesca; Syrbe, Axel; Fischer, Peter; Windhab, Erich J

2015-05-19

This contribution reports on the mass transport kinetics of osmotically imbalanced water-in-oil-in-water (W1/O/W2) emulsions. Although frequently studied, the control of mass transport in W1/O/W2 emulsions is still challenging. We describe a microfluidics-based method to systematically investigate the impact of various parameters, such as osmotic pressure gradient, oil phase viscosity, and temperature, on the mass transport. Combined with optical microscopy analyses, we are able to identify and decouple the various mechanisms, which control the dynamic droplet size of osmotically imbalanced W1/O/W2 emulsions. So, swelling kinetics curves with a very high accuracy are generated, giving a basis for quantifying the kinetic aspects of transport. Two sequential swelling stages, i.e., a lag stage and an osmotically dominated stage, with different mass transport mechanisms are identified. The determination and interpretation of the different stages are the prerequisite to control and trigger the swelling process. We show evidence that both mass transport mechanisms can be decoupled from each other. Rapid osmotically driven mass transport only takes place in a second stage induced by structural changes of the oil phase in a lag stage, which allow an osmotic exchange between both water phases. Such structural changes are strongly facilitated by spontaneous water-in-oil emulsification. The duration of the lag stage is pressure-independent but significantly influenced by the oil phase viscosity and temperature.

A Robust Oil-in-Oil Emulsion for the Nonaqueous Encapsulation of Hydrophilic Payloads.

PubMed

Lu, Xiaocun; Katz, Joshua S; Schmitt, Adam K; Moore, Jeffrey S

2018-03-14

Compartmentalized structures widely exist in cellular systems (organelles) and perform essential functions in smart composite materials (microcapsules, vasculatures, and micelles) to provide localized functionality and enhance materials' compatibility. An entirely water-free compartmentalization system is of significant value to the materials community as nonaqueous conditions are critical to packaging microcapsules with water-free hydrophilic payloads while avoiding energy-intensive drying steps. Few nonaqueous encapsulation techniques are known, especially when considering just the scalable processes that operate in batch mode. Herein, we report a robust oil-in-oil Pickering emulsion system that is compatible with nonaqueous interfacial reactions as required for encapsulation of hydrophilic payloads. A major conceptual advance of this work is the notion of the partitioning inhibitor-a chemical agent that greatly reduces the payload's distribution between the emulsion's two phases, thus providing appropriate conditions for emulsion-templated interfacial polymerization. As a specific example, an immiscible hydrocarbon-amine pair of liquids is emulsified by the incorporation of guanidinium chloride (GuHCl) as a partitioning inhibitor into the dispersed phase. Polyisobutylene (PIB) is added into the continuous phase as a viscosity modifier for suitable modification of interfacial polymerization kinetics. The combination of GuHCl and PIB is necessary to yield a robust emulsion with stable morphology for 3 weeks. Shell wall formation was accomplished by interfacial polymerization of isocyanates delivered through the continuous phase and polyamines from the droplet core. Diethylenetriamine (DETA)-loaded microcapsules were isolated in good yield, exhibiting high thermal and chemical stabilities with extended shelf-lives even when dispersed into a reactive epoxy resin. The polyamine phase is compatible with a variety of basic and hydrophilic actives, suggesting that this encapsulation technology is applicable to other hydrophilic payloads such as polyols, aromatic amines, and aromatic heterocyclic bases. Such payloads are important for the development of extended pot or shelf life systems and responsive coatings that report, protect, modify, and heal themselves without intervention.

Microfluidic control of droplet formation from stable emulsions formed by aqueous two-phase systems

NASA Astrophysics Data System (ADS)

Teixeira, Alyne G.; Tsai, Meng-Chiao; Frampton, John P.

2018-02-01

Aqueous two-phase systems (ATPSs) form from the thermodynamic separation of two dissolved incompatible solutes, such as two polymers, a polymer and a salt, and a polymer and a surfactant. At most supercritical concentrations, ATPS emulsions can be formed by vigorous mixing. These emulsions typically settle into distinct layers in minutes to hours. However, it is also possible to choose ATPS compositions with extremely long settling times that resemble stable emulsions. Here, we generated stable emulsions from a polyethylene glycol (PEG)-dextran ATPS by selecting ATPS compositions at the extreme ends of the tie lines connecting the binodal curve delineating phase-separating compositions. Droplets of PEG in a continuous dextran phase did not coalesce appreciably over the course of several days when stored in a conical tube or syringe. However, upon exposure to laminar flow conditions in a microfluidic channel, droplets were observed to coalesce. Through microscopic characterization of droplet volume, an increase in droplet size and decrease in overall droplet number was observed as a function of channel distance, suggesting a progressive droplet merging phenomenon. This novel approach to control droplet size by encouraging coalescence of stable emulsions under laminar flow in a microfluidic channel enables the production of droplets ranging from fL to several pL, which may enable various future biotechnology applications.

BACLOFEN, RACLOPRIDE, AND NALTREXONE DIFFERENTIALLY REDUCE SOLID FAT EMULSION INTAKE UNDER LIMITED ACCESS CONDITIONS

PubMed Central

RE, Rao; FHE, Wojnicki; J, Coupland; S, Ghosh; RLW, Corwin

2009-01-01

Previous work in rats has demonstrated that an Intermittent (Monday, Wednesday, Friday) schedule of access promotes binge-type consumption of 100% vegetable shortening during a 1-hour period of availability. The present study used novel shortening-derived stable solid emulsions of various fat concentrations. These emulsions were the consistency of pudding and did not demonstrate oil and water phase separation previously reported with oil-based liquid emulsions. Male Sprague-Dawley rats were grouped according to schedule of access (Daily or Intermittent) to one of three concentrations (18%, 32%, 56%) of solid fat emulsion. There were no significant Intermittent vs. Daily differences in amount consumed, due to high intakes in all groups. This indicated the acceptability of the emulsions. Baclofen (GABA-B agonist) and raclopride (D2-like antagonist) both significantly reduced emulsion intake in all Daily groups, but only in the 56% fat Intermittent group. Naltrexone (opioid antagonist), in contrast, significantly reduced 32% and 56% fat emulsion intake in the Intermittent, as well as the Daily groups. These results indicate that the fat intake reducing effects of GABAB activation and D2 blockade depend upon fat concentration and schedule of fat access, while the fat intake reducing effects of opioid blockade depend upon fat concentration but not schedule of access. PMID:18353432

Characterization of starch Pickering emulsions for potential applications in topical formulations.

PubMed

Marku, Diana; Wahlgren, Marie; Rayner, Marilyn; Sjöö, Malin; Timgren, Anna

2012-05-30

The aim of this work has been to characterize starch based Pickering emulsions as a first step to evaluate their possible use as vehicles for topical drug delivery. A minor phase study of emulsions with high oil content has been performed. Emulsion stability against coalescence over eight weeks and after mild centrifugation treatment has been studied. The particle size, rheological properties and in vitro skin penetration of emulsions containing three different oils (Miglyol, paraffin and sheanut oil) was investigated. It was shown that it is possible to produce oil in water starched stabilised Pickering emulsions with oil content as high as 56%. Furthermore, this emulsions show good stability during storage over eight weeks and towards mild centrifugation. The particle size of the systems are only dependent on the ratio between oil and starch and for liquid oils the type of oil do not affect the particle size. The type of oil also affects the cosmetic and rheological properties of the creams but did not affect the transdermal diffusion in in vitro tests. However, it seems as if the Pickering emulsions affected the transport over the skin, as the flux was twice that of what has been previously reported for solutions. Copyright © 2012 Elsevier B.V. All rights reserved.

Biopolymer-based structuring of liquid oil into soft solids and oleogels using water-continuous emulsions as templates.

PubMed

Patel, Ashok R; Rajarethinem, Pravin S; Cludts, Nick; Lewille, Benny; De Vos, Winnok H; Lesaffer, Ans; Dewettinck, Koen

2015-02-24

Physical trapping of a hydrophobic liquid oil in a matrix of water-soluble biopolymers was achieved using a facile two-step process by first formulating a surfactant-free oil-in-water emulsion stabilized by biopolymers (a protein and a polysaccharide) followed by complete removal of the water phase (by either high- or low-temperature drying of the emulsion) resulting in structured solid systems containing a high concentration of liquid oil (above 97 wt %). The microstructure of these systems was revealed by confocal and cryo-scanning electron microscopy, and the effect of biopolymer concentrations on the consistency of emulsions as well as the dried product was evaluated using a combination of small-amplitude oscillatory shear rheometry and large deformation fracture studies. The oleogel prepared by shearing the dried product showed a high gel strength as well as a certain degree of thixotropic recovery even at high temperatures. Moreover, the reversibility of the process was demonstrated by shearing the dried product in the presence of water to obtain reconstituted emulsions with rheological properties comparable to those of the fresh emulsion.

One-pot, single-component synthesis of functional emulsion-templated hybrid inorganic-organic polymer capsules.

PubMed

Harbron, Rachel L; McDonald, Tom O; Rannard, Steve P; Findlay, Paul H; Weaver, Jonathan V M

2012-02-01

Multi-purpose amphiphilic branched copolymer surfactants can be used to simultaneously stabilise and cross-link emulsion droplets to produce encapsulated spheres and hollow capsules. This journal is © The Royal Society of Chemistry 2012

One-step formation of w/o/w multiple emulsions stabilized by single amphiphilic block copolymers.

PubMed

Hong, Liangzhi; Sun, Guanqing; Cai, Jinge; Ngai, To

2012-02-07

Multiple emulsions are complex polydispersed systems in which both oil-in-water (O/W) and water-in-oil (W/O) emulsion exists simultaneously. They are often prepared accroding to a two-step process and commonly stabilized using a combination of hydrophilic and hydrophobic surfactants. Recently, some reports have shown that multiple emulsions can also be produced through one-step method with simultaneous occurrence of catastrophic and transitional phase inversions. However, these reported multiple emulsions need surfactant blends and are usually described as transitory or temporary systems. Herein, we report a one-step phase inversion process to produce water-in-oil-in-water (W/O/W) multiple emulsions stabilized solely by a synthetic diblock copolymer. Unlike the use of small molecule surfactant combinations, block copolymer stabilized multiple emulsions are remarkably stable and show the ability to separately encapsulate both polar and nonpolar cargos. The importance of the conformation of the copolymer surfactant at the interfaces with regards to the stability of the multiple emulsions using the one-step method is discussed.

Controlling Pickering Emulsion Destabilisation: A Route to Fabricating New Materials by Phase Inversion

PubMed Central

Whitby, Catherine P.; Wanless, Erica J.

2016-01-01

The aim of this paper is to review the key findings about how particle-stabilised (or Pickering) emulsions respond to stress and break down. Over the last ten years, new insights have been gained into how particles attached to droplet (and bubble) surfaces alter the destabilisation mechanisms in emulsions. The conditions under which chemical demulsifiers displace, or detach, particles from the interface were established. Mass transfer between drops and the continuous phase was shown to disrupt the layers of particles attached to drop surfaces. The criteria for causing coalescence by applying physical stress (shear or compression) to Pickering emulsions were characterised. These findings are being used to design the structures of materials formed by breaking Pickering emulsions. PMID:28773747

Oil-in-Water Emulsions Stabilized by Saponified Epoxidized Soybean Oil-Grafted Hydroxyethyl Cellulose.

PubMed

Huang, Xujuan; Li, Qiaoguang; Liu, He; Shang, Shibin; Shen, Minggui; Song, Jie

2017-05-03

An oil-in-water emulsion stabilized by saponified epoxidized soybean oil-grafted hydroxyethyl cellulose (H-ESO-HEC) was investigated. By using an ultrasonic method, oil-in-water emulsions were prepared by blending 50 wt % soybean oil and 50 wt % H-ESO-HEC aqueous suspensions. The influence of H-ESO-HEC concentrations on the properties of oil-in-water emulsions was examined. The H-ESO-HEC concentrations in the aqueous phase varied from 0.02 to 0.40 wt %. When the H-ESO-HEC concentration was 0.4 wt %, the emulsion remained stable for >80 days. The mean droplet sizes of the emulsions decreased by increasing the H-ESO-HEC concentration and extending the ultrasonic time. The adsorption amounts of H-ESO-HEC at the oil-water interface increased when the H-ESO-HEC concentrations in the aqueous phase increased. The rheological property revealed that the apparent viscosity of the H-ESO-HEC-stabilized oil-in-water emulsions increased when the H-ESO-HEC concentrations increased. Steady flow curves indicated an interfacial film formation in the emulsions. The evolution of G', G″, and tan η indicated the predominantly elastic behaviors of all the emulsions.

Emulsions of crude glycerin from biodiesel processing with fuel oil for industrial heating.

PubMed

Mize, Hannah E; Lucio, Anthony J; Fhaner, Cassie J; Pratama, Fredy S; Robbins, Lanny A; Karpovich, David S

2013-02-13

There is considerable interest in using crude glycerin from biodiesel production as a heating fuel. In this work crude glycerin was emulsified into fuel oil to address difficulties with ignition and sustained combustion. Emulsions were prepared with several grades of glycerin and two grades of fuel oil using direct and phase inversion emulsification. Our findings reveal unique surfactant requirements for emulsifying glycerin into oil; these depend on the levels of several contaminants, including water, ash, and components in MONG (matter organic non-glycerin). A higher hydrophile-lipophile balance was required for a stable emulsion of crude glycerin in fuel oil compared to water in fuel oil. The high concentration of salts from biodiesel catalysts generally hindered emulsion stability. Geometric close-packing of micelles was carefully balanced to mechanically stabilize emulsions while also enabling low viscosity for pumping and fuel injection. Phase inversion emulsification produced more stable emulsions than direct emulsification. Emulsions were tested successfully as fuel for a waste oil burner.

Highly Transparent w/o Pickering Emulsions without Adjusting the Refractive Index of the Stabilizing Particles.

PubMed

Sihler, Susanne; Lindén, Mika; Ziener, Ulrich

2017-10-03

Pickering emulsions with a remarkable transmittance of up to 86% across the visible spectrum have been prepared without adjusting the refractive index (RI) of the stabilizing particles to those of the aqueous and oil phases. Commercially available hydrophilic silica particles with a diameter of 20 nm, which are hydrophobized partially in situ, were used to stabilize water droplets with diameters below 400 nm in IsoparM. In this system, the stabilizing particles and the emulsion droplets act as one single scattering object, which renders RI-matching of the particles unnecessary. By either evaporation of some water from the droplets or addition of an appropriate organic liquid to the oil phase, it is possible to match the RI of the droplets (aqueous phase + particles) with that of the continuous phase, which minimizes scattering and results in highly transparent emulsions.

Influence of the oil globule fraction on the release rate profiles from multiple W/O/W emulsions.

PubMed

Bonnet, Marie; Cansell, Maud; Placin, Frédéric; Monteil, Julien; Anton, Marc; Leal-Calderon, Fernando

2010-06-15

Water-in-oil-in-water (W/O/W) double emulsions were prepared and the kinetics of release of magnesium ions from the internal to the external water phase was investigated as a function of the formulation and the globule volume fraction. All the emulsions were formulated using the same surface-active species (polyglycerol polyricinoleate and sodium caseinate). Also, the internal droplet and oil globule diameters were almost identical for all the systems. Two types of W/O/W emulsions were prepared based either on a synthetic oil (miglyol) or on an edible oil (olive oil). The globule volume fraction varied from 11% to 72%. At constant temperature (T=25 degrees C) and irrespective of the oil type, the percentage of magnesium released was lowered by increasing the globule fraction. In all cases, magnesium leakage occurred without film rupturing (no coalescence). Thus, the experimental data were interpreted within the frame of a model based on diffusion. The rate of release was determined by the permeation coefficient of magnesium across the oil phase and by the binding (chelation) of magnesium by caseinate molecules. The data could be adequately fitted by considering a time-dependant permeation coefficient. The better retention of magnesium at high globule fractions could account for two distinct phenomena: (i) the reduction of the relative volume of the outer phase, and (ii) the attenuation of the permeation coefficient over time induced by interfacial magnesium binding, all the more important than the globule fraction increased. Copyright 2010 Elsevier B.V. All rights reserved.

Analytical Characterization of an Oil-in-Water Adjuvant Emulsion.

PubMed

Sun, Jenny; Remmele, Richard L; Sanyal, Gautam

2017-07-01

Adjuvants are typically used in subunit vaccine formulations to enhance immune responses elicited by individual antigens. Physical chemical characterization of novel adjuvants is an important step in ensuring their effective use in vaccine formulations. This paper reports application of a panel of quantitative assays developed to analyze and characterize an oil-in-water adjuvant emulsion, which contains glucopyranosyl lipid A (GLA) and is a squalene-based emulsion. GLA is a fully synthetic analogue of monophosphoryl lipid A, which is a Toll-like receptor type 4 agonist and an FDA-approved adjuvant. The GLA-stable emulsion (GLA-SE) is currently being used for a respiratory syncytial virus vaccine in a phase 2 clinical trial. GLA was quantitated using reverse-phased high-performance liquid chromatography (RP-HPLC) coupled to a mass spectrometric detector, achieving higher assay sensitivity than the charged aerosol detection routinely used. Quantitation of the excipients of GLA-SE, including squalene, egg phosphatidyl choline, and Poloxamer 188, was achieved using a simple and rapid RP-HPLC method with evaporative light scattering detection, eliminating chemical derivatization typically required for these chromophore-lacking compounds. DL-α-tocopherol, the antioxidant of the GLA-SE, was quantitated using a RP-HPLC method with conventional UV detection. The experimental results compared well with values expected for these compounds based on targeted composition of the adjuvant. The assays were applied to identify degradation of individual components in a GLA-SE sample that degraded into distinct aqueous and oil phases. The methods developed and reported here are effective tools in monitoring physicochemical integrity of the adjuvant, as well as in formulation studies.

Efficiency and protective effect of encapsulation of milk immunoglobulin G in multiple emulsion.

PubMed

Chen, C C; Tu, Y Y; Chang, H M

1999-02-01

Milk immunoglobulin G (IgG), separated with protein G affinity chromatography, and IgG in colostral whey were encapsulated by 0.5% (w/v) of Tween 80, sucrose stearate, or soy protein, which were used as secondary emulsifiers in the water in oil in water type multiple emulsion. The residual contents of separated IgG and IgG in colostral whey, ranging from 58.7 to 49.7% and from 13.2 to 21.3%, respectively, in the inner water phase (water phase surrounded by oil phase) with emulsifiers were determined by ELISA. However, the emulsion stability decreased after 24 h, and the residual IgG content in the inner water phase was lowered. Encapsulation of IgG in the multiple emulsion increased the stability of separated IgG against acid (pH 2.0) and alkali (pH 12.0) by 21-56% and 33-62%, respectively, depending on the emulsifier used. Moreover, multiple emulsion also provided a remarkable protective effect on separated IgG stability against proteases. The residual contents of separated IgG in multiple emulsion, using Tween 80 as secondary emulsifier, incubated for 2 h with pepsin (pH 2.0) and trypsin and chymotrypsin (pH 7.6) (enzyme/substrate = 1/20) were 35.4, 72.5, and 82.3%, whereas those of separated IgG in enzyme solution were only 7.2, 33. 1, and 35.2%, respectively. However, the separated IgG loss during the preparation of multiple emulsion was almost 41-50%.

Water-in-Water Emulsion Based Synthesis of Hydrogel Nanospheres with Tunable Release Kinetics

NASA Astrophysics Data System (ADS)

Aydın, Derya; Kızılel, Seda

2017-07-01

Poly(ethylene glycol) (PEG) micro/nanospheres have several unique advantages as polymer based drug delivery systems (DDS) such as tunable size, large surface area to volume ratio, and colloidal stability. Emulsification is one of the widely used methods for facile synthesis of micro/nanospheres. Two-phase aqueous system based on polymer-polymer immiscibility is a novel approach for preparation of water-in-water (w/w) emulsions. This method is promising for the synthesis of PEG micro/nanospheres for biological systems, since the emulsion is aqueous and do not require organic solvents or surfactants. Here, we report the synthesis of nano-scale PEG hydrogel particles using w/w emulsions using phase separation of dextran and PEG prepolymer. Dynamic light scattering (DLS) and scaning electron microscopy (SEM) results demonstrated that nano-scale hydrogel spheres could be obtained with this approach. We investigated the release kinetics of a model drug, pregabalin (PGB) from PEG nanospheres and demonstrated the influence of polymerization conditions on loading and release of the drug as well as the morphology and size distribution of PEG nanospheres. The experimental drug release data was fitted to a stretched exponential function which suggested high correlation with experimental results to predict half-time and drug release rates from the model equation. The biocompatibility of nanospheres on human dermal fibroblasts using cell-survival assay suggested that PEG nanospheres with altered concentrations are non-toxic, and can be considered for controlled drug/molecule delivery.

Transformation of eutectic emulsion to nanosuspension fabricating with solvent evaporation and ultrasonication technique

PubMed Central

Phaechamud, Thawatchai; Tuntarawongsa, Sarun

2016-01-01

Eutectic solvent can solubilize high amount of some therapeutic compounds. Volatile eutectic solvent is interesting to be used as solvent in the preparation of nanosuspension with emulsion solvent evaporation technique. The mechanism of transformation from the eutectic emulsion to nanosuspension was investigated in this study. The 30% w/w ibuprofen eutectic solution was used as the internal phase, and the external phase is composed of Tween 80 as emulsifier. Ibuprofen nanosuspension was prepared by eutectic emulsion solvent evaporating method followed with ultrasonication. During evaporation process, the ibuprofen concentration in emulsion droplets was increased leading to a drug supersaturation but did not immediately recrystallize because of low glass transition temperature (Tg) of ibuprofen. The contact angle of the internal phase on ibuprofen was apparently lower than that of the external phase at all times of evaporation, indicating that the ibuprofen crystals were preferentially wetted by the internal phase than the external phase. From calculated dewetting value ibuprofen crystallization occurred in the droplet. Crystallization of the drug was initiated with external mechanical force, and the particle size of the drug was larger due to Ostwald ripening. Cavitation force from ultrasonication minimized the ibuprofen crystals to the nanoscale. Particle size and zeta potential of formulated ibuprofen nanosuspension were 330.87±51.49 nm and −31.1±1.6 mV, respectively, and exhibited a fast dissolution. Therefore, the combination of eutectic emulsion solvent evaporation method with ultrasonication was favorable for fabricating an ibuprofen nanosuspension, and the transformation mechanism was attained successfully. PMID:27366064

Transformation of eutectic emulsion to nanosuspension fabricating with solvent evaporation and ultrasonication technique.

PubMed

Phaechamud, Thawatchai; Tuntarawongsa, Sarun

2016-01-01

Eutectic solvent can solubilize high amount of some therapeutic compounds. Volatile eutectic solvent is interesting to be used as solvent in the preparation of nanosuspension with emulsion solvent evaporation technique. The mechanism of transformation from the eutectic emulsion to nanosuspension was investigated in this study. The 30% w/w ibuprofen eutectic solution was used as the internal phase, and the external phase is composed of Tween 80 as emulsifier. Ibuprofen nanosuspension was prepared by eutectic emulsion solvent evaporating method followed with ultrasonication. During evaporation process, the ibuprofen concentration in emulsion droplets was increased leading to a drug supersaturation but did not immediately recrystallize because of low glass transition temperature (T g) of ibuprofen. The contact angle of the internal phase on ibuprofen was apparently lower than that of the external phase at all times of evaporation, indicating that the ibuprofen crystals were preferentially wetted by the internal phase than the external phase. From calculated dewetting value ibuprofen crystallization occurred in the droplet. Crystallization of the drug was initiated with external mechanical force, and the particle size of the drug was larger due to Ostwald ripening. Cavitation force from ultrasonication minimized the ibuprofen crystals to the nanoscale. Particle size and zeta potential of formulated ibuprofen nanosuspension were 330.87±51.49 nm and -31.1±1.6 mV, respectively, and exhibited a fast dissolution. Therefore, the combination of eutectic emulsion solvent evaporation method with ultrasonication was favorable for fabricating an ibuprofen nanosuspension, and the transformation mechanism was attained successfully.

Process boundaries of irreversible scCO2 -assisted phase separation in biphasic whole-cell biocatalysis.

PubMed

Brandenbusch, Christoph; Glonke, Sebastian; Collins, Jonathan; Hoffrogge, Raimund; Grunwald, Klaudia; Bühler, Bruno; Schmid, Andreas; Sadowski, Gabriele

2015-11-01

The formation of stable emulsions in biphasic biotransformations catalyzed by microbial cells turned out to be a major hurdle for industrial implementation. Recently, a cost-effective and efficient downstream processing approach, using supercritical carbon dioxide (scCO2 ) for both irreversible emulsion destabilization (enabling complete phase separation within minutes of emulsion treatment) and product purification via extraction has been proposed by Brandenbusch et al. (2010). One of the key factors for a further development and scale-up of the approach is the understanding of the mechanism underlying scCO2 -assisted phase separation. A systematic approach was applied within this work to investigate the various factors influencing phase separation during scCO2 treatment (that is pressure, exposure of the cells to CO2 , and changes of cell surface properties). It was shown that cell toxification and cell disrupture are not responsible for emulsion destabilization. Proteins from the aqueous phase partially adsorb to cells present at the aqueous-organic interface, causing hydrophobic cell surface characteristics, and thus contribute to emulsion stabilization. By investigating the change in cell-surface hydrophobicity of these cells during CO2 treatment, it was found that a combination of catastrophic phase inversion and desorption of proteins from the cell surface is responsible for irreversible scCO2 mediated phase separation. These findings are essential for the definition of process windows for scCO2 -assisted phase separation in biphasic whole-cell biocatalysis. © 2015 Wiley Periodicals, Inc.

Systemically administered gp100 encoding DNA vaccine for melanoma using water-in-oil-in-water multiple emulsion delivery systems.

PubMed

Kalariya, Mayurkumar; Amiji, Mansoor M

2013-09-10

The purpose of this study was to develop a water-in-oil-in-water (W/O/W) multiple emulsions-based vaccine delivery system for plasmid DNA encoding the gp100 peptide antigen for melanoma immunotherapy. The gp100 encoding plasmid DNA was encapsulated in the inner-most aqueous phase of squalane oil containing W/O/W multiple emulsions using a two-step emulsification method. In vitro transfection ability of the encapsulated plasmid DNA was investigated in murine dendritic cells by transgene expression analysis using fluorescence microscopy and ELISA methods. Prophylactic immunization using the W/O/W multiple emulsions encapsulated the gp100 encoding plasmid DNA vaccine significantly reduced tumor volume in C57BL/6 mice during subsequent B16-F10 tumor challenge. In addition, serum Th1 cytokine levels and immuno-histochemistry of excised tumor tissues indicated activation of cytotoxic T-lymphocytes mediated anti-tumor immunity causing tumor growth suppression. The W/O/W multiple emulsions-based vaccine delivery system efficiently delivers the gp100 plasmid DNA to induce cell-mediated anti-tumor immunity. Copyright © 2013 Elsevier B.V. All rights reserved.

Tricosane (C23H48) and Octacosane (C28H58) mixture phase transition insight via Light scattering techniques

NASA Astrophysics Data System (ADS)

Kuryakov, V. N.; De Sanctis Lucentini, P. G.; Ivanova, D. D.

2018-04-01

In this study we analyse several emulsion samples of pure Tricosane (C23H48) and Octacosane (C28H58) paraffins as well as their mixtures with different component concentrations, prepared by means of ultrasonic dispersion without the addition of surfactants. We show that from the measurements of Static Light Scattering temperature dependences it is possible to determine the phase transition temperatures of the paraffins emulsion during the heating and cooling cycles (melting, crystallization and rotator phases). The results for the pure paraffin are in good agreement with the literature data. We produce the outcomes of the Dynamic Light Scattering technique to determine the cluster size of the obtained emulsions (radius 70-120 nm). Those emulsions proved to remain stable during several months.

Multi-species mating disruption in cranberries (Ericales: Ericaceae): Early evidence using a flowable emulsion

USDA-ARS?s Scientific Manuscript database

Pheromone-based mating disruption has proven to be a powerful pest management tool in many cropping systems, helping to reduce reliance on insecticide applications. However, a sustainable mating disruption program has not yet been developed for cranberries. In the cranberry system, two of the major ...

Emulsified industrial oils recycling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gabris, T.

1982-04-01

The industrial lubricant market has been analyzed with emphasis on current and/or developing recycling and re-refining technologies. This task has been performed for the United States and other industrialized countries, specifically France, West Germany, Italy and Japan. Attention has been focused at emulsion-type fluids regardless of the industrial application involved. It was found that emulsion-type fluids in the United States represent a much higher percentage of the total fluids used than in other industrialized countries. While recycling is an active matter explored by the industry, re-refining is rather a result of other issues than the mere fact that oil canmore » be regenerated from a used industrial emulsion. To extend the longevity of an emulsion is a logical step to keep expenses down by using the emulsion as long as possible. There is, however, another important factor influencing this issue: regulations governing the disposal of such fluids. The ecological question, the respect for nature and the natural balances, is often seen now as everybody's task. Regulations forbid dumping used emulsions in the environment without prior treatment of the water phase and separation of the oil phase. This is a costly procedure, so recycling is attractive since it postpones the problem. It is questionable whether re-refining of these emulsions - as a business - could stand on its own if these emulsions did not have to be taken apart for disposal purposes. Once the emulsion is separated into a water and an oil phase, however, re-refining of the oil does become economical.« less

Metal-ion retention properties of water-soluble amphiphilic block copolymer in double emulsion systems (w/o/w) stabilized by non-ionic surfactants.

PubMed

Palencia, Manuel; Rivas, Bernabé L

2011-11-15

Metal-ion retention properties of water-soluble amphiphilic polymers in presence of double emulsion were studied by diafiltration. Double emulsion systems, water-in-oil-in-water, with a pH gradient between external and internal aqueous phases were prepared. A poly(styrene-co-maleic anhydride) (PSAM) solution at pH 6.0 was added to the external aqueous phase of double emulsion and by application of pressure a divalent metal-ion stream was continuously added. Metal-ions used were Cu(2+) and Cd(2+) at the same pH of polymer solution. According to our results, metal-ion retention is mainly the result of polymer-metal interaction. Interaction between PSMA and reverse emulsion globules is strongly controlled by amount of metal-ions added in the external aqueous phase. In addition, as metal-ion concentration was increased, a negative effect on polymer retention capacity and promotion of flocculation phenomena were produced. Copyright © 2011 Elsevier Inc. All rights reserved.

Synthesis of magnetic nickel spinel ferrite nanospheres by a reverse emulsion-assisted hydrothermal process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Jilin; Shi Jianxin, E-mail: chemshijx@163.co; Gong Menglian

2009-08-15

Nickel ferrite nanospheres were successfully synthesized by a reverse emulsion-assisted hydrothermal method. The reverse emulsion was composed of water, cetyltrimethyl ammonium bromide, polyoxyethylene(10)nonyl phenyl ether, iso-amyl alcohol and hexane. During the hydrothermal process, beta-FeO(OH) and Ni{sub 0.75}Fe{sub 0.25}(CO{sub 3}){sub 0.125}(OH){sub 2}.0.38H{sub 2}O (INCHH) nanorods formed first and then transformed into nickel spinel ferrite nanospheres. The phase transformation mechanism is proposed based on the results of X-ray powder diffraction, transmission electron microscopy and energy-dispersive X-ray spectroscopy, etc. Nickel ferrite may form at the end of the INCHH nanorods or from the solution accompanied by the dissolution of beta-FeO(OH) and INCHH nanorods.more » The X-ray photoelectron spectroscopy analysis shows that a few Fe{sup 3+} ions have been reduced to Fe{sup 2+} ions during the formation of nickel ferrite. The maximum magnetization of the nickel ferrite nanospheres obtained after hydrothermal reaction for 30 h is 55.01 emu/g, which is close to that of bulk NiFe{sub 2}O{sub 4}. - Graphical abstract: Nickel ferrite nanospheres were obtained through a reverse emulsion-assisted hydrothermal process. The phase transformation as a function of reaction time was studied based on the XRD, TEM and EDS analyses.« less

Double emulsions for the compatibilization of hydrophilic nanocellulose with non-polar polymers and validation in the synthesis of composite fibers.

PubMed

Carrillo, Carlos A; Nypelö, Tiina; Rojas, Orlando J

2016-03-14

A route for the compatibilization of aqueous dispersions of cellulose nanofibrils (CNFs) with a non-polar polymer matrix is proposed to overcome a major challenge in CNF-based material synthesis. Non-ionic surfactants were used in CNF aqueous dispersions equilibrated with an organic phase (for demonstration, a polystyrene solution, PS, was used). Stable water-in-oil-in-water (W/O/W) double emulsions were produced as a result of the compromise between composition and formulation variables. Most remarkably, the proposed route for CNF integration with hydrophobic polymers removed the need for drying or solvent-exchange of the CNF aqueous dispersion prior to processing. The rheological behavior of the double emulsions showed strong shear thinning behavior and facilitated CNF-PS co-mixing in solid nanofibers upon electrospinning. The morphology and thermal properties of the resultant nanofibers revealed that CNFs were efficiently integrated in the hydrophobic matrix which was consistent with the high interfacial area of the precursor double emulsion. In addition, the morphology and quality of the composite nanofibers can be controlled by the conductivity (ionic strength) of the CNF dispersion. Overall, double emulsion systems are proposed as a novel, efficient and scalable platform for CNF co-processing with non-polar systems and they open up the possibility for the redispersion of CNFs after removal of the organic phase.

Treatment method for emulsified petroleum wastes

DOEpatents

Sealock, Jr., L. John; Baker, Eddie G.; Elliott, Douglas C.

1990-01-01

An improved reclamation process for treating petroleum oil and water emulsions derived from producing or processing crude oil is disclosed. The process comprises heating the emulsion to a predetermined temperature at or above about 300.degree. C. and pressurizing the emulsion to a predetermined pressure above the vapor pressure of water at the predetermined temperature. The emulsion is broken by containing the heated and pressurized fluid within a vessel at the predetermined temperature and pressure for a predetermined period of time to effectively separate the emulsion into substantially distinct first, second and third phases. The three phases are then separately withdrawn from the vessel, preferably without any appreciable reduction in temperature and pressure, and at least above a withdraw temperature of about 300.degree. and above the vapor pressure of water at the withdraw temperature.

Extraction of anionic dye from aqueous solutions by emulsion liquid membrane.

PubMed

Dâas, Attef; Hamdaoui, Oualid

2010-06-15

In this work, the extraction of Congo red (CR), an anionic disazo direct dye, from aqueous solutions by emulsion liquid membrane (ELM) was investigated. The important operational parameters governing emulsion stability and extraction behavior of dye were studied. The extraction of CR was influenced by a number of variables such as surfactant concentration, stirring speed, acid concentration in the feed solution and volume ratios of internal phase to organic phase and of emulsion to feed solution. Under most favorable conditions, practically all the CR molecules present in the feed phase were extracted even in the presence of salt (NaCl). At the optimum experimental conditions, total removal of antharaquinonic dye Acid Blue 25 was attained after only 10 min. Influence of sodium carbonate concentration as internal receiving phase on the stripping efficiency of CR was examined. The best sodium carbonate concentration in the internal phase that conducted to excellent stripping efficiency (>99%) and emulsion stability was 0.1N. The membrane recovery was total and the permeation of CR was not decreased up to seven runs. ELM process is a promising alternative to conventional methods and should increase awareness of the potential for recovery of anionic dyes. Copyright 2010 Elsevier B.V. All rights reserved.

Paintable band-edge liquid crystal lasers.

PubMed

Gardiner, Damian J; Morris, Stephen M; Hands, Philip J W; Mowatt, Carrie; Rutledge, Rupert; Wilkinson, Timothy D; Coles, Harry J

2011-01-31

In this paper we demonstrate photonic band-edge laser emission from emulsion-based polymer dispersed liquid crystals. The lasing medium consists of dye-doped chiral nematic droplets dispersed within a polymer matrix that spontaneously align as the film dries. Such lasers can be easily formed on single substrates with no alignment layers. The system combines the self-organizing periodic structure of chiral nematic liquid crystals with the simplicity of the emulsion procedure so as to produce a material that retains the emission characteristics of band-edge lasers yet can be readily coated. Sequential and stacked layers demonstrate the possibility of achieving simultaneous multi-wavelength laser output from glass, metallic, and flexible substrates.

Stability of citral in oil-in-water emulsions prepared with medium-chain triacylglycerols and triacetin.

PubMed

Choi, Seung Jun; Decker, Eric Andrew; Henson, Lulu; Popplewell, L Michael; McClements, David Julian

2009-12-09

Citral is widely used in the beverage, food, and fragrance industries for its characteristic flavor profile. However, it chemically degrades over time in aqueous solutions due to an acid-catalyzed reaction, which leads to loss of desirable flavor notes and formation of off-flavor notes. The objective of this research was to examine the impact of organic phase composition [triacetin and medium-chain triacylglycerols (MCT)] on the oil-water partitioning and chemical degradation of citral in oil-in-water emulsions. MCT was present as emulsion droplets (d approximately 900 nm), whereas triacetin was present as microemulsion droplets (d approximately 10 nm). In the absence of organic phase, the rate of citral degradation increased as the aqueous phase pH was reduced from 7 to 3. The percentage of citral within the aqueous phase increased with increasing triacetin concentration at both pH 3 and 7, which was attributed to a reduction in MCT droplet concentration. There was no significant change in the particle size distribution of the emulsions during storage, independent of triacetin concentration and pH, which indicated that they were physically stable. Both 5 wt % MCT as emulsion droplets and 5 wt % triacetin as microemulsion droplets were able to appreciably slow citral degradation at pH 3. These results may have important implications for understanding and improving the chemical stability of citral in beverage emulsions.

Cold Heat Storage Characteristics of O/W-type Latent Heat Emulsion Including Continuum Phase of Water Treated with a Freezing Point Depression

NASA Astrophysics Data System (ADS)

Inaba, Hideo; Morita, Shin-Ichi

This paper deals with flow and cold heat storage characteristics of the oil (tetradecane, C14H30, freezing point 278.9 K, Latent heat 229 kJ/kg)/water emulsion as a latent heat storage material having a low melting point. The test emulsion includes a water-urea solution as a continuum phase. The freezing point depression of the continuum phase permits enhancement of the heat transfer rate of the emulison, due to the large temperature difference between the latent heat storage material and water-urea solution. The velocity of emulsion flow and the inlet temperature of coolant in a coiled double tube heat exchanger are chosen as the experimental parameters. The pressure drop, the heat transfer coefficient of the emulsion in the coiled tube are measured in the temperture region over solid and liquid phase of the latent heat storage material. The finishing time of the cold heat storage is defined experimentally in the range of sensible and latent heat storage. It is clarified that the flow behavior of the emulsion as a non-Newtonian fluid has an important role in cold heat storage. The useful nondimentional correlation equations for the additional pressure loss coefficient, the heat transfer coefficient and the finishing time of the cold heat storage are derived in terms of Dean number and heat capacity ratio.

Enzymatically structured emulsions in simulated gastrointestinal environment: impact on interfacial proteolysis and diffusion in intestinal mucus.

PubMed

Macierzanka, Adam; Böttger, Franziska; Rigby, Neil M; Lille, Martina; Poutanen, Kaisa; Mills, E N Clare; Mackie, Alan R

2012-12-18

Fundamental knowledge of physicochemical interactions in the gastrointestinal environment is required in order to support rational designing of protein-stabilized colloidal food and pharmaceutical delivery systems with controlled behavior. In this paper, we report on the colloidal behavior of emulsions stabilized with the milk protein sodium caseinate (Na-Cas), and exposed to conditions simulating the human upper gastrointestinal tract. In particular, we looked at how the kinetics of proteolysis was affected by adsorption to an oil-water interface in emulsion and whether the proteolysis and the emulsion stability could be manipulated by enzymatic structuring of the interface. After cross-linking with the enzyme transglutaminase, the protein was digested with use of an in vitro model of gastro-duodenal proteolysis in the presence or absence of physiologically relevant surfactants (phosphatidylcholine, PC; bile salts, BS). Significant differences were found between the rates of digestion of Na-Cas cross-linked in emulsion (adsorbed protein) and in solution. In emulsion, the digestion of a population of polypeptides of M(r) ca. 50-100 kDa was significantly retarded through the gastric digestion. The persistent interfacial polypeptides maintained the original emulsion droplet size and prevented the system from phase separating. Rapid pepsinolysis of adsorbed, non-cross-linked Na-Cas and its displacement by PC led to emulsion destabilization. These results suggest that structuring of emulsions by enzymatic cross-linking of the interfacial protein may affect the phase behavior of emulsion in the stomach and the gastric digestion rate in vivo. Measurements of ζ-potential revealed that BS displaced the remaining protein from the oil droplets during the simulated duodenal phase of digestion. Diffusion of the postdigestion emulsion droplets through ex vivo porcine intestinal mucus was only significant in the presence of BS due to the high negative charge these biosurfactants imparted to the droplets. This implies that the electrostatic repulsion produced can prevent the droplets from being trapped by the mucus matrix and facilitate their transport across the small intestine mucosal barrier.

Effect of lipophilization on the distribution and reactivity of ingredients in emulsions.

PubMed

Leong, Wai Fun; Berton-Carabin, Claire C; Elias, Ryan J; Lecomte, Jérôme; Villeneuve, Pierre; Zhao, Yu; Coupland, John N

2015-12-01

The reactivity of small molecules in emulsions is believed to depend on their partitioning between phases, yet this is hard to verify experimentally in situ. In the present work, we use electron paramagnetic resonance (EPR) spectroscopy to simultaneously measure the distribution and reactivity of a homologous series of lipophilized spin probes in an emulsion. 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL) was derivatized with saturated fatty acids to create a series of spin probes with increasing lipophilicity (C4-, C8-, C12-, and C16-TEMPO). The probes were added to a 10 wt.% tetradecane-in water emulsions (d32∼190 nm) stabilized with sodium caseinate (1 wt.% in the aqueous phase, pH 7). The distribution of the probes between phases was measured by electron paramagnetic resonance (EPR) spectroscopy. TEMPOL partitioned into the aqueous phase, C4-TEMPO distributed between the lipid and aqueous phases (69% and 31% respectively) while the more lipophilic probes dissolved exclusively within the lipid droplets. Interestingly, the more lipophilic probes initially precipitated upon their addition to the emulsion, and only slowly redistributed to the droplets over hours or days, the rate of which was dependent on their carbon chain length. The reactivity of the probes with aqueous an aqueous phase reductant (ascorbate) generally depended on the proportion in the aqueous phase (i.e., TEMPOL>C4-TEMPO>C8-TEMPO∼C12-TEMPO∼C16-TEMPO). Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of propylene glycol on aqueous silica dispersions and particle-stabilized emulsions.

PubMed

Binks, Bernard P; Fletcher, Paul D I; Thompson, Michael A; Elliott, Russell P

2013-05-14

We have studied the influence of adding propylene glycol to both aqueous dispersions of fumed silica nanoparticles and emulsions of paraffin liquid and water stabilized by the same particles. In the absence of oil, aerating mixtures of aqueous propylene glycol and particles yields either stable dispersions, aqueous foams, climbing particle films, or liquid marbles depending on the glycol content and particle hydrophobicity. The presence of glycol in water promotes particles to behave as if they are more hydrophilic. Calculations of their contact angle at the air-aqueous propylene glycol surface are in agreement with these findings. In the presence of oil, particle-stabilized emulsions invert from water-in-oil to oil-in-water upon increasing either the inherent hydrophilicity of the particles or the glycol content in the aqueous phase. Stable multiple emulsions occur around phase inversion in systems of low glycol content, and completely stable, waterless oil-in-propylene glycol emulsions can also be prepared. Accounting for the surface energies at the respective interfaces allows estimation of the contact angle at the oil-polar phase interface; reasonable agreement between measured and calculated phase inversion conditions is found assuming no glycol adsorption on particle surfaces.

Co-delivery of antigen and a lipophilic anti-inflammatory drug to cells via a tailorable nanocarrier emulsion.

PubMed

Chuan, Yap Pang; Zeng, Bi Yun; O'Sullivan, Brendan; Thomas, Ranjeny; Middelberg, Anton P J

2012-02-15

Nanotechnology promises new drug carriers that can be tailored to specific applications. Here we report a new approach to drug delivery based on tailorable nanocarrier emulsions (TNEs), motivated by a need to co-deliver a protein antigen and a lipophilic drug for specific inhibition of nuclear factor kappa B (NF-κB) in antigen presenting cells (APCs). Co-delivery for NF-κB inhibition holds promise as a strategy for the treatment of rheumatoid arthritis. We used a highly surface-active peptide (SAP) to prepare a nanosized emulsion having defined surface properties predictable from the SAP sequence. Incorporating the lipophilic drug into the oil phase at the time of emulsion formation enabled its facile packaging. The SAP is depleted from bulk during emulsification, allowing simple subsequent addition of the drug-loaded oil-in-water emulsion to a solution of protein antigen. Decoration of emulsion surface with antigen was achieved via electrostatic deposition. In vitro data showed that the TNE prepared this way was internalized and well-tolerated by model APCs, and that good suppression of NF-κB expression was achieved. This work reports a new type of nanotechnology-based carrier, a TNE, which can potentially be tailored for co-delivery of multiple therapeutic components, and can be made using simple methods using only biocompatible materials. Copyright © 2011 Elsevier Inc. All rights reserved.

The role of silica nanoparticles on long-term room-temperature stabilization of water-in-oil emulsions containing microalgae.

PubMed

Fernández, L; Scher, H; VanderGheynst, J S

2015-12-01

Prior research has demonstrated that microalgae can be stored for extended periods of time at room temperature in water-in-oil (W/O) emulsions stabilized by surface modified silica nanoparticles. However, little research has been done to examine the impact of nanoparticle concentration on emulsion stability. Such information is important for large-scale production of emulsions for microalgae storage and delivery. Studies were done to examine the impact of silica nanoparticle concentration on emulsion stability and identify the lower limit for nanoparticle concentration. Emulsion physical stability was determined using internal phase droplet size measurements and biological stability was evaluated using cell density measurements. The results demonstrate that nanoparticle concentrations as low as 0·5wt% in the oil phase can be used without significant losses in emulsion stability and microalgae viability. Stabilization technologies are needed for long-term storage and application of microalgae in agricultural-scale systems. While prior work has demonstrated that water-in-oil emulsions containing silica nanoparticles offer a promising solution for long-term microalgae storage at room temperature, little research has been done to examine the impact of nanoparticle concentration on emulsion stability. Here, we show the effects of silica nanoparticle concentration on maintaining physical stability of emulsions and sustaining viable cells. The results enable informed decisions to be made regarding production of emulsions containing silica nanoparticles and associated impacts on stabilization of microalgae. © 2015 The Society for Applied Microbiology.

Interfacial film stabilized W/O/W nano multiple emulsions loaded with green tea and lotus extracts: systematic characterization of physicochemical properties and shelf-storage stability.

PubMed

Mahmood, Tariq; Akhtar, Naveed; Manickam, Sivakumar

2014-05-12

Multiple emulsions have excellent encapsulating potential and this investigation has been aimed to encapsulate two different plant extracts as functional cosmetic agents in the W/O/W multiple emulsions and the resultant system's long term stability has been determined in the presence of a thickener, hydroxypropyl methylcellulose (HPMC). Multiple W/O/W emulsions have been generated using cetyl dimethicone copolyol as lipophilic emulsifier and a blend of polyoxyethylene (20) cetyl ether and cetomacrogol 1000® as hydrophilic emulsifiers. The generated multiple emulsions have been characterized with conductivity, pH, microscopic analysis, phase separation and rheology for a period of 30 days. Moreover, long term shelf-storage stability has been tested to understand the shelf-life by keeping the generated multiple emulsion formulations at 25 ± 10°C and at 40 ± 10% relative humidity for a period of 12 months. It has been observed that the hydrophilic emulsifiers and HPMC have considerably improved the stability of multiple emulsions for the followed period of 12 months at different storage conditions. These multiple emulsions have shown improved entrapment efficiencies concluded on the release rate of conductometric tracer entrapped in the inner aqueous phase of the multiple emulsions. Multiple emulsions have been found to be stable for a longer period of time with promising characteristics. Hence, stable multiple emulsions loaded with green tea and lotus extracts could be explored for their cosmetic benefits.

Heterogeneous Nucleation of Methane Hydrate in a Water-Decane-Methane Emulsion

NASA Astrophysics Data System (ADS)

Shestakov, V. A.; Kosyakov, V. I.; Manakov, A. Yu.; Stoporev, A. S.; Grachev, E. V.

2018-07-01

Heterogeneous nucleation in disperse systems with metastable disperse phases plays an important role in the mechanisms of environmental and technological processes. The effect the concentration and activity of particles that initiate the formation of a new phase have on nucleation processes in such systems is considered. An approach is proposed that allows construction of a spectrum of particle activity characterizing the features of nucleation in a sample, based on the fraction of crystallized droplets depending on the level of supercooling and the use of Weibull's distribution. The proposed method is used to describe experimental data on the heterogeneous nucleation of methane hydrate in an emulsion in a water-decane-methane system.

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

PubMed Central

Patil-Sen, Yogita; Sadeghpour, Amin; Rappolt, Michael; Kulkarni, Chandrashekhar V.

2016-01-01

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G' bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy. PMID:26967650

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes.

PubMed

Patil-Sen, Yogita; Sadeghpour, Amin; Rappolt, Michael; Kulkarni, Chandrashekhar V

2016-02-19

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G' bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

Ultrasonication-assisted preparation and characterization of emulsions and emulsion gels for topical drug delivery.

PubMed

Singh, Vinay K; Behera, Baikuntha; Pramanik, Krishna; Pal, Kunal

2015-03-01

The current study describes the use of ultrasonication for the preparation of biphasic emulsions and emulsion gels for topical drug delivery. Sorbitan monostearate (SMS) was used as the surfactant for stabilizing the interface of sesame oil (apolar phase) and water (polar phase). Emulsions were formed at lower concentrations of SMS, whereas emulsion gels were formed at higher concentrations of SMS. The formulations were characterized by fluorescent microscopy, X-ray diffraction, viscosity, stress relaxation, spreadability, and differential scanning calorimetry studies. Fluorescence microscopy suggested formation of oil-in-water type of formulations. There was an increase in the viscosity, bulk resistance, and firmness of the formulations as the proportions of SMS was increased. The emulsion gels were viscoelastic in nature. Thermal studies suggested higher thermodynamic stability at higher proportions of either SMS or water. Metronidazole, a model antimicrobial drug, was incorporated within the formulations. The release of the drug from the formulations was found to be diffusion mediated. The drug-loaded formulations showed sufficient antimicrobial efficiency to be used as carriers for topical antimicrobial drug delivery. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Thermodynamic compatibility and interactions between Speckled Sugar bean protein and xanthan gum for production of multilayer O/W emulsion.

PubMed

Rahmati, Nazanin Fatemeh; Koocheki, Arash; Varidi, Mehdi; Kadkhodaee, Rassoul

2018-03-01

Thermodynamic compatibility and probable interactions between Speckled Sugar been protein (SSBP) and xanthan gum for production of multilayer O/W emulsion (30% oil) were investigated. Different interactions were observed between SSBP and xanthan at different pH (3-7) including electrostatic interactions and hydrogen bonding. These interactions were predominant at pH 3. When low xanthan gum concentration (0.1%) was used, phase separation and complex coacervation observed at this pH (negative effect of interactions). However, at pH 5, only 0.1% xanthan was enough to drastically reduce non-dissolved protein and its precipitation which normally occurs at this pH. In addition, incompatibility or segregative phase behavior which normally occurs when protein and polysaccharide have same charges was not observed (positive effects of interactions). Protein-gum interactions influenced emulsion properties (zeta potential, particle size, PDI, rheology, emulsion capacity, heat stability and creaming rate). Interactions had considerable influence on emulsion shelf life and produced completely stable emulsions at all pH values. Results confirmed that SSBP-xanthan gum mixture has a high potential for production of multilayer emulsions.

Study the effect of polymers on the stability and rheological properties of oil-in-water (O/W) Pickering emulsion muds

NASA Astrophysics Data System (ADS)

Jha, Praveen Kumar; Mahto, Vikas; Saxena, Vinod Kumar

2018-05-01

A new type of oil-in-water (O/W) Pickering emulsion systems, which were prepared by polymers such as xanthan gum, carboxymethyl cellulose (CMC), and sodium lignosulfonate have been investigated for their properties as multifunctional emulsion muds with respect to rheological control and filtration control properties. Diesel oil was used as dispersed phase and KCl-brine as continuous phase in the developed emulsions. Initially, rheological parameters like apparent viscosity, plastic viscosity, gel strength, and filtration control properties were measured using recommended practices. Emulsion stability was analyzed using steady state shear stress-shear rate and oscillatory (dynamic) rheological measurement techniques. The emulsions were found to exhibit shear-thinning (pseudoplastic) behavior. Experiments conducted for oscillatory rheological measurements have shown that emulsions are stable as per the stability criteria G' (elastic modulus) > G'' (loss modulus) and both are independent of changing ω (Frequency). These fluids have shown stable properties upto 70°C which shows that they can be used as drilling muds for drilling oil and gas wells.

Development and validation of a simple high-performance liquid chromatography analytical method for simultaneous determination of phytosterols, cholesterol and squalene in parenteral lipid emulsions.

PubMed

Novak, Ana; Gutiérrez-Zamora, Mercè; Domenech, Lluís; Suñé-Negre, Josep M; Miñarro, Montserrat; García-Montoya, Encarna; Llop, Josep M; Ticó, Josep R; Pérez-Lozano, Pilar

2018-02-01

A simple analytical method for simultaneous determination of phytosterols, cholesterol and squalene in lipid emulsions was developed owing to increased interest in their clinical effects. Method development was based on commonly used stationary (C 18 , C 8 and phenyl) and mobile phases (mixtures of acetonitrile, methanol and water) under isocratic conditions. Differences in stationary phases resulted in peak overlapping or coelution of different peaks. The best separation of all analyzed compounds was achieved on Zorbax Eclipse XDB C 8 (150 × 4.6 mm, 5 μm; Agilent) and ACN-H 2 O-MeOH, 80:19.5:0.5 (v/v/v). In order to achieve a shorter time of analysis, the method was further optimized and gradient separation was established. The optimized analytical method was validated and tested for routine use in lipid emulsion analyses. Copyright © 2017 John Wiley & Sons, Ltd.

Bioactivity of Epigallocatechin Gallate Nanoemulsions Evaluated in Mice Model.

PubMed

Koutelidakis, Antonios E; Argyri, Konstantina; Sevastou, Zoi; Lamprinaki, Dimitra; Panagopoulou, Elli; Paximada, Evi; Sali, Aggeliki; Papalazarou, Vassilis; Mallouchos, Athanasios; Evageliou, Vasiliki; Kostourou, Vasiliki; Mantala, Ioanna; Kapsokefalou, Maria

2017-09-01

The hypothesis that incorporation of epigallocatechin gallate (EGCG) into nanoemulsions may increase its bioactivity compared with EGCG aqueous solutions was examined in mice. After an in vitro study in a model system with stimulated gastrointestinal conditions, the following EGCG nanoemulsions were used in a mice experiment: Emulsion I: emulsion water in oil (W/O), which contained 0.23 mg/mL EGCG in aqueous phase; Emulsion II: emulsion oil in water (O/W), which contained 10% olive oil and 0.23 mg/mL esterified EGCG in fatty phase; and Emulsion III: emulsion O/W in water (W1/O/W2; 8:32:60), which contained 32% olive oil and 0.23 mg/mL EGCG in aqueous phase. After 2 h of mice administration by gavage with 0.1 mL of EGCG nanoemulsions, total antioxidant capacity (TAC) of plasma and some tissues (especially colon, jejunum, heart, spleen) was measured with Ferric-Reducing Antioxidant Power (FRAP) and Oxygen Radical Absorbance Capacity (ORAC) assays. No toxic effects were observed after administration of 0.23 mg/mL esterified EGCG in CD1 mouse strain. The study concluded that administration of mice with the three EGCG nanoemulsions did not increase their TAC in specific tissues, compared with an aqueous EGCG solution at the same concentration. Nevertheless, the esterified EGCG emulsion (Emulsion II) exerted an increase in mice plasma compared with aqueous EGCG and showed higher values of TAC in several tissues, compared with Emulsions I and III. EGCG nanoemulsions could be considered a useful method in plethora functional food applications, but further research is required for safer results.

Emulsions Stabilized by Chitosan-Modified Silica Nanoparticles: pH Control of Structure-Property Relations.

PubMed

Alison, Lauriane; Demirörs, Ahmet F; Tervoort, Elena; Teleki, Alexandra; Vermant, Jan; Studart, Andre R

2018-05-29

In food-grade emulsions, particles with an appropriate surface modification can be used to replace surfactants and potentially enhance the stability of emulsions. During the life cycle of products based on such emulsions, they can be exposed to a broad range of pH conditions and hence it is crucial to understand how pH changes affect stability of emulsions stabilized by particles. Here, we report on a comprehensive study of the stability, microstructure, and macroscopic behavior of pH-controlled oil-in-water emulsions containing silica nanoparticles modified with chitosan, a food-grade polycation. We found that the modified colloidal particles used as stabilizers behave differently depending on the pH, resulting in unique emulsion structures at multiple length scales. Our findings are rationalized in terms of the different emulsion stabilization mechanisms involved, which are determined by the pH-dependent charges and interactions between the colloidal building blocks of the system. At pH 4, the silica particles are partially hydrophobized through chitosan modification, favoring their adsorption at the oil-water interface and the formation of Pickering emulsions. At pH 5.5, the particles become attractive and the emulsion is stabilized by a network of agglomerated particles formed between the droplets. Finally, chitosan aggregates form at pH 9 and these act as the emulsion stabilizers under alkaline conditions. These insights have important implications for the processing and use of particle-stabilized emulsions. On one hand, changes in pH can lead to undesired macroscopic phase separation or coalescence of oil droplets. On the other hand, the pH effect on emulsion behavior can be harnessed in industrial processing, either to tune their flow response by altering the pH between processing stages or to produce pH-responsive emulsions that enhance the functionality of the emulsified end products.

Preparation of hybrid thiol-acrylate emulsion-templated porous polymers by interfacial copolymerization of high internal phase emulsions.

PubMed

Langford, Caitlin R; Johnson, David W; Cameron, Neil R

2015-05-01

Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 μm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carboxymethylated lignins with low surface tension toward low viscosity and highly stable emulsions of crude bitumen and refined oils.

PubMed

Li, Shuai; Ogunkoya, Dolanimi; Fang, Tiegang; Willoughby, Julie; Rojas, Orlando J

2016-11-15

Kraft and organosolv lignins were subjected to carboxymethylation to produce fractions that were soluble in water, displayed a minimum surface tension as low as 34mN/m (25°C) and a critical aggregation concentration of ∼1.5wt%. The carboxymethylated lignins (CML), which were characterized in terms of their degree of substitution ((31)P NMR), elemental composition, and molecular weight (GPC), were found suitable in the formulation of emulsions with bitumens of ultra-high viscosity, such as those from the Canadian oil sands. Remarkably, the interfacial features of the CML enabled fuel emulsions that were synthesized in a very broad range of internal phase content (30-70%). Cryo-replica transmission electron microscopy, which was used here the first time to assess the morphology of the lignin-based emulsions, revealed the droplets of the emulsion stabilized with the modified lignin. The observed drop size (diameters<2μm) was confirmed by light scattering, which revealed a normal size distribution. Such characteristics led to stable emulsified systems that are amenable for a wide range of applications. Emulsification with CML afforded bitumen emulsions with very high colloidal stability (no change was noted for over one month) and with a strong shear thinning behavior. Both features indicate excellent prospects for storage, transport and spraying, which are relevant in operations for power generation, which also take advantage of the high heating value of the emulsion components. The ability of CML to stabilize emulsions and to contribute in their combustion was tested with light fuels (kerosene, diesel, and jet fuel) after formulation of high internal phase systems (70% oil) that enabled operation of a fuel engine. A significant finding is that under certain conditions and compared to the respective pure fuel, combustion of the O/W emulsions stabilized by CML presented lower NOx and CO emissions and maintained a relatively high combustion efficiency. The results highlight the possibilities in high volume application for lignin biomacromolecules. Copyright © 2016 Elsevier Inc. All rights reserved.

Emulsion Liquid Membrane Removal of Arsenic and Strontium from Wastewater: AN Experimental and Theoretical Study.

NASA Astrophysics Data System (ADS)

Zhou, Ding-Wei

The emulsion liquid membrane (ELM) technique has been successfully applied on the removal of arsenic (As) from metallurgical wastewater and the removal of strontium (Sr) from radioactive wastewater. This study consisted of experimental work and mathematical modeling. Extraction of arsenic by an emulsion liquid membrane was firstly investigated. The liquid membrane used was composed of 2-ethylhexyl alcohol (2EHA) as the extractant, ECA4360J as the surfactant, and Exxsol D-80 solvent (or heptane) as the diluent. The sulfuric acid and sodium hydroxide solutions were used as the external and internal phases, respectively. The arsenic removal efficiency reached 92% within 15 minutes in one stage. Extraction and stripping chemistries were postulated and investigated. It was observed that extraction efficiency and rate increase with the increase of acidic strength and alkali strength in the external and internal phases, respectively. It was also observed that the removal selectivity of arsenic over copper is extremely high. Strontium-90 is one of the major radioactive metals appearing in nuclear wastewater. The emulsion liquid membrane process was investigated as a separation method by using the non-radioactive ^{87}Sr as its substitute. In our study, the membrane phase was composed of di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the extractant, ECA4360J as the surfactant and Exxsol D-80 as the diluent. A sulfuric acid solution was used in the internal phase as the stripping agent. The pH range in the external phase was determined by the extraction isotherm. Under the most favorable operating condition, the strontium removal efficiency can reach 98% in two minutes. Mass transfer of the emulsion liquid membrane (ELM) system was modeled mathematically. Our model took into account the following: mass transfer of solute across the film between the external phase and the membrane phase, chemical equilibrium of the extraction reaction at the external phase-membrane interface, simultaneous diffusion of the solute-carrier complex inside the globule membrane phase and stripping of the complex at the membrane-internal phase interface, chemical equilibrium of the stripping reaction at the membrane-internal phase interface and leakage of the solute from the internal phase to the external phase. Resulting simultaneous partial differential equations were solved analytically by the Laplace transform method. Four dimensionless groups were found with special physical meanings to characterize the emulsion liquid membrane systems. It not only predicted the concentration of solute in the external phase versus time, but also gave the concentration profile inside the membrane globule and the interfacial concentration at the external-membrane phase interface at different time. The model predicted very well the experimental data obtained from the removal of arsenic and strontium by the emulsion liquid membranes.

Microbubble Fabrication of Concave-porosity PDMS Beads

PubMed Central

Bertram, John R.; Nee, Matthew J.

2015-01-01

Microbubble fabrication (by use of a fine emulsion) provides a means of increasing the surface-area-to-volume (SAV) ratio of polymer materials, which is particularly useful for separations applications. Porous polydimethylsiloxane (PDMS) beads can be produced by heat-curing such an emulsion, allowing the interface between the aqueous and aliphatic phases to mold the morphology of the polymer. In the procedures described here, both polymer and crosslinker (triethoxysilane) are sonicated together in a cold-bath sonicator. Following a period of cross-linking, emulsions are added dropwise to a hot surfactant solution, allowing the aqueous phase of the emulsion to separate, and forming porous polymer beads. We demonstrate that this method can be tuned, and the SAV ratio optimized, by adjusting the electrolyte content of the aqueous phase in the emulsion. Beads produced in this way are imaged with scanning electron microscopy, and representative SAV ratios are determined using Brunauer–Emmett–Teller (BET) analysis. Considerable variability with the electrolyte identity is observed, but the general trend is consistent: there is a maximum in SAV obtained at a specific concentration, after which porosity decreases markedly. PMID:26709997

Influence of hydrophilic surfactants on the properties of multiple W/O/W emulsions.

PubMed

Schmidts, T; Dobler, D; Nissing, C; Runkel, F

2009-10-01

Multiple W/O/W emulsions for topical application using Span 80 as a lipophilic emulsifier were prepared. Several hydrophilic emulsifiers were tested in respect of their suitability for the preparation of multiple emulsions. In addition, the effect of different oil-phase compositions on emulsion stability was investigated. The physicochemical parameters of the formulations were characterized and their long-term stability was evaluated by means of rheological measurements, droplet size observations and conductivity analysis. As discovered, the modification of an oil-phase composition results in a decrease in the diffusion coefficient of water and water-soluble substances and, consequently, in enhanced stability. The influence of the release of electrolytes from the inner to the outer water phase on the emulsion stability behaviour was investigated. It was found, that the effect of the hydrophilic emulsifiers on the formulation properties is related not only to its HLB value, but rather to its chemical composition. As a result, polyethoxylated ethers of fatty alcohols (C=16-18) with HLBs between 15.3 and 16.2 appear to be the most suitable ones for creating stable formulations.

An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions.

PubMed

Ruan, Guihua; Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui; Du, Fuyou

2016-04-22

A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of Nα-benzoyl-l-arginine ethyl ester to Nα-benzoyl-l-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. Copyright © 2016 Elsevier Inc. All rights reserved.

FOULING-RESISTANT CERAMIC MEMBRANES FOR TREATMENT OF METASTABLE OIL/WATER EMULSIONS - PHASE II

EPA Science Inventory

Billions of gallons of oily wastewaters are generated daily by a variety of industrial sources. A large fraction of these are oil/water emulsions for which current treatment technologies are often costly and ineffective. Although such emulsions can be separated using crossf...

Rapid, chemical-free breaking of microfluidic emulsions with a hand-held antistatic gun

PubMed Central

Shahi, Payam; Abate, Adam R.

2017-01-01

Droplet microfluidics can form and process millions of picoliter droplets with speed and ease, allowing the execution of huge numbers of biological reactions for high-throughput studies. However, at the conclusion of most experiments, the emulsions must be broken to recover and analyze their contents. This is usually achieved with demulsifiers, like perfluorooctanol and chloroform, which can interfere with downstream reactions and harm cells. Here, we describe a simple approach to rapidly and efficiently break microfluidic emulsions, which requires no chemicals. Our method allows one-pot multi-step reactions, making it useful for large scale automated processing of reactions requiring demulsification. Using a hand-held antistatic gun, we pulse emulsions with the electric field, coalescing ∼100 μl of droplets in ∼10 s. We show that while emulsions broken with chemical demulsifiers exhibit potent PCR inhibition, the antistatic-broken emulsions amplify efficiently. The ability to break emulsions quickly without chemicals should make our approach valuable for most demulsification needs in microfluidics. PMID:28794817

Schizophrenic Diblock-Copolymer-Functionalized Nanoparticles as Temperature-Responsive Pickering Emulsifiers.

PubMed

Ranka, Mikhil; Katepalli, Hari; Blankschtein, Daniel; Hatton, T Alan

2017-11-21

Stimuli-responsive pickering emulsions have received considerable attention in recent years, and the utilization of temperature as a stimulus has been of particular interest. Previous efforts have led to responsive systems that enable the formation of stable emulsions at room temperature, which can subsequently be triggered to destabilize with an increase in temperature. The development of a thermoresponsive system that exhibits the opposite response, however, i.e., one that can be triggered to form stable emulsions at elevated temperatures and subsequently be induced to phase separate at lower temperatures, has so far been lacking. Here, we describe a system that accomplishes this goal by leveraging a schizophrenic diblock copolymer that exhibits both an upper and a lower critical solution temperature. The diblock copolymer was conjugated to 20 nm silica nanoparticles, which were subsequently demonstrated to stabilize O/W emulsions at 65 °C and trigger phase separation upon cooling to 25 °C. The effects of particle concentration, electrolyte concentration, and polymer architecture were investigated, and facile control of emulsion stability was demonstrated for multiple oil types. Our approach is likely to be broadly adaptable to other schizophrenic diblock copolymers and find significant utility in applications such as enhanced oil recovery and liquid-phase heterogeneous catalysis, where stable emulsions are desired only at elevated temperatures.

Emulsion Droplet Combustion in Microgravity: Water/Heptane Emulsions

NASA Technical Reports Server (NTRS)

Avedisian, C. Thomas

1997-01-01

This presentation reviews a series of experiments to further examine parametric effects on sooting processes of droplet flames in microgravity. The particular focus is on a fuel droplet emulsified with water, specifically emulsions of n-heptane as the fuel-phase and water as the dispersed phase. Water was selected as the additive because of its anticipated effect on soot formation, and the heptane fuel phase was chosen to theoretically reduce the likelihood of microexplosions because its boiling point is nearly the same as that of water: 100 C for water and 98 C for heptane. The water content was varied while the initial droplet diameter was kept within a small range. The experiments were carried out in microgravity to reduce the effects of buoyancy and to promote spherical symmetry in the burning process. Spherically symmetric droplet burning is a convenient starting point for analysis, but experimental data are difficult to obtain for this situation as evidenced by the fact that no quantitative data have been reported on unsupported emulsion droplet combustion in a convection-free environment. The present study improves upon past work carried out on emulsion droplet combustion in microgravity which employed emulsion droplets suspended from a fiber. The fiber can be instrusive to the emulsion droplet burning process as it can promote coalescence of the dispersed water phase and heterogeneous nucleation on the fiber. Prior work has shown that the presence of water in liquid hydrocarbons can have both beneficial and detrimental effects on the combustion process. Water is known to reduce soot formation and radiation heat transfer to combustor walls Gollahalli (1979) reduce flame temperatures and thereby NOx emissions, and encourage secondary droplet atomization or microexplosion. Water also tends to retard ignition and and promote early extinction. The former effect restricted the range of water volume fractions as discussed below.

Formulation and Stabilization of Concentrated Edible Oil-in-Water Emulsions Based on Electrostatic Complexes of a Food-Grade Cationic Surfactant (Ethyl Lauroyl Arginate) and Cellulose Nanocrystals.

PubMed

Bai, Long; Xiang, Wenchao; Huan, Siqi; Rojas, Orlando J

2018-05-14

We report on high-internal-phase, oil-in-water Pickering emulsions that are stable against coalescence during storage. Viscous, edible oil (sunflower) was emulsified by combining naturally derived cellulose nanocrystals (CNCs) and a food-grade, biobased cationic surfactant obtained from lauric acid and L-arginine (ethyl lauroyl arginate, LAE). The interactions between CNC and LAE were elucidated by isothermal titration calorimetry (ITC) and supplementary techniques. LAE adsorption on CNC surfaces and its effect on nanoparticle electrostatic stabilization, aggregation state, and emulsifying ability was studied and related to the properties of resultant oil-in-water emulsions. Pickering systems with tunable droplet diameter and stability against oil coalescence during long-term storage were controllably achieved depending on LAE loading. The underlying stabilization mechanism was found to depend on the type of complex formed, the LAE structures adsorbed on the cellulose nanoparticles (as unimer or as adsorbed admicelles), the presence of free LAE in the aqueous phase, and the equivalent alkane number of the oil phase (sunflower and dodecane oils were compared). The results extend the potential of CNC in the formulation of high-quality and edible Pickering emulsions. The functional properties imparted by LAE, a highly effective molecule against food pathogens and spoilage organisms, open new opportunities in food, cosmetics, and pharmaceutical applications, where the presence of CNC plays a critical role in achieving synergistic effects with LAE.

Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals.

PubMed

Pedraza-de la Cuesta, Susana; Keijzers, Lore; van der Wielen, Luuk A M; Cuellar, Maria C

2018-04-01

In multiphase fermentations where the product forms a second liquid phase or where solvents are added for product extraction, turbulent conditions disperse the oil phase as droplets. Surface-active components (SACs) present in the fermentation broth can stabilize the product droplets thus forming an emulsion. Breaking this emulsion increases process complexity and consequently the production cost. In previous works, it has been proposed to promote demulsification of oil/supernatant emulsions in an off-line batch bubble column operating at low gas flow rate. The aim of this study is to test the performance of this recovery method integrated to a fermentation, allowing for continuous removal of the oil phase. A 500 mL bubble column is successfully integrated with a 2 L reactor during 24 h without affecting cell growth or cell viability. However, higher levels of surfactants and emulsion stability are measured in the integrated system compared to a base case, reducing its capacity for oil recovery. This is related to release of SACs due to cellular stress when circulating through the recovery column. Therefore, it is concluded that the gas bubble-induced oil recovery method allows for oil separation and cell recycling without compromising fermentation performance; however, tuning of the column parameters considering increased levels of SACs due to cellular stress is required for improving oil recovery. © 2018 The Authors. Biotechnology Journal Published by Wiley-VCHVerlag GmbH & Co. KGaA, Weinheim.

Pickering emulsion stabilized by cashew gum- poly-l-lactide copolymer nanoparticles: Synthesis, characterization and amphotericin B encapsulation.

PubMed

Richter, A R; Feitosa, J P A; Paula, H C B; Goycoolea, F M; de Paula, R C M

2018-04-01

In this work, we provide proof-of-concept of formation, physical characteristics and potential use as a drug delivery formulation of Pickering emulsions (PE) obtained by a novel method that combines nanoprecipitation with subsequent spontaneous emulsification process. To this end, pre-formed ultra-small (d.∼10 nm) nanoprecipitated nanoparticles of hydrophobic derivatives of cashew tree gum grafted with polylactide (CGPLAP), were conceived to stabilize Pickering emulsions obtained by spontaneous emulsification. These were also loaded with Amphotericin B (AmB), a drug of low oral bioavailability used in the therapy of neglected diseases such as leishmaniasis. The graft reaction was performed in two CG/PLA molar ratio conditions (1:1 and 1:10). Emulsions were prepared by adding the organic phase (Miglyol 812 ® ) in the aqueous phase (nanoprecipitated CGPLAP), resulting the immediate emulsion formation. The isolation by centrifugation does not destabilize or separate the nanoparticles from oil droplets of the PE emulsion. Emulsions with CGPLAP 1:1 presented unimodal distributions at different CGPLA concentration, lower values in size and PDI and the best stability over time. The AmB was incorporated in the emulsions with a process efficiency of 21-47%, as determined by UV-vis. AmB in CGPLAP emulsions is in less aggregated state than observed in commercial AmB formulation. Copyright © 2018 Elsevier B.V. All rights reserved.

Interfacial film stabilized W/O/W nano multiple emulsions loaded with green tea and lotus extracts: systematic characterization of physicochemical properties and shelf-storage stability

PubMed Central

2014-01-01

Background and aims Multiple emulsions have excellent encapsulating potential and this investigation has been aimed to encapsulate two different plant extracts as functional cosmetic agents in the W/O/W multiple emulsions and the resultant system’s long term stability has been determined in the presence of a thickener, hydroxypropyl methylcellulose (HPMC). Methods Multiple W/O/W emulsions have been generated using cetyl dimethicone copolyol as lipophilic emulsifier and a blend of polyoxyethylene (20) cetyl ether and cetomacrogol 1000® as hydrophilic emulsifiers. The generated multiple emulsions have been characterized with conductivity, pH, microscopic analysis, phase separation and rheology for a period of 30 days. Moreover, long term shelf-storage stability has been tested to understand the shelf-life by keeping the generated multiple emulsion formulations at 25 ± 10°C and at 40 ± 10% relative humidity for a period of 12 months. Results It has been observed that the hydrophilic emulsifiers and HPMC have considerably improved the stability of multiple emulsions for the followed period of 12 months at different storage conditions. These multiple emulsions have shown improved entrapment efficiencies concluded on the release rate of conductometric tracer entrapped in the inner aqueous phase of the multiple emulsions. Conclusion Multiple emulsions have been found to be stable for a longer period of time with promising characteristics. Hence, stable multiple emulsions loaded with green tea and lotus extracts could be explored for their cosmetic benefits. PMID:24885994

Influence of membrane material on the production of colloidal emulsions by premix membrane emulsification.

PubMed

Gehrmann, Sandra; Bunjes, Heike

2018-05-01

Premix membrane emulsification is a possibility to produce colloidal emulsions as carrier systems for poorly water soluble drugs. During the extrusion of a coarse pre-emulsion through a porous membrane, the emulsion droplets are disrupted into smaller droplets. The influence of the membrane material on the emulsification success was investigated in dependence on the emulsifier. Premixed medium chain triglyceride (MCT) emulsions stabilized with five different emulsifiers were extruded through seven different hydrophilic polymeric membrane materials with pore sizes of 200nm. The resulting emulsions differed strongly in particle size and particle size distribution with a range of median particle sizes between 0.08μm and 11μm. The particle size of the emulsions did not depend mainly on the structure or thickness of the membrane but on the combination of emulsifier and membrane material. Contact angle measurements indicated that the wetting of the membrane with the continuous phase of the emulsion was decisive for achieving emulsions with colloidal particle sizes. The type of dispersed phase was of minor importance as basically the same results were obtained with peanut oil instead of MCT. To prove the assumption that only sufficiently hydrophilic membrane materials led to emulsions with colloidal particle sizes, two membrane materials were hydrophilized by plasma treatment. After hydrophilization, the emulsifying process led to emulsions with smaller particle sizes. The use of an alumina membrane (Anodisc®) improved the process even more. With this type of membrane, emulsions with a median particle size below 250nm and a narrow particle size distribution could be obtained with all investigated emulsifiers. Copyright © 2016 Elsevier B.V. All rights reserved.

Pickering emulsions stabilized by paraffin wax and Laponite clay particles.

PubMed

Li, Caifu; Liu, Qian; Mei, Zhen; Wang, Jun; Xu, Jian; Sun, Dejun

2009-08-01

Emulsions containing wax in dispersed droplets stabilized by disc-like Laponite clay particles are prepared. Properties of the emulsions prepared at different temperatures are examined using stability, microscopy and droplet-size analysis. At low temperature, the wax crystals in the oil droplets can protrude through the interface, leading to droplet coalescence. But at higher temperatures, the droplet size decreases with wax concentration. Considering the viscosity of the oil phase and the interfacial tension, we conclude that the wax is liquid-like during the high temperature emulsification process, but during cooling wax crystals appear around the oil/water interface and stabilize the droplets. The oil/water ratio has minimal effect on the emulsions between ratios of 3:7 and 7:3. The Laponite is believed to stabilize the emulsions by increasing the viscosity of the continuous phase and also by adsorbing at the oil/water interface, thus providing a physical barrier to coalescence.

Lipid oxidation induced oxidative degradation of cereal beta-glucan.

PubMed

Wang, Yu-Jie; Mäkelä, Noora; Maina, Ndegwa Henry; Lampi, Anna-Maija; Sontag-Strohm, Tuula

2016-04-15

In food systems, lipid oxidation can cause oxidation of other molecules. This research for the first time investigated oxidative degradation of β-glucan induced by lipid oxidation using an oil-in-water emulsion system which simulated a multi-phased aqueous food system containing oil and β-glucan. Lipid oxidation was monitored using peroxide value and hexanal production while β-glucan degradation was evaluated by viscosity and molecular weight measurements. The study showed that while lipid oxidation proceeded, β-glucan degradation occurred. Emulsions containing β-glucan, oil and ferrous ion showed significant viscosity and molecular weight decrease after 1 week of oxidation at room temperature. Elevated temperature (40°C) enhanced the oxidation reactions causing higher viscosity drop. In addition, the presence of β-glucan appeared to retard the hexanal production in lipid oxidation. The study revealed that lipid oxidation may induce the degradation of β-glucan in aqueous food systems where β-glucan and lipids co-exist. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of lipid viscosity and high-pressure homogenization on the physical stability of "Vitamin E" enriched emulsion.

PubMed

Alayoubi, Alaadin; Abu-Fayyad, Ahmed; Rawas-Qalaji, Mutasem M; Sylvester, Paul W; Nazzal, Sami

2015-01-01

Recently there has been a growing interest in vitamin E for its potential use in cancer therapy. The objective of this work was therefore to formulate a physically stable parenteral lipid emulsion to deliver higher doses of vitamin E than commonly used in commercial products. Specifically, the objectives were to study the effects of homogenization pressure, number of homogenizing cycles, viscosity of the oil phase, and oil content on the physical stability of emulsions fortified with high doses of vitamin E (up to 20% by weight). This was done by the use of a 27-run, 4-factor, 3-level Box-Behnken statistical design. Viscosity, homogenization pressure, and number of cycles were found to have a significant effect on particle size, which ranged from 213 to 633 nm, and on the percentage of vitamin E remaining emulsified after storage, which ranged from 17 to 100%. Increasing oil content from 10 to 20% had insignificant effect on the responses. Based on the results it was concluded that stable vitamin E rich emulsions could be prepared by repeated homogenization at higher pressures and by lowering the viscosity of the oil phase, which could be adjusted by blending the viscous vitamin E with medium-chain triglycerides (MCT).

Hierarchical Biomolecular Emulsions Using 3-D Microfluidics with Uniform Surface Chemistry.

PubMed

Toprakcioglu, Zenon; Levin, Aviad; Knowles, Tuomas P J

2017-11-13

Microfluidic devices can be used to produce single, double and higher order emulsions, where droplet sizes can be precisely controlled and modulated. Such emulsions have great potential for the storage and study of biomolecules, including peptides and proteins. However, advancement of this technique has remained challenging due to the tendency of various biomolecules to adhere to the surface of the formed channels, resulting in changes in surface wetting and fouling on the micrometer scale. Thus, precise control of surface wettability plays a crucial role in the processes that govern droplet formation. Here, we report an approach for producing both water-oil-water (w/o/w) and oil-water-oil (o/w/o) double emulsions without any need for surface modification, an enabling feature for biomolecular encapsulation. Using this strategy, we show that the number of monodisperse encapsulated internal droplets can be controlled systematically and reproducibly by suitable adjustment of the relevant flow rates, and ranges from 1 to 40 in the case of w/o/w emulsions. We further demonstrate that the number of internal droplets scales linearly with the reciprocal flow rate of the outer continuous phase, when the inner and middle phase flow rates are kept constant. We demonstrate that this approach is suitable for forming double emulsions where the inner phase consists of reconstituted silk protein solution whereby incubation of the internal droplets can be induced to form a gel resulting in silk fibroin microgels surrounded by an external oil shell. Finally, for o/w/o emulsions, we show that single or multiple monodisperse internal droplets can be encapsulated with a size that ranges over 1 order of magnitude, from ca. 10 μm to >100 μm. Moreover, o/w/o emulsions where the middle phase consists of silk fibroin solution were prepared and by allowing the protein to aggregate, a core-shell structure was formed. This microfluidic strategy allows for multiple emulsions to be generated drop by drop for biomolecular solutions with potential applications in the biomedical and pharmaceutical fields.

Durability of base courses with mineral-cement-emulsion mixes (MCEM)

NASA Astrophysics Data System (ADS)

Kukiełka, J.; Sybilski, D.

2018-05-01

Base courses with mineral-cement-emulsion mixes (MCEM) have been the subject of research, surveys and development of e.g. new requirements included in the Guidelines of 2014 [15]. In this paper the results of sample test and survey of road sections, assessment of transverse cracks and load-bearing capacity with FWD after 13 years of exploitation are presented. On the MCEM samples the following tests were carried out: resilient modulus using NAT, complex stiffness modulus (E*), phase shift angle at various temperatures and loading frequencies thereby obtaining master curves, fatigue life and low-temperature resistance by identifying the tensile stress restrained (TSRST) which allowed for general assessment of constructed base courses.

Crocin loaded nano-emulsions: Factors affecting emulsion properties in spontaneous emulsification.

PubMed

Mehrnia, Mohammad-Amin; Jafari, Seid-Mahdi; Makhmal-Zadeh, Behzad S; Maghsoudlou, Yahya

2016-03-01

Spontaneous emulsification may be used for encapsulating bioactive compounds in food and pharmaceutical industry. It has several advantages over high energy and other low energy methods including, protecting sensitive compounds against severe conditions of high energy method and its ability to minimize surfactant, removal of cosurfactant and thermal stability compared with other low energy methods. In this study, we examined possibility of encapsulating highly soluble crocin in W/O micro-emulsions using spontaneous method which further could be used for making double emulsions. Nonionic surfactants of Span 80 and polyglycerol polyricinoleate (PGPR) were used for making micro-emulsions that showed the high potential of PGPR for spontaneous method. Surfactant to water ratio (SWR%) was evaluated to find the highest amount of aqueous phase which can be dispersed in organic phase. Droplet size decreased by increasing SWR toward the SWR=100% which had the smallest droplet size and then increased at higher levels of surfactant. By increasing SWR, shear viscosity increased which showed the high effect of PGPR on rheological properties. This study shows in addition to W/O micro-emulsions, spontaneous method could be used for preparing stable O/W micro-emulsions. Copyright © 2015 Elsevier B.V. All rights reserved.

Competitive displacement of sodium caseinate by low-molecular-weight emulsifiers and the effects on emulsion texture and rheology.

PubMed

Munk, M B; Larsen, F H; van den Berg, F W J; Knudsen, J C; Andersen, M L

2014-07-29

Low-molecular-weight (LMW) emulsifiers are used to promote controlled destabilization in many dairy-type emulsions in order to obtain stable foams in whippable products. The relation between fat globule aggregation induced by three LMW emulsifiers, lactic acid ester of monoglyceride (LACTEM), saturated monoglyceride (GMS), and unsaturated monoglyceride (GMU) and their effect on interfacial protein displacement was investigated. It was found that protein displacement by LMW emulsifiers was not necessary for fat globule aggregation in emulsions, and conversely fat globule aggregation was not necessarily accompanied by protein displacement. The three LMW emulsifiers had very different effects on emulsions. LACTEM induced shear instability of emulsions, which was accompanied by protein displacement. High stability was characteristic for emulsions with GMS where protein was displaced from the interface. Emulsions containing GMU were semisolid, but only low concentrations of protein were detected in the separated serum phase. The effects of LACTEM, GMS, and GMU may be explained by three different mechanisms involving formation of interfacial α-gel, pickering stabilization and increased exposure of bound casein to the water phase. The latter may facilitate partial coalescence. Stabilizing hydrocolloids did not have any effect on the LMW emulsifiers' ability to induce protein displacement.

Flocculation and coalescence of droplets in oil-in-water emulsions formed with highly hydrolysed whey proteins as influenced by starch.

PubMed

Ye, Aiqian; Hemar, Yacine; Singh, Harjinder

2004-10-10

The effects of added unmodified amylopectin starch, modified amylopectin starch and amylose starch on the formation and properties of emulsions (4 wt.% corn oil) made with an extensively hydrolysed commercial whey protein (WPH) product under a range of conditions were examined. The rate of coalescence was calculated based on the changes in the droplet size of the emulsions during storage at 20 degrees C. The rates of creaming and coalescence in emulsions containing amylopectin starches were enhanced with increasing concentration of the starches during storage for up to 7 days. At a given starch concentration, the rate of coalescence was higher in the emulsions containing modified amylopectin starch than in those containing unmodified amylopectin starch, whereas it was lowest in the emulsions containing amylose starch. All emulsions containing unmodified and modified amylopectin starches showed flocculation of oil droplets by a depletion mechanism. However, flocculation was not observed in the emulsions containing amylose starch. The extent of flocculation was considered to correlate with the rate of coalescence of oil droplets. The different rates of coalescence could be explained on the basis of the strength of the depletion potential, which was dependent on the molecular weight and the radius of gyration of the starches. At high levels of starch addition (>1.5%), the rate of coalescence decreased gradually, apparently because of the high viscosity of the aqueous phase caused by the starch.

Carbon Dioxide-Water Emulsions for Enhanced Oil Recovery and Permanent Sequestration of Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, David; Golomb, Dan; Shi, Guang

2011-09-30

This project involves the use of an innovative new invention Particle Stabilized Emulsions (PSEs) of Carbon Dioxide-in-Water and Water-in-Carbon Dioxide for Enhanced Oil Recovery (EOR) and Permanent Sequestration of Carbon Dioxide. The EOR emulsion would be injected into a semi-depleted oil reservoir such as Dover 33 in Otsego County, Michigan. It is expected that the emulsion would dislocate the stranded heavy crude oil from the rock granule surfaces, reduce its viscosity, and increase its mobility. The advancing emulsion front should provide viscosity control which drives the reduced-viscosity oil toward the production wells. The make-up of the emulsion would be subsequentlymore » changed so it interacts with the surrounding rock minerals in order to enhance mineralization, thereby providing permanent sequestration of the injected CO{sub 2}. In Phase 1 of the project, the following tasks were accomplished: 1. Perform laboratory scale (mL/min) refinements on existing procedures for producing liquid carbon dioxide-in-water (C/W) and water-in-liquid carbon dioxide (W/C) emulsion stabilized by hydrophilic and hydrophobic fine particles, respectively, using a Kenics-type static mixer. 2. Design and cost evaluate scaled up (gal/min) C/W and W/C emulsification systems to be deployed in Phase 2 at the Otsego County semi-depleted oil field. 3. Design the modifications necessary to the present CO{sub 2} flooding system at Otsego County for emulsion injection. 4. Design monitoring and verification systems to be deployed in Phase 2 for measuring potential leakage of CO{sub 2} after emulsion injection. 5. Design production protocol to assess enhanced oil recovery with emulsion injection compared to present recovery with neat CO{sub 2} flooding. 6. Obtain Federal and State permits for emulsion injection. Initial research focused on creating particle stabilized emulsions with the smallest possible globule size so that the emulsion can penetrate even low-permeability crude oilcontaining formations or saline aquifers. The term globule refers to the water or liquid carbon dioxide droplets sheathed with ultrafine particles dispersed in the continuous external medium, liquid CO{sub 2} or H{sub 2}O, respectively. The key to obtaining very small globules is the shear force acting on the two intermixing fluids, and the use of ultrafine stabilizing particles or nanoparticles. We found that using Kenics-type static mixers with a shear rate in the range of 2700 to 9800 s{sup -1} and nanoparticles between 100-300 nm produced globule sizes in the 10 to 20 μm range. Particle stabilized emulsions with that kind of globule size should easily penetrate oil-bearing formations or saline aquifers where the pore and throat size can be on the order of 50 μm or larger. Subsequent research focused on creating particle stabilized emulsions that are deemed particularly suitable for Permanent Sequestration of Carbon Dioxide. Based on a survey of the literature an emulsion consisting of 70% by volume of water, 30% by volume of liquid or supercritical carbon dioxide, and 2% by weight of finely pulverized limestone (CaCO{sub 3}) was selected as the most promising agent for permanent sequestration of CO{sub 2}. In order to assure penetration of the emulsion into tight formations of sandstone or other silicate rocks and carbonate or dolomite rock, it is necessary to use an emulsion consisting of the smallest possible globule size. In previous reports we described a high shear static mixer that can create such small globules. In addition to the high shear mixer, it is also necessary that the emulsion stabilizing particles be in the submicron size, preferably in the range of 0.1 to 0.2 μm (100 to 200 nm) size. We found a commercial source of such pulverized limestone particles, in addition we purchased under this DOE Project a particle grinding apparatus that can provide particles in the desired size range. Additional work focused on attempts to generate particle stabilized emulsions with a flow through, static mixer based apparatus under a variety of conditions that are suitable for permanent sequestration of carbon dioxide. A variety of mixtures of water, CO{sub 2} and particles may also provide suitable emulsions capable of PS. In addition, it is necessary to test the robustness of PSE formation as composition changes to be certain that emulsions of appropriate size and stability form under conditions that might vary during actual large scale EOR and sequestration operations. The goal was to lay the groundwork for an apparatus and formulation that would produce homogenous microemulsions of CO{sub 2}-in-water capable of readily mixing with the waters of deep saline aquifers and allow a safer and more permanent sequestration of carbon dioxide. In addition, as a beneficial use, we hoped to produce homogenous microemulsions of water-in-CO{sub 2} capable of readily mixing with pure liquid or supercritical CO{sub 2} for use in Enhanced Oil Recovery (EOR). However, true homogeneous microemulsions have proven very difficult to produce and efforts have not yielded either a formulation or a mixing strategy that gives emulsions that do not settle out or that can be diluted with the continuous phase in varying proportions. Other mixtures of water, CO{sub 2} and particles, that are not technically homogeneous microemulsions, may also provide suitable emulsions capable of PS and EOR. For example, a homogeneous emulsion that is not a microemulsion might also provide all of the necessary characteristics desired. These characteristics would include easy formation, stability over time, appropriate size and the potential for mineralization under conditions that would be encountered under actual large scale sequestration operations. This report also describes work with surrogate systems in order to test conditions.« less

Effect of salts on formation and stability of vitamin E-enriched mini-emulsions produced by spontaneous emulsification.

PubMed

Saberi, Amir Hossein; Fang, Yuan; McClements, David Julian

2014-11-19

Emulsion-based delivery systems are being utilized to incorporate lipophilic bioactive components into various food, personal care, and pharmaceutical products. This study examined the influence of inorganic salts (NaCl and CaCl2) on the formation, stability, and properties of vitamin E-enriched emulsions prepared by spontaneous emulsification. These emulsions were simply formed by titration of a mixture of vitamin E acetate (VE), carrier oil (MCT), and nonionic surfactant (Tween 80) into an aqueous salt solution with continuous stirring. Salt type and concentration (0-1 N NaCl or 0-0.5 N CaCl2) did not have a significant influence on the initial droplet size of the emulsions. On the other hand, the isothermal and thermal stabilities of the emulsions depended strongly on salt levels. The cloud point of the emulsions decreased with increasing salt concentration, which was attributed to accelerated droplet coalescence in the presence of salts. Dilution (2-6 times) of the emulsions with water appreciably improved their thermal stability by increasing their cloud point, which was mainly attributed to the decrease in aqueous phase salt levels. The isothermal storage stability of the emulsions also depended on salt concentration; however, increasing the salt concentration decreased the rate of droplet growth, which was the opposite of its effect on thermal stability. Potential physicochemical mechanisms for these effects are discussed in terms of the influence of salt ions on van der Waals and electrostatic interactions. This study provides important information about the effect of inorganic salts on the formation and stability of vitamin E emulsions suitable for use in food, personal care, and pharmaceutical products.

Osmosis-driven viscous fingering of oil-in-water emulsions

NASA Astrophysics Data System (ADS)

Liu, Ying; Rallabandi, Bhargav; Baskaran, Mrudhula; Stone, Howard

2017-11-01

Viscous fingering occurs when a low viscosity fluid invades a more viscous fluid. Fingering of two miscible fluids is more complicated than that of immiscible fluids in that there is no sharp fluid-fluid interface and diffusion occurs between the phases. We experimentally studied the fingering of two miscible fluids: an oil-in-water emulsion and a sodium chloride solution. When the concentration of sodium chloride in the water phase in the emulsion exceeds that in the sodium chloride solution, the consequent osmotic flow automatically facilitates the occurrence of the fingering. On the contrary, when the sodium chloride solution has higher concentration, the spreading of emulsion is more uniform than the case without the concentration difference. We provide a model to rationalize and quantify these observations.

Development of eco-friendly submicron emulsions stabilized by a bio-derived gum.

PubMed

Pérez-Mosqueda, Luis María; Ramírez, Pablo; Trujillo-Cayado, Luis Alfonso; Santos, Jenifer; Muñoz, José

2014-11-01

Many traditional organic solvents are being gradually replaced by ecofriendly alternatives. D-Limonene is a terpenic (bio)-solvent that fulfils the requirements to be considered a green solvent. D-Limonene sub-micron emulsions suffer from Ostwald ripening destabilization. In this study, we examined the influence of the addition of a natural gum (rosin gum) to D-limonene in order to prevent Ostwald ripening. This contribution deals with the study of emulsions formulated with a mixture of D-limonene and rosin gum as dispersed phase and Pluronic PE9400 as emulsifier. The procedure followed for the development of these formulations was based on the application of product design principles. This led to the optimum ratio rosin gum/D-limonene and subsequently to the optimum surfactant concentration. The combination of different techniques (rheology, laser diffraction and multiple light scattering) was demonstrated to be a powerful tool to assist in the prediction of the emulsions destabilization process. Not only did the addition of rosin gum highly increase the stability of these emulsions by inhibiting the Ostwald ripening, but it also reduced the emulsions droplet size. Thus, we found that stable sub-micron D-limonene-in-water emulsions have been obtained in the range 3-6 wt% Pluronic PE-9400 by means of a single-step rotor/stator homogenizing process. Copyright © 2014 Elsevier B.V. All rights reserved.

Viscoelasticity of Depletion-Induced Emulsion Gels

NASA Astrophysics Data System (ADS)

Meller, Amit; Stavans, Joel; Gisler, Thomas; Weitz, David A.

1997-03-01

The presence of non-adsorbing polymer in an oil-in-water emulsion results in a depletion attraction between the emulsion droplets, causing a phase separation into an droplet-rich phase and a polymer-rich phase largely devoid of emulsion droplets. At high enough droplet concentration, however, this phase separation is kinetically arrested to a gel-like state where large (diameter>50 μm) clusters of droplets are weakly connected via ramifications, leading to a measurable elastic modulus. We measure the mean-square displacement <Δ r ^2 (t)> of a droplet of size a inside a cluster using diffusing wave spectroscopy (DWS); by means of a generalized Stokes-Einstein relation we obtain frequency dependent storage and loss moduli G'(ω) and G''(ω), respectively. G'(ω) reaches a plateau at frequencies between 1 rad/s and 100 rad/s; this plateau modulus is found to scale with the hard-sphere energy density k_BT/a^3; within the clusters the droplets are densely packed, yet remain undeformed, the droplet volume fraction being determined by the osmotic pressure exerted by the polymer.

Zero-Valent Metal Emulsion for Reductive Dehalogenation of DNAPLs

NASA Technical Reports Server (NTRS)

Reinhart, Debra R. (Inventor); Clausen, Christian (Inventor); Gelger, Cherie L. (Inventor); Quinn, Jacqueline (Inventor); Brooks, Kathleen (Inventor)

2006-01-01

A zero-valent metal emulsion is used to dehalogenate solvents, such as pooled dense non-aqueous phase liquids (DNAPLs), including trichloroethylene (TCE). The zero-valent metal emulsion contains zero-valent metal particles, a surfactant, oil and water, The preferred zero-valent metal particles are nanoscale and microscale zero-valent iron particles.

Double emulsions from a capillary array injection microfluidic device.

PubMed

Shang, Luoran; Cheng, Yao; Wang, Jie; Ding, Haibo; Rong, Fei; Zhao, Yuanjin; Gu, Zhongze

2014-09-21

A facile microfluidic device was developed by inserting an annular capillary array into a collection channel for single-step emulsification of double emulsions. By inserting multiple inner-phase solutions into the capillary array, multicomponent double emulsions or microcapsules with inner droplets of different content could also be obtained from the device.

Zero-Valent Metal Emulsion for Reductive Dehalogenation of DNAPLS

NASA Technical Reports Server (NTRS)

Reinhart, Debra R. (Inventor); Clausen, Christian (Inventor); Geiger, Cherie L. (Inventor); Quinn, Jacqueline (Inventor); Brooks, Kathleen (Inventor)

2003-01-01

A zero-valent metal emulsion is used to dehalogenate solvents, such as pooled dense non-aqueous phase liquids (DNAPLs), including trichloroethylene (TCE). The zero-valent metal emulsion contains zero-valent metal particles, a surfactant, oil and water. The preferred zero-valent metal particles are nanoscale and microscale zero-valent iron particles

Oil-in-oil emulsions stabilised solely by solid particles.

PubMed

Binks, Bernard P; Tyowua, Andrew T

2016-01-21

A brief review of the stabilisation of emulsions of two immiscible oils is given. We then describe the use of fumed silica particles coated with either hydrocarbon or fluorocarbon groups in acting as sole stabilisers of emulsions of various vegetable oils with linear silicone oils (PDMS) of different viscosity. Transitional phase inversion of emulsions, containing equal volumes of the two oils, from silicone-in-vegetable (S/V) to vegetable-in-silicone (V/S) occurs upon increasing the hydrophobicity of the particles. Close to inversion, emulsions are stable to coalescence and gravity-induced separation for at least one year. Increasing the viscosity of the silicone oil enables stable S/V emulsions to be prepared even with relatively hydrophilic particles. Predictions of emulsion type from calculated contact angles of a silica particle at the oil-oil interface are in agreement with experiment provided a small polar contribution to the surface energy of the oils is included. We also show that stable multiple emulsions of V/S/V can be prepared in a two-step procedure using two particle types of different hydrophobicity. At fixed particle concentration, catastrophic phase inversion of emulsions from V/S to S/V can be effected by increasing the volume fraction of vegetable oil. Finally, in the case of sunflower oil + 20 cS PDMS, the study is extended to particles other than silica which differ in chemical type, particle size and particle shape. Consistent with the above findings, we find that only sufficiently hydrophobic particles (clay, zinc oxide, silicone, calcium carbonate) can act as efficient V/S emulsion stabilisers.

Whey protein/polysaccharide-stabilized emulsions: Effect of polymer type and pH on release and topical delivery of salicylic acid.

PubMed

Combrinck, Johann; Otto, Anja; du Plessis, Jeanetta

2014-06-01

Emulsions are widely used as topical formulations in the pharmaceutical and cosmetic industries. They are thermodynamically unstable and require emulsifiers for stabilization. Studies have indicated that emulsifiers could affect topical delivery of actives, and this study was therefore designed to investigate the effects of different polymers, applied as emulsifiers, as well as the effects of pH on the release and topical delivery of the active. O/w emulsions were prepared by the layer-by-layer technique, with whey protein forming the first layer around the oil droplets, while either chitosan or carrageenan was subsequently adsorbed to the protein at the interface. Additionally, the emulsions were prepared at three different pH values to introduce different charges to the polymers. The active ingredient, salicylic acid, was incorporated into the oil phase of the emulsions. Physical characterization of the resulting formulations, i.e., droplet size, zeta potential, stability, and turbidity in the water phase, was performed. Release studies were conducted, after which skin absorption studies were performed on the five most stable emulsions, by using Franz type diffusion cells and utilizing human, abdominal skin membranes. It was found that an increase in emulsion droplet charge could negatively affect the release of salicylic acid from these formulations. Contrary, positively charged emulsion droplets were found to enhance dermal and transdermal delivery of salicylic acid from emulsions. It was hypothesized that electrostatic complex formation between the emulsifier and salicylic acid could affect its release, whereas electrostatic interaction between the emulsion droplets and skin could influence dermal/transdermal delivery of the active.

Nano-sized water-in-oil-in-water emulsion enhances intestinal absorption of calcein, a high solubility and low permeability compound.

PubMed

Koga, Kenjiro; Takarada, Nobuo; Takada, Kanji

2010-02-01

Our goal was to develop safe and stable multilayer emulsions capable of enhancing intestinal absorption of biopharmaceutics classification system (BCS) class III drugs. First, w/o emulsions were prepared using calcein as a model BCS class III compound and condensed ricinoleic acid tetraglycerin ester as a hydrophobic emulsifier. Then water-in-oil-in-water (w/o/w) emulsions were prepared with shirasu porous glass (SPG) membranes. Particle size analyses and calcein leakage from oil droplets in w/o/w emulsions led us to select stearic acid hexaglycerin esters (HS-11) and Gelucire 44/14 as hydrophilic emulsifiers. Analyses of the absorption-enhancing effects of w/o/w emulsions on intestinal calcein absorption in rats showed that calcein bioavailability after intraduodenal (i.d.) administration of HS-11 or Gelucire 44/14+polyvinyl alcohol (PVA) w/o/w emulsions prepared with 0.1-microm pore-sized SPGs was significantly higher than that of the calcein control. However, serum calcein concentration vs. time profiles after i.d. administration of w/o/w emulsions prepared with 1.1-microm and 30-microm pore-sized SPGs and an emulsion prepared with a calcein-containing outer water phase were comparable to control profiles. These results suggested that HS-11 or Gelucire 44/14+PVA are safe outer water phase additives and that 0.1-microm pore-sized SPGs are important for preparing w/o/w emulsions that enhanced intestinal calcein absorption. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Stability of anthocyanin-rich w/o/w-emulsions designed for intestinal release in gastrointestinal environment.

PubMed

Frank, Kerstin; Walz, Elke; Gräf, Volker; Greiner, Ralf; Köhler, Karsten; Schuchmann, Heike Petra

2012-12-01

Anthocyanins belong to the most important hydrophilic plant pigments. Outside their natural environment, these molecules are extremely unstable. Encapsulating them in submicron-sized containers is one possibility to stabilize them for the use in bioactivity studies or functional foods. The containers have to be designed for a target release in the human gastrointestinal system. In this contribution, an anthocyanin-rich bilberry extract was encapsulated in the inner aqueous phase of water-in-oil-in-water-double emulsions. The physical stability as well as the release of free fatty acids and encapsulated, bioactive substances from the emulsions during an in vitro gastrointestinal passage were investigated. The focus was on the influence of emulsion microstructural parameters (for example, inner and outer droplet size, disperse phase content) and required additives (emulsifier systems), respectively. It could be shown that it is possible to stabilize anthocyanins in the inner phase of double emulsions. The release rate of free fatty acids during incubation was independent of the emulsifier used. However, the exterior (O/W)-emulsifier has an impact on the stability of multiple emulsions in gastrointestinal environment and, thus, the location of release. Long-chained emulsifiers like whey proteins are most suitable to transport a maximum amount of bioactive substances to the effective location, being the small intestine for anthocyanins. In addition, it was shown that the dominating release mechanism for entrapped matter was coalescence of the interior W(1) -droplets with the surrounding W(2) -phase. © 2012 Institute of Process Engineering in Life Science I: Food Process Engineering, Karlsruhe Institute of Technology (KIT).

Ultrasound-triggered drug delivery using acoustic droplet vaporization

NASA Astrophysics Data System (ADS)

Fabiilli, Mario Leonardo

The goal of targeted drug delivery is the spatial and temporal localization of a therapeutic agent and its associated bioeffects. One method of drug localization is acoustic droplet vaporization (ADV), whereby drug-laden perfluorocarbon (PFC) emulsions are vaporized into gas bubbles using ultrasound, thereby releasing drug locally. Transpulmonary droplets are converted into bubbles that occlude capillaries, sequestering the released drug within an organ or tumor. This research investigates the relationship between the ADV and inertial cavitation (IC) thresholds---relevant for drug delivery due to the bioffects generated by IC---and explores the delivery of lipophilic and hydrophilic compounds using PFC double emulsions. IC can positively and negatively affect ultrasound mediated drug delivery. The ADV and IC thresholds were determined for various bulk fluid, droplet, and acoustic parameters. At 3.5 MHz, the ADV threshold occurred at a lower rarefactional pressure than the IC threshold. The results suggest that ADV is a distinct phenomenon from IC, the ADV nucleus is internal to the droplet, and the IC nucleus is the bubble generated by ADV. The ADV triggered release of a lipophilic chemotherapeutic agent, chlorambucil (CHL), from a PFC-in-oil-in-water emulsion was explored using plated cells. Cells exposed to a CHL-loaded emulsion, without ADV, displayed 44% less growth inhibition than cells exposed to an equal concentration of CHL in solution. Upon ADV of the CHL-loaded emulsion, the growth inhibition increased to the same level as cells exposed to CHL in solution. A triblock copolymer was synthesized which enabled the formulation of stable water-in-PFC-in-water (W1/PFC/W2) emulsions. The encapsulation of fluorescein in the W1 phase significantly decreased the mass flux of fluorescein; ADV was shown to completely release the fluorescein from the emulsions. ADV was also shown to release thrombin, dissolved in the W1 phase, which could be used in vivo to extend synergistically the duration of ADV-generated, microbubble-based embolizations. Overall, the results suggest that PFC double emulsions can be used as an ultrasound-triggered drug delivery system. Compared to traditional drug delivery systems, ADV could be used to increase the therapeutic efficacy and decrease the systemic toxicity of drug therapy.

Transport and Retention of Emulsion Droplets in Sandy Porous Media

NASA Astrophysics Data System (ADS)

Esahani, S. G.; Muller, K.; Chapra, S. C.; Ramsburg, A.

2014-12-01

Emulsions are commonly used as amendments during remediation; yet, the processes controlling the distribution of droplets within the subsurface are not well understood. Given that inadequate spatial and/or temporal delivery of amendments often leads to ineffective treatment, there is a need to better understand emulsion transport. Experiments were conducted to evaluate the transport and retention of emulsion droplets in columns containing Ottawa sands. Breakthrough curves and deposition profiles from these experiments were interrogated using a mathematical model capable of describing attachment, detachment, and straining to begin to elucidate the physical processes controlling delivery. Emulsions were constructed by stabilizing soybean oil droplets within a continuous aqueous phase. Physical properties of the resulting oil-in-water emulsions were favorable for subsurface delivery (nominal properties: 1 g/mL density; 10 cP viscosity; and 1.5 μm droplet d50). Emulsions were introduced to the columns for approximately two pore volumes and followed by an extended flush of background solution. Effluent droplet size distributions did not vary significantly over the course of the experiment and remained similar to those measured for the influent emulsion. Emulsion breakthrough curves exhibited tailing, and deposition profiles were found to be hyper-exponential and unaffected by extended periods of background flow. Depending on emulsion composition and flow characteristics, 10-30% of the injected emulsion was retained on the sand suggesting a non-negligible influence on accessible porosity over the course of the experiment. Experimental results were further interpreted using a droplet transport model that accounts for temporal and spatial variation in porosity due to the retention of the emulsion droplets. At present the model assumes a uniform size distribution of inelastic emulsion droplets which are transported by advection and dispersion, and exchanged with the solid phase through attachment, detachment, and straining processes. Results examine the relative roles of attachment-detachment and straining in reducing the accessible porosity. Evaluation of how the porosity change influences the flow regime for moderately and slightly clogged media is currently under investigation.

Altering the level of calcium changes the physical properties and digestibility of casein-based emulsion gels.

PubMed

McIntyre, Irene; O Sullivan, Michael; O Riordan, Dolores

2017-04-19

Casein-based emulsion gels prepared with different types of lipid (i.e. milk fat or rapeseed oil) were formulated with high (774 mg Ca per 100 g) or low (357 mg Ca per 100 g) calcium levels by blending acid and rennet casein. Their physicochemical characteristics (i.e. composition, texture, microstructure & water mobility) and in vitro digestibility were compared to conventionally formulated high-calcium (723 mg Ca per 100 g) emulsion gels made from rennet casein with calcium chelating salts (CCS). CCS-free, high-calcium emulsion gels were significantly (p ≤ 0.05) softer than those with low calcium levels (possibly due to their shorter manufacture time and higher pH) and showed the highest rates of disintegration during simulated gastric digestion. Despite having a higher moisture to protein ratio, the high-calcium emulsion gels containing CCS had broadly similar hardness values to those of high-calcium concentration prepared without CCS, but had higher cohesiveness. The high-calcium matrices containing CCS had quite a different microstructure and increased water mobility compared to those made without CCS and showed the slowest rate (p ≤ 0.05) of disintegration in the gastric environment. Gastric resistance was not affected by the type of lipid phase. Conversely, fatty acid release was similar for all emulsion gels prepared from milk fat, however, high-calcium emulsion gels (CCS-free) prepared from rapeseed oil showed higher lipolysis. Results suggest that food matrix physical properties can be modified to alter resistance to gastric degradation which may have consequences for the kinetics of nutrient release and delivery of bioactives sensitive to the gastric environment.

Characterization of konjac glucomannan-ethyl cellulose film formation via microscopy.

PubMed

Xiao, Man; Wan, Li; Corke, Harold; Yan, Wenli; Ni, Xuewen; Fang, Yapeng; Jiang, Fatang

2016-04-01

Konjac glucomannan-ethyl cellulose (KGM-EC, 7:3, w/w) blended film shows good mechanical and moisture resistance properties. To better understand the basis for the KGM-EC film formation, optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) were used to observe the formation of the film from emulsion. Optical microscopy images showed that EC oil droplets were homogeneously dispersed in KGM water phase without obviously coalescence throughout the entire drying process. SEM images showed the surface and cross-sectional structures of samples maintained continuous and homogeneous appearance from the emulsion to dried film. AFM images indicated that KGM molecules entangled EC molecules in the emulsion. Interactions between KGM and EC improved the stability of KGM-EC emulsion, and contributed to uniformed structures of film formation. Based on these output information, a schematic model was built to elucidate KGM-EC film-forming process. Copyright © 2015 Elsevier B.V. All rights reserved.

The Physical State of Emulsified Edible Oil Modulates Its in Vitro Digestion.

PubMed

Guo, Qing; Bellissimo, Nick; Rousseau, Dérick

2017-10-18

Emulsified lipid digestion was tailored by manipulating the physical state of dispersed oil droplets in whey protein stabilized oil-in-water (O/W) emulsions, where the oil phase consisted of one of five ratios of soybean oil (SO) and fully hydrogenated soybean oil (FHSO). The evolution in particle size distribution, structural changes during oral, gastric, and intestinal digestion, and free fatty acid release during intestinal digestion were all investigated. Irrespective of the physical state and structure of the dispersed oil/fat, all emulsions were stable against droplet size increases during oral digestion. During gastric digestion, the 50:50 SO:FHSO emulsion was more stable against physical breakdown than any other emulsion. All emulsions underwent flocculation and coalescence or partial coalescence upon intestinal digestion, with the SO emulsion being hydrolyzed the most rapidly. The melting point of all emulsions containing FHSO was above 37 °C, with the presence of solid fat within the dispersed oil droplets greatly limiting lipolysis. Fat crystal polymorph and nanoplatelet size did not play an important role in the rate and extent of lipid digestion. Free fatty acid release modeled by the Weibull distribution function showed that the rate of lipid digestion (κ) decreased with increasing solid fat content, and followed an exponential relationship (R 2 = 0.95). Overall, lipid digestion was heavily altered by the physical state of the dispersed oil phase within O/W emulsions.

Modified montmorillonite clay microparticles for stable oil-in-seawater emulsions.

PubMed

Dong, Jiannan; Worthen, Andrew J; Foster, Lynn M; Chen, Yunshen; Cornell, Kevin A; Bryant, Steven L; Truskett, Thomas M; Bielawski, Christopher W; Johnston, Keith P

2014-07-23

Environmentally benign clay particles are of great interest for the stabilization of Pickering emulsions. Dodecane-in-synthetic seawater (SSW) emulsions formed with montmorillonite (MMT) clay microparticles modified with bis(2-hydroxyethyl)oleylamine were stable against coalescence, even at clay concentrations down to 0.1% w/v. Remarkably, as little as 0.001% w/v surfactant lowered the hydrophilicity of the clay to a sufficient level for stabilization of oil-in-SSW emulsions. The favorable effect of SSW on droplet size reduction and emulsion stability enhancement is hypothesized to be due to reduced electrostatic repulsion between adsorbed clay particles and a consequent increase in the continuous phase (an aqueous clay suspension) viscosity. Water/oil (W/O) emulsions were inverted to O/W either by decreasing the mass ratio of surfactant-to-clay (transitional inversion) or by increasing the water volume fraction (catastrophic inversion). For both types of emulsions, coalescence was minimal and the sedimentation or creaming was highly correlated with the droplet size. For catastrophic inversions, the droplet size of the emulsions was smaller in the case of the preferred curvature. Suspensions of concentrated clay in oil dispersions in the presence of surfactant were stable against settling. The mass transfer pathways during emulsification of oil containing the clay particles were analyzed on the droplet size/stability phase diagrams to provide insight for the design of dispersant systems for remediating surface and subsurface oceanic oil spills.

One-step formation of multiple Pickering emulsions stabilized by self-assembled poly(dodecyl acrylate-co-acrylic acid) nanoparticles.

PubMed

Zhu, Ye; Sun, Jianhua; Yi, Chenglin; Wei, Wei; Liu, Xiaoya

2016-09-13

In this study, a one-step generation of stable multiple Pickering emulsions using pH-responsive polymeric nanoparticles as the only emulsifier was reported. The polymeric nanoparticles were self-assembled from an amphiphilic random copolymer poly(dodecyl acrylate-co-acrylic acid) (PDAA), and the effect of the copolymer content on the size and morphology of PDAA nanoparticles was determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The emulsification study of PDAA nanoparticles revealed that multiple Pickering emulsions could be generated through a one-step phase inversion process by using PDAA nanoparticles as the stabilizer. Moreover, the emulsification performance of PDAA nanoparticles at different pH values demonstrated that multiple emulsions with long-time stability could only be stabilized by PDAA nanoparticles at pH 5.5, indicating that the surface wettability of PDAA nanoparticles plays a crucial role in determining the type and stability of the prepared Pickering emulsions. Additionally, the polarity of oil does not affect the emulsification performance of PDAA nanoparticles, and a wide range of oils could be used as the oil phase to prepare multiple emulsions. These results demonstrated that multiple Pickering emulsions could be generated via the one-step emulsification process using self-assembled polymeric nanoparticles as the stabilizer, and the prepared multiple emulsions have promising potential to be applied in the cosmetic, medical, and food industries.

The Biophysics and Cell Biology of Lipid Droplets

PubMed Central

Thiam, A. Rachid; Farese, Robert V.; Walther, Tobias C.

2015-01-01

Lipid droplets (LDs) are intracellular organelles that are found in most cells, where they have fundamental and dynamic roles in metabolism. Recent investigations showed the importance of basic biophysical principles of emulsions for LD biology. At their essence, LDs are the dispersed phase of an oil-in-water emulsion in the aqueous cytosol of cells. They function prominently in storing oil-based reserves of metabolic energy and components of membrane lipids. Because of their unique architecture, with an interface between the dispersed oil phase and the aqueous cytosol, LDs require specialized mechanisms for their formation, growth, and shrinkage. Such mechanisms enable cells to use emulsified oil in a controlled manner (e.g., when demands for metabolic energy or membrane synthesis increase). Regulation of the composition of the phospholipid surfactants at the LD surface is crucial for LD growth and catabolism and also modifies protein targeting to LD surfaces. Here, we review new insights into the cell biology of LDs, with an emphasis on concepts of emulsion science and biophysics that apply to this organelle. PMID:24220094

[Fish oil containing lipid emulsions in critically ill patients: Critical analysis and future perspectives].

PubMed

Manzanares, W; Langlois, P L

2016-01-01

Third-generation lipid emulsions (LE) are soybean oil sparing strategies with immunomodulatory and antiinflammatory effects. Current evidence supporting the use of intravenous (i.v) fish oil (FO) LE in critically ill patients requiring parenteral nutrition or receiving enteral nutrition (pharmaconutrient strategy) mainly derives from small phase ii clinical trials in heterogenous intensive care unit patient's population. Over the last three years, there have been published different systematic reviews and meta-analyses evaluating the effects of FO containing LE in the critically ill. Recently, it has been demonstrated that i.v FO based LE may be able to significantly reduce the incidence of infections as well as mechanical ventilation days and hospital length of stay. Nonetheless, more robust evidence is required before giving a definitive recommendation. Finally, we strongly believe that a dosing study is required before new phase iii clinical trials comparing i.v FO containing emulsions versus other soybean oil strategies can be conducted. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

Development and stability evaluation of water-in-edible oils emulsions formulated with the incorporation of hydrophilic Hibiscus sabdariffa extract.

PubMed

Pimentel-Moral, Sandra; Rodríguez-Pérez, Celia; Segura-Carretero, Antonio; Martínez-Férez, Antonio

2018-09-15

New functional oils (extra virgin olive oil, EVOO and sunflower oil, SO) containing antioxidants from Hibiscus sabdariffa extract were developed by W/O emulsion. Their physical and chemical stability was measured over time. The lowest coalescence rate was obtained with 8 and 12 wt% surfactant amount for EVOO and SO emulsions, respectively. Before the evaluation of the oxidative stability, an optimization of phenolic compounds extraction from emulsions by multi-response surface methodology was performed. EVOO emulsions were chemically more stable over time than SO emulsions in terms of total phenolic content (TPC), antioxidant activity and chemical composition measured by HPLC-ESI.TOF-MS. TPC significantly increased (from 2.02 ± 0.07 to 2.71 ± 0.06 mg Eq GAE/g extract) and the antioxidant activity measured by TEAC remained constant for 1 month of storage. Thus, W/O emulsion technology has proven to be a potential method to vehiculize and stabilize bioactive compounds from H. sabdariffa into edible oils. Copyright © 2018 Elsevier Ltd. All rights reserved.

Switchable Pickering Emulsions Stabilized by Awakened TiO2 Nanoparticle Emulsifiers Using UV/Dark Actuation.

PubMed

Zhang, Qing; Bai, Rui-Xue; Guo, Ting; Meng, Tao

2015-08-26

In this work, switchable Pickering emulsions that utilize UV/dark manipulation employ a type of smart TiO2 nanoparticle as emulsifiers. The emulsifiers can be awakened when needed via UV-induced degradation of grafted silanes on TiO2 nanoparticles. By tuning the surface wettability of TiO2 nanoparticles in situ via UV/dark actuation, emulsions stabilized by the nanoparticles can be reversibly switched between the water-in-oil (W/O) type and oil-in-water (O/W) type for several cycles. Due to the convertible wettability, the smart nanoparticle emulsifiers can be settled in either the oil phase or the water phase as desired during phase separation, making it convenient for recycling. The present work provides a facile and noninvasive method to freely manipulate the formation, breakage, and switching of the emulsion; this method has promising potential as a powerful technique for use in energy-efficient and environmentally friendly industries.

Poly High Internal Phase Emulsion for the Immobilization of Chemical Warfare Agents.

PubMed

Wright, Alexander J; Main, Marcus J; Cooper, Nicholas J; Blight, Barry A; Holder, Simon J

2017-09-20

We report a facile method for the absorption (characterized by the weight/weight swelling degree, Q) of a variety of chemical warfare agents (CWAs); including sulfur mustard (HD) (Q = 40) and V-series (VM, VX, i-Bu-VX, n-Bu-VX) of nerve agents (Q ≥ 45) and a simulant, methyl benzoate (Q = 55), through the use of a poly(styrene-co-vinyl benzyl chloride-co-divinylbenzene) lightly cross-linked poly high internal phase emulsion (polyHIPE). By varying the vinyl benzyl chloride (VBC) content and the volume of the internal phase of the precursor emulsion it is demonstrated that absorption is facilitated both by the swelling of the polymer and the uptake of liquid in the pores. In particular the sample prepared from a 95% internal emulsion water content showed rapid swelling (<5 min to total absorption) and the ability to swell both from a monolithic state and from a compressed state, making these systems ideal practical candidates for the rapid immobilization of CWAs.

Instability Mechanisms of Water-in-Oil Nanoemulsions with Phospholipids: Temporal and Morphological Structures.

PubMed

Sommerling, Jan-Hendrik; de Matos, Maria B C; Hildebrandt, Ellen; Dessy, Alberto; Kok, Robbert Jan; Nirschl, Hermann; Leneweit, Gero

2018-01-16

Many food preparations, pharmaceuticals, and cosmetics use water-in-oil (W/O) emulsions stabilized by phospholipids. Moreover, recent technological developments try to produce liposomes or lipid coated capsules from W/O emulsions, but are faced with colloidal instabilities. To explore these instability mechanisms, emulsification by sonication was applied in three cycles, and the sample stability was studied for 3 h after each cycle. Clearly identifiable temporal structures of instability provide evidence about the emulsion morphology: an initial regime of about 10 min is shown to be governed by coalescence after which Ostwald ripening dominates. Transport via molecular diffusion in Ostwald ripening is commonly based on the mutual solubility of the two phases and is therefore prohibited in emulsions composed of immiscible phases. However, in the case of water in oil emulsified by phospholipids, these form water-loaded reverse micelles in oil, which enable Ostwald ripening despite the low solubility of water in oil, as is shown for squalene. As is proved for the phospholipid dipalmitoylphosphatidylcholine (DPPC), concentrations below the critical aggregation concentration (CAC) form monolayers at the interfaces and smaller droplet sizes. In contrast, phospholipid concentrations above the CAC create complex multilayers at the interface with larger droplet sizes. The key factors for stable W/O emulsions in classical or innovative applications are first, the minimization of the phospholipids' capacity to form reversed micelles, and second, the adaption of the initial phospholipid concentration to the water content to enable an optimized coverage of phospholipids at the interfaces for the intended drop size.

One-step production of multiple emulsions: microfluidic, polymer-stabilized and particle-stabilized approaches.

PubMed

Clegg, Paul S; Tavacoli, Joe W; Wilde, Pete J

2016-01-28

Multiple emulsions have great potential for application in food science as a means to reduce fat content or for controlled encapsulation and release of actives. However, neither production nor stability is straightforward. Typically, multiple emulsions are prepared via two emulsification steps and a variety of approaches have been deployed to give long-term stability. It is well known that multiple emulsions can be prepared in a single step by harnessing emulsion inversion, although the resulting emulsions are usually short lived. Recently, several contrasting methods have been demonstrated which give rise to stable multiple emulsions via one-step production processes. Here we review the current state of microfluidic, polymer-stabilized and particle-stabilized approaches; these rely on phase separation, the role of electrolyte and the trapping of solvent with particles respectively.

Agglutination of intravenously administered phosphatidylcholine-containing lipid emulsions with serum C-reactive protein.

PubMed

Tugirimana, Pierrot; Speeckaert, Marijn M; Fiers, Tom; De Buyzere, Marc L; Kint, Jos; Benoit, Dominique; Delanghe, Joris R

2013-04-01

C-reactive protein (CRP) is able to bind phospholipids in the presence of calcium. We wanted to investigate the reaction of CRP with various commercial fat emulsions and to explore the impact of CRP agglutination on serum CRP levels. Serum specimens were mixed with Intralipid 20% (soybean oil-based fat emulsion), Structolipid (structured oil-based fat emulsion), Omegaven (fish oil-based fat emulsion), or SMOFlipid (mixed soybean oil-, olive oil-, and fish oil-based emulsion) in Tris-calcium buffer (pH 7.5). After 30 minutes of incubation at 37°C, CRP-phospholipid complexes were turbidimetrically quantified and flow cytometric analysis was performed. Similarly, CRP complexes were monitored in vivo, following administration of fat emulsion. CRP was able to agglutinate phospholipid-containing lipid droplets present in the soybean oil-based fat emulsion and the structured oil-based fat emulsion. To a lesser extent, agglutination was observed for fish oil-containing fat emulsions, whereas no agglutination was noticed for the mixed soybean oil-, olive oil-, and fish oil-based emulsion. Results for propofol-containing emulsions were comparable. Agglutination correlated with phospholipid content of the emulsions. When in vivo agglutination occurred, plasma CRP values dropped due to consumption of CRP by phospholipid-induced agglutination. In this in vitro experiment, we demonstrated agglutination of CRP with phospholipids in various fat emulsions. Research studies are required in patients to determine which effects occur with various intravenous fat emulsions.

Ultrasound assisted synthesis of stable oil in milk emulsion: Study of operating parameters and scale-up aspects.

PubMed

Patil, Leena; Gogate, Parag R

2018-01-01

In the present work, application of ultrasound and stirring individually or in combination for improved emulsification of turmeric oil in skimmed milk has been investigated. The effect of different operating parameters/strategies such as addition of surfactant, sodium dodecyl sulfate (SDS), at different concentrations, quantity of oil phase, applied power, sonication time and duty cycle on the droplet size have been investigated. The stability of emulsion was analyzed in terms of the fraction of the emulsion that remains stable for a period of 28days. Optimized set of major emulsification process variables has been used at higher emulsion volumes. The effectiveness of treatment approach was analyzed based on oil droplet size, energy density and the time required for the formation of stable emulsion. It was observed that the stable emulsion at 50mL capacity with mean droplet diameter of about 235.4nm was obtained with the surfactant concentration of 5mg/mL, 11% of rated power (power density: 0.31W/mL) and irradiation time of 5min. The emulsion stability was higher in the case of ultrasound assisted approach as compared to the stirring. For the preparation of stable emulsion at 300mL capacity, it was observed that the sequential approach, i.e., stirring followed by ultrasound, gave lower mean droplet diameter (232.6nm) than the simultaneous approach, i.e., ultrasound and stirring together (257.9nm). However, the study also revealed that the simultaneous approach required very less time (15min) to synthesize stable emulsion as compared to the sequential approach (30min stirring and 60min ultrasound). It was successfully demonstrated that the ultrasound-assisted emulsification in the presence of SDS could be used for the preparation of stable turmeric oil-dairy emulsions, also providing insights into the role of SDS in increasing the stability of emulsions and of ultrasound in giving lower droplet sizes. Copyright © 2017 Elsevier B.V. All rights reserved.

Block copolymer stabilized nonaqueous biocompatible sub-micron emulsions for topical applications.

PubMed

Atanase, Leonard Ionut; Riess, Gérard

2013-05-20

Polyethylene glycol (PEG) 400/Miglyol 812 non-aqueous sub-micron emulsions were developed due to the fact that they are of interest for the design of drug-loaded biocompatible topical formulations. These types of emulsions were favourably stabilized by poly (2-vinylpyridine)-b-poly (butadiene) (P2VP-b-PBut) copolymer with DPBut>DP2VP, each of these sequences being well-adapted to the solubility parameters of PEG 400 and Miglyol 812, respectively. This type of block copolymers, which might limit the Ostwald ripening, appeared to be more efficient stabilizers than low molecular weight non-ionic surfactants. The emulsion characteristics, such as particle size, stability and viscosity at different shear rates were determined as a function of the phase ratio, the copolymer concentration and storage time. It was further shown that Acyclovir, as a model drug of low water solubility, could be incorporated into the PEG 400 dispersed phase, with no significant modification of the initial emulsion characteristics. Copyright © 2013 Elsevier B.V. All rights reserved.

Poly(vinyl alcohol) stabilization of acrylic emulsion polymers using the miniemulsion approach

NASA Astrophysics Data System (ADS)

Kim, Noma

Miniemulsion approach was employed to obtain stable acrylic latexes of n-butyl acrylate and methyl methacrylate (50/50 wt%) stabilized with poly(vinyl alcohol) (PVA) and to enhance the grafting reaction between PVA and acrylic monomers at the water/droplet interface. The stability of miniemulsions were studied in terms of the type and concentration of' the stabilizer, and the PVA partitioning were determined as a function of the PVA concentration. Using the comparison of PVA partitioning at droplet surface and grafted PVA as a function of concentration, it was suggested that the water/monomer interface is the main grafting site in the miniemulsion polymerization. Seeded emulsion and miniemulsion copolymerizations initiated with water-soluble (hydrogen peroxide, HPO), partially water-soluble (t-butyl peroxide, TBHP), and oil-soluble (t-butyl peroxyoctoate, TBPO) initiators were carried out to further investigate the oil/water interface as the grafting site for PVA. The interaction between the capillary wall in the CHDF (capillary hydrodynamic fractionation) chromatographic particle sizer and the water-soluble polymers adsorbed on the particle surface was studied using different types of water-soluble polymers and eluants. Different grafting architectures depending on the initiation site were suggested based on the CHDF results. The amounts of grafted PVA produced in miniemulsion polymers initiated with TBHP and TBPO were substantially less than those in the corresponding seeded emulsion polymerizations. The effect on the internal viscosity at the interface was proposed to explain the difference in grafting in terms of polymerization methods. Aqueous phase and interface grafting were studied using the measurement of the degree of hydrolysis (DH) of the serum PVA and adsorbed PVA after miniemulsion polymerizations. Based on the results, it was found that aqueous phase and interface grafting occurred in the HPO system; however, interface grafting dominated the TBHP system. Colloidal instability in conventional emulsion polymerizations was investigated and compared with the corresponding miniemulsion polymerization. It was found that the grafted PVA in conventional emulsion polymerizations was more hydrophobic presumably due to a greater amount of grafted chains than that in similar miniemulsion polymerizations and this could be correlated with the colloidal instability during conventional emulsion polymerizations.

Application of mercapto-silica polymerized high internal phase emulsions for the solid-phase extraction and preconcentration of trace lead(II).

PubMed

Su, Rihui; Ruan, Guihua; Chen, Zhengyi; Du, Fuyou; Li, Jianping

2015-12-01

A new class of solid-phase extraction column prepared with grafted mercapto-silica polymerized high internal phase emulsion particles was used for the preconcentration of trace lead. First, mercapto-silica polymerized high internal phase emulsion particles were synthesized by using high internal phase emulsion polymerization and carefully assembled in a polyethylene syringe column. The influences of various parameters including adsorption pH value, adsorption and desorption solvents, flow rate of the adsorption and desorption procedure were optimized, respectively, and the suitable uploading sample volumes, adsorption capacity, and reusability of solid phase extraction column were also investigated. Under the optimum conditions, Pb(2+) could be preconcentrated quantitatively over a wide pH range (2.0-5.0). In the presence of foreign ions, such as Na(+) , K(+) , Ca(2+) , Zn(2+) , Mg(2+) , Cu(2+) , Fe(2+) , Cd(2+) , Cl(-) and NO3 (-) , Pb(2+) could be recovered successfully. The prepared solid-phase extraction column performed with high stability and desirable durability, which allowed more than 100 replicate extractions without measurable changes of performance. The feasibility of the developed method was further validated by the extraction of Pb(2+) in rice samples. At three spiked levels of 40.0, 200 and 800 μg/kg, the average recoveries for Pb(2+) in rice samples ranged from 87.3 to 105.2%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Double emulsions based on silicone-fluorocarbon-water and their skin penetration.

PubMed

Mahrhauser, Denise-Silvia; Fischer, Claudia; Valenta, Claudia

2016-02-10

Double emulsions have significant potential in pharmacy and cosmetics due to the feasibility of combining incompatible substances in one product and the protection of sensitive compounds by incorporating them into their innermost phase. However, a major drawback of double emulsions is their thermodynamic instability and their strong tendency to coalesce. In the present study, the physicochemical stability, the skin permeation and the skin penetration potential of modified semi-solid double emulsions was investigated. The double emulsions were prepared of the cosmetically applied perfluoropolyethers Fomblin HC/04 or Fomblin HC-OH, silicone, carbomer and water. Measurement of the droplet size and examination of the microscopic images confirmed their physicochemical stability over the observation period of eight weeks. Franz-type diffusion cell experiments revealed no increase in curcumin permeation due to the employed perfluoropolyethers compared to the respective control formulations. The formulations used as control were O/W macroemulsions with or without a Polysorbate 80/Sorbitane monooleate 80 surfactant combination. Likewise, tape stripping studies showed no penetration enhancing effect of the employed perfluoropolyethers which is desirable as both perfluoropolyethers are commonly applied components in human personal-care products. Copyright © 2015 Elsevier B.V. All rights reserved.

Versatile Methodology to Encapsulate Gold Nanoparticles in PLGA Nanoparticles Obtained by Nano-Emulsion Templating.

PubMed

Fornaguera, Cristina; Feiner-Gracia, Natàlia; Dols-Perez, Aurora; García-Celma, Maria José; Solans, Conxita

2017-05-01

Gold nanoparticles have been proved useful for many biomedical applications, specifically, for their use as advanced imaging systems. However, they usually present problems related with stability and toxicity. In the present work, gold-nanoparticles have been encapsulated in polymeric nanoparticles using a novel methodology based on nano-emulsion templating. Firstly, gold nanoparticles have been transferred from water to ethyl acetate, a solvent classified as class III by the NIH guidelines (low toxic potential). Next, the formation of nano-emulsions loaded with gold nanoparticles has been performed using a low-energy, the phase inversion composition (PIC) emulsification method, followed by solvent evaporation giving rise to polymeric nanoparticles. Using this methodology, high concentrations of gold nanoparticles (>100 pM) have been encapsulated. Increasing gold nanoparticle concentration, nano-emulsion and nanoparticle sizes increase, resulting in a decrease on the stability. It is noteworthy that the designed nanoparticles did not produce cytotoxicity neither hemolysis at the required concentration. Therefore, it can be concluded that a novel and very versatile methodology has been developed for the production of polymeric nanoparticles loaded with gold nanoparticles. Graphical Abstract Schematic representation of AuNP-loaded polymeric nanoparticles preparation from nano-emulsion templating.

Reverse water-in-fluorocarbon emulsions for use in pressurized metered-dose inhalers containing hydrofluoroalkane propellants.

PubMed

Butz, N; Porté, C; Courrier, H; Krafft, M P; Vandamme, Th F

2002-05-15

Pulmonary administration of drugs has demonstrated numerous advantages in the treatment of pulmonary diseases due to direct targeting to the respiratory tract. It enables avoiding the first pass effect, reduces the amount of drugs administered, targets drugs to specific sites and reduces their side effects. Reverse water-in-fluorocarbon (FC) emulsions are potential drug delivery systems for pulmonary administration using pressurized metered-dose inhalers (pMDI). The external phase of these emulsions consists of perfluorooctyl bromide (PFOB, perflubron), whereas their internal phase contains the drugs solubilized or dispersed in water. These emulsions are stabilized by a perfluoroalkylated dimorpholinophosphate (F8H11DMP), i.e. a fluorinated surfactant. This study demonstrates the possibility of delivering a reverse fluorocarbon emulsion via the pulmonary route using a CFC-free pMDI. Two hydrofluoroalkanes (HFAs) (Solkane(R) 134a and Solkane(R) 227) were used as propellants, and various solution (or emulsion)/propellant ratios (1/3, 1/2, 2/3, 1/1, 3/2, 3/1 v/v) were investigated. The insolubility of water (with or without the fluorinated surfactant F8H11DMP) in both HFA 227 and HFA 134a was demonstrated. PFOB and the reverse emulsion were totally soluble or dispersible in all proportions in both propellants. This study demonstrated also that the reverse FC emulsion can be successfully used to deliver caffeine in a homogeneous and reproducible way. The mean diameter of the emulsion water droplets in the pressured canister was investigated immediately after packaging and after 1 week of storage at room temperature. Best results were obtained with emulsion/propellant ratios comprised between 2/3 and 3/2, and with HFA 227 as propellant.

Localization and reactivity of a hydrophobic solute in lecithin and caseinate stabilized solid lipid nanoparticles and nanoemulsions.

PubMed

Yucel, Umut; Elias, Ryan J; Coupland, John N

2013-03-15

The distribution and reactivity of the lipophilic spin probe 4-phenyl-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl nitroxide (PTMIO) in tetradecane (C14)- and eicosane (C20)-in-water emulsions and solid lipid nanoparticles (SLN) respectively, were investigated by electron paramagnetic resonance (EPR) spectroscopy. The lipid phase (10 wt% C14 or C20) was emulsified into either caseinate solutions (1 wt%) or lecithin+bile salt dispersions (2.4 wt%+0.6 wt%) at 70-75 °C. In C14 emulsions stabilized with lecithin+bile salt, three populations of PTMIO were observed: a population in the lipid phase (~60%, a(N)~13.9 G), an aqueous phase population (~20%, a(N)~15.4 G) with high mobility, and an immobilized surface layer population (~20%, a(N)~14.2 G) with low mobility. However, in C14 emulsions stabilized by caseinate, only two distinct populations of PTMIO were seen: a lipid phase population (~70%, a(N)~13.8 G) and an aqueous phase population (~30%, a(N)~15.5 G) with high mobility. In C20 SLN stabilized with either lecithin+bile salt or caseinate, PTMIO was excluded from the lipid phase. In lecithin+bile salt-stabilized C20 SLN, the majority of the probe (~77%) was in the interfacial layer. For both surfactant systems the rate of PTMIO reduction by aqueous iron/ascorbate was greater for C20 SLN than C14 emulsions. Lecithin affects the properties of emulsions and SLN as delivery systems by providing a distinct environment for small molecules. Copyright © 2013 Elsevier Inc. All rights reserved.

Utilisation of water-in-oil-water (W1/O/W2) double emulsion in a set-type yogurt model for the delivery of probiotic Lactobacillus paracasei.

PubMed

El Kadri, Hani; Lalou, Sofia; Mantzouridou, FaniTh; Gkatzionis, Konstantinos

2018-05-01

W 1 /O/W 2 emulsion in set-type yogurt has the potential to segregate probiotics in order to avoid interference with the starter culture as well as protection against harsh processing and digestion conditions. Lactobacillus paracasei subsp. paracasei DC 412 probiotic cells in milk-based W 1 /O/W 2 emulsions were incorporated in yogurt, in addition to starter cultures Lactobacillus bulgaricus and Streptococcus thermophilus, and the effect on the fermentation, bacterial growth kinetics, physicochemical properties, and structural characteristics was investigated. Stability of W 1 /O/W 2 was monitored with optical microscopy and cryo-SEM and localisation of encapsulated L. paracasei in yogurt was monitored using fluorescent microscopy. During fermentation, starter culture was not affected by introduction of L. paracasei and/or W 1 /O/W 2 emulsion. The viability of L. paracasei encapsulated in W 1 /O/W 2 emulsion was enhanced during storage and after exposure to simulated gastrointestinal conditions. L. paracasei remained within the inner W 1 phase till the end of the storage period (28 days at 4 °C). Moreover, W 1 /O/W 2 emulsion altered physicochemical and textural properties; however, these were within acceptable range. These results demonstrate the capability of W 1 /O/W 2 emulsion to be utilised for probiotic fortification of yogurt to increase functionality without interfering with starter culture and fermentation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Feasibility of Surfactant-Free Supported Emulsion Liquid Membrane Extraction

NASA Technical Reports Server (NTRS)

Hu, Shih-Yao B.; Li, Jin; Wiencek, John M.

2001-01-01

Supported emulsion liquid membrane (SELM) is an effective means to conduct liquid-liquid extraction. SELM extraction is particularly attractive for separation tasks in the microgravity environment where density difference between the solvent and the internal phase of the emulsion is inconsequential and a stable dispersion can be maintained without surfactant. In this research, dispersed two-phase flow in SELM extraction is modeled using the Lagrangian method. The results show that SELM extraction process in the microgravity environment can be simulated on earth by matching the density of the solvent and the stripping phase. Feasibility of surfactant-free SELM (SFSELM) extraction is assessed by studying the coalescence behavior of the internal phase in the absence of the surfactant. Although the contacting area between the solvent and the internal phase in SFSELM extraction is significantly less than the area provided by regular emulsion due to drop coalescence, it is comparable to the area provided by a typical hollow-fiber membrane. Thus, the stripping process is highly unlikely to become the rate-limiting step in SFSELM extraction. SFSELM remains an effective way to achieve simultaneous extraction and stripping and is able to eliminate the equilibrium limitation in the typical solvent extraction processes. The SFSELM design is similar to the supported liquid membrane design in some aspects.

Penetration studies of an extremely lipophilic active model substance from an oil-in-water emulsion: influence of the lipophilicity of the formulation in human skin - part 2.

PubMed

Naumann, S; Lange, S; Polak, G; Kalhoelfer, V; Motlagh, L; Goebel, A; Wohlrab, J; Neubert, R H H

2014-01-01

The effect of the lipophilicity of a carrier on human skin penetration of an extremely lipophilic active model substance was evaluated by using Franz type diffusion cells. Oil-in-water model emulsions containing different amounts of the oily phase were prepared, and Myritol® PC (M-PC) was selected as lipophilic marker component of the oily phase. The penetrated amounts of the lipophilic model substance salicyloyl phytosphingosine (SP) were determined by high-performance liquid chromatography with ultraviolet detection, while M-PC was detected using gas chromatography coupled with mass spectrometry. It has been ascertained that the amount of the lipid phase within the emulsion influenced the penetration profile of the active ingredient SP. The emulsion containing the lowest proportion of the lipid phase provides the best conditions for SP penetration. Surprisingly, the penetration behavior of M-PC was influenced by the oily phase in the same way. Regarding the M-PC and the SP penetration profiles from each emulsion, a solvent drag mechanism can be assumed whereby M-PC acts as penetration enhancer. In conclusion, the penetration rate of the active ingredient SP and the marker component M-PC are in reverse proportion to the oil content of the formulations. The lipophilicity of SP and M-PC, their solubility and their thermodynamic activity within the vehicle could have an effect on their penetration behavior. Additionally, M-PC has the property to enhance the penetration rates of extremely lipophilic substances even at low concentrations.

Tuning Amphiphilicity of Particles for Controllable Pickering Emulsion

PubMed Central

Wang, Zhen; Wang, Yapei

2016-01-01

Pickering emulsions with the use of particles as emulsifiers have been extensively used in scientific research and industrial production due to their edge in biocompatibility and stability compared with traditional emulsions. The control over Pickering emulsion stability and type plays a significant role in these applications. Among the present methods to build controllable Pickering emulsions, tuning the amphiphilicity of particles is comparatively effective and has attracted enormous attention. In this review, we highlight some recent advances in tuning the amphiphilicity of particles for controlling the stability and type of Pickering emulsions. The amphiphilicity of three types of particles including rigid particles, soft particles, and Janus particles are tailored by means of different mechanisms and discussed here in detail. The stabilization-destabilization interconversion and phase inversion of Pickering emulsions have been successfully achieved by changing the surface properties of these particles. This article provides a comprehensive review of controllable Pickering emulsions, which is expected to stimulate inspiration for designing and preparing novel Pickering emulsions, and ultimately directing the preparation of functional materials. PMID:28774029

Controlled double emulsification utilizing 3D PDMS microchannels

NASA Astrophysics Data System (ADS)

Chang, Fu-Che; Su, Yu-Chuan

2008-06-01

This paper presents a PDMS emulsification device that is capable of generating water-in-oil-in-water double emulsions in a controlled manner. Specially designed 3D microchannels are utilized to steer the independently driven water- and oil-phase flows (especially to restrict the attachment of the middle oil-phase flow on the channel surfaces), and to break the continuous flows into monodisperse double emulsions. In addition to channel geometries and fluid flow rates, surfactants and osmotic agents are employed to facilitate the breakup process and stabilize the resulting emulsion structures. In the prototype demonstration, two-level SU-8 molds were fabricated to duplicate PDMS microstructures, which were surface treated and bonded irreversibly to form 3D microchannels. Throughout the emulsification trials, dripping was intentionally induced to generate monodisperse double emulsions with single or multiple aqueous droplets inside each oil drop. It is found that the overall and core sizes of the resulting double emulsions could be adjusted independently, mainly by varying the outer and inner fluid flow rates, respectively. As such, the presented double emulsification device could potentially realize the controllability on emulsion structure and size distribution, which is desired for a variety of biological and pharmaceutical applications.

Encapsulation of nZVI particles using a Gum Arabic stabilized oil-in-water emulsion.

PubMed

Long, Tao; Ramsburg, C Andrew

2011-05-30

Stabilization of reactive iron particles against aggregation and sedimentation is a critical engineering aspect for successful application of nZVI (nanoscale zero valent iron) within the contaminated subsurface environment. In this work we explore the stability and reactivity of a new encapsulation approach that relies upon Gum Arabic to stabilize high quantities of nZVI (∼ 12 g/L) in the dispersed phase of a soybean oil-in-water emulsion. The emulsion is kinetically stable due to substantial repulsive barriers to droplet-droplet induced deformation and subsequent coalescence. Sedimentation time scales were found to be on the order of hours (τ=4.77 ± 0.02 h). Thus, the use of Gum Arabic represents an advance in stabilizing nZVI-in-oil-in-water emulsions. nZVI within the emulsion was shown to be reactive with both TCE degradation and H(2) production observed. Degradation rates were observed to be on the same order of magnitude as those reported for less stable, aqueous suspensions of nZVI. TCE consumption within the emulsion was described with an equivalent aqueous phase rate coefficient of ∼ 5 × 10(-4)L(aq)/m(2)h. Copyright © 2011 Elsevier B.V. All rights reserved.

Enhancing Nutraceutical Bioavailability from Raw and Cooked Vegetables Using Excipient Emulsions: Influence of Lipid Type on Carotenoid Bioaccessibility from Carrots.

PubMed

Zhang, Ruojie; Zhang, Zipei; Zou, Liqiang; Xiao, Hang; Zhang, Guodong; Decker, Eric Andrew; McClements, David Julian

2015-12-09

The influence of the nature of the lipid phase in excipient emulsions on the bioaccessibility and transformation of carotenoid from carrots was investigated using a gastrointestinal tract (GIT) model. Excipient emulsions were fabricated using whey protein as an emulsifier and medium-chain triglycerides (MCT), fish oil, or corn oil as the oil phase. Changes in particle size, charge, and microstructure were measured as the carrot-emulsion mixtures were passed through simulated mouth, stomach, and small intestine regions. Carotenoid bioaccessibility depended on the type of lipids used to form the excipient emulsions (corn oil > fish oil ≫ MCT), which was attributed to differences in the solubilization capacity of mixed micelles formed from different lipid digestion products. The transformation of carotenoids was greater for fish oil and corn oil than for MCT, which may have been due to greater oxidation or isomerization. The bioaccessibility of the carotenoids was higher from boiled than raw carrots, which was attributed to greater disruption of the plant tissue facilitating carotenoid release. In conclusion, excipient emulsions are highly effective at increasing carotenoid bioaccessibility from carrots, but lipid type must be optimized to ensure high efficacy.

Oleic Acid enhances all-trans retinoic Acid loading in nano-lipid emulsions.

PubMed

Chinsriwongkul, Akhayachatra; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Sila-On, Warisada; Ruktanonchai, Uracha

2010-01-01

The aim of this study was to investigate the enhancement of all-trans retinoic acid (ATRA) loading in nano-lipid emulsions and stability by using oleic acid. The effect of formulation factors including initial ATRA concentration and the type of oil on the physicochemical properties, that is, percentage yield, percentage drug release, and photostability of formulations, was determined. The solubility of ATRA was increased in the order of oleic acid > MCT > soybean oil > water. The physicochemical properties of ATRA-loaded lipid emulsion, including mean particle diameter and zeta potential, were modulated by changing an initial ATRA concentration as well as the type and mixing ratio of oil and oleic acid as an oil phase. The particles of lipid emulsions had average sizes of less than 250 nm and negative zeta potential. The addition of oleic acid in lipid emulsions resulted in high loading capacity. The photodegradation rate was found to be dependent on the initial drug concentration but independent of the type of oily phase used in this study. The release rates were not affected by initial ATRA concentration but were affected by the type of oil, where oleic acid showed the highest release rate of ATRA from lipid emulsions.

Effect of the addition of oxybenzone or octyl-methoxycinnamate on particle size of submicron emulsions.

PubMed

Marti-Mestres, G; Nielloud, F; Fortuné, R; Fernandez, C; Maillols, H

2000-03-01

The formulation of sunscreen products requires understanding of the solubilization of these products in different vehicles to obtain aesthetic preparations and to evaluate long-term stability. For this study, two different ultraviolet (UV) filters were selected: oxybenzone (powder) and octyl-methoxycinnamate (liquid). First, the solubility of these UV filters was tested using a three-component simplex-centroid design strategy. The mixtures were prepared with three oily phases used in this field of cosmetics: liquid paraffin, isopropyl myristate, and coconut oil. A phase diagram method was used to carry out a systematic study of submicron oil-in-water emulsions. Phase diagrams were produced by diluting fixed binary mixtures with water. The surfactant consisted of polyoxyethylene-20-sorbitan monostearate/sorbitan monostearate (50/50, w/w). The oily phase contained equal quantities of each oil studied. From this water/surfactant/oil ternary system, we selected two reference emulsions with receptively 75/5/20 and 68/7/25 proportions. Photon correlation spectroscopy (PCS) was used to investigate the influence of these two UV filters at several concentrations on droplet size and distribution of the oil droplets in the material. All emulsions were stored and checked every month for 6 months.

Effects of a fish oil-based emulsion on rat hepatoma cell invasion in culture.

PubMed

Hagi, Akifumi; Nakayama, Mitsuo; Miura, Yutaka; Yagasaki, Kazumi

2007-01-01

Total parenteral nutrition containing a lipid emulsion is often employed after surgical tumor resection. This study investigated the effects of a fish oil-based infusion on rat hepatoma cell invasion. Rat ascites hepatoma cell line AH109A was precultured with a fish oil-based or safflower oil-based emulsion for 48 h. Changes in membranous fatty acid composition were evaluated by gas chromatography. The invasiveness of hepatoma cells was assessed by coculturing with mesentery-derived mesothelial cells. To examine ex vivo effects of the fish oil-based infusion on hepatoma invasion, sera were prepared from rats infused with fish oil- or safflower oil-based emulsion and the effects of these sera were assessed. To clarify the mechanism of inhibition of invasion by the fish oil-based emulsion, the effects of prostaglandin (PG) E(2) and PGE(3) on invasion were examined. Pretreatment with the fish oil-based emulsion reduced invasiveness without affecting growth compared with the safflower oil-based emulsion. Pretreatment with the sera from rats infused with the fish oil-based emulsion also reduced invasiveness compared with the sera from rats infused with the safflower oil-based emulsion. The addition of PGE(2) eliminated the inhibitory effect of the fish oil-based emulsion, and the addition of PGE(3) reduced the invasiveness of hepatoma cells pretreated with the safflower oil-based emulsion. These results suggest that the fish oil-based emulsion may have anti-invasive effects. Changes in the membranous fatty acid composition and consequent changes in the prostaglandins produced may be involved in this inhibitory effect.

Four reversible and reconfigurable structures for three-phase emulsions: extended morphologies and applications

NASA Astrophysics Data System (ADS)

Ge, Xue-Hui; Geng, Yu-Hao; Zhang, Qiao-Chu; Shao, Meng; Chen, Jian; Luo, Guang-Sheng; Xu, Jian-Hong

2017-02-01

Here in this article, we classify and conclude the four morphologies of three-phase emulsions. Remarkably, we achieve the reversible transformations between every shape. Through theoretical analysis, we choose four liquid systems to form these four morphologies. Then monodispersed droplets with these four morphologies are formed through a microfluidic device and captured in a petri-dish. By replacing their ambient solution of the captured emulsions, in-situ morphology transformations between each shape are achieved. The process is well recorded through photographs and videos and they are systematical and reversible. Finally, we use the droplets structure to form an on-off switch to start and shut off the evaporation of one volatile phase to achieve the process monitoring. This could be used to initiate and quench a reaction, which offers a novel idea to achieve the switchable and reversible reaction control in multiple-phase reactions.

A theory of electrophoresis of emulsion drops in aqueous two-phase polymer systems

NASA Technical Reports Server (NTRS)

Levine, S.

1982-01-01

An electrophoresis study has been carried out in an emulsion formed from an electrically neutral aqueous mixture of dextran and polyethylene glycol equilibrated at sufficient concentrations in the presence of electrolytes. Electrophoresis of a drop of one phase suspended in the other is observed, and the direction of the drop's motion is reversed when the disperse phase and the continuous phase are interchanged. In the presence of sulfate, phosphate, or citrate ions, an electrostatic potential difference of the order of a few mV exists between the two phases. The potential implied by the direction of the electrophoretic motion is opposite to the Donnan potential observed between the two phases. The mobility of an emulsion drop increases with the drop radius and depends on ion concentration. These results are explained in terms of a model postulating an electric dipole layer associated with a mixture of oriented polymer molecules at the surface of a drop, with a potential difference between the interiors of the two phases resulting from the unequal ion distribution.

Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering.

PubMed

Makan, Ashwell C; Spallek, Markus J; du Toit, Madeleine; Klein, Thorsten; Pasch, Harald

2016-04-15

Field flow fractionation (FFF) is an advanced fractionation technique for the analyses of very sensitive particles. In this study, different FFF techniques were used for the fractionation and analysis of polymer emulsions/latexes. As model systems, a pure acrylic emulsion and emulsions containing titanium dioxide were prepared and analyzed. An acrylic emulsion polymerization was conducted, continuously sampled from the reactor and subsequently analyzed to determine the particle size, radius of gyration in specific, of the latex particles throughout the polymerization reaction. Asymmetrical flow field-flow fractionation (AF4) and sedimentation field-flow fractionation (SdFFF), coupled to a multidetector system, multi-angle laser light scattering (MALLS), ultraviolet (UV) and refractive index (RI), respectively, were used to investigate the evolution of particle sizes and particle size distributions (PSDs) as the polymerization progressed. The obtained particle sizes were compared against batch-mode dynamic light scattering (DLS). Results indicated differences between AF4 and DLS results due to DLS taking hydration layers into account, whereas both AF4 and SdFFF were coupled to MALLS detection, hence not taking the hydration layer into account for size determination. SdFFF has additional separation capabilities with a much higher resolution compared to AF4. The calculated radii values were 5 nm larger for SdFFF measurements for each analyzed sample against the corresponding AF4 values. Additionally a low particle size shoulder was observed for SdFFF indicating bimodality in the reactor very early during the polymerization reaction. Furthermore, different emulsions were mixed with inorganic species used as additives in cosmetics and coatings such as TiO2. These complex mixtures of species were analyzed to investigate the retention and particle interaction behavior under different AF4 experimental conditions, such as the mobile phase. The AF4 system was coupled online to inductively coupled plasma mass spectrometry (ICP-MS) for elemental speciation and identification of the inorganic additive. SdFFF had a larger separation power to distinguish different particle size populations whereas AF4 had the capability of separating the organic particles and inorganic TiO2 particles, with high resolution. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of iron (III) oxide doped polystyrene shells

NASA Astrophysics Data System (ADS)

Cai, Pei-Jun; Tang, Yong-Jian; Zhang, Lin; Du, Kai; Feng, Chang-Gen

2004-03-01

A type of iron (III) oxide doped plastic shell used for inertial confinement fusion experiments has been fabricated by emulsion techniques. Three different phases of solution (W1, O, and W2) are used for the fabrication process. The W1 phase is a 1 wt % of sodium lauryl sulfate in water. This W1 phase solution is mixed with a 3 wt % Fe2O3-polystyrene (PS) solution in benzene-dichloroethane (O phase) while stirring. The resulting emulsion (W1/O) is poured into a 3 wt % aqueous polyvinyl alcohol solution (W2 phase) while stirring. The resulting emulsion (W1/O/W2) is then heated to evaporate benzene and dichloroethane, and thus a solid Fe2O3-PS shell is formed. The diameter and wall thickness of the shells range from 150 to 500 μm and 5 to 15 μm, respectively. The average surface roughness of the shells is 40 nm, similar to that of the usual PS shells. .

Electrostatic coalescence system with independent AC and DC hydrophilic electrodes

DOEpatents

Hovarongkura, A. David; Henry, Jr., Joseph D.

1981-01-01

An improved electrostatic coalescence system is provided in which independent AC and DC hydrophilic electrodes are employed to provide more complete dehydration of an oil emulsion. The AC field is produced between an AC electrode array and the water-oil interface wherein the AC electrode array is positioned parallel to the interface which acts as a grounded electrode. The emulsion is introduced into the AC field in an evenly distributed manner at the interface. The AC field promotes drop-drop and drop-interface coalescence of the water phase in the entering emulsion. The continuous oil phase passes upward through the perforated AC electrode array and enters a strong DC field produced between closely spaced DC electrodes in which small dispersed droplets of water entrained in the continuous phase are removed primarily by collection at hydrophilic DC electrodes. Large droplets of water collected by the electrodes migrate downward through the AC electrode array to the interface. All phase separation mechanisms are utilized to accomplish more complete phase separation.

Demulsification of water/oil/solid emulsions by hollow-fiber membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tirmizi, N.P.; Raghuraman, B.; Wiencek, J.

1996-05-01

The demulsification techniques investigated use preferential surface wetting to allow separation of oil and water phases in ultrafiltration and microfiltration membranes. A hydrophobic membrane allows the permeation of an oil phase at almost zero pressure and retains the water phase, even though the molecular weight of the water molecule (18) is much smaller than that of the oil molecule (198 for tetradecane, used in this study). Hydrophobic membranes having pore sizes from 0.02 to 0.2 {micro}m were tested for demulsification of water-in-oil emulsions and water/oil/solid mixtures. The dispersed (aqueous)-phase drop sizes ranged from 1 to 5 {micro}m. High separation rates,more » as well as good permeate quality, were obtained with microfiltration membranes. Water content of permeating oil was 32--830 ppm depending on operating conditions and interfacial properties. For emulsions with high surfactant content, simultaneous operation of a hydrophobic and hydrophilic membrane, or simultaneous membrane separation with electric demulsification was more efficient in obtaining complete phase separation.« less

Multiplicity distributions of shower particles and target fragments in 84 Kr 36-emulsion interactions at 1 GeV per nucleon

NASA Astrophysics Data System (ADS)

Singh, M. K.; Soma, A. K.; Pathak, Ramji; Singh, V.

2014-03-01

This article focuses on multiplicity distributions of shower particles and target fragments for interaction of 84 Kr 36 with NIKFI BR-2 nuclear emulsion target at kinetic energy of 1 GeV per nucleon. Experimental multiplicity distributions of shower particles, grey particles, black particles and heavily ionization particles are well described by multi-component Erlang distribution of multi-source thermal model. We have observed a linear correlation in multiplicities for the above mentioned particles or fragments. Further experimental studies have shown a saturation phenomenon in shower particle multiplicity with the increase of target fragment multiplicity.

Hydrophilic microspheres from water-in-oil emulsions by the water diffusion technique.

PubMed

Trotta, Michele; Chirio, Daniela; Cavalli, Roberta; Peira, Elena

2004-08-01

In this study, we developed and evaluated a novel method to produce insulin-loaded hydrophilic microspheres allowing high encapsulation efficiency and the preservation of peptide stability during particle processing. The preparation method used the diffusion of water by an excess of solvent starting from a water-in-solvent emulsion. The water dispersed phase containing albumin or lactose, or albumin-lactose in different weight ratios, and insulin was emulsified in water-saturated triacetin with and without emulsifiers, producing a water-in-triacetin emulsion. An excess of triacetin was added to the emulsion so that water could be extracted into the continuous phase, allowing the insulin-loaded microsphere precipitation. Insulin stability within the microspheres after processing was evaluated by reverse-phase and size-exclusion high-performance liquid chromatography. The water diffusion extraction process provided spherical microparticles of albumin or albumin-lactose. The mean diameter of the microspheres prepared with or without emulsifiers ranged from 2 to 10 microm, and the encapsulation efficiency of insulin was between 60% and 75%, respectively. The analysis of microsphere content after processing showed that insulin did not undergo any chemical modification within microspheres. The use of lactose alone led to the formation of highly viscous droplets that coalesced during the purification step. The water extraction procedures successfully produced insulin-loaded hydrophilic microspheres allowing the preservation of peptide stability. The type of excipient and the size of the disperse phase of the primary w/o emulsion were crucial determinants of microsphere characteristics.

Emulsion-based encapsulation and delivery of nanoparticles for the controlled release of alkalinity within the subsurface environment

NASA Astrophysics Data System (ADS)

Ramsburg, C. A.; Muller, K.; Gill, J.

2012-12-01

Many current approaches to managing groundwater contamination rely on further advances in amendment delivery in order to initiate and sustain contaminant degradation or immobilization. In fact, limited or ineffective delivery is often cited when treatment objectives are not attained. Emulsions, specifically oil-in-water emulsions, have demonstrated potential to aid delivery of remediation amendments. Emulsions also afford opportunities to control the release of active ingredients encapsulated within the droplets. Our research is currently focused on the controlled release of nanoparticle-based buffering agents using oil-in-water emulsions. This interest is motivated by the fact that chemical and biological processes employed for the remediation and stewardship of contaminated sites often necessitate control of pH during treatment and, in some cases, long thereafter. Alkalinity-release nanoparticles (e.g., CaCO3, MgO) were suspended within soybean oil and subsequently encapsulated by through the creation of oil-in-water emulsions. These oil-in-water emulsions are designed to have physical properties which are favorable for subsurface delivery (nominal properties: 1 g/mL density; 10 cP viscosity; and 1.5 μm droplet diameter). Buffer capacity titrations suggest that MgO particles are moderately more accessible within the oil phase and nearly twice as effective (on a per mass basis) at releasing alkalinity (as compared to the CaCO3 particles). Results from experiments designed to assess the release kinetics suggest that a linear driving force model is capable of describing the release process and mass transfer coefficients are constant through the reactive life of the emulsion. The release kinetics in emulsions containing MgO particles were found to be three orders of magnitude faster than those quantified for emulsions containing CaCO3. The slower release kinetics of the emulsions containing CaCO3 particles may prove beneficial when considering pH control at sites where acid fluxes are lower. The ability of emulsions to sustain alkalinity release within porous media was preliminarily examined using a series of 1-D column experiments. Emulsions were introduced for 2 pore volumes in a medium sand at Darcy velocities of approximately 0.8 cm/hr. Following the emulsion pulse, a pH 4 solution (adjusted with HCl) was introduced into the column and the effluent was monitored for pH, oil content, and droplet size distributions. All un-retained emulsion (~20% wt. was retained) was flushed from the column within approximately 2 pore volumes of terminating the emulsion pulse. The effluent pH at quasi-steady state and the reactive life of the emulsion depended on the retention characteristics, as well as the type and loading of nanoparticles employed within the emulsion. For the scenarios considered here, quasi-steady effluent pHs were observed to be between 6.5 and 10, and reactive lifetimes (i.e., the number of pore volumes for which the retained emulsion resulted in the effluent pH exceeding that of the influent) were between 15 and 100 pore volumes. These results demonstrate the ability of the emulsion to offer longer-term release and highlight the ability to tune the alkalinity release rate to match site characteristics by adjusting the emulsion content. Current research is directed toward evaluation release properties in heterogeneous aquifer cell experiments.

Microstructure and rheology of particle stabilized emulsions: Effects of particle shape and inter-particle interactions.

PubMed

Katepalli, Hari; John, Vijay T; Tripathi, Anubhav; Bose, Arijit

2017-01-01

Using fumed and spherical silica particles of similar hydrodynamic size, we investigated the effects of particle shape and inter-particle interactions on the formation, stability and rheology of bromohexadecane-in-water Pickering emulsions. The interparticle interactions were varied from repulsive to attractive by modifying the salt concentration in the aqueous phase. Optical microscope images revealed smaller droplet sizes for the fumed silica stabilized emulsions. All the emulsions remained stable for several weeks. Cryo-SEM images of the emulsion droplets showed a hexagonally packed single layer of particles at oil-water interfaces in emulsions stabilized with silica spheres, irrespective of the nature of the inter-particle interactions. Thus, entropic, excluded volume interactions dominate the fate of spherical particles at oil-water interfaces. On the other hand, closely packed layers of particles were observed at oil-water interfaces for the fumed silica stabilized emulsions for both attractive and repulsive interparticle interactions. At the high salt concentrations, attractive inter-particles interactions led to aggregation of fumed silica particles, and multiple layers of these particles were then observed on the droplet surfaces. A network of fumed silica particles was also observed between the emulsion droplets, suggesting that enthalpic interactions are responsible for the determining particle configurations at oil-water interfaces as well as in the aqueous phase. Steady shear viscosity measurements over a range of shear stresses, as well as oscillatory shear measurements at 1Hz confirm the presence of a network in fumed silica suspensions and emulsions, and the lack of such a network when spherical particles are used. The fractal structure of fumed silica leads to several contact points and particle interlocking in the water as well as on the bromohexadecane-water interfaces, with corresponding effects on the structure and rheology of the emulsions. The attenuation of droplet motion due to the formation of a particle network can be exploited for stabilizing emulsions and for modulating their rheology. Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical and Physical Characterization of Comp A-3 Type II Prills

DTIC Science & Technology

2013-06-01

the composition and properties of the explosive for implementation into modeling and simulation tools as part of the Multi-scale Response of...emulsion were identified using desorption-gas chromatography/mass spectroscopy (D-GC- MS) and Fourier transform infrared ( FTIR ) spectroscopy. Quantitative...understanding the microstructure of the pressed explosive and provides critical information for the development of a high fidelity particle-based course-grain

High internal phase emulsion (HIPE)-templated biopolymeric oleofilms containing an ultra-high concentration of edible liquid oil.

PubMed

Wijaya, Wahyu; Van der Meeren, Paul; Dewettinck, Koen; Patel, Ashok R

2018-04-25

We report, for the first time, the fabrication of oleofilms (containing more than 97 wt% edible liquid oil) using high internal phase emulsions (with oil volume fraction φoil = 0.82) as templates. Advanced microscopy studies revealed an interesting microstructure of these films where jammed oil droplets were embedded in a dried matrix of biopolymeric complexes.

Nuclear Emulsion Analysis Methods of Locating Neutrino Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, Carolyn Lee

2006-12-01

The Fermilab experiment 872 (DONUT) was the first to directly observe tau neutrinos in the charged current interactionV more » $$\\tau$$+N →$$\\tau$$ +X. The observation was made using a hybrid emulsion-spectrometer detector to identify the signature kink or trident decay of the tau particle. Although nuclear emulsion has the benefit of sub-micron resolution, its use incorporates difficulties such as significant distortions and a high density of data resulting from its continuously active state. Finding events and achieving sub-micron resolution in emulsion requires a multi-pronged strategy of tracking and vertex location to deal with these inherent difficulties. By applying the methods developed in this thesis, event location efficiency can be improved from a value of 58% to 87%.« less

Large area emulsion chamber experiments for the Space Shuttle

NASA Technical Reports Server (NTRS)

Parnell, T. A.

1985-01-01

Emulsion-chamber experiments employing nuclear-track emulsions, etchable plastic detectors, metal plates, and X-ray films continue to demonstrate high productivity and potential in the study of cosmic-ray primaries and their interactions. Emulsions, with unsurpassed track-recording capability, provide an appropriate medium for the study of nucleus-nucleus interactions at high energy, which will likely produce observations of a phase change in nuclear matter. The many advantages of emulsion chambers (excellent multitrack recording capability, large geometry factor, low apparatus cost, simplicity of design and construction) are complemented by the major advantages of the Space Shuttle as an experiment carrier. A Shuttle experiment which could make a significant advance in both cosmic-ray primary and nucleus-nucleus interaction studies is described. Such an experiment would serve as a guide for use of emulsions during the Space Station era. Some practical factors that must be considered in planning a Shuttle exposure of emulsion chambers are discussed.

Bioaccessibility of hydroxytyrosol and n-3 fatty acids as affected by the delivery system: simple, double and gelled double emulsions.

PubMed

Cofrades, Susana; Bou, Ricard; Flaiz, Linda; Garcimartín, Alba; Benedí, Juana; Mateos, Raquel; Sánchez-Muniz, Francisco J; Olivero-David, Raúl; Jiménez-Colmenero, Francisco

2017-06-01

This study examines the influence of different food-grade n-3 PUFA-enriched simple emulsion (SE), double emulsion (DE) and gelled double emulsion (GDE) delivery systems on the extent of lipolysis, antioxidant capacity and the bioaccessibility of hydroxytyrosol (HTy). GDE emulsion offered better protection for HTy (89%) than the other systems (79% in SE and DE). The reducing capacity of the emulsions containing HTy were not altered during oral digestion. However, "in vitro" gastric and intestinal phases significantly reduced the antioxidant activity of all systems. The structural and physical state of GDE entailed a slowing-down of triacylglyceride hydrolysis (36.4%) in comparison with that of SE and DE (22.7 and 24.8% for SE and DE, respectively).

Pickering emulsions stabilized by whey protein nanoparticles prepared by thermal cross-linking.

PubMed

Wu, Jiande; Shi, Mengxuan; Li, Wei; Zhao, Luhai; Wang, Ze; Yan, Xinzhong; Norde, Willem; Li, Yuan

2015-03-01

A Pickering (o/w) emulsion was formed and stabilized by whey protein isolate nanoparticles (WPI NPs). Those WPI NPs were prepared by thermal cross-linking of denatured WPI proteins within w/o emulsion droplets at 80°C for 15 min. During heating of w/o emulsions containing 10% (w/v) WPI proteins in the water phase, the emulsions displayed turbid-transparent-turbid phase transitions, which is ascribed to the change in the size of the protein-containing water droplets caused by thermal cross-linking between denatured protein molecules. The transparent stage indicated the formation of WPI NPs. WPI NPs of different sizes were obtained by varying the mixing speed. WPI NPs of 200-500 nm were selected to prepare o/w Pickering emulsions because of their good stability against coalescence. By Confocal Laser Scanning Microscopy, it was observed that WPI NPs were closely packed and distributed at the surface of the emulsion droplets. By measuring water contact angles of WPI NPs films, it was found that under most conditions WPI NPs present good partial wetting properties, but that at the isoelectric point (pI) and high ionic strength the particles become more hydrophobic, resulting in less stable Pickering emulsion. Thus, at pH above and below the pI of WPI NPs and low to moderate ionic strengths (1-10 mM), and with a WPI NPs concentration of 2% (w/v), a stable Pickering emulsion can be obtained. The results may provide useful information for applications of WPI NPs in environmentally friendly and food grade applications, notably in food, pharmaceutical and cosmetic products. Copyright © 2015 Elsevier B.V. All rights reserved.

Olive Oil Based Emulsions in Frozen Puff Pastry Production

NASA Astrophysics Data System (ADS)

Gabriele, D.; Migliori, M.; Lupi, F. R.; de Cindio, B.

2008-07-01

Puff pastry is an interesting food product having different industrial applications. It is obtained by laminating layers of dough and fats, mainly shortenings or margarine, having specific properties which provides required spreading characteristic and able to retain moisture into dough. To obtain these characteristics, pastry shortenings are usually saturated fats, however the current trend in food industry is mainly oriented towards unsatured fats such as olive oil, which are thought to be safer for human health. In the present work, a new product, based on olive oil, was studied as shortening replacer in puff pastry production. To ensure the desired consistency, for the rheological matching between fat and dough, a water-in-oil emulsion was produced based on olive oil, emulsifier and a hydrophilic thickener agent able to increase material structure. Obtained materials were characterized by rheological dynamic tests in linear viscoelastic conditions, aiming to setup process and material consistency, and rheological data were analyzed by using the weak gel model. Results obtained for tested emulsions were compared to theological properties of a commercial margarine, adopted as reference value for texture and stability. Obtained emulsions are characterized by interesting rheological properties strongly dependent on emulsifier characteristics and water phase composition. However a change in process temperature during fat extrusion and dough lamination seems to be necessary to match properly typical dough rheological properties.

Fabrication of Janus particles composed of poly (lactic-co-glycolic) acid and hard fat using a solvent evaporation method.

PubMed

Matsumoto, Akihiro; Murao, Satoshi; Matsumoto, Michiko; Watanabe, Chie; Murakami, Masahiro

The feasibility of fabricating Janus particles based on phase separation between a hard fat and a biocompatible polymer was investigated. The solvent evaporation method used involved preparing an oil-in-water (o/w) emulsion with a mixture of poly (lactic-co-glycolic) acid (PLGA), hard fat, and an organic solvent as the oil phase and a polyvinyl alcohol aqueous solution as the water phase. The Janus particles were formed when the solvent was evaporated to obtain certain concentrations of PLGA and hard fat in the oil phase, at which phase separation was estimated to occur based on the phase diagram analysis. The hard fat hemisphere was proven to be the oil phase using a lipophilic dye Oil Red O. When the solvent evaporation process was performed maintaining a specific volume during the emulsification process; Janus particles were formed within 1.5 h. However, the formed Janus particles were destroyed by stirring for over 6 h. In contrast, a few Janus particles were formed when enough water to dissolve the oil phase solvent was added to the emulsion immediately after the emulsification process. The optimized volume of the solvent evaporation medium dominantly formed Janus particles and maintained the conformation for over 6 h with stirring. These results indicate that the formation and stability of Janus particles depend on the rate of solvent evaporation. Therefore, optimization of the solvent evaporation rate is critical to obtaining stable PLGA and hard fat Janus particles.

Porous Polystyrene Monoliths and Microparticles Prepared from Core Cross-linked Star (CCS) Polymers-Stabilized Emulsions.

PubMed

Chen, Qijing; Shi, Ting; Han, Fei; Li, Zihan; Lin, Chao; Zhao, Peng

2017-08-17

A hydrophobic CCS polymer of poly(benzyl methacrylate) (PBzMA) was prepared in toluene by reversible addition-fragmentation chain transfer (RAFT)-mediated dispersion polymerization. The CCS polymer, with poly(benzyl methacrylate) as the arm and crosslinked N, N'-bis(acryloyl)cystamine (BAC) as the core, was confirmed by characterization with gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. Three kinds of oils (toluene, anisole and styrene) were chosen to study the emulsification properties of PBzMA CCS polymer. The oils can be emulsified by CCS polymer to form water-in-oil (w/o) emulsions. Moreover, w/o high internal phase emulsions (HIPEs) can be obtained with the increase of toluene and styrene volume fractions from 75% to 80%. Porous polystyrene monolith and microparticles were prepared from the emulsion templates and characterized by the scanning electronic microscopy (SEM). With the internal phase volume fraction increased, open-pore porous monolith was obtained.

Microfluidic generation of particle-stabilized water-in-water emulsions

NASA Astrophysics Data System (ADS)

Abbasi, Niki; Navi, Maryam; Tsai, Scott

2017-11-01

We present a microfluidic platform that generates particle-stabilized water-in-water emulsions, using an aqueous two-phase system (ATPS) of polyethylene glycol (PEG) and Dextran (DEX). DEX droplets are generated passively at a flow focusing junction, in a continuous phase of PEG and carboxylated particles, using weak hydrostatic pressure to drive the flow. As DEX droplets travel inside the microfluidic device, carboxylated particles partition to the interface of the droplets. The number of particles partitioning to the interface of droplets increases as the droplets migrate downstream in the microchannel. As a result, the DEX droplets become stabilized against coalescence. We study the coverage and stability of the DEX droplets further downstream inside a reservoir, by changing the carboxylated particle concentration and the particle size. We anticipate that particle-stabilized water-in-water emulsions may have important biotechnological applications, due to their intrinsic biocompatibility compared to traditional particle-stabilized water-in-oil emulsions, for example for cell encapsulation.

Using emulsion inversion in industrial processes.

PubMed

Salager, Jean-Louis; Forgiarini, Ana; Márquez, Laura; Peña, Alejandro; Pizzino, Aldo; Rodriguez, María P; Rondón-González, Marianna

2004-05-20

Emulsion inversion is a complex phenomenon, often perceived as an instability that is essentially uncontrollable, although many industrial processes make use of it. A research effort that started 2 decades ago has provided the two-dimensional and three-dimensional description, the categorization and the theoretical interpretation of the different kinds of emulsion inversion. A clear-cut phenomenological approach is currently available for understanding its characteristics, the factors that influence it and control it, the importance of fine-tuning the emulsification protocol, and the crucial occurrence of organized structures such as liquid crystals or multiple emulsions. The current know-how is used to analyze some industrial processes involving emulsion inversion, e.g. the attainment of a fine nutrient or cosmetic emulsion by temperature or formulation-induced transitional inversion, the preparation of a silicone oil emulsion by catastrophic phase inversion, the manufacture of a viscous polymer latex by combined inversion and the spontaneous but enigmatic inversion of emulsions used in metal working operations such as lathing or lamination.

Effectiveness of water-air and octanol-air partition coefficients to predict lipophilic flavor release behavior from O/W emulsions.

PubMed

Tamaru, Shunji; Igura, Noriyuki; Shimoda, Mitsuya

2018-01-15

Flavor release from food matrices depends on the partition of volatile flavor compounds between the food matrix and the vapor phase. Thus, we herein investigated the relationship between released flavor concentrations and three different partition coefficients, namely octanol-water, octanol-air, and water-air, which represented the oil, water, and air phases present in emulsions. Limonene, 2-methylpyrazine, nonanal, benzaldehyde, ethyl benzoate, α-terpineol, benzyl alcohol, and octanoic acid were employed. The released concentrations of these flavor compounds from oil-in-water (O/W) emulsions were measured under equilibrium using static headspace gas chromatography. The results indicated that water-air and octanol-air partition coefficients correlated with the logarithms of the released concentrations in the headspace for highly lipophilic flavor compounds. Moreover, the same tendency was observed over various oil volume ratios in the emulsions. Our findings therefore suggest that octanol-air and water-air partition coefficients can be used to predict the released concentration of lipophilic flavor compounds from O/W emulsions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fabrication of Hybrid Capsules via CaCO3 Crystallization on Degradable Coacervate Droplets.

PubMed

Komatsu, Syuuhei; Ikedo, Yui; Asoh, Taka-Aki; Ishihara, Ryo; Kikuchi, Akihiko

2018-04-03

Organic-inorganic CaCO 3 capsules were prepared by crystallization of CaCO 3 on Pickering emulsion prepared using coacervate droplets made from thermoresponsive and degradable poly(2-methylene-1,3-dioxepane- co-2-hydroxyethyl acrylate) (poly(MDO- co-HEA)) in sole aqueous medium. The diameters of CaCO 3 -based Pickering emulsion could be controlled by varying several parameters: diameter of CaCO 3 powders, initial polymer concentration, and copolymer composition. The CaCO 3 Pickering emulsion was able to load low-molecular-weight hydrophobic substances at temperatures above the lower critical solution temperature (LCST) due to formation of polymer-concentrated phases, i.e., coacervate droplets. The diameter of CaCO 3 capsules prepared by crystallization also depended on the diameter of the CaCO 3 Pickering emulsion. The CaCO 3 shell was composed of calcite-type crystals, the most stable polymorph among known CaCO 3 crystals. The facially prepared CaCO 3 capsules are valuable for use in functional biomaterials, such as drug delivery carriers and cell culture scaffolds for noninvasive bone-regenerative medicine.

Rhamnolipids as emulsifying agents for essential oil formulations: antimicrobial effect against Candida albicans and methicillin-resistant Staphylococcus aureus.

PubMed

Haba, Ester; Bouhdid, Samira; Torrego-Solana, Noelia; Marqués, A M; Espuny, M José; García-Celma, M José; Manresa, Angeles

2014-12-10

This work examines the influence of essential oil composition on emulsification with rhamnolipids and their use as therapeutic antimicrobial agents against two opportunistic pathogens, methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans. Rhamnolipids, produced by Pseudomonas aeruginosa, with waste frying oil as the carbon source, were composed of eight rhamnolipid homologues. The rhamnolipid mixture was used to produce emulsions containing essential oils (EOs) of Melaleuca alternifolia, Cinnamomum verum, Origanum compactum and Lavandula angustifolia using the titration method. Ternary phase diagrams were designed to evaluate emulsion stability, which differed depending on the essential oil. The in vitro antimicrobial activity of the EOs alone and the emulsions was evaluated. The antimicrobial activity presented by the essential oils alone increased with emulsification. The surface properties of rhamnolipids contribute to the positive dispersion of EOs and thus increase their availability and antimicrobial activity against C. albicans and S. aureus. Therefore, rhamnolipid-based emulsions represent a promising approach to the development of EO delivery systems. Copyright © 2014 Elsevier B.V. All rights reserved.

α-Tocopherol/chitosan-based nanoparticles: characterization and preliminary investigations for emulsion systems application

NASA Astrophysics Data System (ADS)

Aresta, Antonella; Calvano, Cosima Damiana; Trapani, Adriana; Zambonin, Carlo Giorgio; De Giglio, Elvira

2014-02-01

The processes of lipids oxidation represent a great concern for the consumer health because they are one of the major causes of quality deterioration in fat-containing products. One of the most effective methods of delaying lipid oxidation consists in incorporating antioxidants. The present investigation describes the formulation of chitosan and novel glycol chitosan nanoparticles (NPs) loaded with α-Tocopherol (αToc-NPs). The obtained NPs were characterized by various techniques, such as particle size (showing mean diameters in the range 335-503 nm) and zeta potential measurements, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The NPs were, then, added in the preparation of oil-in-water simple emulsion both to make the lipophilic αToc available in an aqueous medium and to prevent emulsion oxidation. For this purpose, a new highly sensitive, simple and solvent-free method based on a solid phase microextraction (SPME) coupled to gas chromatography mass spectrometry was developed for the determination of αToc in aqueous medium. All the parameters influencing SPME, including fiber coating, time and temperature extraction, pH, ionic strength and desorption conditions, have been carefully screened. The method was successfully applied to the determination of vitamin in the αToc-NPs and its release from NPs-enriched simple emulsion formulations. SPME provided high recovery yields and the limits of detection and of quantification in emulsion were 0.1 and 0.5 μg/mg, respectively. The precision of the method has been also estimated. The delay of the lipid oxidation by the proposed formulations has been evaluated exploiting the Kreis test on αToc-NPs-enriched emulsions.

Physical stability, microstructure and micro-rheological properties of water-in-oil-in-water (W/O/W) emulsions stabilized by porcine gelatin.

PubMed

Zhu, Qiaomei; Qiu, Shuang; Zhang, Hongwei; Cheng, Yongqiang; Yin, Lijun

2018-07-01

Water-in-oil-in-water (W/O/W) emulsions could be utilized for fat-reduced food formulation and delivery of bioactive nutrients. However, due to thermodynamic instability, it is difficult to prepare stable double emulsions. The purpose of this study was to improve the stability of W/O/W double emulsions containing 2.0 M MgCl 2 by adding porcine gelatin in the inner water phase. The impact of gelatin on the physical stability, microstructure and micro-rheological properties of W/O/W emulsions was investigated. It was found that, when the concentration of porcine gelatin exceeded 4.0 wt%, the stability of emulsions was improved, due to increased viscoelasticity of emulsion droplets. When MgCl 2 concentration increased to 2.0 M, the particle size of emulsions increased, due to the osmotic pressure gradient, and the presence of gelatin further increased the droplet size. Confocal microscopy results showed that the presence of gelatin could improve the stability of W/O/W emulsions against coalescence。. Copyright © 2018. Published by Elsevier Ltd.

Induction of instability in water-in-oil-in-water double emulsions by freeze-thaw cycling.

PubMed

Rojas, Edith C; Papadopoulos, Kyriakos D

2007-06-19

Individual water-in-oil-in-water (W1/O/W2) double-emulsion globules loaded with fluorescently labeled bovine serum albumin (FITC-BSA) were optically monitored within cylindrical capillaries during freeze-thaw cycling. Coalescence of internal aqueous droplets (W1) and external aqueous phase (W2), termed external coalescence, was not observed before or during freezing of the oil phase (O). On the other hand, this instability mechanism was readily promoted during thawing. This realization confirms the previously suggested potential of W1/O/W2 double emulsions to trigger release upon oil thawing and demonstrates that it is a direct result of globule breakage through external coalescence. The presented results also identified a threshold in the relative W1 droplet size above which instability occurred, while smaller droplets remained unperturbed and therefore indicate that optimization of the delivery can be achieved by tuning the size of W1 droplets. In addition, we propose a possible explanation for the occurrence of instability during oil thawing and its dependence on the size of W1 droplets. Because this alternative globule-breakage mechanism simply uses temperature increase (solid-to-liquid-phase transition) as external stimulus, W1/O/W2 double-emulsion delivery systems can be easily tailored by choosing an oil phase with the appropriate phase-transition temperature.

Interconnectivity of macroporous molecularly imprinted polymers fabricated by hydroxyapatite-stabilized Pickering high internal phase emulsions-hydrogels for the selective recognition of protein.

PubMed

Sun, Yanhua; Li, Yuqing; Xu, Jiangfeng; Huang, Ling; Qiu, Tianyun; Zhong, Shian

2017-07-01

Hydroxyapatite hybridized molecularly imprinted polydopamine polymers with selective recognition of bovine hemoglobin (BHb) were successfully prepared via Pickering oil-in-water high internal phase emulsions-hydrogels and molecularly imprinting technique. The emulsions were stabilized by hydroxyapatite of which the wettability was modified by 3-methacryloxypropyltrimethoxysilane. The materials were characterized by SEM, IR and TGA. The results showed that the BHb imprinted polymers based on Pickering hydrogels (Hydro-MIPs) possess macropores ranging from 20μm to 50μm, and their large numbers of amino groups and hydroxyl groups result in a favorable adsorption capacity for BHb. The maximum adsorption capacity of Hydro-MIPs for BHb was 438mg/g, 3.27 times more than that of the non-imprinted polymers (Hydro-NIPs). The results indicated that Hydro-MIPs possessing well-defined hierarchical porous structures exhibited outstanding recognition behavior towards the target protein molecules. This work provided a promising alternative method for the fabrication of polymer materials with tunable and interconnected pores structures for the separation and purification of protein in vitro. Copyright © 2017. Published by Elsevier B.V.

A new solution to emulsion liquid membrane problems by non-Newtonian conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skelland, A.H.P.; Meng, X.

1996-02-01

Surfactant-stabilized emulsion liquid membrane processes constitute an emerging separation technology that has repeatedly been shown to be highly suited for such diverse separation processes as metal recovery or removal from dilute aqueous solutions; separations in the food industry; removal of organic bases and acids from water; and separation of hydrocarbons. Emulsion liquid membrane separation processes remain excessively vulnerable to one or more of four major problems. Difficulties lie in developing liquid membranes that combine high levels of both stability and permeability with acceptably low levels of swelling and ease of subsequent demulsification for membrane and solute recovery. This article providesmore » a new technique for simultaneously overcoming the first three problems, while identifying physical indications that the proposed solution may have little adverse effect on the fourth problem (demulsification) and may even alleviate it. Numerous benefits of optimized conversion of the membrane phase into suitable non-Newtonian form are identified, their mechanisms outlined, and experimental verifications provided. These include increased stability, retained (or enhanced) permeability, reduced swelling, increased internal phase volume, and increased stirrer speeds. The highly favorable responsiveness of both aliphatic and aromatic membranes to the new technique is demonstrated.« less

In vitro evaluation of suspoemulsions for in situ-forming polymeric microspheres and controlled release of progesterone.

PubMed

Turino, Ludmila N; Mariano, Rodolfo N; Mengatto, Luciano N; Luna, Julio A

2015-01-01

One possibility to obtain a higher dose of drug in a lower formulation volume can be by using of saturated quantity of drug in one of the phases of an emulsion. These formulations are called suspoemulsions (S/O/W). When a hydrophobic polymer is added to the organic phase of suspoemulsions, these formulations can be used to entrap the drug inside microspheres after in situ precipitation of the polymer-drug-excipients mix. In this work, performance and stability of progesterone suspensions in triacetin as organic phase of suspoemulsions were evaluated. These formulations were compared with O/W emulsions. Mathematical models were used to study in vitro release profiles. The results confirmed that S/O/W systems could be an attractive alternative to O/W formulations for the entrapment of progesterone inside poly(d,l-lactide-co-glycolide) microspheres. Diffusive-based models fit the in vitro release of progesterone from in situ-formed microspheres. For longer release periods, a time-dependent diffusion coefficient was successfully estimated.

Grating-based X-ray tomography of 3D food structures

NASA Astrophysics Data System (ADS)

Miklos, Rikke; Nielsen, Mikkel Schou; Einarsdottir, Hildur; Lametsch, René

2016-10-01

A novel grating based X-ray phase-contrast tomographic method has been used to study how partly substitution of meat proteins with two different types of soy proteins affect the structure of the formed protein gel in meat emulsions. The measurements were performed at the Swiss synchrotron radiation light source using a grating interferometric set-up.

W/O/W multiple emulsions containing nitroimidazole derivates for vaginal delivery.

PubMed

Ozer, Ozgen; Ozyazici, Mine; Tedajo, Muriel; Taner, Memduh S; Köseoglu, Kamil

2007-03-01

The aim of our study was to formulate a stable multiple emulsions containing two nitroimidazole derivates, metronidazole (MT) and ornidazole (OR), for vaginal therapy. MT and OR were located internal and external phases of multiple emulsion, respectively, and the in vitro release studies were realized in phosphate (pH 7) and lactate buffer (pH 4.5) solutions to investigate better the effect of pH and location of active substance on the release. The imaging studies were realized in rabbits following labeling MT and OR with Technethium-99m ((99m)Tc) to evaluate the in vivo absorption characteristics. The percentage of MT and OR released from the multiple emulsions in alkaline media were 3.2- and 2.8-fold greater than that observed in acidic media, respectively, when they were introduced in the internal phase of the multiple emulsions. The absorption rate of MT from vaginal epithelium was faster than OR. We observed that especially in alkaline medium a high release was found that was convenient for the vaginal infections seen in the alkaline pH. We concluded that W/O/W multiple emulsions were locally effective in vagina and they could be introduced as a new drug carrier system for vaginal delivery.

Peculiarities of the photochemical processing of relief-phase holograms registered in a thin layer of silver halide emulsion

NASA Astrophysics Data System (ADS)

Brui, E. B.; Galashkina, I. A.

1993-12-01

Peculiarities of the photo-chemical processing of the relief-phase holograms, registered in the layers of argentum-halogenide emulsion PE-2 with the thickness 1 micrometers , are presented in the paper. It was found that in the case of such thickness the tanning processing does not provide the improvement of the maximal relief depth in comparison with the non-tanning process.

Phase recording for formation of holographic optical elements on silver-halide photographic emulsions

NASA Astrophysics Data System (ADS)

Ganzherli, Nina M.; Gulyaev, Sergey N.; Maurer, Irina A.; Chernykh, Dmitrii F.

2009-05-01

Holographic fabrication methods of regular and nonregular relief-phase structures on silver-halide photographic emulsions are considered. Methods of gelatin photodestruction under short-wave ultra-violet radiation and chemical hardening with the help of dichromated solutions were used as a technique for surface relief formation. The developed techniques permitted us to study specimens of holographic diffusers and microlens rasters with small absorption and high light efficiency.

Making and breaking bridges in a Pickering emulsion.

PubMed

French, David J; Taylor, Phil; Fowler, Jeff; Clegg, Paul S

2015-03-01

Particle bridges form in Pickering emulsions when the oil-water interfacial area generated by an applied shear is greater than that which can be stabilised by the available particles and the particles have a slight preference for the continuous phase. They can subsequently be broken by low shear or by modifying the particle wettability. We have developed a model oil-in-water system for studying particle bridging in Pickering emulsions stabilised by fluorescent Stöber silica. A mixture of dodecane and isopropyl myristate was used as the oil phase. We have used light scattering and microscopy to study the degree to which emulsions are bridged, and how this is affected by parameters including particle volume fraction, particle wettability and shear rate. We have looked for direct evidence of droplets sharing particles using freeze fracture scanning electron microscopy. We have created strongly aggregating Pickering emulsions using our model system. This aggregating state can be accessed by varying several different parameters, including particle wettability and particle volume fraction. Particles with a slight preference for the continuous phase are required for bridging to occur, and the degree of bridging increases with increasing shear rate but decreases with increasing particle volume fraction. Particle bridges can subsequently be removed by applying low shear or by modifying the particle wettability. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

NASA Astrophysics Data System (ADS)

Freeburg, Eric Thomas

Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed outside the boundary layer. Vaporization of FC-72 droplets in the boundary layer next to the heated surface was not observed.

Deposition of Methylammonium Lead Triiodide by Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation

NASA Astrophysics Data System (ADS)

Barraza, E. Tomas; Dunlap-Shohl, Wiley A.; Mitzi, David B.; Stiff-Roberts, Adrienne D.

2018-02-01

Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) was used to deposit the metal-halide perovskite (MHP) CH3NH3PbI3 (methylammonium lead triiodide, or MAPbI), creating phase-pure films. Given the moisture sensitivity of these crystalline, multi-component organic-inorganic hybrid materials, deposition of MAPbI by RIR-MAPLE required a departure from the use of water-based emulsions as deposition targets. Different chemistries were explored to create targets that properly dissolved MAPbI components, were stable under vacuum conditions, and enabled resonant laser energy absorption. Secondary phases and solvent contamination in the resulting films were studied through Fourier transform infrared (FTIR) absorbance and x-ray diffraction (XRD) measurements, suggesting that lingering excess methylammonium iodide (MAI) and low-vapor pressure solvents can distort the microstructure, creating crystalline and amorphous non-perovskite phases. Thermal annealing of films deposited by RIR-MAPLE allowed for excess solvent to be evaporated from films without degrading the MAPbI structure. Further, it was demonstrated that RIR-MAPLE does not require excess MAI to create stoichiometric films with optoelectronic properties, crystal structure, and film morphology comparable to films created using more established spin-coating methods for processing MHPs. This work marks the first time a MAPLE-related technique was used to deposit MHPs.

Dual function of tributyrin emulsion: solubilization and enhancement of anticancer effect of celecoxib.

PubMed

Kang, Sung Nam; Hong, Soon-Seok; Lee, Mi-Kyung; Lim, Soo-Jeong

2012-05-30

Tributyrin, a triglyceride analogue of butyrate, can act as a prodrug of an anticancer agent butyrate after being cleaved by intracellular enzymes. We recently demonstrated that the emulsion containing tributyrin as an inner oil phase possesses a potent anticancer activity. Herein we sought to develop tributyrin emulsion as a carrier of celecoxib, a poorly-water soluble drug with anticancer activity. Combined treatment of human HCT116 colon cancer cells with free celecoxib plus tributyrin emulsion inhibited the cellular proliferation more effectively than that of each drug alone, suggesting the possibility of tributyrin emulsion as a potential celecoxib carrier. The mean droplet size of emulsions tended to increase as the tributyrin content in emulsion increases and the concentration of celecoxib loaded in emulsions was affected by tributyrin content and the initial amount of celecoxib, but not by the total amount of surfactant mixture. The concentration of celecoxib required to inhibit the growth of HCT116 and B16-F10 cancer cells by 50% was 2.6- and 3.1-fold lowered by loading celecoxib in tributyrin emulsions, compared with free celecoxib. These data suggest that the anticancer activity of celecoxib was enhanced by loading in tributyrin emulsions, probably due to the solubilization capacity and anticancer activity of tributyrin emulsion. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of the degree of substitution of octenyl succinic anhydride-banana starch on emulsion stability.

PubMed

Bello-Pérez, Luis A; Bello-Flores, Christopher A; Nuñez-Santiago, María del Carmen; Coronel-Aguilera, Claudia P; Alvarez-Ramirez, J

2015-11-05

Banana starch was esterified with octenylsuccinic anhydride (OSA) at different degree substitution (DS) and used to stabilize emulsions. Morphology, emulsion stability, emulsification index, rheological properties and particle size distribution of the emulsions were tested. Emulsions dyed with Solvent Red 26 showed affinity for the oil phase. Backscattering light showed three regions in the emulsion where the emulsified region was present. Starch concentration had higher effect in the emulsification index (EI) than the DS used in the study because similar values were found with OSA-banana and native starches. However, OSA-banana presented greater stability of the emulsified region. Rheological tests in emulsions with OSA-banana showed G'>G" values and low dependence of G' with the frequency, indicating a dominant elastic response to shear. When emulsions were prepared under high-pressure conditions, the emulsions with OSA-banana starch with different DS showed a bimodal distribution of particle size. The emulsion with OSA-banana starch and the low DS showed similar mean droplet diameter than its native counterpart. In contrast, the highest DS led to the highest mean droplet diameter. It is concluded that OSA-banana starch with DS can be used to stabilize specific emulsion types. Copyright © 2015 Elsevier Ltd. All rights reserved.

Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates†

PubMed Central

Wolf, Stephan E.; Müller, Lars; Barrea, Raul; Kampf, Christopher J.; Leiterer, Jork; Panne, Ulrich; Hoffmann, Thorsten

2011-01-01

During the mineralisation of metal carbonates MCO3 (M = Ca, Sr, Ba, Mn, Cd, Pb) liquid-like amorphous intermediates emerge. These intermediates that form via a liquid/liquid phase separation behave like a classical emulsion and are stabilized electrostatically. The occurrence of these intermediates is attributed to the formation of highly hydrated networks whose stability is mainly based on weak interactions and the variability of the metal-containing pre-critical clusters. Their existence and compositional freedom are evidenced by electrospray ionization mass spectrometry (ESI-MS). Liquid intermediates in non-classical crystallisation pathways seem to be more common than assumed. PMID:21218241

An update on safety and immunogenicity of vaccines containing emulsion-based adjuvants.

PubMed

Fox, Christopher B; Haensler, Jean

2013-07-01

With the exception of alum, emulsion-based vaccine adjuvants have been administered to far more people than any other adjuvant, especially since the 2009 H1N1 influenza pandemic. The number of clinical safety and immunogenicity evaluations of vaccines containing emulsion adjuvants has correspondingly mushroomed. In this review, the authors introduce emulsion adjuvant composition and history before detailing the most recent findings from clinical and postmarketing data regarding the effects of emulsion adjuvants on vaccine immunogenicity and safety, with emphasis on the most widely distributed emulsion adjuvants, MF59® and AS03. The authors also present a summary of other emulsion adjuvants in clinical development and indicate promising avenues for future emulsion-based adjuvant development. Overall, emulsion adjuvants have demonstrated potent adjuvant activity across a number of disease indications along with acceptable safety profiles.

Shedding light on the different behavior of ionic and nonionic surfactants in emulsion polymerization: from atomistic simulations to experimental observations.

PubMed

Magi Meconi, Giulia; Ballard, Nicholas; Asua, José M; Zangi, Ronen

2017-12-06

Although surfactants are known to play a vital role in polymerization reactions carried out in dispersed media, many aspects of their use are poorly understood, perhaps none more so than the vastly different action of ionic and nonionic surfactants in emulsion polymerization. In this work, we combine experimental measurements of emulsion polymerization of styrene with atomistic molecular dynamics simulations to better understand the behavior of surfactants at monomer/polymer-water interfaces. In a batch emulsion polymerization of styrene, the nonionic surfactant Disponil AFX 1080 leads to two nucleation periods, in contrast to the behavior observed for the ionic surfactant SDS. This can be explained by the absorption of the nonionic surfactant into the organic phase at the early stages of the polymerization reaction which is then released as the reaction progresses. Indeed, we find that the partition coefficient of the surfactant between the organic phase and water increases with the amount of monomer in the former, and preferential partitioning is detected to organic phases containing at least 55% styrene. Results from molecular dynamics simulations confirm that spontaneous dissolution of the non-ionic surfactant into a styrene-rich organic phase occurs above a critical concentration of the surfactant adsorbed at the interface. Above this critical concentration, a linear correlation between the amount of surfactant adsorbed at the interface and that absorbed inside the organic phase is observed. To facilitate this absorption into a completely hydrophobic medium, water molecules accompany the intruding surfactants. Similar simulations but with the ionic surfactant instead did not result in any absorption of the surfactant into a neat styrene phase, likely because of its strongly hydrophilic head group. The unusual partitioning behavior of nonionic surfactants explains a number of observable features of emulsion polymerization reactions which use nonionic surfactants and should help with future development of processes for improved control over polymerization.

A New Emulsion Liquid Membrane Based on a Palm Oil for the Extraction of Heavy Metals

PubMed Central

Björkegren, Sanna; Fassihi Karimi, Rose; Martinelli, Anna; Jayakumar, Natesan Subramanian; Hashim, Mohd Ali

2015-01-01

The extraction efficiency of hexavalent chromium, Cr(VI), from water has been investigated using a vegetable oil based emulsion liquid membrane (ELM) technique. The main purpose of this study was to create a novel ELM formulation by choosing a more environmentally friendly and non-toxic diluent such as palm oil. The membrane phase so formulated includes the mobile carrier tri-n-octylmethylammonium chloride (TOMAC), to facilitate the metal transport, and the hydrophilic surfactant Tween 80 to facilitate the dispersion of the ELM phase in the aqueous solution. Span 80 is used as surfactant and butanol as co-surfactant. Our results demonstrate that this novel ELM formulation, using the vegetable palm oil as diluent, is useful for the removal of hexavalent chromium with an efficiency of over 99% and is thus competitive with the already existing, yet less environmentally friendly, ELM formulations. This result was achieved with an optimal concentration of 0.1 M NaOH as stripping agent and an external phase pH of 0.5. Different water qualities have also been investigated showing that the type of water (deionized, distilled, or tap water) does not significantly influence the extraction rate. PMID:25915191

New Technology for Oil/Water Emulsion Treatment: Phases I and II

DTIC Science & Technology

1998-05-15

m.(Aŕ) Emulsions have long been of practical interest because of their extensive everyday applications. Emulsions are used in foods ( milk and...separating cream from milk . Valve-discharge centrifuges periodically discharge accumulated solids. Split-bowl centrifuges have a bowl that allows...fresh air. Call a physician. RVF CONTACT: Flush with water for 15 minutes. Call a physician. Wash thSroSghly with soap and rinse with water. Call

Interfacial bioconjugation on emulsion droplet for biosensors.

PubMed

Zhang, Qifan; Scigliano, Anita; Biver, Tarita; Pucci, Andrea; Swager, Timothy M

2018-04-13

Interfacial bioconjugation methods are developed for intact liquid emulsion droplets. Complex emulsion droplets having internal hydrocarbon and fluorocarbon immiscible structured phases maintain a dynamic interface for controlled interfacial reactivity. The internal morphological change after binding to biomolecules is readily visualized and detected by light transmission, which provides a platform for the formation of inexpensive and portable bio-sensing assays for enzymes, antibodies, nucleic acids and carbohydrates. Copyright © 2018. Published by Elsevier Ltd.

Dispersed phase volume fraction, weak acids and Tween 80 in a model emulsion: Effect on the germination and growth of Bacillus weihenstephanensis KBAB4 spores.

PubMed

Léonard-Akkari, Lucie; Guégan, Stéphanie; Courand, Fabienne; Couvert, Olivier; Lepage, Jean-François; Rondeau-Mouro, Corinne; Desriac, Noémie; Mathot, Anne-Gabrielle; Leguérinel, Ivan; Coroller, Louis; Decourcelle, Nicolas

2018-07-01

In foodstuffs, physico-chemical interactions and/or physical constraints between spores, inhibitors and food components may exist. Thus, the objective of this study was to investigate such interactions using a model emulsion as a microbial medium in order to improve bacterial spore control with better knowledge of the interactions in the formulation. Emulsions were prepared with hexadecane mixed with nutrient broth using sonication and were stabilized by Tween 80 and Span 80. The hexadecane ratio was either 35% (v/v) or 50% (v/v) and each emulsion was studied in the presence of organic acid (acetic, lactic or hexanoic) at two pH levels (5.5 and 6). Self-diffusion coefficients of emulsion components and the organic acids were measured by Pulsed Field Gradient-Nuclear Magnetic Resonance (PFG-NMR). The inhibition effect on the spore germination and cell growth of Bacillus weihenstephanensis KBAB4 was characterized by the measure of the probability of growth using the most probable number methodology, and the measure of the time taken for the cells to germinate and grow using a single cell Bioscreen® method and using flow cytometry. The inhibition of spore germination and growth in the model emulsion depended on the dispersed phase volume fraction and the pH value. The effect of the dispersed phase volume fraction was due to a combination of (i) the lipophilicity of the biocide, hexanoic acid, that may have had an impact on the distribution of organic acid between hexadecane and the aqueous phases and (ii) the antimicrobial activity of the emulsifier Tween 80 detected at the acidic pH value. The interface phenomena seemed to have a major influence. Future work will focus on the exploration of these phenomena at the interface. Copyright © 2018 Elsevier Ltd. All rights reserved.

Controlled microfluidic emulsification of oil in a clay nanofluid: Role of salt for Pickering stabilization

NASA Astrophysics Data System (ADS)

Gholamipour-Shirazi, A.; Carvalho, M. S.; Fossum, J. O.

2016-07-01

Research on emulsions is driven by their widespread use in different industries, such as food, cosmetic, pharmaceutical and oil recovery. Emulsions are stabilized by suitable surfactants, polymers, solid particles or a combination of them. Microfluidic emulsification is the process of droplet formation out of two or more liquids under strictly controlled conditions, without pre-emulsification step. Microfluidic technology offers a powerful tool for investigating the properties of emulsions themselves. In this work stable oil in water emulsions were formed with hydrophilic Laponite RD® nanoparticles adsorbed at the interface of the oil phase and aqueous clay nanofluid in a T junction microfluidic chip. Emulsion stability up to at least 40 days could be observed.

The physicochemical characterization and in vitro/in vivo evaluation of natural surfactants-based emulsions as vehicles for diclofenac diethylamine.

PubMed

Vucinić-Milanković, Nada; Savić, Snezana; Vuleta, Gordana; Vucinić, Slavica

2007-03-01

Two sugar-based emulsifiers, cetearyl alcohol & cetearyl glycoside and sorbitan stearate & sucrose cocoate, known as potential promoters of lamellar liquid crystals/gel phases, were investigated in order to formulate an optimal vehicle for amphiphilic drug - diclofenac diethylamine (DDA). Physico-chemical characterization and study of vehicle's physical stability were performed. Then, the in vitro DDA liberation profile, dependent on the mode of drug incorporation to the system, and the in vivo, short-term effects of chosen samples on skin parameters were examined. Droplets size distribution and rheological behavior indicated satisfying physical stability of both types of vehicles. Unexpectedly, the manner of DDA incorporation to the system had no significant influence on DDA release. In vivo study pointed to emulsion's favorable potential for skin hydration and barrier improvement, particularly in cetearyl glycoside-based vehicle.

High loading efficiency and sustained release of siRNA encapsulated in PLGA nanoparticles: quality by design optimization and characterization.

PubMed

Cun, Dongmei; Jensen, Ditte Krohn; Maltesen, Morten Jonas; Bunker, Matthew; Whiteside, Paul; Scurr, David; Foged, Camilla; Nielsen, Hanne Mørck

2011-01-01

Poly(DL-lactide-co-glycolide acid) (PLGA) is an attractive polymer for delivery of biopharmaceuticals owing to its biocompatibility, biodegradability and outstanding controlled release characteristics. The purpose of this study was to understand and define optimal parameters for preparation of small interfering RNA (siRNA)-loaded PLGA nanoparticles by the double emulsion solvent evaporation method and characterize their properties. The experiments were performed according to a 2(5-1) fractional factorial design based on five independent variables: The volume ratio between the inner water phase and the oil phase, the PLGA concentration, the sonication time, the siRNA load and the amount of acetylated bovine serum albumin (Ac-BSA) in the inner water phase added to stabilize the primary emulsion. The effects on the siRNA encapsulation efficiency and the particle size were investigated. The most important factors for obtaining an encapsulation efficiency as high as 70% were the PLGA concentration and the volume ratio whereas the size was mainly affected by the PLGA concentration. The viscosity of the oil phase was increased at high PLGA concentration, which explains the improved encapsulation by stabilization of the primary emulsion and reduction of siRNA leakage to the outer water phase. Addition of Ac-BSA increased the encapsulation efficiency at low PLGA concentrations. The PLGA matrix protected siRNA against nuclease degradation, provided a burst release of surface-localized siRNA followed by a triphasic sustained release for two months. These results enable careful understanding and definition of optimal process parameters for preparation of PLGA nanoparticles encapsulating high amounts of siRNA with immediate and long-term sustained release properties. Copyright © 2010 Elsevier B.V. All rights reserved.

Direct Numerical Simulation of Surfactant-Stabilized Emulsions Morphology and Shear Viscosity in Starting Shear Flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roar Skartlien; Espen Sollum; Andreas Akselsen

2012-07-01

A 3D lattice Boltzmann model for two-phase flow with amphiphilic surfactant was used to investigate the evolution of emulsion morphology and shear stress in starting shear flow. The interfacial contributions were analyzed for low and high volume fractions and varying surfactant activity. A transient viscoelastic contribution to the emulsion rheology under constant strain rate conditions was attributed to the interfacial stress. For droplet volume fractions below 0.3 and an average capillary number of about 0.25, highly elliptical droplets formed. Consistent with affine deformation models, gradual elongation of the droplets increased the shear stress at early times and reduced it atmore » later times. Lower interfacial tension with increased surfactant activity counterbalanced the effect of increased interfacial area, and the net shear stress did not change significantly. For higher volume fractions, co-continuous phases with a complex topology were formed. The surfactant decreased the interfacial shear stress due mainly to advection of surfactant to higher curvature areas. Our results are in qualitative agreement with experimental data for polymer blends in terms of transient interfacial stresses and limited enhancement of the emulsion viscosity at larger volume fractions where the phases are co-continuous.« less

How does oil type determine emulsion characteristics in concentrated Na-caseinate emulsions?

PubMed

Tan, Hui Lin; McGrath, Kathryn M

2013-08-01

Macroscopic properties and ensemble average diffusion of concentrated (dispersed phase 50-60 wt%) Na-caseinate-stabilised emulsions for three different oils (soybean oil, palm olein and tetradecane) were explored. On a volume fraction basis, pulsed gradient stimulated echo (PGSTE)-NMR data show that droplet dynamics for all three systems are similar within a region of the emulsion morphology diagram. The exact limits of the emulsion space depend however on which oil is considered. The reduced solubility of tetradecane in water, and Na-caseinate in tetradecane, result in the stabilisation of flocs during formulation. Floc formation is not observed when soybean oil or palm olein is used under identical emulsion formulation conditions. Linear rheology experiments provide indirect evidence that the local structure and the properties of the thin film interfacial domain of tetradecane emulsions vary from those of soybean oil and palm olein emulsions. Collectively these data indicate that protein/oil interactions within a system dominate over specific oil droplet structure and size distribution, which are similar in the three systems. Copyright © 2013 Elsevier Inc. All rights reserved.

Microfluidic preparation and self diffusion PFG-NMR analysis of monodisperse water-in-oil-in-water double emulsions.

PubMed

Hughes, Eric; Maan, Abid Aslam; Acquistapace, Simone; Burbidge, Adam; Johns, Michael L; Gunes, Deniz Z; Clausen, Pascal; Syrbe, Axel; Hugo, Julien; Schroen, Karin; Miralles, Vincent; Atkins, Tim; Gray, Richard; Homewood, Philip; Zick, Klaus

2013-01-01

Monodisperse water-in-oil-in-water (WOW) double emulsions have been prepared using microfluidic glass devices designed and built primarily from off the shelf components. The systems were easy to assemble and use. They were capable of producing double emulsions with an outer droplet size from 100 to 40 μm. Depending on how the devices were operated, double emulsions containing either single or multiple water droplets could be produced. Pulsed-field gradient self-diffusion NMR experiments have been performed on the monodisperse water-in-oil-in-water double emulsions to obtain information on the inner water droplet diameter and the distribution of the water in the different phases of the double emulsion. This has been achieved by applying regularization methods to the self-diffusion data. Using these methods the stability of the double emulsions to osmotic pressure imbalance has been followed by observing the change in the size of the inner water droplets over time. Copyright © 2012 Elsevier Inc. All rights reserved.

Dispersion Stability of O/W Emulsions with Different Oil Contents Under Various Freezing and Thawing Conditions.

PubMed

Katsuki, Kazutaka; Miyagawa, Yayoi; Nakagawa, Kyuya; Adachi, Shuji

2017-07-01

Freezing and thawing of oil-in-water (O/W) emulsion-type foods bring about oil-water separation and deterioration; hence, the effects of freezing and thawing conditions on the destabilization of O/W emulsions were examined. The freezing rate and thawing temperature hardly affected the stability of the O/W emulsion. O/W emulsions having different oil fractions were stored at temperatures ranging from -30 to -20 °C and then thawed. The stability after thawing depended on the storage temperature, irrespective of the oil fraction of the emulsion. A good correlation was found between the time at which the stability began to decrease and the time taken for the oil to crystalize. These results indicated that the dominant cause for the destabilization of the O/W emulsion during freezing and thawing is the crystallization of the oil phase and that the effects of the freezing and thawing rates on the stability are insignificant. © 2017 Institute of Food Technologists®.

Dynamically reconfigurable complex emulsions via tunable interfacial tensions

PubMed Central

Zarzar, Lauren D.; Sresht, Vishnu; Sletten, Ellen M.; Kalow, Julia A.; Blankschtein, Daniel; Swager, Timothy M.

2015-01-01

Emulsification is a powerful, well-known technique for mixing and dispersing immiscible components within a continuous liquid phase. Consequently, emulsions are central components of medicine, food and performance materials. Complex emulsions, including multiple emulsions and Janus droplets which contain hemispheres of differing material, are of increasing importance1 in pharmaceuticals and medical diagnostics2, in the fabrication of microparticles and capsules3–5 for food6, in chemical separations7, in cosmetics8, and in dynamic optics9. Because complex emulsion properties and functions are related to the droplet geometry and composition, the development of rapid, simple fabrication approaches allowing precise control over the droplets’ physical and chemical characteristics is critical. Significant advances in the fabrication of complex emulsions have been made using a number of procedures, ranging from large-scale, less precise techniques that give compositional heterogeneity using high-shear mixers and membranes10, to small-volume but more precise microfluidic methods11,12. However, such approaches have yet to create droplet morphologies that can be controllably altered after emulsification. Reconfigurable complex liquids potentially have greatly increased utility as dynamically tunable materials. Here we describe an approach to the one-step fabrication of three- and four-phase complex emulsions with highly controllable and reconfigurable morphologies. The fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone and fluorocarbon liquids, and is applied to both the microfluidic and the scalable batch production of complex droplets. We demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by varying the interfacial tensions using hydrocarbon and fluorinated surfactants including stimuli-responsive and cleavable surfactants. This yields a generalizable strategy for the fabrication of multiphase emulsions with controllably reconfigurable morphologies and the potential to create a wide range of responsive materials. PMID:25719669

Dynamically reconfigurable complex emulsions via tunable interfacial tensions.

PubMed

Zarzar, Lauren D; Sresht, Vishnu; Sletten, Ellen M; Kalow, Julia A; Blankschtein, Daniel; Swager, Timothy M

2015-02-26

Emulsification is a powerful, well-known technique for mixing and dispersing immiscible components within a continuous liquid phase. Consequently, emulsions are central components of medicine, food and performance materials. Complex emulsions, including Janus droplets (that is, droplets with faces of differing chemistries) and multiple emulsions, are of increasing importance in pharmaceuticals and medical diagnostics, in the fabrication of microparticles and capsules for food, in chemical separations, in cosmetics, and in dynamic optics. Because complex emulsion properties and functions are related to the droplet geometry and composition, the development of rapid, simple fabrication approaches allowing precise control over the droplets' physical and chemical characteristics is critical. Significant advances in the fabrication of complex emulsions have been made using a number of procedures, ranging from large-scale, less precise techniques that give compositional heterogeneity using high-shear mixers and membranes, to small-volume but more precise microfluidic methods. However, such approaches have yet to create droplet morphologies that can be controllably altered after emulsification. Reconfigurable complex liquids potentially have great utility as dynamically tunable materials. Here we describe an approach to the one-step fabrication of three- and four-phase complex emulsions with highly controllable and reconfigurable morphologies. The fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone and fluorocarbon liquids, and is applied to both the microfluidic and the scalable batch production of complex droplets. We demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by varying the interfacial tensions using hydrocarbon and fluorinated surfactants including stimuli-responsive and cleavable surfactants. This yields a generalizable strategy for the fabrication of multiphase emulsions with controllably reconfigurable morphologies and the potential to create a wide range of responsive materials.

Dynamically reconfigurable complex emulsions via tunable interfacial tensions

NASA Astrophysics Data System (ADS)

Zarzar, Lauren D.; Sresht, Vishnu; Sletten, Ellen M.; Kalow, Julia A.; Blankschtein, Daniel; Swager, Timothy M.

2015-02-01

Emulsification is a powerful, well-known technique for mixing and dispersing immiscible components within a continuous liquid phase. Consequently, emulsions are central components of medicine, food and performance materials. Complex emulsions, including Janus droplets (that is, droplets with faces of differing chemistries) and multiple emulsions, are of increasing importance in pharmaceuticals and medical diagnostics, in the fabrication of microparticles and capsules for food, in chemical separations, in cosmetics, and in dynamic optics. Because complex emulsion properties and functions are related to the droplet geometry and composition, the development of rapid, simple fabrication approaches allowing precise control over the droplets' physical and chemical characteristics is critical. Significant advances in the fabrication of complex emulsions have been made using a number of procedures, ranging from large-scale, less precise techniques that give compositional heterogeneity using high-shear mixers and membranes, to small-volume but more precise microfluidic methods. However, such approaches have yet to create droplet morphologies that can be controllably altered after emulsification. Reconfigurable complex liquids potentially have great utility as dynamically tunable materials. Here we describe an approach to the one-step fabrication of three- and four-phase complex emulsions with highly controllable and reconfigurable morphologies. The fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone and fluorocarbon liquids, and is applied to both the microfluidic and the scalable batch production of complex droplets. We demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by varying the interfacial tensions using hydrocarbon and fluorinated surfactants including stimuli-responsive and cleavable surfactants. This yields a generalizable strategy for the fabrication of multiphase emulsions with controllably reconfigurable morphologies and the potential to create a wide range of responsive materials.

A soluble star-shaped silsesquioxane-cored polymer-towards novel stabilization of pH-dependent high internal phase emulsions.

PubMed

Xing, Yuxiu; Peng, Jun; Xu, Kai; Gao, Shuxi; Gui, Xuefeng; Liang, Shengyuan; Sun, Longfeng; Chen, Mingcai

2017-08-30

A well-defined pH-responsive star-shaped polymer containing poly(N,N-dimethylaminoethyl methacrylate) (PDMA) arms and a cage-like methacryloxypropyl silsesquioxane (CMSQ-T 10 ) core was used as an interfacial stabilizer for emulsions consisting of m-xylene and water. We explored the properties of the CMSQ/PDMA star-shaped polymer using the characteristic results of nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), dynamic light scattering (DLS), and zeta potential and conductivity measurements. The interfacial tension results showed that the CMSQ/PDMA star-shaped polymer reduced the interfacial tension between water and oil in a pH-dependent manner. Gelled high internal phase emulsions (HIPEs) including o/w and w/o types were formed in the pH ranges of 1.2-5.8 and 9.1-12.3 with the CMSQ/PDMA star-shaped polymer as a stabilizer, when the oil fractions were 80-90 vol% and 10-20 vol%, respectively. The soluble star-shaped polymer aggregated spontaneously to form a microgel that adsorbed to the two immiscible phases. Images of the fluorescently labeled polymers demonstrated that there was a star-shaped polymer in the continuous phase, and the non-Pickering stabilization based on the percolating network of the star-shaped polymer also contributed to the stabilization of the HIPE. This pH-dependent HIPE was prepared with a novel stabilization mechanism consisting of microgel adsorption and non-Pickering stabilization. Moreover, the preparation of HIPEs provided the possibility of their application in porous materials and responsive materials.

Development of Safe and Potent Oil-in-Water Emulsion of Paclitaxel to Treat Peritoneal Dissemination.

PubMed

Ogawara, Ken-Ichi; Fukuoka, Yoshiko; Yoshizawa, Yuta; Kimura, Toshikiro; Higaki, Kazutaka

2017-04-01

To develop a safer and more potent paclitaxel (PTX) formulation, we prepared various oil-in-water emulsions by using egg phosphatidylcholine, Tween 80, and a mixture of triglycerides with different fatty acid chain lengths as the cosurfactant, surfactant, and oil phase component, respectively. The mean particle diameters of the PTX-emulsions prepared were around 100 nm. The PTX-emulsions did not provoke histamine release from rat mast cells and did not show any significant hemolytic activity, suggesting that PTX-emulsions are biocompatible. In vivo antitumor activity after single intraperitoneal injection of PTX-emulsions to ascites tumor-bearing mice revealed that the formulation containing tricaproin and triacetin (3:1, wt/wt, PTX-emulsion B) significantly prolonged the survival time and suppressed the accumulation of ascites fluid. Two distinct in vitro release studies showed that the release of PTX from emulsion B was significantly faster than those from other preparations. These results indicate that the adequately sustained PTX release would lead to potent in vivo antitumor activity and that PTX-emulsion B would offer an alternative approach to treat peritoneal dissemination. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Characterization of cinematographic films by Laser Induced Breakdown Spectroscopy

NASA Astrophysics Data System (ADS)

Gaspard, S.; Oujja, M.; Rebollar, E.; Abrusci, C.; Catalina, F.; Castillejo, M.

2007-12-01

The emulsion-coated transparent plastic-base film has been the main carrier for production and preservation of motion picture contents since the 19th century. The knowledge of the composition of black and white silver gelatine cinematographic films is of great importance for the characterization of the photographic process and for identifying the optimum conditions for conservation. A cinematographic film is a multi-component system that consists of a layer of photographic emulsion overcoating a polymeric support (plasticized cellulose triacetate) and a protective transparent cross-linked gelatine layer coating the emulsion. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) is used to characterize the composition of the materials of cinematographic films. LIB spectra of film samples and of different individual film components, polymeric support and reference gelatines, were acquired in vacuum by excitation at 266 nm (Q-switched Nd:YAG laser, 6 ns, 10 Hz). In the cinematographic film, silver lines from the light-sensitive silver halide salts of the photographic emulsion are accompanied by iron, lead, chrome and phosphorus lines. Iron and lead are constituents of film developers, chrome is included in the composition of the hardening agents and phosphorus has its origin in the plasticizer used in the polymeric support. By applying successive pulses on the same spot of the film sample, it was possible to observe through stratigraphic analysis the different layers composition. Additionally, the results obtained reveal the analytical capacity of LIBS for the study and classification of the different gelatine types and qualities used for the protecting layer and the photographic emulsion.

High-Performance Single Cell Genetic Analysis Using Microfluidic Emulsion Generator Arrays

PubMed Central

Zeng, Yong; Novak, Richard; Shuga, Joe; Smith, Martyn T.; Mathies, Richard A.

2010-01-01

High-throughput genetic and phenotypic analysis at the single cell level is critical to advance our understanding of the molecular mechanisms underlying cellular function and dysfunction. Here we describe a high-performance single cell genetic analysis (SCGA) technique that combines high-throughput microfluidic emulsion generation with single cell multiplex PCR. Microfabricated emulsion generator array (MEGA) devices containing 4, 32 and 96 channels are developed to confer a flexible capability of generating up to 3.4 × 106 nanoliter-volume droplets per hour. Hybrid glass-polydimethylsiloxane diaphragm micropumps integrated into the MEGA chips afford uniform droplet formation, controlled generation frequency, and effective transportation and encapsulation of primer functionalized microbeads and cells. A multiplex single cell PCR method is developed to detect and quantify both wild type and mutant/pathogenic cells. In this method, microbeads functionalized with multiple forward primers targeting specific genes from different cell types are used for solid-phase PCR in droplets. Following PCR, the droplets are lysed, the beads are pooled and rapidly analyzed by multi-color flow cytometry. Using E. coli bacterial cells as a model, we show that this technique enables digital detection of pathogenic E. coli O157 cells in a high background of normal K12 cells, with a detection limit on the order of 1:105. This result demonstrates that multiplex SCGA is a promising tool for high-throughput quantitative digital analysis of genetic variation in complex populations. PMID:20192178

High pressure-resistant nonincendive emulsion explosive

DOEpatents

Ruhe, Thomas C.; Rao, Pilaka P.

1994-01-01

An improved emulsion explosive composition including hollow microspheres/bulking agents having high density and high strength. The hollow microspheres/bulking agents have true particle densities of about 0.2 grams per cubic centimeter or greater and include glass, siliceous, ceramic and synthetic resin microspheres, expanded minerals, and mixtures thereof. The preferred weight percentage of hollow microspheres/bulking agents in the composition ranges from 3.0 to 10.0 A chlorinated paraffin oil, also present in the improved emulsion explosive composition, imparts a higher film strength to the oil phase in the emulsion. The emulsion is rendered nonincendive by the production of sodium chloride in situ via the decomposition of sodium nitrate, a chlorinated paraffin oil, and sodium perchlorate. The air-gap sensitivity is improved by the in situ formation of monomethylamine perchlorate from dissolved monomethylamine nitrate and sodium perchlorate. The emulsion explosive composition can withstand static pressures to 139 bars and dynamic pressure loads on the order of 567 bars.

Effects of the inner droplet of double emulsions on the film drainage during a head-on collision

NASA Astrophysics Data System (ADS)

Wang, Jingtao; Jing, Hefeng; Xu, Genmiao; Wang, Xiaoyong; Duan, Zhenya

2015-07-01

As a critical stage which severely affects the final coalescence of droplets, film drainage in the collision process of two simple droplets has been deeply studied for many years. However, the collision of multiple emulsions which contain other phases (like daughter droplets or particles) has never been studied although multiple emulsions are very important in emulsion industries nowadays. In this paper, the head-on collision of two core-shell double emulsions with equal sizes is investigated through a boundary integral method to disclose the effects of the inner droplet on the film drainage. When capillary number Ca is relatively high, due to the effect of the inner droplet on the inner circulation of mother droplets, the film drainage of double emulsions includes three stages: drainage, drainage halt, and second drainage, instead of two stages for that of simple droplets: drainage and drainage halt.

Quinoa starch granules as stabilizing particles for production of Pickering emulsions.

PubMed

Rayner, Marilyn; Sjöö, Malin; Timgren, Anna; Dejmek, Petr

2012-01-01

Intact starch granules isolated from quinoa (Chenopodium quinoa Willd.) were used to stabilize emulsion drops in so-called Pickering emulsions. Miglyol 812 was used as dispersed phase and a phosphate buffer (pH7) with different salt (NaCl) concentrations was used as the continuous phase. The starch granules were hydrophobically modified to different degrees by octenyl succinic anhydride (OSA) or by dry heat treatment at 120 degrees C in order to study the effect on the resulting emulsion drop size. The degree of OSA-modification had a low to moderate impact on drop size. The highest level of modification (4.66%) showed the largest mean drop size, and lowest amount of free starch, which could be an effect of a higher degree of aggregation of the starch granules and, thereby, also the emulsion drops stabilized by them. The heat treated starch granules had a poor stabilizing ability and only the starch heated for the longest time (150 min at 120 degrees C) had a better emulsifying capacity than the un-modified native starch granules. The effect of salt concentration was rather limited. However, an increased concentration of salt slightly increased the mean drop size and the elastic modulus.

Optimization of cyanide extraction from wastewater using emulsion liquid membrane system by response surface methodology.

PubMed

Xue, Juan Qin; Liu, Ni Na; Li, Guo Ping; Dang, Long Tao

To solve the disposal problem of cyanide wastewater, removal of cyanide from wastewater using a water-in-oil emulsion type of emulsion liquid membrane (ELM) was studied in this work. Specifically, the effects of surfactant Span-80, carrier trioctylamine (TOA), stripping agent NaOH solution and the emulsion-to-external-phase-volume ratio on removal of cyanide were investigated. Removal of total cyanide was determined using the silver nitrate titration method. Regression analysis and optimization of the conditions were conducted using the Design-Expert software and response surface methodology (RSM). The actual cyanide removals and the removals predicted using RSM analysis were in close agreement, and the optimal conditions were determined to be as follows: the volume fraction of Span-80, 4% (v/v); the volume fraction of TOA, 4% (v/v); the concentration of NaOH, 1% (w/v); and the emulsion-to-external-phase volume ratio, 1:7. Under the optimum conditions, the removal of total cyanide was 95.07%, and the RSM predicted removal was 94.90%, with a small exception. The treatment of cyanide wastewater using an ELM is an effective technique for application in industry.

Development of multiple W/O/W emulsions as dermal carrier system for oligonucleotides: effect of additives on emulsion stability.

PubMed

Schmidts, T; Dobler, D; Schlupp, P; Nissing, C; Garn, H; Runkel, F

2010-10-15

Multiple water-in-oil-in-water (W/O/W) emulsions are of major interest as potential skin delivery systems for water-soluble drugs like oligonucleotides due to their distinct encapsulation properties. However, multiple emulsions are highly sensitive in terms of variations of the individual components. The presence of osmotic active ingredients in the inner water phase is crucial for the generation of stable multiple emulsions. In order to stabilize the emulsions the influence of NaCl, MgSO(4), glucose and glycine and two cellulose derivatives was investigated. Briefly, multiple W/O/W emulsions using Span 80 as a lipophilic emulsifier and different hydrophilic emulsifiers (PEG-40/50 stearate, steareth-20 and polysorbate 80) were prepared. Stability of the emulsions was analyzed over a period of time using rheological measurements, droplet size observations and conductivity analysis. In this study we show that additives strongly influence the properties stability of multiple emulsions. By increasing the concentration of the osmotic active ingredients, smaller multiple droplets are formed and the viscosity is significantly increased. The thickening agents resulted in a slightly improved stability. The most promising emulsions were chosen and further evaluated for their suitability and compatibility to incorporate a DNAzyme oligonucleotide as active pharmaceutical ingredient. Copyright 2010 Elsevier B.V. All rights reserved.

Influence of acetazolamide loading on the (in vitro) performances of non-phospholipid-based cationic nanosized emulsion in comparison with phospholipid-based anionic and neutral-charged nanosized emulsions.

PubMed

Tamilvanan, Shunmugaperumal; Kumar, Balakrishnan Ajith

2011-09-01

Acetazolamide (ACZM)-loaded anionic, cationic, and neutral-charged oil-in-water nanosized emulsions were prepared and compared with their mean droplet diameter, surface charge, entrapment efficiency, freeze-thaw cycling stability, in vitro drug release, and transcorneal permeation. The present study aims to determine the influence of ACZM loading on the performances of non-phospholipid-based cationic nanosized emulsion in comparison with phospholipid-based anionic and neutral-charged nanosized emulsions. Regardless of charges, all of these emulsions exhibited a nanometer range mean particle diameter (240-443 nm) following autoclave sterilization. While the anionic and cationic emulsions did show high negative (-36.9 mV) and positive zeta potential (+41.4 mV) values, the neutral-charged emulsion did not. Presence of cryoprotectants (5% w/w sucrose + 5% w/w sorbitol) improved the stability of cationic emulsion to droplet aggregation during freeze-thaw cycling. The in vitro release kinetic behavior of drug exchange with physiological anions present in the simulated tear solution appears to be complex and difficult to characterize using mathematical fitting model equations. Augmentation in drug permeation through goat cornea, in vitro, was noticed for cationic emulsion. ACZM-loaded cationic nanosized emulsion could be suitable for topical application into eye to elicit better therapeutic effect in comparison with its anionic and neutral-charged emulsions.

Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

PubMed Central

Chen, Xingtao; Lv, Guoyu; Zhang, Jue; Tang, Songchao; Yan, Yonggang; Wu, Zhaoying; Su, Jiacan; Wei, Jie

2014-01-01

A multi-(amino acid) copolymer (MAC) based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA) were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 μm to 79.7 μm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery. PMID:24855351

Food grade duplex emulsions designed and stabilised with different osmotic pressures.

PubMed

Pawlik, Aleksandra; Cox, Philip W; Norton, Ian T

2010-12-01

In this study we have investigated the production of food grade W(1)/O/W(2) duplex emulsions with salt partitioned into one water phase but not the other. Investigations were carried out with and without balancing osmotic pressures with glucose. A stable 30% primary W(1)/O emulsions containing salt could be produced with more than or equal to 2% polyglycerol polyricinoleate (PGPR) in the oil phase. We suggest that the addition of salt strengthens the interactions between surfactant molecules in the adsorbed film. This is supported by interfacial viscosity and elasticity measurements both of which increased on addition of salt and the fact that in the presence of salt the emulsion was more stable. These simple emulsions were then processed to construct duplex emulsions. When osmotic pressures were balanced with glucose there was still a release of salt in storage. The extent and rate of release was proportional to glucose concentration. This effect was followed over a period of 60days. These data suggest that the release is driven by the chemical potential difference between the two water compartments rather than the unbalanced osmotic pressures. These observations are explained in the context of a water structuring effect from the added glucose, which lowers the interfacial tension of oil-water interface and thus facilitates micellar transport of hydrated salt ions across the oil layer. Copyright © 2010 Elsevier Inc. All rights reserved.

Increased antioxidant efficacy of tocopherols by surfactant solubilization in oil-in-water emulsions.

PubMed

Kiralan, S Sezer; Doğu-Baykut, Esra; Kittipongpittaya, Ketinun; McClements, David Julian; Decker, Eric A

2014-10-29

The physical location of antioxidants in oil-in-water emulsions can have significant influence on their free radical scavenging activity and ability to inhibit lipid oxidation. We aimed to determine the effect of the surfactant concentration on the partitioning behavior of tocopherols (α, γ, and δ) in oil-in-water emulsions. Tween 20 (0.1, 0.5, and 1%) increased the partitioning of the tocopherols into the aqueous phase via the formation of Tween 20-tocopherol comicelles. Partitioning behavior of antioxidants was dependent upon the number of methyl groups and, thus, polarity of the tocopherols. δ-Tocopherol (one methyl group) exhibited the most partitioning into the aqueous phase, while α-tocopherol (three methyl groups) had the lowest partitioning. Lipid oxidation studies showed that the antioxidant activity of δ- and α-tocopherols was enhanced by adding Tween 20 to oil-in-water emulsions. This work suggests that surfactant micelles could increase the antioxidant activity of tocopherols by changing their physical location.

Lipid transfer in oil-in-water isasome emulsions: influence of arrested dynamics of the emulsion droplets entrapped in a hydrogel.

PubMed

Iglesias, Guillermo Ramón; Pirolt, Franz; Sadeghpour, Amin; Tomšič, Matija; Glatter, Otto

2013-12-17

The transfer kinetics of lipids between internally self-assembled droplets of O/W emulsions is studied. The droplets (isasomes) consist of various liquid-crystalline phases or W/O microemulsions stabilized by a polymeric stabilizer F127. The various internal phases were identified by the relative peak positions in the small-angle X-ray scattering (SAXS) curves. An arrested system composed of isasomes embedded in a gel matrix actually provides an additional possibility to control these systems in terms of the release of various host molecules. These experiments have been applied to examine the kinetics of the internal phase reorganization imposed by the lipids' release and uptake by the droplets embedded in a κ-carrageenan (KC) hydrogel network. Increasing the concentration of the gelling agent slows down the transfer from one droplet to the other through the aqueous phase. We examined the region where the free diffusion is stopped. i.e., the point where the system changes from the ergodic to the nonergodic state and the kinetics is essentially slowed down. This effect can be balanced by the addition of small amounts of free polymeric stabilizer, which speeds up the kinetics. This is even possible in the case of highly arrested dynamics of the emulsion droplets, as found for the highest KC hydrogel concentrations forming nonergodic systems.

Endocytosis of Corn Oil-Caseinate Emulsions In Vitro: Impacts of Droplet Sizes

PubMed Central

Fan, Yuting; Yokoyama, Wally; Yi, Jiang

2017-01-01

The relative uptake and mechanisms of lipid-based emulsions of three different particle diameters by Caco-2 cells were studied. The corn oil-sodium caseinate emulsions showed little or no cytotoxicity even at 2 mg/mL protein concentration for any of the three droplet size emulsions. Confocal laser scanning microscopy (CLSM) of Nile red containing emulsions showed that the lipid-based emulsions were absorbed by Caco-2 cells. A negative correlation between the mean droplet size and cellular uptake was observed. There was a time-dependent and energy-dependent uptake as shown by incubation at different times and treatment with sodium azide a general inhibitor of active transport. The endocytosis of lipid-based emulsions was size-dependent. The internalization of nanoemulsion droplets into Caco-2 cells mainly occurred through clathrin- and caveolae/lipid raft-related pathways, while macropinocytosis route played the most important role for 556 nm emulsion endocytosis as shown by the use of specific pathway inhibitors. Permeability of the emulsion through the apical or basal routes also suggested that active transport may be the main route for lipid-based nanoemulsions. The results may assist in the design and application of lipid-based nanoemulsions in nutraceuticals and pharmaceuticals delivery. PMID:29072633

A multi-criteria decision making approach to identify a vaccine formulation.

PubMed

Dewé, Walthère; Durand, Christelle; Marion, Sandie; Oostvogels, Lidia; Devaster, Jeanne-Marie; Fourneau, Marc

2016-01-01

This article illustrates the use of a multi-criteria decision making approach, based on desirability functions, to identify an appropriate adjuvant composition for an influenza vaccine to be used in elderly. The proposed adjuvant system contained two main elements: monophosphoryl lipid and α-tocopherol with squalene in an oil/water emulsion. The objective was to elicit a stronger immune response while maintaining an acceptable reactogenicity and safety profile. The study design, the statistical models, the choice of the desirability functions, the computation of the overall desirability index, and the assessment of the robustness of the ranking are all detailed in this manuscript.

Electrochemically driven emulsion inversion

NASA Astrophysics Data System (ADS)

Johans, Christoffer; Kontturi, Kyösti

2007-09-01

It is shown that emulsions stabilized by ionic surfactants can be inverted by controlling the electrical potential across the oil-water interface. The potential dependent partitioning of sodium dodecyl sulfate (SDS) was studied by cyclic voltammetry at the 1,2-dichlorobenzene|water interface. In the emulsion the potential control was achieved by using a potential-determining salt. The inversion of a 1,2-dichlorobenzene-in-water (O/W) emulsion stabilized by SDS was followed by conductometry as a function of added tetrapropylammonium chloride. A sudden drop in conductivity was observed, indicating the change of the continuous phase from water to 1,2-dichlorobenzene, i.e. a water-in-1,2-dichlorobenzene emulsion was formed. The inversion potential is well in accordance with that predicted by the hydrophilic-lipophilic deviation if the interfacial potential is appropriately accounted for.

Emulsion of Chloramphenicol: an Overwhelming Approach for Ocular Delivery.

PubMed

Ashara, Kalpesh C; Shah, Ketan V

2017-03-01

Ophthalmic formulations of chloramphenicol have poor bioavailability of chloramphenicol in the ocular cavity. The present study aimed at exploring the impact of different oil mixtures in the form of emulsion on the permeability of chloramphenicol after ocular application. Selection of oil mixture and ratio of the components was made by an equilibrium solubility method. An emulsifier was chosen according to its emulsification properties. A constrained simplex centroid design was used for the assessment of the emulsion development. Emulsions were evaluated for physicochemical properties; zone of inhibition, in-vitro diffusion and ex-vivo local accumulation of chloramphenicol. Validation of the design using check-point batch and reduced polynomial equations were also developed. Optimization of the emulsion was developed by software Design® expert 6.0.8. Assessment of the osmolarity, ocular irritation, sterility testing and isotonicity of optimized batch were also made. Parker Neem®, olive and peppermint oils were selected as an oil phase in the ratio 63.64:20.2:16.16. PEG-400 was selected as an emulsifier according to a pseudo-ternary phase diagram. Constrained simplex-centroid design was applied in the range of 25-39% water, 55-69% PEG-400, 5-19% optimized oil mixture, and 1% chloramphenicol. Unpaired Student's t-test showed for in-vitro and ex-vivo studies that there was a significant difference between the optimized batch of emulsion and Chloramphenicol eye caps (a commercial product) according to both were equally safe. The optimized batch of an emulsion of chloramphenicol was found to be as safe as and more effective than Chloramphenicol eye caps.

Determination of Formulation Conditions Allowing Double Emulsions Stabilized by PGPR and Sodium Caseinate to Be Used as Capsules.

PubMed

Nollet, Maxime; Laurichesse, Eric; Besse, Samantha; Soubabère, Olivier; Schmitt, Véronique

2018-02-27

Water-in-oil-in-water (W 1 /O/W 2 ) double emulsions stabilized by polyglycerol polyricinoleate (PGPR), a lipophilic food grade small polymer, and sodium caseinate, a hydrophilic milk protein, were developed to encapsulate vitamin B12, a model hydrophilic substance easy to titrate. Using rheology, sensitive to drop size evolution and water fluxes, static light scattering, and microscopy both giving the evolution of drops' size and vitamin B12 titration assessing the encapsulation, we were able to detect independently the double emulsion drop size, the encapsulation loss, and the flux of water as a function of time. By differentiating the PGPR required to cover the W 1 -droplets' surface from PGPR in excess in the oil phase, we built a PGPR-inner droplet volume fraction diagram highlighting the domains where the double emulsion is stable toward encapsulation and/or water fluxes. We demonstrated the key role played by nonadsorbed PGPR concentration in the intermediate sunflower oil phase on the emulsion stability while, surprisingly, the inner droplet volume fraction had no effect on the emulsion stability. At low PGPR concentration, a release of vitamin B12 was observed and the leakage mechanism of coalescence between droplets and oil-water interface of the oily drops (also called globules hereafter), was identified using confocal microscopy. For high enough PGPR content, the emulsions were stable and may therefore serve as efficient capsules without need of an additional gelling, thickening, complexion or interface rigidifying agent. We generalized these results with the encapsulation of an insecticide: Cydia pomonella granulovirus used in organic arboriculture.

Process for recovering uranium from waste hydrocarbon oils containing the same. [Uranium contaminated lubricating oils from gaseous diffusion compressors

DOEpatents

Conrad, M.C.; Getz, P.A.; Hickman, J.E.; Payne, L.D.

1982-06-29

The invention is a process for the recovery of uranium from uranium-bearing hydrocarbon oils containing carboxylic acid as a degradation product. In one aspect, the invention comprises providing an emulsion of water and the oil, heating the same to a temperature effecting conversion of the emulsion to an organic phase and to an acidic aqueous phase containing uranium carboxylate, and recovering the uranium from the aqueous phase. The process is effective, simple and comparatively inexpensive. It avoids the use of toxic reagents and the formation of undesirable intermediates.

FOULING-RESISTANT CERAMIC MEMBRANES FOR TREATMENT OF METASTABLE OIL/WATER EMULSIONS - PHASE I

EPA Science Inventory

Billions of gallons of oily wastewaters are generated daily by a variety of industrial sources. One class of oily wastewaters, metastable oil/water emulsions, encompasses waste streams for which a need exists for more cost-effective and reliable treatment. Current treatment...

Methodological assessment of the reduction of the content of impurities in nimodipine emulsion via the use of 21 amino acid protection

PubMed Central

Xie, Yiqiao; Zhuang, Zhiquan; Zhang, Shu; Xia, Zihua; Chen, De; Fan, Kaiyan; Ren, Jialin; Lin, CuiCui; Chen, Yanzhong; Yang, Fan

2017-01-01

Purpose The present study examined the factors affecting the content of impurities of nimodipine (NMP) emulsion and the associated methods of compound protection. Methods Destructive testing of NMP emulsion and its active pharmaceutical ingredient (API) were conducted, and ultracentrifugation was used to study the content of impurities in two phases. The impurity of NMP was measured under different potential of hydrogen (pH) conditions, antioxidants and pH-adjusting agents. Results Following destruction, the degradation of NMP notably occurred in the basic environment. The consumption of the pH-adjusting agent NaOH was proportional to the production of impurities since the inorganic base and/or acid promoted the degradation of NMP. The organic antioxidants, notably amino acids with an appropriate length of intermediate chain and electron-donating side group, exhibited improved antioxidant effects compared with inorganic antioxidants. The minimal amount of impurities was produced following addition of 0.04% lysine and 0.06% leucine in the aqueous phase and adjustment of the pH to a range of 7.5–8.0 in the presence of acetic acid solution. Conclusion NMP was more prone to degradation in an oxidative environment, in an aqueous phase and/or in the presence of inorganic pH-adjusting agents and antioxidants. The appropriate antioxidant and pH-adjusting agent should be selected according to the chemical structure, while destructive testing of the drug is considered to play the optimal protective effect. PMID:28490879

Designing excipient emulsions to increase nutraceutical bioavailability: emulsifier type influences curcumin stability and bioaccessibility by altering gastrointestinal fate.

PubMed

Zou, Liqiang; Liu, Wei; Liu, Chengmei; Xiao, Hang; McClements, David Julian

2015-08-01

The influence of emulsifier type on the ability of excipient emulsions to improve the solubility, stability, and bioaccessibility of powdered curcumin was examined. Oil-in-water emulsions prepared using three different emulsifiers (whey protein isolate, caseinate, or Tween 80) were mixed with curcumin powder and then incubated at either 30 °C (to simulate applications of salad dressings) or 100 °C (to simulate applications of cooking sauces). The transfer of curcumin into the excipient emulsions was appreciably higher for excipient emulsions held at 100 °C than those held at 30 °C, and was appreciably higher for surfactant-stabilized emulsions than protein-stabilized emulsions. For example, the amounts of curcumin transferred into emulsions held at 30 and 100 °C were 66 and 280 μg mL(-1) for Tween 80, but only 17 and 208 μg mL(-1) for caseinate. The total curcumin concentration in the digesta and mixed micelle phases collected after excipient emulsions were exposed to a simulated gastrointestinal tract (mouth, stomach, and small intestine) depended on emulsifier type. The total amount of curcumin within the digesta was higher for protein-stabilized emulsions than surfactant-stabilized ones, which was attributed to the ability of the proteins to protect curcumin from chemical degradation. For example, the digesta contained 204 μg mL(-1) curcumin for caseinate emulsions, but only 111 μg mL(-1) for Tween 80 emulsions. This study shows the potential of designing excipient emulsions to increase the oral bioavailability of curcumin for food and pharmaceutical applications.

The effect of prime emulsion components as a function of equilibrium headspace concentration of soursop flavor compounds

PubMed Central

2014-01-01

Background Perceptions of food products start when flavor compounds are released from foods, transported and appropriate senses in the oral and nose are triggered. However, the long-term stability of flavor compounds in food product has been a major concern in the food industry due to the complex interactions between key food ingredients (e.g., polysaccharides and proteins). Hence, this study was conducted to formulate emulsion-based beverage using natural food emulsifiers and to understand the interactions between emulsion compositions and flavor compounds. Results The influences of modified starch (x 1 ), whey protein isolate (x 2 ), soursop flavor oil (x 3 ) and deionized water (x 4 ) on the equilibrium headspace concentration of soursop volatile flavor compounds were evaluated using a four-component with constrained extreme vertices mixture design. The results indicated that the equilibrium headspace concentration of soursop flavor compounds were significantly (p < 0.05) influenced by the matrix and structural compositions of the beverage emulsions. Interface formed using modified starch and whey protein isolate (WPI) proved to be capable of inhibiting the release of volatile flavor compounds from the oil to the aqueous phase. Modified starch could retard the overall flavor release through its hydrophobic interactions with volatile flavor compounds and viscosity enhancement effect. Excessive amount of modified starch was also shown to be detrimental to the stability of emulsion system. However, both modified starch and WPI showed to be a much more effective barrier in inhibiting the flavor release of flavor compounds when used as individual emulsifier than as a mixture. Conclusions Overall, the mixture design can be practical in elucidating the complex interactions between key food components and volatile flavor compounds in an emulsion system. These studies will be useful for the manufacturers for the formulation of an optimum beverage emulsion with desirable emulsion properties and desirable flavor release profile. PMID:24708894

Influence of the Supramolecular Micro-Assembly of Multiple Emulsions on their Biopharmaceutical Features and In vivo Therapeutic Response.

PubMed

Cilurzo, Felisa; Cristiano, Maria Chiara; Di Marzio, Luisa; Cosco, Donato; Carafa, Maria; Ventura, Cinzia Anna; Fresta, Massimo; Paolino, Donatella

2015-01-01

The ability of some surfactants to self-assemble in a water/oil bi-phase environment thus forming supramolecular structure leading to the formation of w/o/w multiple emulsions was investigated. The w/o/w multiple emulsions obtained by self-assembling (one-step preparation method) were compared with those prepared following the traditional two-step procedure. Methyl-nicotinate was used as a hydrophilic model drug. The formation of the multiple emulsion structure was evidenced by optical microscopy, which showed a mean size of the inner oil droplets of 6 μm and 10 μm for one-step and two-step multiple emulsions, respectively. The in vitrobiopharmaceutical features of the various w/o/w multiple emulsion formulations were evaluated by means of viscosimetry studies, drug release and in vitro percutaneous permeation experiments through human stratum corneum and viable epidermis membranes. The self-assembled multiple emulsions allowed a more gradual percutaneous permeation (a zero-order permeation rate) than the two-step ones. The in vivotopical carrier properties of the two different multiple emulsions were evaluated on healthy human volunteers by using the spectrophotometry of reflectance, an in vivonon invasive method. These multiple emulsion systems were also compared with conventional emulsion formulations. Our findings demonstrated that the multiple emulsions obtained by self-assembling were able to provide a more sustained drug delivery into the skin and hence a longer therapeutic action than two-step multiple emulsions and conventional emulsion formulations. Finally, our findings showed that the supramolecular micro-assembly of multiple emulsions was able to influence not only the biopharmaceutical characteristics but also the potential in vivotherapeutic response.

Nanostructured lipid carriers: effect of solid phase fraction and distribution on the release of encapsulated materials.

PubMed

Dan, Nily

2014-11-25

Emulsions, solid lipid nanoparticles (SLN), and nanostructured lipid carriers (NLC) containing a mix of liquid and solid domains are of interest as encapsulation vehicles for hydrophobic compounds. Studies of the release rate from these particles yield contradictory results: Some find that increasing the fraction of solid phase increases the rate of release and others the opposite. In this paper we study the release of encapsulated materials from lipid-based nanoparticles using Monte Carlo simulations. We find that, quite surprisingly, the release rate is largely insensitive to the size of solid domains or the fraction of solid phase. However, the distribution of the domains significantly affects the rate of release: Solid domains located at the interface with the surrounding solution inhibit transport, while nanoparticles where the solid domains are concentrated in the center enhance it. The latter can lead to release rates in NLCs that are faster than in the equivalent emulsions. We conclude that controlling the release rate from NLCs requires the ability to determine the location and distribution of the solid phase, which may be achieved through choice of the surfactants stabilizing the particles, incorporation of nucleation sites, and/or the cooling rates and temperatures.

Impact of sodium caseinate concentration and location on magnesium release from multiple W/O/W emulsions.

PubMed

Bonnet, Marie; Cansell, Maud; Placin, Frédéric; Anton, Marc; Leal-Calderon, Fernando

2010-06-15

Water-in-oil-in-water (W/O/W) double emulsions were prepared and the rate of release of magnesium ions from the internal to the external aqueous phase was followed. Sodium caseinate was used not only as a hydrophilic surface-active species but also as a chelating agent able to bind magnesium ions. The release occurred without film rupturing (no coalescence). The kinetics of the release process depended on the location (in only one or in both aqueous compartments) and on the concentration of sodium caseinate. The rate of release increased with the concentration of sodium caseinate in the external phase and decreased when sodium caseinate was present in the inner droplets. The experiments were interpreted within the frame of a mean-field model based on diffusion, integrating the effect of ion binding. The data could be adequately fitted by considering a time-dependent permeation coefficient of the magnesium ions across the oil phase. Our results suggested that ion permeability was influenced by the state of the protein interfacial layers which itself depended on the extent of magnesium binding.

Phase Transitions of Nanoemulsions Using Ultrasound: Experimental Observations

PubMed Central

Singh, Ram; Husseini, Ghaleb A.; Pitt, William G.

2012-01-01

The ultrasound-induced transformation of perfluorocarbon liquids to gases is of interest in the area of drug and gene delivery. In this study, three independent parameters (temperature, size, and perfluorocarbon species) were selected to investigate the effects of 476-kHz and 20-kHz ultrasound on nanoemulsion phase transition. Two levels of each factor (low and high) were considered at each frequency. The acoustic intensities at gas bubble formation and at the onset of inertial cavitation were recorded and subsequently correlated with the acoustic parameters. Experimental data showed that low frequencies are more effective in forming and collapsing a bubble. Additionally, as the size of the emulsion droplet increased, the intensity required for bubble formation decreased. As expected, perfluorohexane emulsions require greater intensity to form cavitating bubbles than perfluoropentane emulsions. PMID:22444691

A two-step approach for copper and nickel extracting and recovering by emulsion liquid membrane.

PubMed

Bi, Qiang; Xue, Juanqin; Guo, Yingjuan; Li, Guoping; Cui, Haibin

2016-11-01

The recycling of copper and nickel from metallurgical wastewater using emulsion liquid membrane (ELM) was studied. P507 (2-ethylhexyl phosphonic acid-2-ethylhexyl ester) and TBP (tributyl phosphate) were used as carriers for the extraction of copper and nickel by ELMs, respectively. The influence of four emulsion composition variables, namely, the internal phase volume fraction (ϕ), surfactant concentration (Wsurf), internal phase stripping acid concentration (Cio) and the carrier concentration (Cc), and the process variable treat ratio on the extraction efficiencies of copper or nickel were studied. Under the optimum conditions, 98% copper and nickel were recycled by using ELM. The results indicated that ELM extraction is a promising industrial application technology to retrieve valuable metals in low concentration metallurgical wastewater.

Preparation and impact of multiple (water-in-oil-in-water) emulsions in meat systems.

PubMed

Cofrades, S; Antoniou, I; Solas, M T; Herrero, A M; Jiménez-Colmenero, F

2013-11-01

The aim of this paper was to prepare and characterise multiple emulsions and assess their utility as pork backfat replacers in meat gel/emulsion model systems. In order to improve the fat content (in quantitative and qualitative terms) pork backfat was replaced by a water-in-oil-in-water emulsion (W1/O/W2) prepared with olive oil (as lipid phase), polyglycerol ester of polyricinoleic acid (PGPR) as a lipophilic emulsifier, and sodium caseinate (SC) and whey protein concentrate (WP) as hydrophilic emulsifiers. The emulsion properties (particle size and distribution, stability, microstructure) and meat model system characteristics (composition, texture, fat and water binding properties, and colour) of the W1/O/W2, as affected by reformulation, were evaluated. Multiple emulsions showed a well-defined monomodal distribution. Freshly prepared multiple emulsions showed good thermal stability (better using SC) with no creaming. The meat systems had good water and fat binding properties irrespective of formulation. The effect on texture by replacement of pork backfat by W1/O/W2 emulsions generally depends on the type of double emulsion (associated with the hydrophilic emulsifier used in its formulation) and the fat level in the meat system. Copyright © 2013 Elsevier Ltd. All rights reserved.

Integrated microfluidic system with simultaneous emulsion generation and concentration.

PubMed

Koppula, Karuna S; Fan, Rong; Veerapalli, Kartik R; Wan, Jiandi

2016-03-15

Because the size, size distribution, and concentration of emulsions play an important role in most of the applications, controlled emulsion generation and effective concentration are of great interest in fundamental and applied studies. While microfluidics has been demonstrated to be able to produce emulsion drops with controlled size, size distribution, and hierarchical structures, progress of controlled generation of concentrated emulsions is limited. Here, we present an effective microfluidic emulsion generation system integrated with an orifice structure to separate aqueous droplets from the continuous oil phase, resulting in concentrated emulsion drops in situ. Both experimental and simulation results show that the efficiency of separation is determined by a balance between pressure drop and droplet accumulation near the orifice. By manipulating this balance via changing flow rates and microfluidic geometry, we can achieve monodisperse droplets on chip that have a concentration as high as 80,000 drops per microliter (volume fraction of 66%). The present approach thus provides insights to the design of microfluidic device that can be used to concentrate emulsions (drops and bubbles), colloidal particles (drug delivery polymer particles), and biological particles (cells and bacteria) when volume fractions as high as 66% are necessary. Copyright © 2015 Elsevier Inc. All rights reserved.

Incorporation of water-in-oil-in-water (W1/O/W2) double emulsion in a set-type yogurt model.

PubMed

Lalou, Sofia; Kadri, Hani El; Gkatzionis, Konstantinos

2017-10-01

The effect of W 1 /O/W 2 emulsion incorporation in set-type yogurt on the acidification process, physicochemical properties, bacterial growth kinetics and structural characteristics was investigated. The W 1 /O/W 2 emulsion was formed by using a two-step homogenisation process and milk as the W 1 and W 2 phases, and stability was monitored with optical microscopy and cryo-SEM. Adding the W 1 /O/W 2 emulsions reduced the acidification rate, viscosity and water retention capacity. Texture (adhesiveness, cohesiveness, hardness, and gumminess) differed in yogurts containing W 1 /O/W 2 emulsion compared to controls during the acidification process, however, trends became stable during storage. The growth of S. thermophilus during the acidification process of yogurt was reduced in the presence of W 1 /O/W 2 emulsion while L. bulgaricus trended higher during storage. This study shows that yogurts containing W 1 /O/W 2 emulsion are feasible subject to processing modification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Wetting-induced formation of controllable monodisperse multiple emulsions in microfluidics.

PubMed

Deng, Nan-Nan; Wang, Wei; Ju, Xiao-Jie; Xie, Rui; Weitz, David A; Chu, Liang-Yin

2013-10-21

Multiple emulsions, which are widely applied in a myriad of fields because of their unique ability to encapsulate and protect active ingredients, are typically produced by sequential drop-formations and drop-encapsulations using shear-induced emulsification. Here we report a qualitatively novel method of creating highly controlled multiple emulsions from lower-order emulsions. By carefully controlling the interfacial energies, we adjust the spreading coefficients between different phases to cause drops of one fluid to completely engulf other drops of immiscible fluids; as a result multiple emulsions are directly formed by simply putting preformed lower-order emulsion drops together. Our approach has highly controllable flexibility. We demonstrate this in preparation of both double and triple emulsions with a controlled number of inner drops and precisely adjusted shell thicknesses including ultra-thin shells. Moreover, this controllable drop-engulfing-drop approach has a high potential in further investigations and applications of microfluidics. Importantly, this innovative approach opens a window to exploit new phenomena occurring in fluids at the microscale level, which is of great significance for developing novel microfluidics.

Lecithin-linker formulations for self-emulsifying delivery of nutraceuticals.

PubMed

Chu, Jacquelene; Cheng, Yu-Ling; Rao, A Venketeshwer; Nouraei, Mehdi; Zarate-Muñoz, Silvia; Acosta, Edgar J

2014-08-25

Lecithin-linker microemulsions are formulations produced with soybean lecithin in combination with a highly lipophilic (lipophilic linker) and highly hydrophilic (hydrophilic linkers) surfactant-like additives. In this work, lecithin-linker systems were formulated to produce self-emulsifying delivery systems for β-carotene and β-sitosterol. The concentration of the lipophilic linker, sorbitan monooleate, was adjusted to minimize the formation of liquid crystals. The concentration of hydrophilic linkers, decaglyceryl caprylate/caprate and PEG-6-caprylic/capric glycerides, was gradually increased (scanned) until single phase clear microemulsions were obtained. For these scans, the oil (ethyl caprate) to water ratio was set to 1. The single phase, clear microemulsions were diluted with fed-state simulated intestinal fluid (FeSSIF) and produced stable emulsions, with drop sizes close to 200 nm. Using pseudo-ternary phase diagrams to evaluate the process of dilution of microemulsion preconcentrates (mixtures of oil, lecithin and linkers with little or no water) with FeSSIF, it was determined that self-emulsifying systems are obtained when the early stages of the dilution produce single phase microemulsions. If liquid crystals or multiple phase systems are obtained during those early stages, then the emulsification yields unstable emulsions with large drop sizes. An in vitro permeability study conducted using a Flow-Thru Dialyzer revealed that stable emulsions with drop sizes of 150-300 nm produce large and irreversible permeation of β-carotene to sheep intestine. On the other hand, unstable emulsions produced without the linker combination separated in the dialyzer chamber. Copyright © 2014 Elsevier B.V. All rights reserved.

Cellulose acetate-based SiO2/TiO2 hybrid microsphere composite aerogel films for water-in-oil emulsion separation

NASA Astrophysics Data System (ADS)

Yang, Xue; Ma, Jianjun; Ling, Jing; Li, Na; Wang, Di; Yue, Fan; Xu, Shimei

2018-03-01

The cellulose acetate (CA)/SiO2-TiO2 hybrid microsphere composite aerogel films were successfully fabricated via water vapor-induced phase inversion of CA solution and simultaneous hydrolysis/condensation of 3-aminopropyltrimethoxysilane (APTMS) and tetrabutyl titanate (TBT) at room temperature. Micro-nano hierarchical structure was constructed on the surface of the film. The film could separate nano-sized surfactant-stabilized water-in-oil emulsions only under gravity. The flux of the film for the emulsion separation was up to 667 L m-2 h-1, while the separation efficiency was up to 99.99 wt%. Meanwhile, the film exhibited excellent stability during multiple cycles. Moreover, the film performed excellent photo-degradation performance under UV light due to the photocatalytic ability of TiO2. Facile preparation, good separation and potential biodegradation maked the CA/SiO2-TiO2 hybrid microsphere composite aerogel films a candidate in oil/water separation application.

Doxycycline hyclate-loaded bleached shellac in situ forming microparticle for intraperiodontal pocket local delivery.

PubMed

Phaechamud, Thawatchai; Chanyaboonsub, Nuttapong; Setthajindalert, Orn

2016-10-10

Bleached shellac (BS) is a water-insoluble polyester resin made up of sesquiterpenoid acids esterified with hydroxy aliphatic acids. In this study, BS dissolved in N-methyl pyrrolidone (NMP), dimethyl sulfoxide (DMSO) and 2-pyrrolidone was used as the internal phase of oil in oil emulsion using olive oil emulsified with glyceryl monostearate (GMS) as the external phase of in situ forming microparticles (ISM). Doxycycline hyclate (DH)-loaded BS ISMs were tested for emulsion stability, viscosity, rheology, transformation into microparticles, syringeability, drug release, surface topography, in vitro degradation and antimicrobial activities against Staphylococcus aureus, Streptococcus mutans and Porphyromonas gingivalis. All emulsions exhibited pseudoplastic flow and notably low syringeability force. Slower transformation from emulsion into microparticles of ISM prepared with 2-pyrrolidone was owing to slower solvent exchange of this solvent which promoted less porous structure of obtained BS matrix microparticles. The system containing 2-pyrrolidone exhibited a higher degradability than that prepared with DMSO. Developed DH-loaded BS ISMs exhibited a sustainable drug release for 47days with Fickian diffusion and effectively inhibited P. gingivalis, S. mutans and S. aureus. Therefore a DH-loaded BS ISM using olive oil containing GMS as the external phase and 2-pyrrolidone as a solvent was a suitable formulation for periodontitis treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

Method of making fine-grained triaminotrinitrobenzene

DOEpatents

Benziger, T.M.

1983-07-26

A method is given for forming a fine-grained species of the insensitive high explosive sym-triaminotrinitrobenzene (TATB) without grinding. In accordance with the method, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) is aminated by reaction with gaseous ammonia in an emulsion of toluene in water. The ratio of water to toluene in the emulsion is selected so that toluene is the dispersed phase in the emulsion. The size of the dispersed TCTNB-containing toluene droplets determines the particle size of the resulting TATB. The emulsion is preferably formed with an emulsifier such as ammonium oleate, which may be generated in situ from oleic acid, and stabilized with a protective colloid such as polyvinyl alcohol.

Method of making fine-grained triaminotrinitrobenzene

DOEpatents

Benziger, Theodore M.

1984-01-01

A method of forming a fine-grained species of the insensitive high explosive sym-triaminotrinitrobenzene (TATB) without grinding. In accordance with the method, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) is aminated by reaction with gaseous ammonia in an emulsion of toluene in water. The ratio of water to toluene in the emulsion is selected so that toluene is the dispersed phase in the emulsion. The size of the dispersed TCTNB-containing toluene droplets determines the particle size of the resulting TATB. The emulsion is preferably formed with an emulsifier such as ammonium oleate, which may be generated in situ from oleic acid, and stabilized with a protective colloid such as polyvinyl alcohol.

Preparation of microcapsules by complex coacervation of gum Arabic and chitosan.

PubMed

Butstraen, Chloé; Salaün, Fabien

2014-01-01

Gum Arabic-chitosan microcapsules containing a commercially available blend of triglycerides (Miglyol 812 N) as core phase were synthesized by complex coacervation. This study was conducted to clarify the influence of different parameters on the encapsulation process, i.e. during the emulsion formation steps and during the shell formation, using conductometry, zeta potential, surface and interface tension measurement and Fourier-transform infrared spectroscopy. By carefully analyzing the influencing factors including phase volume ratio, stirring rate and time, pH, reaction time, biopolymer ratio and crosslinking effect, the optimum synthetic conditions were found out. For the emulsion step, the optimum phase volume ratio chosen was 0.10 and an emulsion time of 15 min at 11,000 rpm was selected. The results also indicated that the optimum formation of these complexes appears at a pH value of 3.6 and a weight ratio of chitosan to gum Arabic mixtures of 0.25. Copyright © 2013 Elsevier Ltd. All rights reserved.

On the thermodynamics of particle-stabilized emulsions: curvature effects and catastrophic phase inversion.

PubMed

Kralchevsky, P A; Ivanov, I B; Ananthapadmanabhan, K P; Lips, A

2005-01-04

The flexural properties of a particle adsorption monolayer are investigated theoretically. If the particles are not densely packed, the interfacial bending moment and the spontaneous curvature (due to the particles) are equal to zero. The situation changes if the particles are closely packed. Then the particle adsorption monolayer possesses a significant bending moment, and the interfacial energies of bending and dilatation become comparable. In this case, the bending energy can either stabilize or destabilize the Pickering emulsion, depending on whether the particle contact angle is smaller or greater than 90 degrees . Theoretical expressions are derived for the bending moment, for the curvature elastic modulus, and for the work of interfacial deformation and emulsification. The latter is dominated by the work for creation of a new oil-water interface and by the work for particle adsorption. The curvature effects give a contribution of second order, which is significant only for emulsification at 50:50 water/oil volume fractions. A thermodynamic criterion for the type of the formed emulsion is proposed. It predicts the existence of a catastrophic phase inversion in particle-stabilized emulsions, in agreement with the experimental observations. The derived theoretical expressions could find application for interpretation of experimental data on production and stability of Pickering emulsions.

Physical and oxidative stability of fish oil-in-water emulsions stabilized with beta-lactoglobulin and pectin.

PubMed

Katsuda, Marly S; McClements, D J; Miglioranza, Lucia H S; Decker, Eric A

2008-07-23

The oxidation of fatty acids can be inhibited by engineering the surface of oil-in-water emulsion droplets to decrease interactions between aqueous phase prooxidants and lipids. The objective of this research was to evaluate whether emulsions stabilized by a multilayer emulsifier systems consisting of beta-lactoglobulin and citrus or sugar beet pectin could produce fish oil-in-water emulsions that had good physical and oxidative stability. Sugar beet pectin was compared to citrus pectin because the sugar beet pectin contains the known antioxidant, ferulic acid. A primary Menhaden oil-in-water emulsion was prepared with beta-lactoglobulin upon which the pectins were electrostatically deposited at pH 3.5. Emulsions prepared with 1% oil, 0.05% beta-lactoglobulin, and 0.06% pectins were physically stable for up to 16 days. As determined by monitoring lipid hydroperoxide and headspace propanal formation, emulsions prepared with the multilayer system of beta-lactoglobulin and citrus pectin were more stable than emulsions stabilized with beta-lactoglobulin alone. Emulsions prepared with the multilayer system of beta-lactoglobulin and sugar beet pectin were less stable than emulsions stabilized with beta-lactoglobulin alone despite the presence of ferulic acid in the sugar beet pectin. The lower oxidative stability of the emulsions with the sugar beet pectin could be due to its higher iron and copper concentrations which would produce oxidative stress that would overcome the antioxidant capacity of ferulic acid. These data suggest that the oxidative stability of oil-in-water emulsions containing omega-3 fatty acids could be improved by the use of multilayer emulsion systems containing pectins with low metal concentrations.

Antioxidant Behavior of Olive Phenolics in Oil-in-Water Emulsions.

PubMed

Paradiso, Vito Michele; Di Mattia, Carla; Giarnetti, Mariagrazia; Chiarini, Marco; Andrich, Lucia; Caponio, Francesco

2016-07-27

The effect of the surrounding molecular environment (β-lactoglobulin as an emulsion stabilizer and maltodextrin as a viscosity modifier) on the antioxidant activity of three olive oil phenolic compounds (PCs) in olive oil-in-water emulsions was investigated. Oxidation potential, phenolic partitioning, and radical quenching capacity were assessed in solution and in emulsion for oleuropein, hydroxytyrosol, and tyrosol; the influence of β-lactoglobulin and maltodextrin concentration was also evaluated. Finally, the observed properties were related to the oxidative stability of the emulsions containing the PCs to explain their behavior. The order hydroxytyrosol > oleuropein > tyrosol was observed among the antioxidants for both oxidation potential and radical quenching activity. Radical quenching capacity in emulsion and anodic potential were complementary indices of antioxidant effectiveness. As the intrinsic susceptibility of an antioxidant to oxidation expressed by its anodic potential decreased, the environmental conditions (molecular interactions and changes in continuous phase viscosity) played a major role in the antioxidant effectiveness in preventing hydroperoxide decomposition.

Tri-fuel (diesel-biodiesel-ethanol) emulsion characterization, stability and the corrosion effect

NASA Astrophysics Data System (ADS)

Low, M. H.; Mukhtar, N. A. M.; Yohaness Hagos, Ftwi; Noor, M. M.

2017-10-01

This paper presents the result of experimenting emulsified tri-fuel in term of stability, physico-chemical properties and corrosion effect on three common metals. The results were interpreted in terms of the impact of five minutes emulsification approach. Tri-fuel emulsions were varied in proportion ratio consist of biodiesel; 0%, 5%, 10%, and ethanol; 5%, 10%, 15%. Fuel characterization includes density, calorific value, flash point, and kinematic viscosity. Flash point of tri-fuel emulsion came with range catalog. Calorific value of tri-fuel emulsion appeared in declining pattern as more ethanol and biodiesel were added. Biodiesel promoted flow resistance while ethanol with opposite effect. 15% ethanol content in tri-fuel emulsion separated faster than 10% ethanol content but ethanol content with 5% yield no phase separation at all. Close cap under static immersion with various ratio of tri-fuel emulsions for over a month, corrosiveness attack was detected via weight loss technique on aluminum, stainless steel and mild steel.

Particulate Coacervation of Associative Polymer Brushes-Grafted Nanoparticles To Produce Structurally Stable Pickering Emulsions.

PubMed

Yang, Taeseung; Choi, Sang Koo; Park, Daehwan; Lee, Yea Ram; Chung, Chan Bok; Kim, Jin Woong

2016-12-20

This study introduces a new type of associative nanoparticle (ANP) that provides controlled chain-to-chain attraction with an associative polymer rheology modifier (APRM) to produce highly stable Pickering emulsions. The ANPs were synthesized by grafting hydrophobically modified hygroscopic zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine-co-stearyl methacrylate) brushes onto 20 nm sized silica NPs via surface-mediated living radical polymerization. The ANP-stabilized Pickering emulsions show significant viscosity enhancement in the presence of the APRM. This indicates that the ANPs act as particulate concentration agents at the interface owing to their hydrophobic association with the APRM in the aqueous phase, which leads to the generation of an ANP-mediated complex colloidal film. Consequently, the described ANP-reinforced Pickering emulsion system exhibits improved resistance to pH and salinity changes. This coacervation approach is advantageous because the complex colloidal layer at the interface provides the emulsion drops with a mechanically robust barrier, thus guaranteeing the improved Pickering emulsion stability against harsh environmental factors.

Study of Water-Oil Emulsion Breaking by Stabilized Solution Consisting of Anionic Surface Acting Agent - Soda Ash - Polymer (ASP)

NASA Astrophysics Data System (ADS)

Kulichkov, S. V.; Avtomonov, E. G.; Andreeva, L. V.; Solomennik, S. F.; Nikitina, A. V.

2018-01-01

The paper provides a laboratory research of breaking natural water-oil emulsions: - by non-stabilized ASP; by stabilized ASP; by mixture of stabilized and non-stabilized ASP in different proportions and production of refinery water of the required quality with the use of IronGuard 2495 as flocculant. Oil-in-water emulsion is stable. Classic methods are not suitable for residual water treatment: sediment gravity flow; filtration; centrifuge test. Microemulsion formed after ASP application has low boundary tension and high pH. It contributes to transfer of oil phase into a water one, forming oil-in-water emulsion. Alkaline condition has adverse effect on demulsifying ability of agents, flocculation and boundary tension. For breaking of water-oil emulsion at EBU before the interchanger water or water-oil emulsion from the wells that were not APS-treated in ratio of 1:9 shall be delivered. Residual water after EBU must be prepared in water tanks by dilution in great volume.

Experimental study on latent heat storage characteristics of W/O emulsion -Supercooling rate of dispersed water drops by direct contact heat exchange-

NASA Astrophysics Data System (ADS)

Morita, Shin-ichi; Hayamizu, Yasutaka; Horibe, Akihiko; Haruki, Naoto; Inaba, Hideo

2013-04-01

Recently, much attention has been paid to investigate the latent heat storage system. Using of ice heat storage system brings an equalization of electric power demand, because it will solved the electric -power-demand-concentration on day-time of summer by the air conditioning. The flowable latent heat storage material, Oil/Water type emulsion, microencapsulated latent heat material-water mixture or ice slurry, etc., is enable to transport the latent heat in a pipe. The flowable latent heat storage material can realize the pipe size reduction and system efficiency improvement. Supercooling phenomenon of the dispersed latent heat storage material in continuous phase brings the obstruction of latent heat storage. The latent heat storage rates of dispersed water drops in W/O (Water/Oil) emulsion are investigated experimentally in this study. The water drops in emulsion has the diameter within 3 ˜ 25μm, the averaged water drop diameter is 7.3μm and the standard deviation is 2.9μm. The direct contact heat exchange method is chosen as the phase change rate evaluation of water drops in W/O emulsion. The supercooled temperature and the cooling rate are set as parameters of this study. The evaluation is performed by comparison between the results of this study and the past research. The obtained experimental result is shown that the 35K or more degree from melting point brings 100% latent heat storage rate of W/O emulsion. It was clarified that the supercooling rate of dispersed water particles in emulsion shows the larger value than that of the bulk water.

Heteroaggregation of lipid droplets coated with sodium caseinate and lactoferrin.

PubMed

de Figueiredo Furtado, Guilherme; Michelon, Mariano; de Oliveira, Davi Rocha Bernardes; da Cunha, Rosiane Lopes

2016-11-01

Formation and characterization of droplet heteroaggregates were investigated by mixing two emulsions previously stabilized by proteins oppositely charged. Emulsions were composed of 5vol.% of sunflower oil and 95vol.% of sodium caseinate or lactoferrin aqueous dispersions. They were produced using ultrasound with fixed power (300W) and sonication time (6min). Different volume ratios (0-100%) of sodium caseinate-stabilized emulsion (droplet diameter around 1.75μm) to lactoferrin-stabilized emulsion (droplet diameter around 1.55μm) were mixed under conditions that both proteins showed opposite charges (pH7). Influence of ionic strength (0-400mM NaCl) on the heteroaggregates stability was also evaluated. Creaming stability, zeta potential, microstructure, mean particle diameter and rheological properties of the heteroaggregates were measured. These properties depended on the volume ratio (0-100%) of sodium caseinate to lactoferrin-stabilized emulsion (C:L) and the ionic strength. In the absence of salt, different zeta potential values were obtained, rheological properties (viscosity and elastic moduli) were improved and the largest heteroaggregates were formed at higher content of lactoferrin-stabilized emulsion (60-80%). The system containing 40 and 60vol.% of sodium caseinate and lactoferrin stabilized emulsion, respectively, presented good stability against phase separation besides showing enhanced rheological and size properties due to extensive droplets aggregation. Phase separation was observed only in the absence of sodium caseinate, demonstrating the higher susceptibility of lactoferrin to NaCl. The heteroaggregates produced may be useful functional agents for texture modification and controlled release since different rheological properties and sizes can be achieved depending on protein concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Effect of Surfactant and Compatibilizer on Inorganic Loading and Properties of PPO-based EPMM Membranes

NASA Astrophysics Data System (ADS)

Bissadi, Golnaz

Hybrid membranes represent a promising alternative to the limitations of organic and inorganic materials for high productivity and selectivity gas separation membranes. In this study, the previously developed concept of emulsion-polymerized mixed matrix (EPMM) membranes was further advanced by investigating the effects of surfactant and compatibilizer on inorganic loading in poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based EPMM membranes, in which inorganic part of the membranes originated from tetraethylorthosilicate (TEOS). The polymerization of TEOS, which consists of hydrolysis of TEOS and condensation of the hydrolyzed TEOS, was carried out as (i) one- and (ii) two-step processes. In the one-step process, the hydrolysis and condensation take place in the same environment of a weak acid provided by the aqueous solution of aluminum hydroxonitrate and sodium carbonate. In the two-step process, the hydrolysis takes place in the environment of a strong acid (solution of hydrochloric acid), whereas the condensation takes place in weak base environment obtained by adding excess of the ammonium hydroxide solution to the acidic solution of the hydrolyzed TEOS. For both one- and two-step processes, the emulsion polymerization of TEOS was carried out in two types of emulsions made of (i) pure trichloroethylene (TCE) solvent, and (ii) 10 w/v% solution of PPO in TCE, using different combinations of the compatibilizer (ethanol) and the surfactant (n-octanol). The experiments with pure TCE, which are referred to as a gravimetric powder method (GPM) allowed assessing the effect of different experimental parameters on the conversion of TEOS. The GPM tests also provided a guide for the synthesis of casting emulsions containing PPO, from which the EPMM membranes were prepared using a spin coating technique. The synthesized EPMM membranes were characterized using 29Si nuclear magnetic resonance (29Si NMR), differential scanning calorimetry (DSC), inductively coupled plasma mass spectrometry (ICP-MS), and gas permeation measurements carried out in a constant pressure (CP) system. The 29Si NMR analysis verified polymerization of TEOS in the emulsions made of pure TCE, and the PPO solution in TCE. The conversions of TEOS in the two-step process in the two types of emulsions were very close to each other. In the case of the one-step process, the conversions in the TCE emulsion were significantly greater than those in the emulsion of the PPO solution in TCE. Consequently, the conversions of TEOS in the EPMM membranes made in the two-step process were greater than those in the EPMM membranes made in the one-step process. The latter ranged between 10 - 20%, while the highest conversion in the two-step process was 74% in the presence of pure compatibilizer with no surfactant. Despite greater conversions and hence the greater inorganic loadings, the EPMM membranes prepared in the two-step process had glass transition temperatures (Tg) only slightly greater than the reference PPO membranes. In contrast, despite relatively low inorganic loadings, the EPMM membranes prepared in the one-step process had Tgs markedly greater than PPO, and showed the expected trend of an increase in Tg with the inorganic loading. These results indicate that in the case of the one-step process the polymerized TEOS was well integrated with the PPO chains and the interactions between the two phases lead to high Tgs. On the other hand, this was not the case for the EPMM membranes prepared in the two-step process, suggesting possible phase separation between the polymerized TEOS and the organic phase. The latter was confirmed by detecting no selectivity in the EPMM membranes prepared by the two-step process. In contrast, the EPMM membranes prepared in the one-step process in the presence of the compatibilizer and no surfactant showed 50% greater O2 permeability coefficient and a slightly greater O2/N2 permeability ratio compared to the reference PPO membranes.

Ionic Liquid Microemullsions, Templates for Directing Morphology of Cellulose Biopolymer Nanoparticles (Briefing Charts)

DTIC Science & Technology

2015-08-19

Morphologies Emulsion Directed Cellulose Morphology (NOT nanocellulose) T. Suzuki et al. / Journal of Colloid and Interface Science 418 (2014) 126–131...Ternary phase diagram constructed with BmimCl/Span80/Tween20/Sunflower Oil. Warm emulsion technique adapted at 50 °C, for reduced viscosity. Cellulose

Nanoemulsions prepared by a low-energy emulsification method applied to edible films

USDA-ARS?s Scientific Manuscript database

Catastrophic phase inversion (CPI) was used as a low-energy emulsification method to prepare oil-in-water (O/W) nanoemulsions in a lipid (Acetem)/water/nonionic surfactant (Tween 60) system. CPIs in which water-in-oil emulsions (W/O) are transformed into oil-in-water emulsions (O/W) were induced by ...

Boiling of an emulsion in a yield stress fluid.

PubMed

Guéna, Geoffroy; Wang, Ji; d'Espinose, Jean-Baptiste; Lequeux, François; Talini, Laurence

2010-11-01

We report the boiling behavior of pentane emulsified in a yield stress fluid, a colloidal clay (Laponite) suspension. We have observed that a superheated state is easily reached: the emulsion, heated more than 50 °C above the alkane boiling point, does not boil. Superheating is made possible by the suppression of heterogeneous nucleation in pentane, resulting from the emulsification process, a phenomenon evidenced decades ago in studies of the superheating of two phase fluids. We have furthermore studied the growth of isolated bubbles nucleated in the emulsion. The rate of increase of the bubble radius with time depends on both the temperature and emulsion volume fraction but, rather unexpectedly, does not depend on the fluid rheology. We show that the bubbles grow by diffusion of the alkane through the aqueous phase between liquid droplets and bubbles, analogously to an Ostwald ripening process. The peculiarity of the process reported here is that a layer depleted in oil droplets forms around the bubble, layer to which the alkane concentration gradient is confined. We successfully describe our experimental results with a simple transfer model.

Electrospun composite matrices of poly(ε-caprolactone)-montmorillonite made using tenside free Pickering emulsions.

PubMed

Samanta, Archana; Takkar, Sonam; Kulshreshtha, Ritu; Nandan, Bhanu; Srivastava, Rajiv K

2016-12-01

The production of composite electrospun matrices of poly(ε-caprolactone) (PCL) using an emulsifier-free emulsion, made with minimal organic solvent, as precursor is reported. Pickering emulsions of PCL were prepared using modified montmorillonite (MMT) clay as the stabilizer. Hydrophobic tallow group of the modified MMT clay resulted in analogous interaction of clay with oil and aqueous phase and its adsorption at the interface to provide stability to the resultant emulsion. Composite fibrous matrices of PCL and MMT were produced using electrospinning under controlled conditions. The fiber fineness was found to alter with PCL concentration and volume fraction of the aqueous and oil phases. A higher tensile strength and modulus was obtained with inclusion of MMT in PCL electrospun matrix in comparison to a matrix made using neat PCL. The presence of clay in the fibrous matrix did not change the cell proliferation efficiency in comparison to neat PCL matrix. Composite fibrous matrices of PCL/MMT bearing enhanced tensile properties may find applications in areas other than tissue engineering for example food packaging and filtration. Copyright © 2016 Elsevier B.V. All rights reserved.

Genesis of emulsion texture due to magma mixing: a case study from Chotanagpur Granite Gneiss Complex of Eastern India

NASA Astrophysics Data System (ADS)

Gogoi, Bibhuti; Saikia, Ashima; Ahmad, Mansoor

2016-04-01

The emulsion texture is a rare magma mixing feature in which rounded bodies of one magmatic phase remain dispersed in the other coherent phase (Freundt and Schmincke, 1992). This type of special texture in hybrid rocks can significantly contribute toward understanding the mechanisms facilitating magma mixing and magma chamber dynamics involving two disparate magmas as the exact processes by which mixing occurs still remain unclear. Recent developments in microfluidics have greatly helped us to understand the complex processes governing magma mixing occurring at micro-level. Presented work uses some of the results obtained from microfluidic experiments with a view to understand the formation mechanism of emulsions preserved in the hybrid rocks of the Ghansura Rhyolite Dome (GRD) of Proterozoic Chotanagpur Granite Gneiss Complex (CGGC), Eastern India. The GRD has preserved hybrid rocks displaying emulsion texture that formed due to the interaction of a phenocryst-rich basaltic magma and host rhyolite magma. The emulsions are more or less spherical in shape and dominantly composed of amphibole having biotite rinds set in a matrix of biotite, plagioclase, K-feldspar and quartz. Amphibole compositions were determined from the core of the emulsions to the rim with a view to check for cationic substitutions. The amphibole constituting the emulsions is actinolite in composition, and commonly shows tschermakite (Ts) and pargasite (Prg) substitutions. From petrographical and mineral-chemical analyses we infer that when mafic magma, containing phenocrysts of augite, came in contact with felsic magma, diffusion of cations like H+, Al3+and others occurred from the felsic to the mafic system. These cations reacted with the clinopyroxene phenocrysts in the mafic magma to form amphibole (actinolite) crystals. The formation of amphibole crystals in the mafic system greatly increased the viscosity of the system allowing the amphibole crystals to venture into the adjacent felsic magma as veins. As these veins traversed in the felsic medium they underwent sinuous perturbations as a result of the competition between the viscous torque, due to difference in drag on each side of the veins, and the dynamic viscous bending resistance (Cubaud and Mason, 2009). Further downstream, the undulations amplified and swirls started to develop on the sinuous veins by accumulating the high viscosity mafic phase into central bulbs and depleting the regions in between them forming tails. Gradually the tails thinned out and blended into the surrounding felsic melt forming discrete viscous emulsions/swirls. After separation, the amphibole constituting the emulsions started interacting with the surrounding felsic magma forming biotite at the periphery of the emulsions. Eventually, biotite is eroded away and new rinds simultaneously form on freshly eroded surfaces of emulsions facilitating the mixing process (Farner et al., 2014). Cubaud T and Mason TG (2009) New J. Phys. 11, 075029. Farner et al. (2014) Earth and Planetary Science Letters 393, 49-59. Freundt A and Schmincke HU (1992) Contrib Mineral Petrol 112, 1-19.

Application of D-optimal experimental design method to optimize the formulation of O/W cosmetic emulsions.

PubMed

Djuris, J; Vasiljevic, D; Jokic, S; Ibric, S

2014-02-01

This study investigates the application of D-optimal mixture experimental design in optimization of O/W cosmetic emulsions. Cetearyl glucoside was used as a natural, biodegradable non-ionic emulsifier in the relatively low concentration (1%), and the mixture of co-emulsifiers (stearic acid, cetyl alcohol, stearyl alcohol and glyceryl stearate) was used to stabilize the formulations. To determine the optimal composition of co-emulsifiers mixture, D-optimal mixture experimental design was used. Prepared emulsions were characterized with rheological measurements, centrifugation test, specific conductivity and pH value measurements. All prepared samples appeared as white and homogenous creams, except for one homogenous and viscous lotion co-stabilized by stearic acid alone. Centrifugation testing revealed some phase separation only in the case of sample co-stabilized using glyceryl stearate alone. The obtained pH values indicated that all samples expressed mild acid value acceptable for cosmetic preparations. Specific conductivity values are attributed to the multiple phases O/W emulsions with high percentages of fixed water. Results of the rheological measurements have shown that the investigated samples exhibited non-Newtonian thixotropic behaviour. To determine the influence of each of the co-emulsifiers on emulsions properties, the obtained results were evaluated by the means of statistical analysis (ANOVA test). On the basis of comparison of statistical parameters for each of the studied responses, mixture reduced quadratic model was selected over the linear model implying that interactions between co-emulsifiers play the significant role in overall influence of co-emulsifiers on emulsions properties. Glyceryl stearate was found to be the dominant co-emulsifier affecting emulsions properties. Interactions between the glyceryl stearate and other co-emulsifiers were also found to significantly influence emulsions properties. These findings are especially important as they can be used for development of the product that meets users' requirements, as represented in the study. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Analysis of in vitro release through reconstructed human epidermis and synthetic membranes of multi-vitamins from cosmetic formulations.

PubMed

Gabbanini, Simone; Matera, Riccardo; Beltramini, Claudia; Minghetti, Andrea; Valgimigli, Luca

2010-08-01

A convenient method for in vitro investigation of the release of lipid- and water-soluble vitamins from cosmetic formulations was developed. The permeation of (d)-alpha-tocopherol (vitamin E), retinyl acetate (pro-vitamin A), ascorbic acid (vitamin C) and pyridoxine (vitamin B6) through SkinEthic reconstructed human epidermis (RHE), and synthetic polyethersulfone and polycarbonate membranes was studied in vitro using a Franz-type diffusion apparatus, coupled either to a spectrophotometer for continuous reading (dynamic setting) or to HPLC-DAD analysis of the receptor medium (static setting). O/W and W/O emulsions were compared with simple aqueous solutions for their kinetic of vitamins release, to evaluate the influence of the cosmetic formulation on the bioavailability of active ingredients. Results indicate that synthetic membranes offer a limited barrier to the diffusion of vitamins, but may provide information on the release ability of the formulation. Penetration was more effective when water was the external phase of the formulation, i.e. W/O emulsions were less effective in the release of vitamins than O/W emulsion or aqueous solutions. RHE (17 days old) offered a significantly higher barrier to penetration of vitamins, as expected for native human epidermis. The relative ranking in coefficient of permeability (Ps (cm/h)) was: ascorbic acid>pyridoxine>retinyl acetate>alpha-tocopherol approximately 0, the absolute values depending on the formulation. The method herein described showed to be a practical and convenient tool for the quality-control and efficacy evaluation of cosmetic formulations. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Interfacial engineering using mixed protein systems: emulsion-based delivery systems for encapsulation and stabilization of β-carotene.

PubMed

Mao, Yingyi; Dubot, Marie; Xiao, Hang; McClements, David Julian

2013-05-29

Emulsion-based delivery systems are needed to encapsulate, protect, and deliver lipophilic bioactive components in the food, personal care, and pharmaceutical industries. The functional performance of these systems can be controlled by engineering the composition and structure of the interfacial layer coating the lipid droplets. In this study, interfacial properties were controlled using two globular proteins with widely differing isoelectric points: lactoferrin (LF: pI ≈ 8.5) and β-lactoglobulin (BLG: pI ≈ 5). Oil-in-water emulsions were prepared with different interfacial properties: [LF]-only; [BLG]-only; [LF]-[BLG]-(laminated); [BLG]-[LF]-(laminated); and [BLG/LF]-(mixed). The influence of pH, ionic strength, and temperature on the physical stability of β-carotene-enriched emulsions was investigated. [LF]-emulsions were stable to droplet aggregation from pH 2 to 9 (0 mM NaCl), but all other emulsions aggregated at intermediate pH values. [BLG]-emulsions aggregated at high salt levels (≥50 mM NaCl), but all other emulsions were stable (0 to 300 mM NaCl). [BLG/LF]-emulsions were unstable to heating (≥60 °C), but all other emulsions were stable (30 to 90 °C). Color fading due to β-carotene degradation occurred relatively quickly in [BLG]-emulsions (37 °C) but was considerably lower in all other emulsions, which was attributed to the ability of LF to bind iron or interact with β-carotene. This study provides useful information for designing emulsion-based delivery systems to encapsulate and protect bioactive lipids, such as carotenoids.

Interconnected Porous Polymers with Tunable Pore Throat Size Prepared via Pickering High Internal Phase Emulsions.

PubMed

Xu, Hongyun; Zheng, Xianhua; Huang, Yifei; Wang, Haitao; Du, Qiangguo

2016-01-12

Interconnected macroporous polymers were prepared by copolymerizing methyl acrylate (MA) via Pickering high internal phase emulsion (HIPE) templates with modified silica particles. The pore structure of the obtained polymer foams was observed by field-emission scanning electron microscopy (FE-SEM). Gas permeability was characterized to evaluate the interconnectivity of macroporous polymers. The polymerization shrinkage of continuous phase tends to form open pores while the solid particles surrounding the droplets act as barriers to produce closed pores. These two conflicting factors are crucial in determining the interconnectivity of macroporous polymers. Thus, poly-Pickering HIPEs with high permeability and well-defined pore structure can be achieved by tuning the MA content, the internal phase fraction, and the content of modified silica particles.

Immunomodulatory and Physical Effects of Oil Composition in Vaccine Adjuvant Emulsions

PubMed Central

Fox, Christopher B.; Baldwin, Susan L.; Duthie, Malcolm S.; Reed, Steven G.; Vedvick, Thomas S.

2011-01-01

Squalene-based oil-in-water emulsions have been used for years in some seasonal and pandemic influenza vaccines. However, concerns have been expressed regarding squalene source and potential biological activities. Little information is available regarding the immunomodulatory activity of squalene in comparison with other metabolizable oils in the context of oil-in-water emulsions formulated with vaccines. The present work describes the manufacture and physical characterization of emulsions composed of different classes of oils, including squalene, long chain triglycerides, a medium chain triglyceride, and a perfluorocarbon, all emulsified with egg phosphatidylcholine. Some differences were apparent among the non-squalene oils in terms of emulsion stability, including higher size polydispersity in the perfluorocarbon emulsion, more rapid visual instability at 60 °C for the long-chain triglyceride and perfluorocarbon emulsions, and an increased creaming rate in the medium-chain triglyceride emulsion at 60 °C as detected by laser scattering optical profiling. The biological activity of each of these emulsions was compared when formulated with either a recombinant malaria antigen or a split-virus inactivated influenza vaccine. Overall, vaccines containing the squalene emulsion elicited higher antibody titers and more abundant long-lived plasma cells than vaccines containing emulsions based on other oils. Since squalene-based emulsions show higher adjuvant potency compared to the other oils tested, non-squalene oils may be more suitable as carriers of amphiphilic or hydrophobic immunostimulatory molecules (such as TLR agonists) rather than as stand-alone adjuvants. PMID:21906648

Cell separations and the demixing of aqueous two phase polymer solutions in microgravity

NASA Technical Reports Server (NTRS)

Brooks, Donald E.; Bamberger, Stephan; Harris, J. M.; Van Alstine, James M.

1991-01-01

Partition in phase separated aqueous polymer solutions is a cell separation procedure thought to be adversely influenced by gravity. In preparation for performing cell partitioning experiments in space, and to provide general information concerning the demixing of immiscible liquids in low gravity, a series of phase separated aqueous polymer solutions have been flown on two shuttle flights. Fluorocarbon oil and water emulsions were also flown on the second flight. The aqueous polymer emulsions, which in one g demix largely by sedimentation and convection due to the density differences between the phases, demixed more slowly than on the ground and the final disposition of the phases was determined by the wetting of the container wall by the phases. The demixing behavior and kinetics were influenced by the phase volume ratio, physical properties of the systems and chamber wall interaction. The average domain size increased linearly with time as the systems demixed.

Influence of surfactants on gas-hydrate formation' kinetics in water-oil emulsion

NASA Astrophysics Data System (ADS)

Zemenkov, Yu D.; Shirshova, A. V.; Arinstein, E. A.; Shuvaev, A. N.

2018-05-01

The kinetics of gas hydrate formation of propane in a water-oil emulsion is experimentally studied when three types of surfactants (SAA (surface acting agent)) - anionic type emulsifiers - are added to the aqueous phase. It is shown that all three types of surfactants decelerate the growth of the gas-hydrate in the emulsion and can be considered as anti-agglutinating and kinetic low-dose inhibitors. The most effective inhibitor of hydrate formation in water-oil emulsion of SV-102 surfactant was revealed. For comparison, experimental studies of gas-hydrate formation under the same conditions for bulk water have been carried out. It is shown that in bulk water, all the surfactants investigated act as promoters (accelerators) of hydrate formation. A qualitative explanation of the action mechanisms of emulsifiers in the process of gas-hydrate formation in water-oil emulsion is given.

Production, deformation and mechanical investigation of magnetic alginate capsules

NASA Astrophysics Data System (ADS)

Zwar, Elena; Kemna, Andre; Richter, Lena; Degen, Patrick; Rehage, Heinz

2018-02-01

In this article we investigated the deformation of alginate capsules in magnetic fields. The sensitivity to magnetic forces was realised by encapsulating an oil in water emulsion, where the oil droplets contained dispersed magnetic nanoparticles. We solved calcium ions in the aqueous emulsion phase, which act as crosslinking compounds for forming thin layers of alginate membranes. This encapsulating technique allows the production of flexible capsules with an emulsion as the capsule core. It is important to mention that the magnetic nanoparticles were stable and dispersed throughout the complete process, which is an important difference to most magnetic alginate-based materials. In a series of experiments, we used spinning drop techniques, capsule squeezing experiments and interfacial shear rheology in order to determine the surface Young moduli, the surface Poisson ratios and the surface shear moduli of the magnetically sensitive alginate capsules. In additional experiments, we analysed the capsule deformation in magnetic fields. In spinning drop and capsule squeezing experiments, water droplets were pressed out of the capsules at elevated values of the mechanical load. This phenomenon might be used for the mechanically triggered release of water-soluble ingredients. After drying the emulsion-filled capsules, we produced capsules, which only contained a homogeneous oil phase with stable suspended magnetic nanoparticles (organic ferrofluid). In the dried state, the thin alginate membranes of these particles were rather rigid. These dehydrated capsules could be stored at ambient conditions for several months without changing their properties. After exposure to water, the alginate membranes rehydrated and became flexible and deformable again. During this swelling process, water diffused back in the capsule. This long-term stability and rehydration offers a great spectrum of different applications as sensors, soft actuators, artificial muscles or drug delivery systems.

Stabilization Improves Theranostic Properties of Lipiodol®-Based Emulsion During Liver Trans-arterial Chemo-embolization in a VX2 Rabbit Model.

PubMed

Deschamps, F; Farouil, G; Gonzalez, W; Robic, C; Paci, A; Mir, L M; Tselikas, L; de Baère, T

2017-06-01

To demonstrate that stability is a crucial parameter for theranostic properties of Lipiodol ® -based emulsions during liver trans-arterial chemo-embolization. We compared the theranostic properties of two emulsions made of Lipiodol ® and doxorubicin in two successive animal experiments (One VX2 tumour implanted in the left liver lobe of 30 rabbits). Emulsion-1 reproduced one of the most common way of preparation (ratio of oil/water: 1/1), and emulsion-2 was designed to obtain a water-in-oil emulsion with enhanced stability (ratio of oil/water: 3/1, plus an emulsifier). The first animal experiment compared the tumour selectivity of the two emulsions: seven rabbits received left hepatic arterial infusion (HAI) of emulsion-1 and eight received HAI of emulsion-2. 3D-CBCT acquisitions were acquired after HAI of every 0.1 mL to measure the densities' ratios between the tumours and the left liver lobes. The second animal experiment compared the plasmatic and tumour doxorubicin concentrations after HAI of 1.5 mg of doxorubicin administered either alone (n = 3) or in emulsion-1 (n = 6) or in emulsion-2 (n = 6). Emulsion-2 resulted in densities' ratios between the tumours and the left liver lobes that were significantly higher compared to emulsion-1 (up to 0.4 mL infused). Plasmatic doxorubicin concentrations (at 5 min) were significantly lower after HAI of emulsion-2 (19.0 μg/L) than emulsion-1 (275.3 μg/L, p < 0.01) and doxorubicin alone (412.0 μg/L, p < 0.001), and tumour doxorubicin concentration (day-1) was significantly higher after HAI of emulsion-2 (20,957 ng/g) than in emulsion-1 (8093 ng/g, p < 0.05) and doxorubicin alone (2221 ng/g, p < 0.01). Stabilization of doxorubicin in a water-in-oil Lipiodol ® -based emulsion results in better theranostic properties.

Stabilization Improves Theranostic Properties of Lipiodol{sup ®}-Based Emulsion During Liver Trans-arterial Chemo-embolization in a VX2 Rabbit Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deschamps, F., E-mail: frederic.deschamps@gustaveroussy.fr; Farouil, G.; Gonzalez, W.

PurposeTo demonstrate that stability is a crucial parameter for theranostic properties of Lipiodol{sup ®}-based emulsions during liver trans-arterial chemo-embolization.Materials and MethodsWe compared the theranostic properties of two emulsions made of Lipiodol{sup ®} and doxorubicin in two successive animal experiments (One VX2 tumour implanted in the left liver lobe of 30 rabbits). Emulsion-1 reproduced one of the most common way of preparation (ratio of oil/water: 1/1), and emulsion-2 was designed to obtain a water-in-oil emulsion with enhanced stability (ratio of oil/water: 3/1, plus an emulsifier). The first animal experiment compared the tumour selectivity of the two emulsions: seven rabbits received leftmore » hepatic arterial infusion (HAI) of emulsion-1 and eight received HAI of emulsion-2. 3D-CBCT acquisitions were acquired after HAI of every 0.1 mL to measure the densities’ ratios between the tumours and the left liver lobes. The second animal experiment compared the plasmatic and tumour doxorubicin concentrations after HAI of 1.5 mg of doxorubicin administered either alone (n = 3) or in emulsion-1 (n = 6) or in emulsion-2 (n = 6).ResultsEmulsion-2 resulted in densities’ ratios between the tumours and the left liver lobes that were significantly higher compared to emulsion-1 (up to 0.4 mL infused). Plasmatic doxorubicin concentrations (at 5 min) were significantly lower after HAI of emulsion-2 (19.0 μg/L) than emulsion-1 (275.3 μg/L, p < 0.01) and doxorubicin alone (412.0 μg/L, p < 0.001), and tumour doxorubicin concentration (day-1) was significantly higher after HAI of emulsion-2 (20,957 ng/g) than in emulsion-1 (8093 ng/g, p < 0.05) and doxorubicin alone (2221 ng/g, p < 0.01).ConclusionStabilization of doxorubicin in a water-in-oil Lipiodol{sup ®}-based emulsion results in better theranostic properties.« less

Emulsion-Based Intradermal Delivery of Melittin in Rats.

PubMed

Han, Sang Mi; Kim, Se Gun; Pak, Sok Cheon

2017-05-19

Bee venom (BV) has long been used as a traditional medicine. The aim of the present study was to formulate a BV emulsion with good rheological properties for dermal application and investigate the effect of formulation on the permeation of melittin through dermatomed rat skin. A formulated emulsion containing 1% ( w / v ) BV was prepared. The emulsion was compared with distilled water (DW) and 25% ( w / v ) N -methyl-2-pyrrolidone (NMP) in DW. Permeation of melittin from aqueous solution through the dermatomed murine skin was evaluated using the Franz diffusion cells. Samples of receptor cells withdrawn at pre-determined time intervals were measured for melittin amount. After the permeation study, the same skin was used for melittin extraction. In addition, a known amount of melittin (5 μg/mL) was added to stratum corneum, epidermis, and dermis of the rat skin, and the amount of melittin was measured at pre-determined time points. The measurement of melittin from all samples was done with HPLC-MS/MS. No melittin was detected in the receptor phase at all time points in emulsion, DW, or NMP groups. When the amount of melittin was further analyzed in stratum corneum, epidermis, and dermis from the permeation study, melittin was still not detected. In an additional experiment, the amount of melittin added to all skin matrices was corrected against the amount of melittin recovered. While the total amount of melittin was retained in the stratum corneum, less than 10% of melittin remained in epidermis and dermis within 15 and 30 min, respectively. Skin microporation with BV emulsion facilitates the penetration of melittin across the stratum corneum into epidermis and dermis, where emulsified melittin could have been metabolized by locally-occurring enzymes.

Emulsion based cast booster - a priming system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, R.N.; Mishra, A.K.

2005-07-01

This paper explores the potential of emulsion based cast booster to be used as primer to initiate bulk delivered emulsion explosives used in mines. An attempt has been made for comparative study between conventional cast booster and emulsion based cast booster in terms of the initiation process developed and their capability to develop and maintain the stable detonation process in the column explosives. The study has been conducted using a continuous velocity of detonation (VOD) measuring instrument. During this study three blasts have been monitored. In each blast two holes have been selected for study, the first hole being initiatedmore » with conventional cast booster while the other one with emulsion based cast booster. The findings of the study advocates that emulsion based cast booster is capable of efficient priming of bulk delivered column explosive with stable detonation process in the column. Further, the booster had advantages over the conventional PETN/TNT based cast booster. 5 refs., 2 figs., 1 tab., 1 photo.« less

Liquid Crystal Formation from Sunflower Oil: Long Term Stability Studies.

PubMed

da Rocha-Filho, Pedro Alves; Maruno, Mônica; Ferrari, Márcio; Topan, José Fernando

2016-06-09

The Brazilian biodiversity offers a multiplicity of raw materials with great potential in cosmetics industry applications. Some vegetable oils and fatty esters increase skin hydration by occlusivity, keeping the skin hydrated and with a shiny appearance. Sunflower (Helianthus annus L.) oil is widely employed in cosmetic emulsions in the form of soaps, creams, moisturizers and skin cleansers due to the presence of polyphenols and its high vitamin E content. Liquid crystals are systems with many applications in both pharmaceutical and cosmetic formulations and are easily detected by microscopy under polarized light due to their birefringence properties. The aim of this research was to develop emulsions from natural sunflower oil for topical uses. Sunflower oil (75.0% w/w) was combined with liquid vaseline (25.0% w/w) employing a natural self-emulsifying base (SEB) derivative. The high temperature of the emulsification process did not influence the antioxidant properties of sunflower oil. Fatty esters were added to cosmetic formulations and extended stability tests were performed to characterize the emulsions. Fatty esters like cetyl palmitate and cetyl ester increase the formation of anisotropic structures. O/W emulsions showed acidic pH values and pseudoplastic behavior. The presence of a lamellar phase was observed after a period of 90 days under different storage conditions.

Characterization of ultrahigh-molecular weight cationic polyacrylamide using frit-inlet asymmetrical flow field-flow fractionation and multi-angle light scattering.

PubMed

Woo, Sohee; Lee, Ju Yong; Choi, Woonjin; Moon, Myeong Hee

2016-01-15

In this study, frit inlet asymmetrical flow field-flow fractionation (FlFFF) with multi-angle light scattering (MALS) and differential refractive index (DRI) detection is utilized for size separation, determination of molecular weight (MW), and conformation of ultrahigh-MW (10(7)-10(9) g/mol) cationic polyacrylamides (C-PAMs), a class of water-soluble copolymers based on acrylamide and vinyl-type comonomers with quaternary ammonium cations that are widely used in wastewater treatment and in paper industries. Linear and branched C-PAM copolymers prepared in two different polymerization methods (solution and emulsion) from varying amounts of crosslinking agent and initiator were size fractionated by FlFFF with field-programming. It was found experimentally that the linear copolymers from both polymerization methods were less than 10(8) g/mol in MW with compact, nearly spherical structures, while the branched C-PAM copolymers from the emulsion polymerization showed a significant increase in average MW up to ∼ 10(9)g/mol, which was about 20-fold greater than those from the solution method, and the branched copolymers had more compact or shrunken conformations. While both linear and branched copolymers less than 10(8) g/mol MW were well resolved in an increasing order of MW (normal mode), it was noted that branched copolymers prepared through emulsion polymerization exhibited significantly larger MWs of 10(8-)10(9) g/mol and eluted in the steric/hyperlayer mode, in which the elution order is reversed in an extreme run condition (strong initial field strength followed by a fast field decay during programming). Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of solid lipid nanoparticles from W/O/W emulsions: preliminary studies on insulin encapsulation.

PubMed

Gallarate, Marina; Trotta, Michele; Battaglia, Luigi; Chirio, Daniela

2009-08-01

A method to produce solid lipid nanoparticles (SLN) from W/O/W multiple emulsions was developed applying the solvent-in-water emulsion-diffusion technique. Insulin was chosen as hydrophilic peptide drug to be dissolved in the acidic inner aqueous phase of multiple emulsions and to be consequently carried in SLN. Several partially water-miscible solvents with low toxicity were screened in order to optimize emulsions and SLN composition, after assessing that insulin did not undergo any chemical modification in the presence of the different solvents and under the production process conditions. SLN of spherical shape and with mean diameters in the 600-1200 nm range were obtained by simple water dilution of the W/O/W emulsion. Best results, in terms of SLN mean diameter and encapsulation efficiencies, were obtained using glyceryl monostearate as lipid matrix, butyl lactate as a solvent, and soy lecithin and Pluronic F68 as surfactants. Encapsulation efficiencies up to 40% of the loaded amount were obtained, owing to the actual multiplicity of the system; the use of multiple emulsion-derived SLN can be considered a useful strategy to encapsulate a hydrophilic drug in a lipid matrix.

New insights about flocculation process in sodium caseinate-stabilized emulsions.

PubMed

Huck-Iriart, Cristián; Montes-de-Oca-Ávalos, Juan; Herrera, María Lidia; Candal, Roberto Jorge; Pinto-de-Oliveira, Cristiano Luis; Linares-Torriani, Iris

2016-11-01

Flocculation process was studied in emulsions formulated with 10wt.% sunflower oil, 2, 5 or 7.5wt.% NaCas, and with or without addition of sucrose (0, 5, 10, 15, 20 or 30wt.%). Two different processing conditions were used to prepare emulsions: ultraturrax homogenization or further homogenization by ultrasound. Emulsions with droplets with diameters above (coarse) or below (fine) 1μm were obtained. Emulsions were analyzed for droplet size distribution by static light scattering (SLS), stability by Turbiscan, and structure by confocal laser scanning microscopy (CLSM) and small angle X-ray scattering (SAXS). SAXS data were fitted by a theoretical model that considered a system composed of poly dispersed spheres with repulsive interaction and presence of aggregates. Flocculation behavior was caused by the self-assembly properties of NaCas, but the process was more closely related to interfacial protein content than micelles concentration in the aqueous phase. The results indicated that casein aggregation was strongly affected by disaccharide addition, hydrophobic interaction of the emulsion droplets, and interactions among interfacial protein molecules. The structural changes detected in the protein micelles in different environments allowed understanding the macroscopic physical behavior observed in concentrated NaCas emulsions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simulation model based on non-newtonian fluid mechanics applied to the evaluation of the embolic effect of emulsions of iodized oil and anticancer drug.

PubMed

Demachi, H; Matsui, O; Abo, H; Tatsu, H

2000-01-01

To verify the difference in embolic effect between oil-in-water (O-W) and water-in-oil (W-O) emulsions composed of iodized oil and an anticancer drug, epirubicin, using a simulation model based on non-Newtonian fluid mechanics. Flow curves of pure iodized oil and two types of O-W and W-O emulsions immediately and 1 hr after preparation were examined with a viscometer. Using the yield stress data obtained, we simulated the stagnation of each fluid with steady flow in a rigid tube. The W-O emulsions were observed to stagnate in the thin tube at a low pressure gradient. However, the embolic effect of the W-O emulsions decreased 1 hr after preparation. The O-W emulsions were stable and did not stagnate under the conditions in which the W-O emulsions stagnated. The simulation model showed that the embolic effect of the W-O emulsions was superior to that of the O-W emulsions.

Preparation and physicochemical properties of surfactant-free emulsions using electrolytic-reduction ion water containing lithium magnesium sodium silicate.

PubMed

Okajima, Masahiro; Wada, Yuko; Hosoya, Takashi; Hino, Fumio; Kitahara, Yoshiyasu; Shimokawa, Ken-ichi; Ishii, Fumiyoshi

2013-04-01

Surfactant-free emulsions by adding jojoba oil, squalane, olive oil, or glyceryl trioctanoate (medium chain fatty acid triglycerides, MCT) to electrolytic-reduction ion water containing lithium magnesium sodium silicate (GE-100) were prepared, and their physiochemical properties (thixotropy, zeta potential, and mean particle diameter) were evaluated. At an oil concentration of 10%, the zeta potential was ‒22.3 ‒ ‒26.8 mV, showing no marked differences among the emulsions of various types of oil, but the mean particle diameters in the olive oil emulsion (327 nm) and MCT emulsion (295 nm) were smaller than those in the other oil emulsions (452-471 nm). In addition, measurement of the hysteresis loop area of each type of emulsion revealed extremely high thixotropy of the emulsion containing MCT at a low concentration and the olive emulsion. Based on these results, since surfactants and antiseptic agents markedly damage sensitive skin tissue such as that with atopic dermatitis, surfactant- and antiseptic-free emulsions are expected to be new bases for drugs for external use.

Structural micro-porous carbon anode for rechargeable lithium-ion batteries

DOEpatents

Delnick, Frank M.; Even, Jr., William R.; Sylwester, Alan P.; Wang, James C. F.; Zifer, Thomas

1995-01-01

A secondary battery having a rechargeable lithium-containing anode, a cathode and a separator positioned between the cathode and anode with an organic electrolyte solution absorbed therein is provided. The anode comprises three-dimensional microporous carbon structures synthesized from polymeric high internal phase emulsions or materials derived from this emulsion source, i.e., granules, powders, etc.

Exploring the Dynamics and Structure of Soft Colloids at Oil-water Interfaces

NASA Astrophysics Data System (ADS)

Kwok, Man Hin

The ability of solid colloidal particles to physically stabilize emulsions, also referred to as Pickering emulsions, has been studied for a long time since their activity at the interface was discovered one hundred years ago. Pickering emulsions display various interesting phenomena because of it high desorption energy at the interface compared with conventional surfactant stabilizers. In addition, Pickering emulsions are considered to be 'surfactant free' emulsion and the adverse effects of using surfactants could be eliminated. In the past few years, the use of submicrometer, poly(N-isopropylacrylamide) (PNIPAM)-based mcirogel particles for stabilizing emulsions has captured the interest of many scientists. Being soft, the microgels, which are spherical in solution, become deformed at the oil-water interface. This deformability leads to the special dynamic properties of interfacial layers and packing structures, which in turn alters the interfacial tension and the rheological properties of the interface. In addition, being responsiveness, PNIPAM microgels enable emulsions to be prepared and broken on demand. Despite all of the practical advantages and unique properties that have already been demonstrated, the mechanisms that govern emulsion stabilization and destabilization using microgels are far from completely understood. The study of soft colloids at the interface thus is of great academic interest and the fundamental understanding of them is the key to achieve the application potential of such novel materials. This thesis focuses on the dynamics and structure of soft colloidal particles at the oil-water interfaces. First, in order to prepare tailored colloids for the study, the syntheses of multi-responsive PNIPAM microgels with different size, co-monomers, deformability and morphologies were thoroughly investigated. The combination of semi-batch synthesis and temperature-programmed technique resulted in a novel preparation of micron-sized PNIPAM microgels. Various experimental parameters were tested and modified in order to give microgels with optimized quality. The thermo- and pH- responsiveness of these microgels were characterized by laser diffraction and dynamic light scattering (DLS). Next, a novel labeling technique of the soft PNIPAM microgel particles was developed. This technique was based on the physical adsorption of small fluorescent molecules. Instead of chemically bonded dye molecules, these adsorbed fluorescent dyes could move freely inside the polymer network of the microgel particle. It was also found that the fluorescent dye interacted with different parts of the microgel differently. Therefore, the internal structure and morphology of microgels could be directly visualized by confocal laser scanning microscopy (CLSM) in aqueous environment. The improvement of imaging techniques of microgel particles is essential for studying their behavior at the oil-water interface. It is because conventional scanning electron microscopy (SEM) requires dried sample, which might not reflects the actual states of microgels in aqueous environment. With the improved labeling method under CLSM mentioned above, the conformation of micron-sized PNIPAM microgel particles was captured at the oil-water interface. Particularly, anisotropic deformation of soft pH-responsive microgels was observed at the oil-water interface. Nevertheless, it was found that microgels were not likely to deform significantly unless they were extremely swollen. We also use Langmuir trough to study the dynamics of microgel at an interface with changing area. Forced desorption-spontaneous adsorption cycles of microgel particles at the oil-water interface were successfully demonstrated. More interestingly, it was discovered that the microgel particles would be desorbed before having a significant deformation in Langmuir trough compression. Finally, the emulsion stability of the microgel stabilized Pickering emulsion was characterized by centrifugation. By comparing the stability of different microgels in different conditions, the correlation between the microgel properties and the corresponding Pickering emulsion stability was found. The emulsion stability and the interfacial behaviors of PNIPAM based microgels can now be better controlled and predicted, which gives great advantages for future applications using soft colloids as stabilizers.

Small particle size lipid emulsions, satiety and energy intake in lean men.

PubMed

Chan, Y K; Budgett, S C; MacGibbon, A K; Quek, S Y; Kindleysides, S; Poppitt, S D

2017-02-01

Lipid emulsions have been proposed to suppress hunger and food intake. Whilst there is no consensus on optimal structural properties or mechanism of action, small particle size (small-PS) stable emulsions may have greatest efficacy. Fabuless®, a commercial lipid emulsion reported in some studies to decrease energy intake (EI), is a small-PS, 'hard' fat emulsion comprising highly saturated palm oil base (PS, 82nm). To determine whether small-PS dairy lipid emulsions can enhance satiety, firstly, we investigated 2 'soft' fat dairy emulsions generated using dairy and soy emulsifying agents (PS, 114nm and 121nm) and a non-emulsified dairy control. Secondly, we investigated a small-PS palmolein based 'hard' fat emulsion (fractionated palm oil, PS, 104nm) and non-emulsified control. This was a 6 arm, randomized, cross-over study in 18 lean men, with test lipids delivered in a breakfast meal: (i) Fabuless® emulsion (F EM ); (ii) dairy emulsion with dairy emulsifier (DE DE ); (iii) dairy emulsion with soy lecithin emulsifier (DE SE ); (iv) dairy control (DC ON ); (v) palmolein emulsion with dairy emulsifier (PE DE ); (vi) palmolein control (PC ON ). Participants rated postprandial appetite sensations using visual analogue scales (VAS), and ad libitum energy intake (EI) was measured at a lunch meal 3.5h later. Dairy lipid emulsions did not significantly alter satiety ratings or change EI relative to dairy control (DE DE , 4035kJ; DE SE , 3904kJ; DC ON , 3985kJ; P>0.05) nor did palm oil based emulsion relative to non-emulsified control (PE DE, 3902 kJ; PC ON, 3973kJ; P>0.05). There was no evidence that small-PS dairy lipid emulsions or commercial Fabuless altered short-term appetite or food intake in lean adults. Copyright © 2016. Published by Elsevier Inc.

Development of Octyl Methoxy Cinnamates (OMC)/Silicon Dioxide (SiO₂) Nanoparticles by Sol-Gel Emulsion Method.

PubMed

Wu, Pey-Shiuan; Lee, Yi-Ching; Kuo, Yi-Ching; Lin, Chih-Chien

2017-12-07

Although octyl methoxy cinnamates (OMC) is the most used Ultraviolet B (UVB) filter in sunscreen, it has poor light stability in emulsion system. In this study, OMC/SiO₂ nanoparticles were prepared via sol-gel emulsion method. Tetraethoxy silane (TEOS) was used as the silica source to encapsulate OMC. Modification of experimental parameters such as stirring speed of condensation reaction and emulsion condition, pH value of acid-catalyzed, surfactant and different percentage of TEOS and OMC, adding of OMC and surfactant to different phase may affect the particle size, and yield and entrapment efficiency in preparation process of OMC/SiO₂ nanoparticles. Concluding all the parameter, we found that when condensation reaction and emulsion conditions are at 1000 rpm, pH 1.5, Span 80/Tween 20, TEOS/OMC ratios 1:1, OMC and surfactants added in oil phase, resulting in smaller particle sizes 476.5 nm, higher yield 95.8%, and higher entrapment efficiency 61.09%. Fourier transform infrared (FTIR) analysis demonstrated that OMC/SiO₂ nanoparticles were successfully prepared. In vitro release profile supposed that OMC/SiO₂ nanoparticles can delay OMC releasing and had 60.83% decreasing of cumulative amount. Therefore, the OMC/SiO₂ nanoparticles have the potential to develop as new sunscreen materials in the use for cosmetics field in the future.

Combinatorial microfluidic droplet engineering for biomimetic material synthesis

PubMed Central

Bawazer, Lukmaan A.; McNally, Ciara S.; Empson, Christopher J.; Marchant, William J.; Comyn, Tim P.; Niu, Xize; Cho, Soongwon; McPherson, Michael J.; Binks, Bernard P.; deMello, Andrew; Meldrum, Fiona C.

2016-01-01

Although droplet-based systems are used in a wide range of technologies, opportunities for systematically customizing their interface chemistries remain relatively unexplored. This article describes a new microfluidic strategy for rapidly tailoring emulsion droplet compositions and properties. The approach uses a simple platform for screening arrays of droplet-based microfluidic devices and couples this with combinatorial selection of the droplet compositions. Through the application of genetic algorithms over multiple screening rounds, droplets with target properties can be rapidly generated. The potential of this method is demonstrated by creating droplets with enhanced stability, where this is achieved by selecting carrier fluid chemistries that promote titanium dioxide formation at the droplet interfaces. The interface is a mixture of amorphous and crystalline phases, and the resulting composite droplets are biocompatible, supporting in vitro protein expression in their interiors. This general strategy will find widespread application in advancing emulsion properties for use in chemistry, biology, materials, and medicine. PMID:27730209

Preparation of Paraffin@Poly(styrene-co-acrylic acid) Phase Change Nanocapsules via Combined Miniemulsion/Emulsion Polymerization.

PubMed

Zhang, Feng; Liu, Tian-Yu; Hou, Gui-Hua; Guan, Rong-Feng; Zhang, Jun-Hao

2018-06-01

The fast development of solid-liquid phase change materials calls for nanomaterials with large specific surface area for rapid heat transfer and encapsulation of phase change materials to prevent potential leakage. Here we report a combined miniemulsion/emulsion polymerization method to prepare poly(styrene-co-acrylic acid)-encapsulated paraffin (paraffin@P(St-co-AA)) nanocapsules. The method could suppress the shortcomings of common miniemulsion polymerization (such as evaporation of monomer and decomposition of initiator during ultrasonication). The paraffin@P(St-co-AA) nanocapsules are uniform in size and the polymer shell can be controlled by the weight ratio of St to paraffin. The phase change behavior of the nanocapsules is similar to that of pure paraffin. We believe our method can also be utilized to synthesize other core-shell phase change materials.

Determination of haplotypes at structurally complex regions using emulsion haplotype fusion PCR.

PubMed

Tyson, Jess; Armour, John A L

2012-12-11

Genotyping and massively-parallel sequencing projects result in a vast amount of diploid data that is only rarely resolved into its constituent haplotypes. It is nevertheless this phased information that is transmitted from one generation to the next and is most directly associated with biological function and the genetic causes of biological effects. Despite progress made in genome-wide sequencing and phasing algorithms and methods, problems assembling (and reconstructing linear haplotypes in) regions of repetitive DNA and structural variation remain. These dynamic and structurally complex regions are often poorly understood from a sequence point of view. Regions such as these that are highly similar in their sequence tend to be collapsed onto the genome assembly. This is turn means downstream determination of the true sequence haplotype in these regions poses a particular challenge. For structurally complex regions, a more focussed approach to assembling haplotypes may be required. In order to investigate reconstruction of spatial information at structurally complex regions, we have used an emulsion haplotype fusion PCR approach to reproducibly link sequences of up to 1kb in length to allow phasing of multiple variants from neighbouring loci, using allele-specific PCR and sequencing to detect the phase. By using emulsion systems linking flanking regions to amplicons within the CNV, this led to the reconstruction of a 59kb haplotype across the DEFA1A3 CNV in HapMap individuals. This study has demonstrated a novel use for emulsion haplotype fusion PCR in addressing the issue of reconstructing structural haplotypes at multiallelic copy variable regions, using the DEFA1A3 locus as an example.

Engineering of acidic O/W emulsions with pectin.

PubMed

Alba, K; Sagis, L M C; Kontogiorgos, V

2016-09-01

Pectins with distinct molecular design were isolated by aqueous extraction at pH 2.0 or 6.0 and were examined in terms of their formation and stabilisation capacity of model n-alkane-in-water emulsions at acidic pH (pH 2.0). The properties and stability of the resulting emulsions were examined by means of droplet size distribution analysis, Lifshitz-Slyozov-Wagner modelling, bulk rheology, interfacial composition analysis, large-amplitude oscillatory surface dilatational rheology, electrokinetic analysis and fluorescence microscopy. Both pectin preparations were able to emulsify alkanes in water but exhibited distinct ageing characteristics. Emulsions prepared using pectin isolated at pH 6.0 were remarkably stable with respect to droplet growth after thirty days of ageing, while those prepared with pectin isolated at pH 2.0 destabilised rapidly. Examination of chemical composition of interfacial layers indicated multi-layered adsorption of pectins at the oil-water interface. The higher long-term stability of emulsions prepared with pectin isolated at high pH is attributed to mechanically stronger interfaces, the highly branched nature and the low hydrodynamic volume of the chains that result in effective steric stabilisation whereas acetyl and methyl contents do not contribute to the long-term stability. The present work shows that it is possible by tailoring the fine structure of pectin to engineer emulsions that operate in acidic environments. Copyright © 2016 Elsevier B.V. All rights reserved.

Particles at fluid-fluid interfaces: A new Navier-Stokes-Cahn-Hilliard surface- phase-field-crystal model.

PubMed

Aland, Sebastian; Lowengrub, John; Voigt, Axel

2012-10-01

Colloid particles that are partially wetted by two immiscible fluids can become confined to fluid-fluid interfaces. At sufficiently high volume fractions, the colloids may jam and the interface may crystallize. The fluids together with the interfacial colloids form an emulsion with interesting material properties and offer an important route to new soft materials. A promising approach to simulate these emulsions was presented in Aland et al. [Phys. Fluids 23, 062103 (2011)], where a Navier-Stokes-Cahn-Hilliard model for the macroscopic two-phase fluid system was combined with a surface phase-field-crystal model for the microscopic colloidal particles along the interface. Unfortunately this model leads to spurious velocities which require very fine spatial and temporal resolutions to accurately and stably simulate. In this paper we develop an improved Navier-Stokes-Cahn-Hilliard-surface phase-field-crystal model based on the principles of mass conservation and thermodynamic consistency. To validate our approach, we derive a sharp interface model and show agreement with the improved diffuse interface model. Using simple flow configurations, we show that the new model has much better properties and does not lead to spurious velocities. Finally, we demonstrate the solid-like behavior of the crystallized interface by simulating the fall of a solid ball through a colloid-laden multiphase fluid.

Venlafaxine intoxication with development of takotsubo cardiomyopathy: successful use of extracorporeal life support, intravenous lipid emulsion and CytoSorb®.

PubMed

Schroeder, Ines; Zoller, Michael; Angstwurm, Matthias; Kur, Felix; Frey, Lorenz

2017-07-05

We describe a young patient who ingested 18 g (240 times the daily therapeutic dose) of venlafaxine in a suicide attempt. She developed severe cardiomyopathy in a takotsubo distribution causing cardiogenic shock and multi-organ dysfunction syndrome (MODS). She was successfully treated with intravenous lipid emulsion (ILE), extracorporeal life support (ECLS) and CytoSorb®. This is remarkable as, to the best of the authors' knowledge, this is the highest amount of venlafaxine intake seen in the literature with a nonfatal outcome.

Incorporation of β-glucans in meat emulsions through an optimal mixture modeling systems.

PubMed

Vasquez Mejia, Sandra M; de Francisco, Alicia; Manique Barreto, Pedro L; Damian, César; Zibetti, Andre Wüst; Mahecha, Hector Suárez; Bohrer, Benjamin M

2018-09-01

The effects of β-glucans (βG) in beef emulsions with carrageenan and starch were evaluated using an optimal mixture modeling system. The best mathematical models to describe the cooking loss, color, and textural profile analysis (TPA) were selected and optimized. The cubic models were better to describe the cooking loss, color, and TPA parameters, with the exception of springiness. Emulsions with greater levels of βG and starch had less cooking loss (<1%), intermediate L* (>54 and <62), and greater hardness, cohesiveness and springiness values. Subsequently, during the optimization phase, the use of carrageenan was eliminated. The optimized emulsion contained 3.13 ± 0.11% βG, which could cover the intake daily of βG recommendations. However, the hardness of the optimized emulsion was greater (60,224 ± 1025 N) than expected. The optimized emulsion had a homogeneous structure and normal thermal behavior by DSC and allowed for the manufacture of products with high amounts of βG and desired functional attributes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Emulsion Inks for 3D Printing of High Porosity Materials.

PubMed

Sears, Nicholas A; Dhavalikar, Prachi S; Cosgriff-Hernandez, Elizabeth M

2016-08-01

Photocurable emulsion inks for use with solid freeform fabrication (SFF) to generate constructs with hierarchical porosity are presented. A high internal phase emulsion (HIPE) templating technique was utilized to prepare water-in-oil emulsions from a hydrophobic photopolymer, surfactant, and water. These HIPEs displayed strong shear thinning behavior that permitted layer-by-layer deposition into complex shapes and adequately high viscosity at low shear for shape retention after extrusion. Each layer was actively polymerized with an ultraviolet cure-on-dispense (CoD) technique and compositions with sufficient viscosity were able to produce tall, complex scaffolds with an internal lattice structure and microscale porosity. Evaluation of the rheological and cure properties indicated that the viscosity and cure rate both played an important role in print fidelity. These 3D printed polyHIPE constructs benefit from the tunable pore structure of emulsion templated material and the designed architecture of 3D printing. As such, these emulsion inks can be used to create ultra high porosity constructs with complex geometries and internal lattice structures not possible with traditional manufacturing techniques. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiple emulsions as soft templates for the synthesis of multifunctional silicone porous particles.

PubMed

Vilanova, Neus; Kolen'ko, Yury V; Solans, Conxita; Rodríguez-Abreu, Carlos

2015-01-01

Multiple emulsion templating is a versatile strategy for the synthesis of porous particles. The present work addresses the synthesis of multifunctional poly(dimethylsiloxane) porous particles using multiple water-in-oil-in-water emulsions as soft templates with an oil phase constituted by a crosslinkable poly(dimethylsiloxane) (PDMS) oil. Herewith, the impact of the viscosity of PDMS oil (i.e., molecular weight) on the properties of both the emulsion templates and the resulting particles was evaluated. The viscosity of PDMS oil has a strong effect on the size and polydispersity of the emulsion templates as well as on the mechanical properties of the derived particles. The elastic modulus can be tuned by mixing PDMS oils of different viscosities to form bimodal crosslinked networks. Iron oxide nanoparticles can be readily incorporated into the emulsion templates to provide additional functionalities to the silicone particles, such as magnetic separation or magnetic hyperthermia. The synthesized composite magnetic particles were found to be useful as recoverable absorbent materials (e.g., for oil spills) by taking advantage of their high buoyancy and high hydrophobicity. Copyright © 2014 Elsevier Inc. All rights reserved.

Biocompatible Stimuli-Responsive W/O/W Multiple Emulsions Prepared by One-Step Mixing with a Single Diblock Copolymer Emulsifier.

PubMed

Protat, Marine; Bodin, Noémie; Gobeaux, Frédéric; Malloggi, Florent; Daillant, Jean; Pantoustier, Nadège; Guenoun, Patrick; Perrin, Patrick

2016-09-22

Multiple water-in-oil-in-water (W/O/W) emulsions are promising materials in designing carriers of hydrophilic molecules or drug delivery systems, provided stability issues are solved and biocompatible chemicals can be used. In this work, we designed a biocompatible amphiphilic copolymer, poly(dimethylsiloxane)-b-poly(2-(dimethylamino)ethyl methacrylate) (PDMS-b-PDMAEMA), that can stabilize emulsions made with various biocompatible oils. The hydrophilic/hydrophobic properties of the copolymer can be adjusted using both pH and ionic strength stimuli. Consequently, the making of O/W (oil in water), W/O (water in oil), and W/O/W emulsions can be achieved by sweeping the pH and ionic strength. Of importance, W/O/W emulsions are formulated over a large pH and ionic strength domain in a one-step emulsification process via transitional phase inversion and are stable for several months. Cryo-TEM and interfacial tension studies show that the formation of these W/O/W emulsions is likely to be correlated to the interfacial film curvature and microemulsion morphology.

Magnetic properties of the Fe{sup II} spin crossover complex in emulsion polymerization of trifluoroethylmethacrylate using poly(vinyl alcohol)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Atsushi, E-mail: suzuki@mat.usp.ac.j; Iguchi, Motoi; Oku, Takeo

2010-04-15

Influence of chemical substitution in the Fe{sup II} spin crossover complex on magnetic properties in emulsion polymerization of trifluoroethylmethacrylate using poly(vinyl alcohol) as a protective colloid was investigated near its high spin/low spin (HS/LS) phase transition. The obvious bi-stability of the HS/LS phase transition was considered by the identification of multiple spin states between the quintet (S=2) states to single state (S=0) across the excited triplet state (S=1). Magnetic parameters of gradual shifts of anisotropy g-tensor supported by the molecular distortion of the spin crossover complex would arise from a Jahn-Teller effect regarding ligand field theory on the basis ofmore » a B3LYP density functional theory using electron spin resonance (ESR) spectrum and X-ray powder diffraction. - Graphical abstract: AFM surface image of the emulsion particles with the spin crossover complex.« less

Synthesis of mesoporous poly(melamine-formaldehyde) particles by inverse emulsion polymerization.

PubMed

Schwarz, Dana; Weber, Jens

2017-07-15

Mesoporous poly(melamine-formaldehyde) (MF) particles with surface areas of up to 200m 2 g -1 were synthesized by an inverse emulsion polymerization using dodecane and Span80® as continuous phase. The finer details of the shape control (using emulsion techniques) and the porosity control (using silica nanoparticles as hard-template) are discussed. The impact of phase-separation processes on the observable porosity of the 20-200µm sized spherical particles is analysed by gas sorption methods and electron microscopy. The high density of amine and triazine functional groups in the porous MF particles make the material a promising adsorber for heavy metal ions and methylene blue. In a preliminary column experiment, the synthesized material exhibited a total capacity of 2.54mmol/g (≙ 812.4mg/g) for the adsorption of methylene blue. Copyright © 2017 Elsevier Inc. All rights reserved.

Enhancement of the antimicrobial properties of bacteriophage-K via stabilization using oil-in-water nano-emulsions.

PubMed

Esteban, Patricia Perez; Alves, Diana R; Enright, Mark C; Bean, Jessica E; Gaudion, Alison; Jenkins, A T A; Young, Amber E R; Arnot, Tom C

2014-01-01

Bacteriophage therapy is a promising new treatment that may help overcome the threat posed by antibiotic-resistant pathogenic bacteria, which are increasingly identified in hospitalized patients. The development of biocompatible and sustainable vehicles for incorporation of viable bacterial viruses into a wound dressing is a promising alternative. This article evaluates the antimicrobial efficacy of Bacteriophage K against Staphylococcus aureus over time, when stabilized and delivered via an oil-in-water nano-emulsion. Nano-emulsions were formulated via thermal phase inversion emulsification, and then bacterial growth was challenged with either native emulsion, or emulsion combined with Bacteriophage K. Bacteriophage infectivity, and the influence of storage time of the preparation, were assessed by turbidity measurements of bacterial samples. Newly prepared Bacteriophage K/nano-emulsion formulations have greater antimicrobial activity than freely suspended bacteriophage. The phage-loaded emulsions caused rapid and complete bacterial death of three different strains of S. aureus. The same effect was observed for preparations that were either stored at room temperature (18-20°C), or chilled at 4°C, for up to 10 days of storage. A response surface design of experiments was used to gain insight on the relative effects of the emulsion formulation on bacterial growth and phage lytic activity. More diluted emulsions had a less significant effect on bacterial growth, and diluted bacteriophage-emulsion preparations yielded greater antibacterial activity. The enhancement of bacteriophage activity when delivered via nano-emulsions is yet to be reported. This prompts further investigation into the use of these formulations for the development of novel anti-microbial wound management strategies. © 2014 American Institute of Chemical Engineers.

Microemulsion utility in pharmaceuticals: Implications for multi-drug delivery.

PubMed

Callender, Shannon P; Mathews, Jessica A; Kobernyk, Katherine; Wettig, Shawn D

2017-06-30

Emulsion technology has been utilized extensively in the pharmaceutical industry. This article presents a comprehensive review of the literature on an important subcategory of emulsions, microemulsions. Microemulsions are optically transparent, thermodynamically stable colloidal systems, 10-100nm diameter, that form spontaneously upon mixing of oil, water and emulsifier. This review is the first to address advantages and disadvantages, as well as considerations and challenges in multi-drug delivery. For the period 1 January 2011-30 April 2016, 431 publications related to microemulsion drug delivery were identified and screened according to microemulsion, drug classification, and surfactant types. Results indicate the use of microemulsions predominantly in lipophilic drug delivery (79.4%) via oil-in-water microemulsions and non-ionic surfactants (90%) for oral or topical administration. Cancer is the disease state most targeted followed by inflammatory diseases, microbial infections and cardiovascular disease. Key generalizations from this analysis include: 1) microemulsion formulation is largely based on trial-and-error despite over 1200 publications related to microemulsion drug delivery since their discovery in 1943; 2) characterization using methods including interfacial tension, droplet size, electrical conductivity, turbidity and viscosity may provide additional information for greater predictability; 3) microemulsion drug delivery publications arise primarily from China (27%) and India (21%) suggesting additional research opportunities elsewhere. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of resveratrol or ascorbic acid on the stability of α-tocopherol in O/W emulsions stabilized by whey protein isolate: Simultaneous encapsulation of the vitamin and the protective antioxidant.

PubMed

Wang, Lei; Gao, Yahui; Li, Juan; Subirade, Muriel; Song, Yuanda; Liang, Li

2016-04-01

Food proteins have been widely used as carrier materials due to their multiple functional properties. Hydrophobic bioactives are generally dissolved in the oil phase of O/W emulsions. Ligand-binding properties provide the possibility of binding bioactives to the protein membrane of oil droplets. In this study, the influence of whey protein isolate (WPI) concentration and amphiphilic resveratrol or hydrophilic ascorbic acid on the decomposition of α-tocopherol in the oil phase of WPI emulsions is considered. Impact of ascorbic acid, in the continuous phase, on the decomposition depended on the vitamin concentration. Resveratrol partitioned into the oil-water interface and the cis-isomer contributed most of the protective effect of this polyphenol. About 94% of α-tocopherol and 50% of resveratrol were found in the oil droplets stabilized by 0.01% WPI. These results suggest the feasibility of using the emulsifying and ligand-binding properties of WPI to produce carriers for simultaneous encapsulation of bioactives with different physicochemical properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cross-linking proteins by laccase: Effects on the droplet size and rheology of emulsions stabilized by sodium caseinate.

PubMed

Sato, A C K; Perrechil, F A; Costa, A A S; Santana, R C; Cunha, R L

2015-09-01

The aim of this work was to evaluate the influence of laccase and ferulic acid on the characteristics of oil-in-water emulsions stabilized by sodium caseinate at different pH (3, 5 and 7). Emulsions were prepared by high pressure homogenization of soybean oil with sodium caseinate solution containing varied concentrations of laccase (0, 1 and 5mg/mL) and ferulic acid (5 and 10mM). Laccase treatment and pH exerted a strong influence on the properties with a consequent effect on stability, structure and rheology of emulsions stabilized by Na-caseinate. At pH7, O/W emulsions were kinetically stable due to the negative protein charge which enabled electrostatic repulsion between oil droplets resulting in an emulsion with small droplet size, low viscosity, pseudoplasticity and viscoelastic properties. The laccase treatment led to emulsions showing shear-thinning behavior as a result of a more structured system. O/W emulsions at pH5 and 3 showed phase separation due to the proximity to protein pI, but the laccase treatment improved their stability of emulsions especially at pH3. At pH3, the addition of ferulic acid and laccase produced emulsions with larger droplet size but with narrower droplet size distribution, increased viscosity, pseudoplasticity and viscoelastic properties (gel-like behavior). Comparing laccase treatments, the combined addition of laccase and ferulic acid generally produced emulsions with lower stability (pH5), larger droplet size (pH3, 5 and 7) and higher pseudoplasticity (pH5 and 7) than emulsion with only ferulic acid. The results suggested that the cross-linking of proteins by laccase and ferulic acid improved protein emulsifying properties by changing functional mechanisms of the protein on emulsion structure and rheology, showing that sodium caseinate can be successfully used in acid products when treated with laccase. Copyright © 2015 Elsevier Ltd. All rights reserved.

Functional liquid structures by emulsification of graphene and other two-dimensional nanomaterials.

PubMed

Large, Matthew J; Ogilvie, Sean P; Meloni, Manuela; Amorim Graf, Aline; Fratta, Giuseppe; Salvage, Jonathan; King, Alice A K; Dalton, Alan B

2018-01-25

Pickering emulsions stabilised with nanomaterials provide routes to a range of functional macroscopic assemblies. We demonstrate the formation and properties of water-in-oil emulsions prepared through liquid-phase exfoliation of graphene. Due to the functional nature of the stabiliser, the emulsions exhibit conductivity due to inter-particle tunnelling. We demonstrate a strain sensing application with a large gauge factor of ∼40; the highest reported in a liquid. Our methodology can be applied to other two-dimensional layered materials opening up applications such as energy storage materials, and flexible and printable electronics.

Design and development of aqueous nanoformulations for mosquito control.

PubMed

Montefuscoli, Antonela Rita; Werdin González, Jorge Omar; Palma, Santiago Daniel; Ferrero, Adriana Alicia; Fernández Band, Beatriz

2014-02-01

Microemulsions (ME) are thermodynamically stable isotropic mixtures of oil, water, and surfactant; they would also be attractive as potential insecticidal products due to the high bioviability of the active ingredient, attributable to the small sizes of the oil drops. A laboratory study was conducted in order to compare the biological effect of oil in water (o/w) geranium essential oil (EO) and geraniol MEs and emulsions, against Culex pipiens pipiens mosquito larvae. The systems were based on three nonionic surfactants (Cremophor EL, Brij 35, Tween 80). The MEs showed dispersed phase diameters in the range of 8 to 14 nm and had low PDI values (<0.2). The MEs were analyzed by TEM, indicating that they had nearly spherical morphology. The microemulsified systems based on geranium EO and those of geraniol produced a notable increase of the larvicidal activity when compared with the respectably emulsions, concluding that the biological effect is related with the diameter of the dispersed phase. The smallest drops achieved the highest larvicidal activity, being the aqueous nanoformulations based on geraniol most effective than those of geranium EO. However, geranium microemulsions are preferred due to their residual toxicological profiles. The results indicate that these novel systems could be used in integrated pest management program for the C. pipiens pipiens.

Demixing of aqueous polymer two-phase systems in low gravity

NASA Technical Reports Server (NTRS)

Bamberger, S.; Harris, J. M.; Baird, J. K.; Boyce, J.; Vanalstine, J. M.; Snyder, R. S.; Brooks, D. E.

1986-01-01

When polymers such as dextran and poly(ethylene glycol) are mixed in aqueous solution biphasic systems often form. On Earth the emulsion formed by mixing the phases rapidly demixes because of phase density differences. Biological materials can be purified by selective partitioning between the phases. In the case of cells and other particulates the efficiency of these separations appears to be somewhat compromised by the demixing process. To modify this process and to evaluate the potential of two-phase partitioning in space, experiments on the effects of gravity on phase emulsion demixing were undertaken. The behavior of phase systems with essentially identical phase densities was studied at one-g and during low-g parabolic aircraft maneuvers. The results indicate the demixing can occur rather rapidly in space, although more slowly than on Earth. The demixing process was examined from a theoretical standpoint by applying the theory of Ostwald ripening. This theory predicts demizing rates many orders of magnitude lower than observed. Other possible demixing mechanisms are considered.

A single microfluidic chip with dual surface properties for protein drug delivery.

PubMed

Bokharaei, Mehrdad; Saatchi, Katayoun; Häfeli, Urs O

2017-04-15

Principles of double emulsion generation were incorporated in a glass microfluidic chip fabricated with two different surface properties in order to produce protein loaded polymer microspheres. The microspheres were produced by integrating two microfluidic flow focusing systems and a multi-step droplet splitting and mixing system into one chip. The chip consists of a hydrophobic and a hydrophilic section with two different heights, 12μm and 45μm, respectively. As a result, the protein is homogenously distributed throughout the polymer microsphere matrix, not just in its center (which has been studied before). In our work, the inner phase was bovine serum albumin (BSA) in phosphate buffered saline, the disperse phase was poly (lactic acid) in chloroform and the continuous phase was an aqueous solution of poly(vinyl alcohol). After solvent removal, BSA loaded microspheres with an encapsulation efficiency of up to 96% were obtained. Our results show the feasibility of producing microspheres loaded with a hydrophilic drug in a microfluidic system that integrates different microfluidic units into one chip. Copyright © 2017 Elsevier B.V. All rights reserved.

Emulsification Of Eutectic Salt Mixtures In Fluid Vehicles

NASA Astrophysics Data System (ADS)

Vanderhoff, J. W.; El-Aasser, M. S.; Hawkins, T. W.

1988-05-01

High-internal-phase-volume emulsions of 75 volt 3/18/79 potassium iodide/sodium iodide/ urea model eutectic salt mixture in 83.5/16.5 Sartomer R-45HT hydroxy-terminated polybutadi-ene/Nujol mineral oil binder mixture were prepared at 60°C using water-in-oil emulsifiers and cured with isophorone diisocyanate or Desmodur N-100. The Nujol mineral oil enhanced the emulsification with a negligible reduction in the tensile properties of the cured elastomer. The average emulsion droplet sizes were ca. 200 nm initially, but increased slowly during curing to 500-1000 nm. The coalescence of the emulsion droplets followed the second-order dependence predicted by the von Smoluchowski diffusion-controlled flocculation; the rate constants were 1.05x10-18 and 9.58x10-18 cc/droplet-sec for dirnethyldioctadecylammonium bromide and Span 85 sorbitan trioleate, respectively. The isophorone diisocyanate reacted with emulsifiers containing primary hydroxyl or amine groups, to give unstable emulsions or no emulsions at all. Dimethyldioctadecylammonium bromide with no primary hydroxyl or amine groups, however, did not react with isocyanates and gave stable emulsions. The reaction of the R-45HT hydroxy-terminated polybutadiene with isophorone diisocyanate followed the expec-ted second-order kinetics with a rate constant of 3.42x10-4 liters/mole-sec at 60°C. The tensile properties of the cured elastomers and emulsions generally increased with increasing NCO/OH ratio up to 1.6/1.0. With increasing volume fraction of dispersed phase, the maximum stress (tensile strength) decreased, the maximum strain (percent elongation) increased, and the initial modulus (tensile modulus) decreased, in contrast to the behavior of conventional filled polymer systems; however, the maximum stresses were in accord with theoretical values for a filled polymer in which the filler particles bear no load, the initial moduli were in accord with the predictions of an isostrain model, and the maximum strain increased with in-creasing volume fraction of dispersed phase; these unusual variations, which were attributed to the liquid nature of the emulsion droplets, were used to estimate the elastomer proper-ties required to give the desired properties: 60-100 psi maximum stress, 80-150% maximum strain, and 500-2000 psi initial modulus for an 88/12 eutectic salt/crosslinked polybutadi-ene composite containing 20% aluminum particles. The addition of 20% aluminum particles gave a modest improvement in tensile properties, and the addition of 2.5% or 3.5% submicroscopic carbon black particles gave a greater improvement; however, the tensile properties were still slightly short of the desired properties.

Structural micro-porous carbon anode for rechargeable lithium-ion batteries

DOEpatents

Delnick, F.M.; Even, W.R. Jr.; Sylwester, A.P.; Wang, J.C.F.; Zifer, T.

1995-06-20

A secondary battery having a rechargeable lithium-containing anode, a cathode and a separator positioned between the cathode and anode with an organic electrolyte solution absorbed therein is provided. The anode comprises three-dimensional microporous carbon structures synthesized from polymeric high internal phase emulsions or materials derived from this emulsion source, i.e., granules, powders, etc. 6 figs.

Bioaccessibility and Cellular Uptake of β-Carotene Encapsulated in Model O/W Emulsions: Influence of Initial Droplet Size and Emulsifiers

PubMed Central

Kelly, Alan L.

2017-01-01

The effects of the initial emulsion structure (droplet size and emulsifier) on the properties of β-carotene-loaded emulsions and the bioavailability of β-carotene after passing through simulated gastrointestinal tract (GIT) digestion were investigated. Exposure to GIT significantly changed the droplet size, surface charge and composition of all emulsions, and these changes were dependent on their initial droplet size and the emulsifiers used. Whey protein isolate (WPI)-stabilized emulsion showed the highest β-carotene bioaccessibility, while sodium caseinate (SCN)-stabilized emulsion showed the highest cellular uptake of β-carotene. The bioavailability of emulsion-encapsulated β-carotene based on the results of bioaccessibility and cellular uptake showed the same order with the results of cellular uptake being SCN > TW80 > WPI. An inconsistency between the results of bioaccessibility and bioavailability was observed, indicating that the cellular uptake assay is necessary for a reliable evaluation of the bioavailability of emulsion-encapsulated compounds. The findings in this study contribute to a better understanding of the correlation between emulsion structure and the digestive fate of emulsion-encapsulated nutrients, which make it possible to achieve controlled or potential targeted delivery of nutrients by designing the structure of emulsion-based carriers. PMID:28930195

How to fabricate robust microfluidic systems for a dollar

NASA Astrophysics Data System (ADS)

Lapierre, Florian; Cameron, Neil R.; Oakeshott, John; Peat, Thomas; Zhu, Yonggang

2013-12-01

Since the past decade, the interest towards microfluidic devices has sensibly grown due to the wide variety of multidisciplinary applications. One branch of the microfluidic domain consists in the synthesis of various types of emulsions requested by cosmetic, food and biotechnological industries In particular, monodisperse water-in-oil microemulsion synthetised in microfluidic devices are quickly becoming the new generation of emulsions for precise bead control and high surface area. These microemulsions are generally aqueous bioreactors in the form of droplets from 500 nm to 10 μm in diameter, enclosed in an oil environment. An increasing demand for bigger emulsions has led us to investigate new techniques for fabricating fluidic devices allowing a better control over the final size of the droplets. An easy, cheap, reproducible and fast technology for generating emulsions in the range of 100s μm with high throughout (up to mL/h) is reported. Simply using pipette tips and tubing, an innovative microfluidic device was fabricated, able to synthetise water-in-oil emulsions within the range 50 - 500 _μm and double emulsions. These new emulsions are currently used for the synthesis of highly porous polymers beads from High Internal Phase Emulsion (HIPE). These beads will find high potential in 3D cell culture due to their high porosity (up to 90%) and pore size (from 5 to 30μm).

A novel headspace gas chromatographic method for in situ monitoring of monomer conversion during polymerization in an emulsion environment.

PubMed

Chai, Xin-Sheng; Zhong, Jin-Feng; Hu, Hui-Chao

2012-05-18

This paper describes a novel multiple-headspace extraction/gas chromatographic (MHE-GC) technique for monitoring monomer conversion during a polymerization reaction in a water-based emulsion environment. The polymerization reaction of methyl methacrylate (MMA) in an aqueous emulsion is used as an example. The reaction was performed in a closed headspace sample vial (as a mini-reactor), with pentane as a tracer. In situ monitoring of the vapor concentration of the tracer, employing a multiple headspace extraction (sampling) scheme, coupled to a GC, makes it possible to quantitatively follow the conversion of MMA during the early stages of polymerization. Data on the integrated amount of the tracer vapor released from the monomer droplet phase during the polymerization is described by a mathematic equation from which the monomer conversion can be calculated. The present method is simple, automated and economical, and provides an efficient tool in the investigation of the reaction kinetics and effects of the reaction conditions on the early stage of polymerization. Copyright © 2012 Elsevier B.V. All rights reserved.

Determination of the charge of relativistic heavy nuclei from emulsion tracks

NASA Technical Reports Server (NTRS)

Morgan, S. H., Jr.; Eby, P. B.

1971-01-01

The number of delta rays with energies between 50 and 150 keV that are produced by heavy nuclei in emulsions is calculated. The Z(2) dependence predicted by the first Born approximation is corrected by a direct calculation of the Mott exact phase-shift scattering cross section. Comparisons are made with corrections predicted by the second Born approximation. When the phase-shift results are applied to the problem of charge identification, corrections of up to 4 units of charge for 1.457-GeV/nucleon nuclei with charge Z = 75 are found.

Preparation of microemulsions with soybean oil-based surfactants

USDA-ARS?s Scientific Manuscript database

Emulsions are widely applied in food, cosmeceutical and medicinal formulations. Smaller and highly stable droplets of emulsions are important for their application. This research reports that by using soybean oil-based surfactants, the higher stabilized oil-in-water emulsions were obtained via an ul...

Structure- and oil type-based efficacy of emulsion adjuvants.

PubMed

Jansen, Theo; Hofmans, Marij P M; Theelen, Marc J G; Manders, Frans; Schijns, Virgil E J C

2006-06-29

Oil-based emulsions are well-known immunopotentiators for inactivated, "killed" vaccines. We addressed the relationship between emulsion structure and levels of in vivo antibody formation to inactivated New Castle Disease virus (NDV) and Infectious Bronchitis virus (IBV) as antigens in 3-week-old chickens. The use of a polymeric emulsifier allowed for direct comparison of three types of emulsions, water-in-oil (W/O), oil-in-water (O/W) and W/O-in-water (W/O/W), while maintaining an identical content of components for each vehicle. They were prepared with either non-metabolizable, mineral oil or metabolizable, Miglyol 840. In addition, we assessed the inherent release capacity of each emulsion variant in vitro. Remarkably, we noted that W/O-type emulsions induced the best immune responses, while they released no antigen during 3 weeks. In general, mineral oil vaccines showed superior efficacy compared to Miglyol 840-based vaccines.

Effect of cationic monomer content on polyacrylamide copolymers by frit-inlet asymmetrical flow field-flow fractionation/multi-angle light scattering.

PubMed

Lee, Hyejin; Kim, Jin Yong; Choi, Woonjin; Moon, Myeong Hee

2017-06-23

In this study, ultrahigh-molecular-weight (MW) (>10 7 Da) cationic polyacrylamides (C-PAMs), which are water-soluble polymers used in waste water treatment, were characterized using frit-inlet asymmetrical flow field-flow fractionation coupled with multi-angle light scattering and differential refractive detection. C-PAMs copolymerized with acryloxyethyltrimethyl ammonium chloride (DAC) were prepared by varying the feed amount of cationic monomer, polymerization method (solution vs. emulsion), and degree of branching. The MW of the copolymers prepared using emulsion polymerization (10 7 -10 9 Da) was generally larger than that of copolymers prepared using solution polymerization (4×10 7 -10 8 Da). When the amount of cationic monomer was increased from 10 to 55mol% in solution polymerization, hydrophobic contraction of the core induced formation of more compact C-PAMs. The copolymers prepared using emulsion polymerization formed highly aggregated or supercoil structures owing to increased intermolecular hydrophobic interaction when less cationic monomer was used. However, the MW decreased with increased cationic group content. In addition, C-PAMs larger than ∼10 8 Da prepared using the emulsion method were separated by steric/hyperlayer elution mode while those in the 10 7 -10 8 Da range were analyzed in either normal or steric/hyperlayer mode depending on the decay patterns of field programming. Moreover, branched copolymers were found to be resolved with different elution modes under the same field decay pattern depending on the degree of branching: steric/hyperlayer for low-branching and normal for high-branching C-PAMs. Copyright © 2017 Elsevier B.V. All rights reserved.

PLGA nanoparticles from nano-emulsion templating as imaging agents: Versatile technology to obtain nanoparticles loaded with fluorescent dyes.

PubMed

Fornaguera, C; Feiner-Gracia, N; Calderó, G; García-Celma, M J; Solans, C

2016-11-01

The interest in polymeric nanoparticles as imaging systems for biomedical applications has increased notably in the last decades. In this work, PLGA nanoparticles, prepared from nano-emulsion templating, have been used to prepare novel fluorescent imaging agents. Two model fluorescent dyes were chosen and dissolved in the oil phase of the nano-emulsions together with PLGA. Nano-emulsions were prepared by the phase inversion composition (PIC) low-energy method. Fluorescent dye-loaded nanoparticles were obtained by solvent evaporation of nano-emulsion templates. PLGA nanoparticles loaded with the fluorescent dyes showed hydrodynamic radii lower than 40nm; markedly lower than those reported in previous studies. The small nanoparticle size was attributed to the nano-emulsification strategy used. PLGA nanoparticles showed negative surface charge and enough stability to be used for biomedical imaging purposes. Encapsulation efficiencies were higher than 99%, which was also attributed to the nano-emulsification approach as well as to the low solubility of the dyes in the aqueous component. Release kinetics of both fluorescent dyes from the nanoparticle dispersions was pH-independent and sustained. These results indicate that the dyes could remain encapsulated enough time to reach any organ and that the decrease of the pH produced during cell internalization by the endocytic route would not affect their release. Therefore, it can be assumed that these nanoparticles are appropriate as systemic imaging agents. In addition, in vitro toxicity tests showed that nanoparticles are non-cytotoxic. Consequently, it can be concluded that the preparation of PLGA nanoparticles from nano-emulsion templating represents a very versatile technology that enables obtaining biocompatible, biodegradable and safe imaging agents suitable for biomedical purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

Aqueous enzymatic extraction of Moringa oleifera oil.

PubMed

Mat Yusoff, Masni; Gordon, Michael H; Ezeh, Onyinye; Niranjan, Keshavan

2016-11-15

This paper reports on the extraction of Moringa oleifera (MO) oil by using aqueous enzymatic extraction (AEE) method. The effect of different process parameters on the oil recovery was discovered by using statistical optimization, besides the effect of selected parameters on the formation of its oil-in-water cream emulsions. Within the pre-determined ranges, the use of pH 4.5, moisture/kernel ratio of 8:1 (w/w), and 300stroke/min shaking speed at 40°C for 1h incubation time resulted in highest oil recovery of approximately 70% (goil/g solvent-extracted oil). These optimized parameters also result in a very thin emulsion layer, indicating minute amount of emulsion formed. Zero oil recovery with thick emulsion were observed when the used aqueous phase was re-utilized for another AEE process. The findings suggest that the critical selection of AEE parameters is key to high oil recovery with minimum emulsion formation thereby lowering the load on the de-emulsification step. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bespoke contrast-matched diblock copolymer nanoparticles enable the rational design of highly transparent Pickering double emulsions

NASA Astrophysics Data System (ADS)

Rymaruk, Matthew J.; Thompson, Kate L.; Derry, Matthew J.; Warren, Nicholas J.; Ratcliffe, Liam P. D.; Williams, Clive N.; Brown, Steven L.; Armes, Steven P.

2016-07-01

We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56-poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA-PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20-100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56-poly(benzyl methacrylate)300 [PGMA56-PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56-PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39-poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39-PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to substantial spectral attenuation.We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56-poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA-PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20-100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56-poly(benzyl methacrylate)300 [PGMA56-PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56-PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39-poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39-PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to substantial spectral attenuation. Electronic supplementary information (ESI) available: GPC chromatograms, additional transmission electron micrographs, digital photographs, visible absorption spectra and laser diffraction data, further optical and fluorescence micrographs. See DOI: 10.1039/c6nr03856e

Oil-in-water lipid emulsions: implications for parenteral and ocular delivering systems.

PubMed

Tamilvanan, S

2004-11-01

Lipid emulsions (LEs) are heterogenous dispersions of two immiscible liquids (oil-in-water or water-in-oil) and they are subjected to various instability processes like aggregation, flocculation, coalescence and hence eventual phase separation according to the second law of thermodynamics. However, the physical stability of the LE can substantially be improved with help of suitable emulsifiers that are capable of forming a mono- or multi-layer coating film around the dispersed liquid droplets in such a way to reduce interfacial tension or to increase droplet-droplet repulsion. Depending on the concentrations of these three components (oil-water-emulsifier) and the efficiency of the emulsification equipments used to reduce droplet size, the final LE may be in the form of oil-in-water (o/w), water-in-oil (w/o), micron, submicron and double or multiple emulsions (o/w/o and w/o/w). The o/w type LEs (LE) are colloidal drug carriers, which have various therapeutic applications. As an intravenous delivery system it incorporates lipophilic water non-soluble drugs, stabilize drugs that tend to undergo hydrolysis and reduce side effects of various potent drugs. When the LE is used as an ocular delivery systems they increase local bioavailability, sustain the pharmacological effect of drugs and decrease systemic side effects of the drugs. Thus, the rationale of using LE as an integral part of effective treatment is clear. Following administration of LE through these routes, the biofate of LE associated bioactive molecules are somehow related to the vehicles disposition kinetics inside blood or eyeball. However, the LE is not devoid from undergoing various bio-process while exerting their efficacious actions. The purpose of this review is therefore to give an implication of LE for parenteral and ocular delivering systems.

An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruan, Guihua, E-mail: guihuaruan@hotmail.com; Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004; Wu, Zhenwei

A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N{sub α}-benzoyl-L-arginine ethyl ester to N{sub α}-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast andmore » easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.« less

The effect of butter grains on physical properties of butter-like emulsions.

PubMed

Rønholt, Stine; Buldo, Patrizia; Mortensen, Kell; Andersen, Ulf; Knudsen, Jes C; Wiking, Lars

2014-01-01

Milk fat exists as globules in its natural state in milk. The potential of using globular fat to modulate the rheological properties and crystallization behavior in butter-like emulsions was studied in the present work. We conducted a comparative study of butter-like emulsions, with a fat phase consisting of 0, 10, 25, 50, or 100% anhydrous milk fat (AMF), the remaining fat being butter grains, and all samples containing 20% water, to obtain systematic variation in the ratio of globular fat. All emulsions were studied over 4wk of storage at 5°C. By combining small and large deformation rheology, we conducted a detailed characterization of the rheological behavior of butter-like emulsions. We applied differential scanning calorimetry to monitor thermal behavior, confocal laser scanning microscopy for microstructural analysis, and low-field pulsed nuclear magnetic resonance spectrometry to measure solid fat content. By combining these techniques, we determined that increasing the fraction of globular fat (by mixing with butter grains) decreases the hardness of butter-like emulsions up to an order of magnitude at d 1. However, no difference was observed in thermal behavior as a function of butter grain content, as all emulsions containing butter grains revealed 2 endothermal peaks corresponding to the high (32.7°C ± 0.6) and medium (14.6°C ± 0.1) melting fractions of fatty acids. In terms of microstructure, decreasing the amount of butter grains in the emulsions resulted in formation of a denser fat crystal network, corresponding to increased hardness. Moreover, microstructural analysis revealed that the presence of butter grains resulted in faster formation of a continuous fat crystal network compared with the 100% AMF sample, which was dominated by crystal clusters surrounded by liquid oil. During storage, hardness remained stable and no changes in thermal behavior were observed, despite an increase in solid fat content of up to 5%. After 28d of storage, we observed no difference in either microstructural or rheological properties, indicating that formation of primary bonds occurs primarily within the first day of storage. The rheological behavior of butter-like emulsions is not determined solely by hardness, but also by stiffness related to secondary bonds within the fat crystal network. The complex rheological behavior of milk fat-based emulsions is better characterized using multiple parameters. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Cold-in-place recycling in New York State.

DOT National Transportation Integrated Search

2010-07-01

Cold in-place recycling (CIPR) is a continuous multi-step process in which the existing asphalt pavement is : recycled using specialized equipment that cold mills the asphaltic pavement and blends asphalt emulsion and : aggregate (if necessary) with ...

Hydrophilic Modification of Multi-Walled Carbon Nanotube for Building Photonic Crystals with Enhanced Color Visibility and Mechanical Strength.

PubMed

Li, Feihu; Tang, Bingtao; Xiu, Jinghai; Zhang, Shufen

2016-04-28

Low color visibility and poor mechanical strength of polystyrene (PS) photonic crystal films have been the main shortcomings for the potential applications in paints or displays. This paper presents a simple method to fabricate PS/MWCNTs (multi-walled carbon nanotubes) composite photonic crystal films with enhanced color visibility and mechanical strength. First, MWCNTs was modified through radical addition reaction by aniline 2,5-double sulfonic acid diazonium salt to generate hydrophilic surface and good water dispersity. Then the MWCNTs dispersion was blended with PS emulsion to form homogeneous PS/MWCNTs emulsion mixtures and fabricate composite films through thermal-assisted method. The obtained films exhibit high color visibility under natural light and improved mechanical strength owing to the light-adsorption property and crosslinking effect of MWCNTs. The utilization of MWCNTs in improving the properties of photonic crystals is significant for various applications, such as in paints and displays.

Impact of formulation and particle size on stability and immunogenicity of oil-in-water emulsion adjuvants

PubMed Central

Iyer, Vidyashankara; Cayatte, Corinne; Guzman, Bernardo; Schneider-Ohrum, Kirsten; Matuszak, Ryan; Snell, Angie; Rajani, Gaurav Manohar; McCarthy, Michael P; Muralidhara, Bilikallahalli

2015-01-01

Oil-in-water emulsions have gained consideration as vaccine adjuvants in recent years due to their ability to elicit a differentiated immunogenic response compared to traditional aluminum salt adjuvants. Squalene, a cholesterol precursor, is a natural product with immunostimulatory properties, making it an ideal candidate for such oil-in-water emulsions. Particle size is a key parameter of these emulsions and its relationship to stability and adjuvanticity has not been extensively studied. This study evaluates the effect of particle size on the stability and immunogenicity of squalene emulsions. We investigated the effect of formulation parameters such as surfactant concentration on particle size, resulting in particles with average diameter of 80 nm, 100 nm, 150 nm, 200 nm, or 250 nm. Emulsions were exposed to shear and temperature stresses, and stability parameters such as pH, osmolarity, size, and in-depth visual appearance were monitored over time. In addition, adjuvanticity of different particle size was assessed in a mouse model using Respiratory Syncytial Virus Fusion protein (RSV-F) as a model antigen. Temperature dependent phase separation appeared to be the most common route of degradation occurring in the higher particle sizes emulsions. The emulsions below 150 nm size maintained stability at either 5°C or 25°C, and the 80 nm diameter ones showed no measurable changes in size even after one month at 40°C. In vivo studies using the emulsions as an adjuvant with RSV F antigen revealed that superior immunogenicity could be achieved with the 80 nm particle size emulsion. PMID:26090563

Emulsion-Based RIR-MAPLE Deposition of Conjugated Polymers: Primary Solvent Effect and Its Implications on Organic Solar Cell Performance.

PubMed

Ge, Wangyao; Li, Nan K; McCormick, Ryan D; Lichtenberg, Eli; Yingling, Yaroslava G; Stiff-Roberts, Adrienne D

2016-08-03

Emulsion-based, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been demonstrated as an alternative technique to deposit conjugated polymer films for photovoltaic applications; yet, a fundamental understanding of how the emulsion target characteristics translate into film properties and solar cell performance is unclear. Such understanding is crucial to enable the rational improvement of organic solar cell (OSC) efficiency and to realize the expected advantages of emulsion-based RIR-MAPLE for OSC fabrication. In this paper, the effect of the primary solvent used in the emulsion target is studied, both experimentally and theoretically, and it is found to determine the conjugated polymer cluster size in the emulsion as well as surface roughness and internal morphology of resulting polymer films. By using a primary solvent with low solubility-in-water and low vapor pressure, the surface roughness of deposited P3HT and PCPDTBT polymer films was reduced to 10 nm, and the efficiency of P3HT:PC61BM OSCs was increased to 3.2% (∼100 times higher compared to the first MAPLE OSC demonstration [ Caricato , A. P. ; Appl. Phys. Lett. 2012 , 100 , 073306 ]). This work unveils the mechanism of polymer film formation using emulsion-based RIR-MAPLE and provides insight and direction to determine the best ways to take advantage of the emulsion target approach to control film properties for different applications.

Preparation of hydroxyapatite/poly(lactic acid) hybrid microparticles for local drug delivery

NASA Astrophysics Data System (ADS)

Loca, D.; Locs, J.; Berzina-Cimdina, L.

2013-12-01

Calcium phosphate (CaP) bioceramic is well known as bioactive and biocompatible material in bone tissue regeneration applications. Apatitic CaP, especially nano sized hydroxyapatite (NHAp), is more similar to the natural apatite presented in the bone tissue than CaP bioceramics. In the current research NHAp was modified using biodegradable polymer - poly(lactic acid) (PLA) to develop composites providing bone regeneration and local drug delivery. NHAp/PLA microcapsules were prepared using solid-in-water-in-oil-in-water (s/w1/o/w2) encapsulation technology. The impact of primary and secondary emulsion stability on the emulsion droplet and microparticle properties was evaluated. The stability of final emulsion can be increased by varying the process parameters. Stable s/w1/o/w2 emulsion using 3ml of NHAp suspension, not less than 100ml of 4% PVA water solution and 10ml of 10% PLA solution in dichloromethane can be obtained. S/w1/o/w2 microencapuslation method can be effectively used for the preparation of multi-domain microcapsules achieving high NHAp encapsulation efficacy (93%).

In-Situ Swelling For Holographic Color Control

NASA Astrophysics Data System (ADS)

Walker Parker, Julie L.; Benton, Stephen A.

1989-05-01

Deliberate variations of the emulsion thickness between holographic exposures and reconstruction produce a range of output wavelengths from a fixed exposure wavelength, a technique known as "pseudo-color" multi-color reflection holography. Usual methods require the removal of the film or plate from the holographic setup between exposures for imbibition of a swelling agent, followed by drying and replacement, so that a retention of the swelling agent forces a physical increase in the thickness of the emulsion. The density (and hence the thickness) of the gelatin binder can also be varied by changing its electrolytic environment. By immersing the holographic emulsion in a suitable solution, allowing it to come to a new equilibrium thickness, and exposing with a long-wavelength laser, shorter wavelength reconstructions can be obtained without removing the film or plate from the setup. Accurate changes of solution can make a precise sequence of swellings possible, producing multiple reconstruction colors from a set of constant-wavelength recordings. Here we describe pre-treatments of the emulsion that make rapid and stable equilibria possible, and swelling bath sequences that produce color primaries suitable for full-color computer-graphic holographic imagery.

Polydispersed O/W emulsions in porous media: segregation at low-tension conditions.

PubMed

Török, János; Tóth, János; Gesztesi, Gyula

2006-03-15

The segregation of polydispersed oil was studied in theoretical models, sand packs, and plugs from consolidated cores at low tension and atmospheric conditions. The height of the oil belt formed at the top of the porous column and its change in time were measured. The analysis of the segregation curves indicates the subsequent appearance and rise of three pseudo-phases. The primary phase, which contains the dominant fraction of oil in the system, rises with a relatively high steady state velocity. Unsteady state and decreasing velocity characterize the transitional secondary phase which is a lean emulsion left behind. The ternary phase, which follows it with a semi-steady state low velocity, is a lean emulsion of the smallest oil blobs present in low concentration. The process terminates at the segregation of the mobile oil particles in the subsequent phases where a small fraction of the total oil content remains in the porous bed, mainly from the last stage of segregation due to the entrapment in suitable microstructures. According to the postulated mechanism, the decreasing probability of the repeated coalescence in pore bodies and dispersion at the connecting pore throats are responsible for the development of the mobile phases at the sufficiently low-tension conditions. The structure of the pore network, the size-distribution of the oil droplets, the density of their population, and the length of paths affect the mechanism, properties, and behaviour of the systems.

Fire Resistant Fuel

DTIC Science & Technology

2011-12-15

just two of the major UNCLASSIFIED UNCLASSIFIED vi technical hurdles that the FRF program was unable to clear. The logistical burden associated...Differences between JP-8 and DF-2 fuel are also discussed. The vehicle fuel fires experienced in combat situations occur in two distinct phases. The first...segregated in two groups, micro and macro-emulsions. These groups differ by the size of the suspended water droplets. Most of the emulsions

Synthesis of monodisperse spherical nanometer ZrO{sub 2} (Y{sub 2}O{sub 3}) powders via the coupling route of w/o emulsion with urea homogenous precipitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Ying; Dong, Shijie, E-mail: dongsjsj@163.com; Wang, Huihu

2012-03-15

Graphical abstract: In this paper, the weight loss and reaction evolution of ZrO{sub 2} precursor powders are determined by TG-DTA, and 600 Degree-Sign C is the most reasonable calcination temperature of precursor according to the TG-DTA. At the same time, we study the effect of reaction conditions upon the particle sizes, such as concentration of zirconium nitrate solution, reaction temperature and urea content. TEM micrographs of zirconia powders indicated that ZrO{sub 2} nano-powders prepared via the coupling route of w/o emulsion with homogenous precipitation possess spherical shape and excellent dispersing. Highlights: Black-Right-Pointing-Pointer The monodisperse spherical nanometer ZrO{sub 2} (Y{sub 2}O{submore » 3}) powders have been prepared via the coupling route of w/o emulsion with urea homogenous precipitation. Black-Right-Pointing-Pointer The principle of the coupling route of emulsion with homogenous precipitation has been studied. Black-Right-Pointing-Pointer The concentration of zirconium nitrate, reaction temperature of water bath and the quantity of urea effect regularly on the average particle size of products. -- Abstract: Using xylol as the oil phase, span-80 as the surfactant, and an aqueous solution containing zirconium (3 mol% Y{sub 2}O{sub 3}) and urea as the water phase, tetragonal phase ZrO{sub 2} nano-powders have been prepared via the coupling route of w/o emulsion with urea homogenous precipitation. The effects of the zirconium concentration, the reaction temperature and the urea content on the average size of the products have been examined. The as-prepared ZrO{sub 2} powders and the precursor powders were characterized by TGA-DTA, XRD, TEM and BET. Experimental results indicate that ZrO{sub 2} powders prepared via the coupling route of w/o emulsion with urea homogenous precipitation possess some excellent characteristics, such as well-rounded spherical shape and excellent dispersing.« less

Determination of haplotypes at structurally complex regions using emulsion haplotype fusion PCR

PubMed Central

2012-01-01

Background Genotyping and massively-parallel sequencing projects result in a vast amount of diploid data that is only rarely resolved into its constituent haplotypes. It is nevertheless this phased information that is transmitted from one generation to the next and is most directly associated with biological function and the genetic causes of biological effects. Despite progress made in genome-wide sequencing and phasing algorithms and methods, problems assembling (and reconstructing linear haplotypes in) regions of repetitive DNA and structural variation remain. These dynamic and structurally complex regions are often poorly understood from a sequence point of view. Regions such as these that are highly similar in their sequence tend to be collapsed onto the genome assembly. This is turn means downstream determination of the true sequence haplotype in these regions poses a particular challenge. For structurally complex regions, a more focussed approach to assembling haplotypes may be required. Results In order to investigate reconstruction of spatial information at structurally complex regions, we have used an emulsion haplotype fusion PCR approach to reproducibly link sequences of up to 1kb in length to allow phasing of multiple variants from neighbouring loci, using allele-specific PCR and sequencing to detect the phase. By using emulsion systems linking flanking regions to amplicons within the CNV, this led to the reconstruction of a 59kb haplotype across the DEFA1A3 CNV in HapMap individuals. Conclusion This study has demonstrated a novel use for emulsion haplotype fusion PCR in addressing the issue of reconstructing structural haplotypes at multiallelic copy variable regions, using the DEFA1A3 locus as an example. PMID:23231411

In vitro β-Carotene Bioaccessibility and Lipid Digestion in Emulsions: Influence of Pectin Type and Degree of Methyl-Esterification.

PubMed

Verrijssen, Tina A J; Christiaens, Stefanie; Verkempinck, Sarah H E; Boeve, Jeroen; Grauwet, Tara; Van Loey, Ann M; Salvia-Trujillo, Laura; Hendrickx, Marc E

2016-10-01

Citrus pectin (CP) and sugar beet pectin (SBP) were demethoxylated and fully characterized in terms of pectin properties in order to investigate the influence of the pectin degree of methyl-esterification (DM) and the pectin type on the in vitro β-carotene bioaccessibility and lipid digestion in emulsions. For the CP based emulsions containing β-carotene enriched oil, water and pectin, the β-carotene bioaccessibility, and lipid digestion were higher in the emulsions with pectin with a higher DM (57%; "CP57 emulsion") compared to the emulsions with pectin with a lower DM (30%; "CP30 emulsion") showing that the DM plays an important role. In contrast, in SBP-based emulsions, nor β-carotene bioaccessibility nor lipid digestion were dependent on pectin DM. Probably here, other pectin properties are more important factors. It was observed that β-carotene bioaccessibility and lipid digestion were lower in the CP30 emulsion in comparison with the CP57, SBP32, and SBP58 emulsions. However, the β-carotene bioaccessibility of CP57 emulsion was similar to that of the SBP emulsions, whereas the lipid digestion was not. It seems that pectin type and pectin DM (in case of CP) are determining which components can be incorporated into micelles. Because carotenoids and lipids have different structures and polarities, their incorporation may be different. This knowledge can be used to engineer targeted (digestive) functionalities in food products. If both high β-carotene bioaccessibility and high lipid digestion are targeted, SBP emulsions are the best options. The CP57 emulsion can be chosen if high β-carotene bioaccessibility but lower lipid digestion is desired. © 2016 Institute of Food Technologists®.

Analysis of Multiallelic CNVs by Emulsion Haplotype Fusion PCR.

PubMed

Tyson, Jess; Armour, John A L

2017-01-01

Emulsion-fusion PCR recovers long-range sequence information by combining products in cis from individual genomic DNA molecules. Emulsion droplets act as very numerous small reaction chambers in which different PCR products from a single genomic DNA molecule are condensed into short joint products, to unite sequences in cis from widely separated genomic sites. These products can therefore provide information about the arrangement of sequences and variants at a larger scale than established long-read sequencing methods. The method has been useful in defining the phase of variants in haplotypes, the typing of inversions, and determining the configuration of sequence variants in multiallelic CNVs. In this description we outline the rationale for the application of emulsion-fusion PCR methods to the analysis of multiallelic CNVs, and give practical details for our own implementation of the method in that context.

Bacteria interface pickering emulsions stabilized by self-assembled bacteria-chitosan network.

PubMed

Wongkongkatep, Pravit; Manopwisedjaroen, Khajohnpong; Tiposoth, Perapon; Archakunakorn, Somwit; Pongtharangkul, Thunyarat; Suphantharika, Manop; Honda, Kohsuke; Hamachi, Itaru; Wongkongkatep, Jirarut

2012-04-03

An oil-in-water Pickering emulsion stabilized by biobased material based on a bacteria-chitosan network (BCN) was developed for the first time in this study. The formation of self-assembled BCN was possible due to the electrostatic interaction between negatively charged bacterial cells and polycationic chitosan. The BCN was proven to stabilize the tetradecane/water interface, promoting formation of highly stable oil-in-water emulsion (o/w emulsion). We characterized and visualized the BCN stabilized o/w emulsions by scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM). Due to the sustainability and low environmental impact of chitosan, the BCN-based emulsions open up opportunities for the development of an environmental friendly new interface material as well as the novel type of microreactor utilizing bacterial cells network.

Phase Transitions of Isotropic to Anisotropic Biocompatible Lipid-Based Drug Delivery Systems Overcoming Insoluble Benznidazole Loading.

PubMed

Streck, Letícia; Sarmento, Víctor H V; Machado, Paula R L; Farias, Kleber J S; Fernandes-Pedrosa, Matheus F; da Silva-Júnior, Arnóbio Antônio

2016-06-30

Previous studies reported low benznidazole (BNZ) loading in conventional emulsions due to the weak interaction of the drug with the most common oils used to produce foods or pharmaceuticals. In this study, we focused on how the type of surfactant, surfactant-to-oil ratio w/w (SOR) and oil-to-water ratio w/w (OWR) change the phase behavior of different lipid-based drug delivery systems (LBDDS) produced by emulsion phase inversion. The surfactant mixture composed of soy phosphatidylcholine and sodium oleate (1:7, w/w, hydrophilic lipophilic balance = 16) stabilized medium chain triglyceride in water. Ten formulations with the clear aspect or less turbid dispersions (five with the SOR ranging from 0.5 to 2.5 and five with the OWR from 0.06 to 0.4) were selected from the phase behavior diagram to assess structural features and drug-loading capacity. The rise in the SOR induced the formation of distinct lipid-based drug delivery systems (nanoemulsions and liquid crystal lamellar type) that were identified using rheological measurements and cross-polarized light microscopy images. Clear dispersions of small and narrow droplet-sized liquid-like nanoemulsions, Newtonian flow-type, were produced at SOR from 0.5 to 1.5 and OWR from 0.12 to 0.4, while clear liquid or gel-like liquid crystals were produced at SOR from 1.5 to 2.5. The BNZ loading was improved according to the composition and type of LBDDS produced, suggesting possible drug location among surfactant layers. The cell viability assays proved the biocompatibility for all of the prepared nanoemulsions at SOR less than 1.5 and liquid crystals at SOR less than 2.5, demonstrating their promising features for the oral or parenteral colloidal delivery systems containing benznidazole for Chagas disease treatment.

Phase Transitions of Isotropic to Anisotropic Biocompatible Lipid-Based Drug Delivery Systems Overcoming Insoluble Benznidazole Loading

PubMed Central

Streck, Letícia; Sarmento, Víctor H. V.; Machado, Paula R. L.; Farias, Kleber J. S.; Fernandes-Pedrosa, Matheus F.; da Silva-Júnior, Arnóbio Antônio

2016-01-01

Previous studies reported low benznidazole (BNZ) loading in conventional emulsions due to the weak interaction of the drug with the most common oils used to produce foods or pharmaceuticals. In this study, we focused on how the type of surfactant, surfactant-to-oil ratio w/w (SOR) and oil-to-water ratio w/w (OWR) change the phase behavior of different lipid-based drug delivery systems (LBDDS) produced by emulsion phase inversion. The surfactant mixture composed of soy phosphatidylcholine and sodium oleate (1:7, w/w, hydrophilic lipophilic balance = 16) stabilized medium chain triglyceride in water. Ten formulations with the clear aspect or less turbid dispersions (five with the SOR ranging from 0.5 to 2.5 and five with the OWR from 0.06 to 0.4) were selected from the phase behavior diagram to assess structural features and drug-loading capacity. The rise in the SOR induced the formation of distinct lipid-based drug delivery systems (nanoemulsions and liquid crystal lamellar type) that were identified using rheological measurements and cross-polarized light microscopy images. Clear dispersions of small and narrow droplet-sized liquid-like nanoemulsions, Newtonian flow-type, were produced at SOR from 0.5 to 1.5 and OWR from 0.12 to 0.4, while clear liquid or gel-like liquid crystals were produced at SOR from 1.5 to 2.5. The BNZ loading was improved according to the composition and type of LBDDS produced, suggesting possible drug location among surfactant layers. The cell viability assays proved the biocompatibility for all of the prepared nanoemulsions at SOR less than 1.5 and liquid crystals at SOR less than 2.5, demonstrating their promising features for the oral or parenteral colloidal delivery systems containing benznidazole for Chagas disease treatment. PMID:27376278

Solid colloidal particles inducing coalescence in bitumen-in-water emulsions.

PubMed

Legrand, J; Chamerois, M; Placin, F; Poirier, J E; Bibette, J; Leal-Calderon, F

2005-01-04

Silica particles are dispersed in the continuous phase of bitumen-in-water emulsions. The mixture remains dispersed in quiescent storage conditions. However, rapid destabilization occurs once a shear is applied. Observations under the microscope reveal that the bitumen droplets form a colloidal gel and coalesce upon application of a shear. We follow the kinetic evolution of the emulsions viscosity, eta, at constant shear rate: eta remains initially constant and exhibits a dramatic increase after a finite time, tau. We study the influence of various parameters on the evolution of tau: bitumen droplet size and volume fraction, silica diameter and concentration, shear rate, etc.

Photopolymerization of complex emulsions with irregular shapes fabricated by multiplex coaxial flow focusing

NASA Astrophysics Data System (ADS)

Wu, Qiang; Yang, Chaoyu; Yang, Jianxin; Huang, Fangsheng; Liu, Guangli; Zhu, Zhiqiang; Si, Ting; Xu, Ronald X.

2018-02-01

We fabricate complex emulsions with irregular shapes in the microscale by a simple but effective multiplex coaxial flow focusing process. A multiphase cone-jet structure is steadily formed, and the compound liquid jet eventually breaks up into Janus microdroplets due to the perturbations propagating along the jet interfaces. The microdroplet shapes can be exclusively controlled by interfacial tensions of adjacent phases. Crescent-moon-shaped microparticles and microcapsules with designated structural characteristics are further produced under ultraviolet light of photopolymerization after removing one hemisphere of the Janus microdroplets. These complex emulsions have potential applications in bioscience, food, functional materials, and controlled drug delivery.

Development of neutron measurement in high gamma field using new nuclear emulsion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawarabayashi, J.; Ishihara, K.; Takagi, K.

2011-07-01

To precisely measure the neutron emissions from a spent fuel assembly of a fast breeder reactor, we formed nuclear emulsions based on a non-sensitized Oscillation Project with Emulsion tracking Apparatus (OPERA) film with AgBr grain sizes of 60, 90, and 160 nm. The efficiency for {sup 252}Cf neutron detection of the new emulsion was calculated to be 0.7 x 10{sup -4}, which corresponded to an energy range from 0.3 to 2 MeV and was consistent with a preliminary estimate based on experimental results. The sensitivity of the new emulsion was also experimentally estimated by irradiating with 565 keV and 14more » MeV neutrons. The emulsion with an AgBr grain size of 60 nm had the lowest sensitivity among the above three emulsions but was still sensitive enough to detect protons. Furthermore, the experimental data suggested that there was a threshold linear energy transfer of 15 keV/{mu}m for the new emulsion, below which no silver clusters developed. Further development of nuclear emulsion with an AgBr grain size of a few tens of nanometers will be the next stage of the present study. (authors)« less

Double emulsion formation through hierarchical flow-focusing microchannel

NASA Astrophysics Data System (ADS)

Azarmanesh, Milad; Farhadi, Mousa; Azizian, Pooya

2016-03-01

A microfluidic device is presented for creating double emulsions, controlling their sizes and also manipulating encapsulation processes. As a result of three immiscible liquids' interaction using dripping instability, double emulsions can be produced elegantly. Effects of dimensionless numbers are investigated which are Weber number of the inner phase (Wein), Capillary number of the inner droplet (Cain), and Capillary number of the outer droplet (Caout). They affect the formation process, inner and outer droplet size, and separation frequency. Direct numerical simulation of governing equations was done using volume of fluid method and adaptive mesh refinement technique. Two kinds of double emulsion formation, the two-step and the one-step, were simulated in which the thickness of the sheath of double emulsions can be adjusted. Altering each dimensionless number will change detachment location, outer droplet size and droplet formation period. Moreover, the decussate regime of the double-emulsion/empty-droplet is observed in low Wein. This phenomenon can be obtained by adjusting the Wein in which the maximum size of the sheath is discovered. Also, the results show that Cain has significant influence on the outer droplet size in the two-step process, while Caout affects the sheath in the one-step formation considerably.

Creating nanoscale emulsions using condensation.

PubMed

Guha, Ingrid F; Anand, Sushant; Varanasi, Kripa K

2017-11-08

Nanoscale emulsions are essential components in numerous products, ranging from processed foods to novel drug delivery systems. Existing emulsification methods rely either on the breakup of larger droplets or solvent exchange/inversion. Here we report a simple, scalable method of creating nanoscale water-in-oil emulsions by condensing water vapor onto a subcooled oil-surfactant solution. Our technique enables a bottom-up approach to forming small-scale emulsions. Nanoscale water droplets nucleate at the oil/air interface and spontaneously disperse within the oil, due to the spreading dynamics of oil on water. Oil-soluble surfactants stabilize the resulting emulsions. We find that the oil-surfactant concentration controls the spreading behavior of oil on water, as well as the peak size, polydispersity, and stability of the resulting emulsions. Using condensation, we form emulsions with peak radii around 100 nm and polydispersities around 10%. This emulsion formation technique may open different routes to creating emulsions, colloidal systems, and emulsion-based materials.

Oxidative degradation and non-enzymatic browning due to the interaction between oxidised lipids and primary amine groups in different marine PL emulsions.

PubMed

Lu, F S H; Nielsen, N S; Baron, C P; Jacobsen, C

2012-12-15

Due to the beneficial health effects of marine phospholipids (PL) there is an increasing industrial interest in using them for nutritional applications including emulsified foods. This study was undertaken to investigate both oxidative and hydrolytic stability of marine PL emulsions in relation to the chemical composition of the marine PL used. Moreover, non-enzymatic browning reactions were also investigated. Emulsions were prepared by high pressure homogenizer using different concentrations and sources of marine PL. In some formulations, fish oil was added in order to study the effect of increasing levels of triglycerides in the emulsions. The oxidative and hydrolytic stability of emulsions was investigated through measurement of peroxide value, free fatty acids, and (31)P NMR during storage at 2°C for up to 32 days. The oxidative stability of marine PL emulsions during storage was further investigated through the measurement of secondary volatile compounds by solid-phase microextraction (SPME) and dynamic headspace (DHS) connected to gas chromatography (GC-MS). Non-enzymatic browning reactions were investigated through the measurement of Strecker derived volatiles, colour changes and pyrrole content. The results suggested that the oxidative stability of marine PL emulsions was significantly influenced by the chemical composition and the concentration of marine PL used to prepare them. Emulsions with good oxidative stability could be prepared from marine PL of high purity and high content of PL and antioxidant and low TAG content. Copyright © 2012 Elsevier Ltd. All rights reserved.

Adjuvanted pandemic influenza vaccine: variation of emulsion components affects stability, antigen structure, and vaccine efficacy

PubMed Central

Fox, Christopher B.; Barnes V, Lucien; Evers, Tara; Chesko, James D.; Vedvick, Thomas S.; Coler, Rhea N.; Reed, Steven G.; Baldwin, Susan L.

2012-01-01

Please cite this paper as: Fox et al. (2012) Adjuvanted pandemic influenza vaccine: variation of emulsion components affects stability, antigen structure, and vaccine efficacy. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12031. Abstract Background  Adjuvant formulations are critical components of modern vaccines based on recombinant proteins, which are often poorly immunogenic without additional immune stimulants. Oil‐in‐water emulsions comprise an advanced class of vaccine adjuvants that are components of approved seasonal and pandemic influenza vaccines. However, few reports have been published that systematically evaluate the in vitro stability and in vivo adjuvant effects of different emulsion components. Objectives  To evaluate distinct classes of surfactants, oils, and excipients, for their effects on emulsion particle size stability, antigen structural interactions, and in vivo activity when formulated with a recombinant H5N1 antigen. Methods  Emulsions were manufactured by high pressure homogenization and characterized alone or in the presence of vaccine antigen by dynamic light scattering, zeta potential, viscosity, pH, hemolytic activity, electron microscopy, fluorescence spectroscopy, and SDS‐PAGE. In vivo vaccine activity in the murine model was characterized by measuring antibody titers, antibody‐secreting plasma cells, hemagglutination inhibition titers, and cytokine production. Results  We demonstrate that surfactant class and presence of additional excipients are not critical for biological activity, whereas oil structure is crucial. Moreover, we report that simplified two‐component emulsions appear more stable by particle size than more complex formulations.Finally, differences in antigen structural interactions with the various emulsions do not appear to correlate with in vivo activity. Conclusions  Oil‐in‐water emulsions can significantly enhance antibody and cellular immune responses to a pandemic influenza antigen. The dramatic differences in adjuvant activity between squalene‐based emulsion and medium chain triglyceride‐based emulsion are due principally to the biological activity of the oil composition rather than physical interactions of the antigen with the emulsion. PMID:23122325

Compositions, methods, and systems comprising fluorous-soluble polymers

DOEpatents

Swager, Timothy M.; Lim, Jeewoo; Takeda, Yohei

2015-10-13

The present invention generally relates to compositions, methods, and systems comprising polymers that are fluorous-soluble and/or organize at interfaces between a fluorous phase and a non-fluorous phase. In some embodiments, emulsions or films are provided comprising a polymer. The polymers, emulsions, and films can be used in many applications, including for determining, treating, and/or imaging a condition and/or disease in a subject. The polymer may also be incorporated into various optoelectronic device such as photovoltaic cells, organic light-emitting diodes, organic field effect transistors, or the like. In some embodiments, the polymers comprise pi-conjugated backbones, and in some cases, are highly emissive.

Morphological study of polymethyl methacrylate microcapsules filled with self-healing agents

NASA Astrophysics Data System (ADS)

Ahangaran, Fatemeh; Hayaty, Mehran; Navarchian, Amir H.

2017-03-01

Polymethyl methacrylate (PMMA) microcapsules filled with epoxy prepolymer, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, and pentaerythritol tetrakis (3-mercaptopropionate) as healing agents have been prepared separately through internal phase separation method for self-healing purposes. PMMA with two different molecular weights (M bar1 = 36,000 g/mol and M bar2 = 550,000 g/mol) were used with two types of different emulsifiers (ionic and polymeric) to prepare microcapsules. The morphology of healing agent microcapsules was investigated using field emission scanning electron microscopy (FESEM). It was found that PMMA microcapsules separately filled with epoxy and amine had core-shell morphologies with smooth surfaces. The mercaptan/PMMA particles exhibited core-shell and acorn-shape morphologies. The surface morphology of mercaptan microcapsules changed from holed to plain in different emulsion systems. The spreading coefficient (S) of phases in the prepared emulsion systems were calculated from interfacial tension (σ) and contact angle (θ) measurements. The theoretical equilibrium morphology of PMMA microcapsules was predicted according to spreading coefficient values of phases in emulsion systems. It was also found that the surface morphology of PMMA microcapsules depended strongly on the nature of the core, molecular weight of PMMA, type and concentration of emulsifier.

Ultrasonic energy input influence οn the production of sub-micron o/w emulsions containing whey protein and common stabilizers.

PubMed

Kaltsa, O; Michon, C; Yanniotis, S; Mandala, I

2013-05-01

Ultrasonication may be a cost-effective emulsion formation technique, but its impact on emulsion final structure and droplet size needs to be further investigated. Olive oil emulsions (20wt%) were formulated (pH∼7) using whey protein (3wt%), three kinds of hydrocolloids (0.1-0.5wt%) and two different emulsification energy inputs (single- and two-stage, methods A and B, respectively). Formula and energy input effects on emulsion performance are discussed. Emulsions stability was evaluated over a 10-day storage period at 5°C recording the turbidity profiles of the emulsions. Optical micrographs, droplet size and viscosity values were also obtained. A differential scanning calorimetric (DSC) multiple cool-heat cyclic method (40 to -40°C) was performed to examine stability via crystallization phenomena of the dispersed phase. Ultrasonication energy input duplication from 11kJ to 25kJ (method B) resulted in stable emulsions production (reduction of back scattering values, dBS∼1% after 10days of storage) at 0.5wt% concentration of any of the stabilizers used. At lower gum amount samples became unstable due to depletion flocculation phenomena, regardless of emulsification energy input used. High energy input during ultrasonic emulsification also resulted in sub-micron oil-droplets emulsions (D(50)=0.615μm compared to D(50)=1.3μm using method A) with narrower particle size distribution and in viscosity reduction. DSC experiments revealed no presence of bulk oil formation, suggesting stability for XG 0.5wt% emulsions prepared by both methods. Reduced enthalpy values found when method B was applied suggesting structural modifications produced by extensive ultrasonication. Change of ultrasonication conditions results in significant changes of oil droplet size and stability of the produced emulsions. Copyright © 2012 Elsevier B.V. All rights reserved.

High hydrostatic pressure inactivation of Lactobacillus plantarum cells in (O/W)-emulsions is independent from cell surface hydrophobicity and lipid phase parameters

NASA Astrophysics Data System (ADS)

Kafka, T. A.; Reitermayer, D.; Lenz, C. A.; Vogel, R. F.

2017-07-01

Inactivation efficiency of high hydrostatic pressure (HHP) processing of food is strongly affected by food matrix composition. We investigated effects of fat on HHP inactivation of spoilage-associated Lactobacillus (L.) plantarum strains using defined oil-in-water (O/W)-emulsion model systems. Since fat-mediated effects on HHP inactivation could be dependent on interactions between lipid phase and microbial cells, three major factors possibly influencing such interactions were considered, that is, cell surface hydrophobicity, presence and type of surfactants, and oil droplet size. Pressure tolerance varied noticeably among L. plantarum strains and was independent of cell surface hydrophobicity. We showed that HHP inactivation of all strains tended to be more effective in presence of fat. The observation in both, surfactant-stabilized and surfactant-free (O/W)-emulsion, indicates that cell surface hydrophobicity is no intrinsic pressure resistance factor. In contrast to the presence of fat per se, surfactant type and oil droplet size did not affect inactivation efficiency.

Particles at fluid-fluid interfaces: A new Navier-Stokes-Cahn-Hilliard surface-phase-field-crystal model

PubMed Central

Aland, Sebastian; Lowengrub, John; Voigt, Axel

2013-01-01

Colloid particles that are partially wetted by two immiscible fluids can become confined to fluid-fluid interfaces. At sufficiently high volume fractions, the colloids may jam and the interface may crystallize. The fluids together with the interfacial colloids form an emulsion with interesting material properties and offer an important route to new soft materials. A promising approach to simulate these emulsions was presented in Aland et al. [Phys. Fluids 23, 062103 (2011)], where a Navier-Stokes-Cahn-Hilliard model for the macroscopic two-phase fluid system was combined with a surface phase-field-crystal model for the microscopic colloidal particles along the interface. Unfortunately this model leads to spurious velocities which require very fine spatial and temporal resolutions to accurately and stably simulate. In this paper we develop an improved Navier-Stokes-Cahn-Hilliard-surface phase-field-crystal model based on the principles of mass conservation and thermodynamic consistency. To validate our approach, we derive a sharp interface model and show agreement with the improved diffuse interface model. Using simple flow configurations, we show that the new model has much better properties and does not lead to spurious velocities. Finally, we demonstrate the solid-like behavior of the crystallized interface by simulating the fall of a solid ball through a colloid-laden multiphase fluid. PMID:23214691

Preparation of uniform-sized PELA microspheres with high encapsulation efficiency of antigen by premix membrane emulsification.

PubMed

Wei, Qiang; Wei, Wei; Tian, Rui; Wang, Lian-Yan; Su, Zhi-Guo; Ma, Guang-Hui

2008-07-15

Relatively uniform-sized poly(lactide-co-ethylene glycol) (PELA) microspheres with high encapsulation efficiency were prepared rapidly by a novel method combining emulsion-solvent extraction and premix membrane emulsification. Briefly, preparation of coarse double emulsions was followed by additional premix membrane emulsification, and antigen-loaded microspheres were obtained by further solidification. Under the optimum condition, the particle size was about 1 mum and the coefficient of variation (CV) value was 18.9%. Confocal laser scanning microscope and flow cytometer analysis showed that the inner droplets were small and evenly dispersed and the antigen was loaded uniformly in each microsphere when sonication technique was occupied to prepare primary emulsion. Distribution pattern of PEG segment played important role on the properties of microspheres. Compared with triblock copolymer PLA-PEG-PLA, the diblock copolymer PLA-mPEG yielded a more stable interfacial layer at the interface of oil and water phase, and thus was more suitable to stabilize primary emulsion and protect coalescence of inner droplets and external water phase, resulting in high encapsulation efficiency (90.4%). On the other hand, solidification rate determined the time for coalescence during microspheres fabrication, and thus affected encapsulation efficiency. Taken together, improving the polymer properties and solidification rate are considered as two effective strategies to yield high encapsulation.

FORMULATION AND STABILITY EVALUATION OF BAUHINIA VARIEGATA EXTRACT TOPICAL EMULSION.

PubMed

Mohsin, Sabeeh; Akhtar, Naveed

2017-05-01

This study presents the results for the development of water in oil (W/O) emulsion containing 2 % Bauhinia variegata (BV) extract with good antioxidant potential for cosmetic application. Different ratios of surfactant, oil and water were investigated to optimize the ratio of ingredients. It was found that emulsifier and oil4ratio were important in improving the stability of emulsion. The formulation having 2.5% Abil EM90, 12% liquid paraffin, 83.5% distilled water and 2% BV extract was found to be most stable. Stability of the formulation was further evaluated by characterizing for organoleptic, sedimentation, microscopic and rheological properties at a range of storage conditions for a period of 12 weeks. Experimental findings showed stable formulation behavior with respect to color change, liquefaction and phase separation. Centrifugation test was carried out to predict the long term stability..The rheological parameters were evaluated from Power Law and the flow index value less than 1 suggested non-Newtonian behavior of the W/O emulsion. The mean droplet size of the internal phase of freshly prepared formulation was 4.06 ? 1.99 pm that did not change significantly (p > 0.05) during the storage. The newly developed formulation exhibited promising attributes over long term storage and open opportunities for the topical delivery of natural antioxidants for cosmetic and pharmaceutical objectives.

Optimization of perfluoro nano-scale emulsions: the importance of particle size for enhanced oxygen transfer in biomedical applications.

PubMed

Fraker, Christopher A; Mendez, Armando J; Inverardi, Luca; Ricordi, Camillo; Stabler, Cherie L

2012-10-01

Nano-scale emulsification has long been utilized by the food and cosmetics industry to maximize material delivery through increased surface area to volume ratios. More recently, these methods have been employed in the area of biomedical research to enhance and control the delivery of desired agents, as in perfluorocarbon emulsions for oxygen delivery. In this work, we evaluate critical factors for the optimization of PFC emulsions for use in cell-based applications. Cytotoxicity screening revealed minimal cytotoxicity of components, with the exception of one perfluorocarbon utilized for emulsion manufacture, perfluorooctylbromide (PFOB), and specific w% limitations of PEG-based surfactants utilized. We optimized the manufacture of stable nano-scale emulsions via evaluation of: component materials, emulsification time and pressure, and resulting particle size and temporal stability. The initial emulsion size was greatly dependent upon the emulsion surfactant tested, with pluronics providing the smallest size. Temporal stability of the nano-scale emulsions was directly related to the perfluorocarbon utilized, with perfluorotributylamine, FC-43, providing a highly stable emulsion, while perfluorodecalin, PFD, coalesced over time. The oxygen mass transfer, or diffusive permeability, of the resulting emulsions was also characterized. Our studies found particle size to be the critical factor affecting oxygen mass transfer, as increased micelle size resulted in reduced oxygen diffusion. Overall, this work demonstrates the importance of accurate characterization of emulsification parameters in order to generate stable, reproducible emulsions with the desired bio-delivery properties. Copyright © 2012 Elsevier B.V. All rights reserved.

Oil-in-water emulsions for encapsulated delivery of reactive iron particles.

PubMed

Berge, Nicole D; Ramsburg, C Andrew

2009-07-01

Treatment of dense nonaqueous phase liquid (DNAPL) source zones using suspensions of reactive iron particles relies upon effective transport of the nano- to submicrometer scale iron particles within the subsurface. Recognition that poor subsurface transport of iron particles results from particle-particle and particle-soil interactions permits development of strategies which increase transport. In this work, experiments were conducted to assess a novel approach for encapsulated delivery of iron particles within porous media using oil-in-water emulsions. Objectives of this study included feasibility demonstration of producing kinetically stable, iron-containing, oil-in-water emulsions and evaluating the transport of these iron-containing, oil-in-water emulsions within water-saturated porous media. Emulsions developed in this study have mean droplet diameters between 1 and 2 microm, remain kinetically stable for > 1.5 h, and possess densities (0.996-1.00 g/mL at 22 degrees C) and dynamic viscosities (2.4-9.3 mPa x s at 22 degrees C and 20 s(-1)) that are favorable to transport within DNAPL source zones. Breakthrough curves and post-experiment extractions from column experiments conducted with medium and fine sands suggest little emulsion retention (< 0.20% wt) at a Darcy velocity of 0.4 m/day. These findings demonstrate that emulsion encapsulation is a promising method for delivery of iron particles and warrants further investigation.

Effect of fish gelatin-gum arabic interactions on structural and functional properties of concentrated emulsions.

PubMed

Anvari, Mohammad; Joyner Melito, Helen S

2017-12-01

Concentrated emulsions containing both proteins and polysaccharides are the basis for many commercial products; however, the effects of protein-polysaccharide interactions on the functional properties of these complex systems are often poorly understood from a fundamental standpoint. Hence, the objective of this study was to determine the effects of fish gelatin (FG)-gum arabic (GA) complexation at different aqueous phase pH (3.6, 5.0, and 9.0) on concentrated emulsion structure-function relationships. Concentrated emulsions were prepared using FG-GA mixtures and characterized by rheometry and confocal scanning laser microscopy (CSLM). CSLM images showed that all samples were O/W emulsions; emulsions with lower pH showed smaller oil droplets, greater homogeneity in size distribution, and higher stability. This was attributed to an increased number of FG-GA complexes in the emulsification. Electrostatic attractive interactions and charge neutralization created biopolymer associations with increased emulsification capacity. Samples with FG-GA mixtures at lower pH showed higher elastic moduli under small deformation and exhibited greater deviation between apparent and complex viscosities under the Cox-Merz rule, indicating increased gel network extension and greater intermolecular connectivity between adsorbed layers of adjacent oil droplets. These results can be used to incorporate protein-polysaccharide complexes as a suitable emulsifier in materials comprising concentrated emulsions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Droplet-based microfluidics and the dynamics of emulsions

NASA Astrophysics Data System (ADS)

Baret, Jean-Christophe; Brosseau, Quentin; Semin, Benoit; Qu, Xiaopeng

2012-02-01

Emulsions are complex fluids already involved for a long time in a wide-range of industrial processes, such as, for example, food, cosmetics or materials synthesis [1]. More recently, applications of emulsions have been extended to new fields like biotechnology or biochemistry where the compartmentalization of compounds in emulsion droplets is used to parallelise (bio-) chemical reactions [2]. Interestingly, these applications pinpoint to fundamental questions dealing with surfactant dynamics, dynamic surface tension, hydrodynamic interactions and electrohydrodynamics. Droplet-based microfluidics is a very powerful tool to quantitatively study the dynamics of emulsions at the single droplet level or even at the single interface level: well-controlled emulsions are produced and manipulated using hydrodynamics, electrical forces, optical actuation and combination of these effects. We will describe here how droplet-based microfluidics is used to extract quantitative informations on the physical-chemistry of emulsions for a better understanding and control of the dynamics of these systems [3].[4pt] [1] J. Bibette et al. Rep. Prog. Phys., 62, 969-1033 (1999)[0pt] [2] A. Theberge et al., Angewandte Chemie Int. Ed. 49, 5846 (2010)[0pt] [3] J.-C. Baret et al., Langmuir, 25, 6088 (2009)

Fabrication of Concentrated Fish Oil Emulsions Using Dual-Channel Microfluidization: Impact of Droplet Concentration on Physical Properties and Lipid Oxidation.

PubMed

Liu, Fuguo; Zhu, Zhenbao; Ma, Cuicui; Luo, Xiang; Bai, Long; Decker, Eric Andrew; Gao, Yanxiang; McClements, David Julian

2016-12-21

Chemically unstable lipophilic bioactives, such as polyunsaturated lipids, often have to be encapsulated in emulsion-based delivery systems before they can be incorporated into foods, supplements, and pharmaceuticals. The objective of this study was to develop highly concentrated emulsion-based fish oil delivery systems using natural emulsifiers. Fish oil-in-water emulsions were fabricated using a highly efficient dual-channel high-pressure microfluidizer. The impact of oil concentration on the formation, physical properties, and oxidative stability of fish oil emulsions prepared using two natural emulsifiers (quillaja saponins and rhamnolipids) and one synthetic emulsifier (Tween-80) was examined. The mean droplet size, polydispersity, and apparent viscosity of the fish oil emulsions increased with increasing oil content. However, physically stable emulsions with high fish oil levels (30 or 40 wt %) could be produced using all three emulsifiers, with rhamnolipids giving the smallest droplet size (d < 160 nm). The stability of the emulsions to lipid oxidation increased as the oil content increased. The oxidative stability of the emulsions also depended on the nature of the emulsifier coating the lipid droplets, with the oxidative stability decreasing in the following order: rhamnolipids > saponins ≈ Tween-80. These results suggest that rhamnolipids may be particularly effective at producing emulsions containing high concentrations of ω-3 polyunsaturated fatty acids-rich fish oil.

Study on stress-strain response of multi-phase TRIP steel under cyclic loading

NASA Astrophysics Data System (ADS)

Dan, W. J.; Hu, Z. G.; Zhang, W. G.; Li, S. H.; Lin, Z. Q.

2013-12-01

The stress-strain response of multi-phase TRIP590 sheet steel is studied in cyclic loading condition at room temperature based on a cyclic phase transformation model and a multi-phase mixed kinematic hardening model. The cyclic martensite transformation model is proposed based on the shear-band intersection, where the repeat number, strain amplitude and cyclic frequency are used to control the phase transformation process. The multi-phase mixed kinematic hardening model is developed based on the non-linear kinematic hardening rule of per-phase. The parameters of transformation model are identified with the relationship between the austenite volume fraction and the repeat number. The parameters in Kinematic hardening model are confirmed by the experimental hysteresis loops in different strain amplitude conditions. The responses of hysteresis loop and stress amplitude are evaluated by tension-compression data.

In vitro permeation and in vivo anti-inflammatory and analgesic properties of nanoscaled emulsions containing ibuprofen for topical delivery

PubMed Central

Abdullah, Ghassan Z; Abdulkarim, Muthanna F; Salman, Ibrahim M; Ameer, Omar Z; Yam, Mun F; Mutee, Ahmed F; Chitneni, Mallikarjun; Mahdi, Elrashid S; Basri, Mahiran; Sattar, Munavvar A; Noor, Azmin M

2011-01-01

Introduction: As a topical delivery system, a nanoscaled emulsion is considered a good carrier of several active ingredients that convey several side effects upon oral administration, such as nonsteroidal anti-inflammatory drugs (NSAIDs). Objective: We investigated the in vitro permeation properties and the in vivo pharmacodynamic activities of different nanoscaled emulsions containing ibuprofen, an NSAID, as an active ingredient and newly synthesized palm olein esters (POEs) as the oil phase. Methodology: A ratio of 25:37:38 of oil phase:aqueous phase:surfactant was used, and different additives were used for the production of a range of nanoscaled emulsions. Carbopol® 940 dispersion neutralized by triethanolamine was employed as a rheology modifier. In some circumstances, menthol and limonene were employed at different concentrations as permeation promoters. All formulae were assessed in vitro using Franz diffusion cell fitted with full-thickness rat skin. This was followed by in vivo evaluation of the anti-inflammatory and analgesic activities of the promising formulae and comparison of the effects with that of the commercially available gel. Results and discussion: Among all other formulae, formula G40 (Carbopol® 940-free formula) had a superior ability in transferring ibuprofen topically compared with the reference. Carbopol® 940 significantly decreased the amount of drug transferred from formula G41 through the skin as a result of swelling, gel formation, and reduction in drug thermodynamic activity. Nonetheless, the addition of 10% w/w of menthol and limonene successfully overcame this drawback since, relative to the reference, higher amount of ibuprofen was transferred through the skin. By contrast, these results were relatively comparable to that of formula G40. Pharmacodynamically, the G40, G45, and G47 formulae exhibited the highest anti-inflammatory and analgesic effects compared with other formulae. Conclusion: The ingredients and the physical properties of the nanoscaled emulsions produced by using the newly synthesized POEs succeeded to deliver ibuprofen competently. PMID:21499428

Effect of emulsifier type and concentration, aqueous phase volume and wax ratio on physical, material and mechanical properties of water in oil lipsticks.

PubMed

Beri, A; Norton, J E; Norton, I T

2013-12-01

Water-in-oil emulsions in lipsticks could have the potential to improve moisturizing properties and deliver hydrophilic molecules to the lips. The aims of this work were (i) to investigate the effect of emulsifier type (polymer vs. monomer, and saturated vs. unsaturated chain) and concentration on droplet size and (ii) to investigate the effect of wax ratio (carnauba wax, microcrystalline wax, paraffin wax and performalene) and aqueous phase volume on material properties (Young's modulus, point of fracture, elastic modulus and viscous modulus). Emulsion formation was achieved using a high shear mixer. Results showed that the saturated nature of the emulsifier had very little effect on droplet size, neither did the use of an emulsifier with a larger head group (droplet size ~18-25 μm). Polyglycerol polyricinoleate (PGPR) resulted in emulsions with the smallest droplets (~3-5 μm), as expected from previous studies that show that it produces a thick elastic interface. The results also showed that both Young's modulus and point of fracture increase with increasing percentage of carnauba wax (following a power law dependency of 3), but decrease with increasing percentage of microcrystalline wax, suggesting that the carnauba wax is included in the overall wax network formed by the saturated components, whereas the microcrystalline wax forms irregular crystals that disrupt the overall wax crystal network. Young's modulus, elastic modulus and viscous modulus all decrease with increasing aqueous phase volume in the emulsions, although the slope of the decrease in elastic and viscous moduli is dependent on the addition of solid wax, as a result of strengthening the network. This work suggests the potential use for emulsions in lipstick applications, particularly when PGPR is used as an emulsifier, and with the addition of solid wax, as it increases network strength. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

DIMENSION STABILIZED FIXED PHOTOGRAPHIC TYPE EMULSION AND A METHOD FOR PRODUCING SAME

DOEpatents

Gilbert, F.C.

1962-03-13

A process is given for stabilizing the dimensions of fixed gelatin-base photographic type emulsions containing silver halide, and particularly to such emulsions containing large amounts of silver chloride for use as nuclear track emulsions, so that the dimensions of the final product are the same as or in a predetermined fixed ratio to the dimensions of the emulsions prior to exposure. The process comprises contacting an exposed, fixed emulsion with a solution of wood rosin dissolved in ethyl alcohol for times corresponding to the dimensions desired, and thereafter permitting the alcohol to evaporate. (AEC)

Enhanced oral bioavailability and antiasthmatic efficacy of curcumin using redispersible dry emulsion.

PubMed

Jang, Dong-Jin; Kim, Sung Tae; Oh, Euichaul; Lee, Kooyeon

2014-01-01

Dry emulsion containing curcumin (DE-CUR) was prepared for oral delivery of poorly water-soluble curcumin, and its oral bioavailability and antiasthmatic efficacy was evaluated. After comparison of the solubility of curcumin in various oils, Plurol® Oleique CC497 was selected to be the oil phase due to its higher solubility of CUR than other oils. A dry emulsion prepared by spray-drying of a homogenized oil-in-water emulsion was well-reconstituted in water, fabricating similar particle distribution and in vitro release to that of a dispersed homogeneous emulsion before spraying. The release of DE-CUR was much higher than that of curcumin (85.3 vs. 1.7% release at 60 min). Consequently, DE-CUR resulted in 12.0- and 7.1-fold higher Cmax and AUC0-24h than curcumin. In a murine asthma model, DE-CUR effectively suppressed airway hyperresponsiveness and levels of T-helper cytokines such as interleukin-4, inteleukin-5, and interleukin-13. These findings demonstrate that the DE-CUR shows a potential for the development of functional foods or medicines including CUR.

Studies on gum of Moringa oleifera for its emulsifying properties.

PubMed

Panda, Dibya Sundar

2014-04-01

Emulsion has been a form of presenting water insoluble substances for a long period of time. Now a day, it has been a way of presenting various intravenous additives and diagnostic agents in X-ray examinations. Various substances can be used as emulsifying agent, which can be operationally defined as a stabilizer of the droplets formed of the internal phase. Gum from Moringa oleifera was evaluated for its emulsifying properties. Castor oil emulsions 30 percent (o/w), containing 2 to 4% Moringa oleifera gum was prepared. Emulsions containing equivalent concentration of acacia were also prepared for comparison. All the emulsions prepared were stored at room temperature and studied for stability at various time intervals for 8 weeks. The prepared emulsions were evaluated for creaming rate, globule size and rate of coalescence. 23 factorial design was chosen to investigate the effects of centrifugation, pH, temperature changes and electrolytes on the creaming rate and globule size. The results of the investigations show that the gum of Moringa oleifera possesses better emulsifying properties as compared to gum acacia. Gum of Moringa oleifera could be used in pharmaceutical and non-pharmaceutical preparation.

High pressure inactivation of Clostridium botulinum type E endospores in model emulsion systems

NASA Astrophysics Data System (ADS)

Schnabel, Juliane; Lenz, Christian A.; Vogel, Rudi F.

2015-01-01

Clostridium botulinum type E is a cold-tolerant, neurotoxigenic, endospore-forming organism, primarily associated with aquatic environments. High pressure thermal (HPT) processing presents a promising tool to enhance food safety and stability. The effect of fat on HPT inactivation of C. botulinum type E spores was investigated using an emulsion model system. The distribution of spores in oil-in-water (O/W) emulsions and their HPT (300-750 MPa, 45-75 °C, 10 min) inactivation was determined as a function of emulsion fat content (30-70% (v/v) soybean oil in buffer). Approximately 26% and 74% of the spores were located at the oil-buffer interface and the continuous phase, respectively. Spore inactivation in emulsion systems decreased with increasing oil contents, which suggests that the fat content of food plays an important role in the protection of C. botulinum type E endospores against HPT treatments. These results can be helpful for future safety considerations. This paper was presented at the 8th International Conference on High Pressure Bioscience & Biotechnology (HPBB 2014), in Nantes (France), 15-18 July 2014.

Manufacture and characterisation of EmDerm-novel hierarchically structured bio-active scaffolds for tissue regeneration.

PubMed

Lim, Xuxin; Potter, Matthew; Cui, Zhanfeng; Dye, Julian F

2018-06-05

There are significant challenges for using emulsion templating as a method of manufacturing macro-porous protein scaffolds. Issues include protein denaturation by adsorption at hydrophobic interfaces, emulsion instability, oil droplet and surfactant removal after protein gelation, and compatible cross-linking methods. We investigated an oil-in-water macro-emulsion stabilised with a surfactant blend, as a template for manufacturing protein-based nano-structured bio-intelligent scaffolds (EmDerm) with tuneable micro-scale porosity for tissue regeneration. Prototype EmDerm scaffolds were made using either collagen, through thermal gelation, fibrin, through enzymatic coagulation or collagen-fibrin composite. Pore size was controlled via surfactant-to-oil phase ratio. Scaffolds were crosslink-stabilised with EDC/NHS for varying durations. Scaffold micro-architecture and porosity were characterised with SEM, and mechanical properties by tensiometry. Hydrolytic and proteolytic degradation profiles were quantified by mass decrease over time. Human dermal fibroblasts, endothelial cells and bone marrow derived mesenchymal stem cells were used to investigate cytotoxicity and cell proliferation within each scaffold. EmDerm scaffolds showed nano-scale based hierarchical structures, with mean pore diameters ranging from 40-100 microns. The Young's modulus range was 1.1-2.9 MPa, and ultimate tensile strength was 4-16 MPa. Degradation rate was related to cross-linking duration. Each EmDerm scaffold supported excellent cell ingress and proliferation compared to the reference materials Integra™ and Matriderm™. Emulsion templating is a novel rapid method of fabricating nano-structured fibrous protein scaffolds with micro-scale pore dimensions. These scaffolds hold promising clinical potential for regeneration of the dermis and other soft tissues, e.g., for burns or chronic wound therapies.

A Sensitive Microplate Assay for Lipase Activity Measurement Using Olive Oil Emulsion Substrate: Modification of the Copper Soap Colorimetric Method.

PubMed

Mustafa, Ahmad; Karmali, Amin; Abdelmoez, Wael

2016-01-01

The present work involves a sensitive high-throughput microtiter plate based colorimetric assay for estimating lipase activity using cupric acetate pyridine reagent (CAPR). In the first approach, three factors two levels factorial design methodology was used to evaluate the interactive effect of different parameters on the sensitivity of the assay method. The optimization study revealed that the optimum CAPR concentration was 7.5% w/v, the optimum solvent was heptane and the optimum CAPR pH was 6. In the second approach, the optimized colorimetric microplate assay was used to measure lipase activity based on enzymatic hydrolysis of olive oil emulsion substrate at 37°C and 150 rpm. The emulsion substrates were formulated by using olive oil, triton X-100 (10% v/v in pH 8) and sodium phosphate buffer of pH 8 in ratio of 1:1:1 in the case of Candida sp. lipase. While in the case of immobilized lipozyme RMIM, The emulsion substrates were formulated by using olive oil, triton X-100 (1% v/v in pH 8) and sodium phosphate buffer of pH 8 in ratio of 2:1:1. Absorbance was measured at 655 nm. The stability of this assay (in terms of colored heptane phase absorbance readings) retained more than 92.5% after 24 h at 4°C compared to the absorbance readings measured at zero time. In comparison with other lipase assay methods, beside the developed sensitivity, the reproducibility and the lower limit of detection (LOD) of the proposed method, it permits analyzing of 96 samples at one time in a 96-well microplate. Furthermore, it consumes small quantities of chemicals and unit operations.

Study of chemical stability of lemon oil components in sodium caseinate-lactose glycoconjugate-stabilized oil-in-water emulsions using solid-phase microextraction-gas chromatography.

PubMed

Sabik, Hassan; Achouri, Allaoua; Alfaro, Maria; Pelletier, Marylène; Belanger, Denis; Britten, Michel; Fustier, Patrick

2014-07-25

A headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC/MS) method was developed to quantify lemon oil components and their degradation products in oil-in-water (O/W) emulsions prepared with sodium caseinate-heated-lactose (NaC-T + Lact) glycoconjugates as wall materials at two pH values (3.0 and 6.8). NaC-T + Lact conjugates had a significantly lower solubility at both pHs. Hydrolysis prior to glycation enhanced the solubility of glycoconjugates. Glycation with lactose did not improve the emulsion activity of NaC, while caseinate glycoconjugates showed much stronger antioxidant activity than the NaC-control sample. This might be due to the presence of melanoidins formed between the sugar and amino acid compounds as supported by the increase in browning intensity. Among the SPME-fibres tested, carboxen/polydimethylsiloxane (CAR/PDMS) provided better results in terms of sensitivity and selectivity for oil lemon components and their degradation products. Storage studies of these emulsions demonstrated that glycated NaC-T + Lact showed protection against peroxidation compared to the control. However, acidic pH conditions altered their stability over storage time. The major off-flavor components (α-terpineol and carvone) were inhibited in emulsions stabilized with glycated NaC, particularly at pH 6.8. The use of NaC-T + Lact conjugates showed improved encapsulation efficiency and stability and could be used as potential food ingredient-emulsifiers for stabilising citrus oils against oxidative degradation in food and beverage applications.

Disintegration and cancer immunotherapy efficacy of a squalane-in-water delivery system emulsified by bioresorbable poly(ethylene glycol)-block-polylactide.

PubMed

Chen, Wei-Lin; Liu, Shih-Jen; Leng, Chih-Hsiang; Chen, Hsin-Wei; Chong, Pele; Huang, Ming-Hsi

2014-02-01

Vaccine adjuvant is conferred on the substance that helps to enhance antigen-specific immune response. Here we investigated the disintegration characteristics and immunotherapy potency of an emulsified delivery system comprising bioresorbable polymer poly(ethylene glycol)-polylactide (PEG-PLA), phosphate buffer saline (PBS), and metabolizable oil squalane. PEG-PLA-stabilized oil-in-water emulsions show good stability at 4 °C and at room temperature. At 37 °C, squalane/PEG-PLA/PBS emulsion with oil/aqueous weight ratio of 7/3 (denominated PELA73) was stable for 6 weeks without phase separation. As PEG-PLA being degraded, 30% of free oil at the surface layer and 10% of water at the bottom disassociated from the PELA73 emulsion were found after 3 months. A MALDI-TOF MS study directly on the DIOS plate enables us to identify low molecular weight components released during degradation. Our results confirm the loss of PLA moiety of the emulsifier PEG-PLA directly affected the stability of PEG-PLA-stabilized emulsion, leading to emulsion disintegration and squalane/water phase separation. As adjuvant for cancer immunotherapeutic use, an HPV16 E7 peptide antigen formulated with PELA73 plus immunostimulatory CpG molecules could strongly enhance antigen-specific T-cell responses as well as anti-tumor ability with respected to non-formulated or Alum-formulated peptide. Accordingly, these advances may be a potential immunoregulatory strategy in manipulating the immune responses induced by tumor-associated antigens. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Highway Binder Materials from Modified Sulfur-Water Emulsions

DOT National Transportation Integrated Search

1982-04-01

This project had the objectives of developing and characterizing stable modified-sulfur water emulsions using sulfur-extended-asphalt and Sulphlex as base stocks. Anionic and cationic emulsions which had rapid and slow setting characteristics were st...

Enzymatically interesterified fats based on mutton tallow and walnut oil suitable for cosmetic emulsions.

PubMed

Kowalska, M; Mendrycka, M; Zbikowska, A; Stawarz, S

2015-02-01

Formation of emulsion systems based on interesterified fats was the objective of the study. Enzymatic interesterification was carried out between enzymatic mutton tallow and walnut oil in the proportions 2 : 3 (w/w) to produce fats not available in nature. At the beginning of the interesterification process, the balance between the interesterification and fat hydrolysis was intentionally disturbed by adding more water to the catalyst (Lipozyme IR MR) of the reaction to produce more of the polar fraction monoacylglycerols [MAGs] and diacylglycerols [DAGs]. To obtain a greater quantity of MAGs and DAGs in the reaction environment via hydrolysis, water was added (11, 13, 14, 16 w-%) to the enzymatic preparation. The obtained fats were used to form emulsions. The emulsions were evaluated with respect to sensory and skin moisturizing properties by 83 respondents. Determination of emulsion stability using temperature and centrifugal tests was carried out. Morphology and the type of emulsions were determined. The respondents described the skin to which the emulsions in testing were applied as smooth, pleasant to touch and adequately moisturized. The work has demonstrated that interesterification of a mutton tallow and walnut oil blend resulted in new fats with very interesting characteristics of triacylglycerols that are not present in the environment. The results of the present work indicate the possibility of application of fats with the largest quantity of MAGs and DAGs as a fat base of emulsions in the cosmetic industries. The hypothesis assumed in this work of producing additional quantities of MAGs and DAGs (in the process of enzymatic interesterification) responsible for the stability of the system was confirmed. It should be pointed out that the emulsions based on interesterified fats exhibited a greater level of moisturization of the skin than the emulsions containing non-interesterified fat. Also, in the respondents' opinion, the emulsion containing fat, which was modified during enzymatic interesterification when 13% of water was added to the enzymatic preparation, exhibited the best sensory profile. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Does lactobionic acid affect the colloidal structure and skin moisturizing potential of the alkyl polyglucoside-based emulsion systems?

PubMed

Tasic-Kostov, M Z; Reichl, S; Lukic, M Z; Jaksic, I N; Savic, S D

2011-11-01

Moisturizing creams are the most prescribed products in dermatology, essential in maintaining healthy skin as well as in the topical treatment of some diseases. The irritation potential of commonly used emulsifiers and moisturizing ingredients, but also their mutual interactions, could affect the functionality and safety of those dermopharmaceutics. The aim of this study was to promote moisturizing alkyl polyglucoside (APG)-based emulsion as vehicle for lactobionic acid (LA), advantageous representative of the alphahydroxyacids (AHAs)-multifunctional moisturizers, assessing the safety for use (in vitro acute skin irritation test using cytotoxicity assay compared with in vivo data obtained using skin bioengineering methods) and in vivo moisturizing capacity (bioengineering of the skin). In order to investigate possible interactions between APG mild natural emulsifier-based emulsion and LA, a deeper insight into the colloidal structure of the placebo and the emulsion with LA was given using polarization and transmission electron microscopy, rheology, thermal and texture analysis. This study showed that APG-based emulsions could be promoted as safe cosmetic/dermopharmaceutical vehicles and carriers for extremely acidic and hygroscopic AHA class of actives (specifically LA); prospective safety for human use of both APG and LA with the correlation between in vivo and in vitro findings was shown. However, it was revealed that LA strongly influenced the colloidal structure of the emulsion based on APGs and promoted the formation of lamellar structures which reflects onto the mode of water distribution within the cream. The advantageous skin hydrating potential of LA-containing emulsion vs. placebo was unlikely to be achieved, pointing that emulsions stabilized by lamellar liquid crystalline structures probably are not satisfying carriers for highly hygroscopic actives in order to reach the full moisturizing potential. Safe and effective use on dry skin is presumed.

Rheological behavior on treated Malaysian crude oil

NASA Astrophysics Data System (ADS)

Chandran, Krittika; Sinnathambi, Chandra Mohan

2016-11-01

Crude oil is always produced with water. This association causes many problems during oil production, arising from the formation of emulsion. Emulsion is an undesirable substance that increases operational and capital cost in the pipeline and processing equipment. To overcome this issue, demulsifiers are formulated to break the emulsion, where they are able to separate the water-oil emulsions to their respective phases. The emulsifier's main function is to reduce the interfacial tension properties of the emulsion. For this research, both the EOR and natural water-in-oil emulsions were treated with low a concentration demulsifier. The main objective of this paper is to determine the dynamic viscosity and rheological properties of the treated EOR and natural emulsion. The dynamic viscosity was obtained using the Brook-field Digital Viscometer. The components that influence the emulsion's rheological properties are the temperature, shear rate and shear stress. The results obtained demonstrate that the viscosity of the treated crude decreases and portrays the Non-Newtonian shear thinning "pseudo-plastic" behavior. Besides that, to determine the interfacial film of the treated crude, the spinning drop tensiometer was used. With the addition of demulsifier, the thinning rate of the oil film accelerates whereby there is a linear decrease in the interfacial tension with an increase in time. Therefore, from the results, it can be observed that the rheology study plays a significant role in the demulsification test. Furthermore, both the rheology approaches showed that time, temperature, shear rate and shear stress have a great impact on the viscosity behavior as well as the IFT.

Interfacial rheology of model particles at liquid interfaces and its relation to (bicontinuous) Pickering emulsions

NASA Astrophysics Data System (ADS)

Thijssen, J. H. J.; Vermant, J.

2018-01-01

Interface-dominated materials are commonly encountered in both science and technology, and typical examples include foams and emulsions. Conventionally stabilised by surfactants, emulsions can also be stabilised by micron-sized particles. These so-called Pickering-Ramsden (PR) emulsions have received substantial interest, as they are model arrested systems, rather ubiquitous in industry and promising templates for advanced materials. The mechanical properties of the particle-laden liquid-liquid interface, probed via interfacial rheology, have been shown to play an important role in the formation and stability of PR emulsions. However, the morphological processes which control the formation of emulsions and foams in mixing devices, such as deformation, break-up, and coalescence, are complex and diverse, making it difficult to identify the precise role of the interfacial rheological properties. Interestingly, the role of interfacial rheology in the stability of bicontinuous PR emulsions (bijels) has been virtually unexplored, even though the phase separation process which leads to the formation of these systems is relatively simple and the interfacial deformation processes can be better conceptualised. Hence, the aims of this topical review are twofold. First, we review the existing literature on the interfacial rheology of particle-laden liquid interfaces in rheometrical flows, focussing mainly on model latex suspensions consisting of polystyrene particles carrying sulfate groups, which have been most extensively studied to date. The goal of this part of the review is to identify the generic features of the rheology of such systems. Secondly, we will discuss the relevance of these results to the formation and stability of PR emulsions and bijels.

Acquisition of Co metal from spent lithium-ion battery using emulsion liquid membrane technology and emulsion stability test

NASA Astrophysics Data System (ADS)

Yuliusman; Wulandari, P. T.; Amiliana, R. A.; Huda, M.; Kusumadewi, F. A.

2018-03-01

Lithium-ion batteries are the most common type to be used as energy source in mobile phone. The amount of lithium-ion battery wastes is approximated by 200 – 500 ton/year. In one lithium-ion battery, there are 5 – 20% of cobalt metal, depend on the manufacturer. One of the way to recover a valuable metal from waste is leaching process then continued with extraction, which is the aim of this study. Spent lithium-ion batteries will be characterized with EDX and AAS, the result will show the amount of cobalt metal with form of LiCoO2 in the cathode. Hydrochloric acid concentration used is 4 M, temperature 80°C, and reaction time 1 hour. This study will discuss the emulsion stability test on emulsion liquid membrane. The purpose of emulsion stability test in this study was to determine optimum concentration of surfactant and extractant to produce a stable emulsion. Surfactant and extractant used were SPAN 80 and Cyanex 272 respectively with both concentrations varied. Membrane and feed phase ratios used in this experiment was 1 : 2. The optimum results of this study were SPAN 80 concentrations of 10% w/v and Cyanex 272 0.7 M.

In-air microfluidics: Drop and jet coalescence enables rapid multi-phase 3D printing

NASA Astrophysics Data System (ADS)

Visser, Claas Willem; Kamperman, Tom; Lohse, Detlef; Karperien, Marcel; University of Twente Collaboration

2016-11-01

For the first time, we connect and integrate the fields of microfluidics and additive manufacturing, by presenting a unifying technology that we call In-air microfluidics (IAMF). We impact two liquid jets or a jet and a droplet train while flying in-air, and control their coalescence and solidification. This approach enables producing monodisperse emulsions, particles, and fibers with controlled shape and size (10 to 300 µm) and production rates 100x higher than droplet microfluidics. A single device is sufficient to process a variety of materials, and to produce different particle or fiber shapes, in marked contrast to current microfluidic devices or printers. In-air microfluidics also enables rapid deposition onto substrates, for example to form 3D printed (bio)materials which are partly-liquid but still shape-stable.

Management of the diffusion of 4-methylumbelliferone across phases in microdroplet-based systems for in vitro protein evolution.

PubMed

Wu, Nan; Courtois, Fabienne; Zhu, Yonggang; Oakeshott, John; Easton, Chris; Abell, Chris

2010-09-01

Fluorongenic reagents based on 4-methylumbelliferone (4-MU) have been widely used for the detection of phosphatase, sulfatase, esterase, lipase and glycosidase activities in conventionally formatted enzyme assay systems. However, the sensitivity of assays based on these substrates is also potentially very useful in the microdroplet formats now being developed for high throughput in vitro evolution experiments. In this article, we report the investigation of diffusion of 4-MU as a model dye from water-in-oil droplets and the internal aqueous phase of water-in-oil-in-water droplets in microfluidics. The effect of BSA in the aqueous phase on the diffusion of 4-MU is also discussed. Based on these results, we provided here proof-of-concept of the reaction of the enzyme OpdA with the substrate coumaphos in water-in-oil-in-water droplets. In this double-emulsion system, the reaction of OpdA and coumaphos was achieved by allowing coumaphos to diffuse from the continuous aqueous phase across the oil phase into the internal aqueous droplets.

Enzymatically Crosslinked Emulsion Gels Using Star-Polymer Stabilizers.

PubMed

Ma, Kai; An, Zesheng

2016-10-01

A novel type of emulsion gel based on star-polymer-stabilized emulsions is highlighted, which contains discrete hydrophobic oil and hydrophilic aqueous solution domains. Well-defined phenol-functionalized core-crosslinked star polymers are synthesized via reversible addition-fragmentation chain transfer (RAFT)-mediated dispersion polymerization and are used as stabilizers for oil-in-water emulsions. Horseradish-peroxidase-catalyzed polymerization of the phenol moieties in the presence of H 2 O 2 enables rapid formation of crosslinked emulsion gels under mild conditions. The crosslinked emulsion gels exhibit enhanced mechanical strength, as well as widely tunable composition. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emulsion templated scaffolds with tunable mechanical properties for bone tissue engineering.

PubMed

Owen, Robert; Sherborne, Colin; Paterson, Thomas; Green, Nicola H; Reilly, Gwendolen C; Claeyssens, Frederik

2016-02-01

Polymerised High Internal Phase Emulsions (PolyHIPEs) are manufactured via emulsion templating and exhibit a highly interconnected microporosity. These materials are commonly used as thin membranes for 3D cell culture. This study uses emulsion templating in combination with microstereolithography to fabricate PolyHIPE scaffolds with a tightly controlled and reproducible architecture. This combination of methods produces hierarchical structures, where the microstructural properties can be independently controlled from the scaffold macrostructure. PolyHIPEs were fabricated with varying ratios of two acrylate monomers (2-ethylhexyl acrylate (EHA) and isobornyl acrylate (IBOA)) and varying nominal porosity to tune mechanical properties. Young's modulus, ultimate tensile stress (UTS) and elongation at failure were determined for twenty EHA/IBOA compositions. Moduli ranged from 63.01±9.13 to 0.36±0.04MPa, UTS from 2.03±0.33 to 0.11±0.01MPa and failure strain from 21.86±2.87% to 2.60±0.61%. Selected compositions were fabricated into macro-porous woodpile structures, plasma treated with air or acrylic acid and seeded with human embryonic stem-cell derived mesenchymal progenitor cells (hES-MPs). Confocal and two-photon microscopy confirmed cell proliferation and penetration into the micro- and macro-porous architecture. The scaffolds supported osteogenic differentiation of mesenchymal cells and interestingly, the stiffest IBOA-based scaffolds that were plasma treated with acrylic acid promoted osteogenesis more strongly than the other scaffolds. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

A numerical multi-scale model to predict macroscopic material anisotropy of multi-phase steels from crystal plasticity material definitions

NASA Astrophysics Data System (ADS)

Ravi, Sathish Kumar; Gawad, Jerzy; Seefeldt, Marc; Van Bael, Albert; Roose, Dirk

2017-10-01

A numerical multi-scale model is being developed to predict the anisotropic macroscopic material response of multi-phase steel. The embedded microstructure is given by a meso-scale Representative Volume Element (RVE), which holds the most relevant features like phase distribution, grain orientation, morphology etc., in sufficient detail to describe the multi-phase behavior of the material. A Finite Element (FE) mesh of the RVE is constructed using statistical information from individual phases such as grain size distribution and ODF. The material response of the RVE is obtained for selected loading/deformation modes through numerical FE simulations in Abaqus. For the elasto-plastic response of the individual grains, single crystal plasticity based plastic potential functions are proposed as Abaqus material definitions. The plastic potential functions are derived using the Facet method for individual phases in the microstructure at the level of single grains. The proposed method is a new modeling framework and the results presented in terms of macroscopic flow curves are based on the building blocks of the approach, while the model would eventually facilitate the construction of an anisotropic yield locus of the underlying multi-phase microstructure derived from a crystal plasticity based framework.

Emulsification properties of biosurfactant produced from Pseudomonas aeruginosa RB 28.

PubMed

Sifour, Mohamed; Al-Jilawi, Majid H; Aziz, Ghazi M

2007-04-15

Biosurfactant produced from P. aeruginosa RB 28 was extracted, purified and characterized. Thin layer chromatography results showed that the extract contained two different compounds. The identification of the nature of the two compounds showed that they were glycolipids and rhamnose was the sugar moiety in these glycolipids. It was concluded that these compounds were rhamnolipids. The production of biosurfactant was started at late log phase and reached its maximal level (2.7 g L(-1)) at the stationary phase. Study of some rhamnolipid properties showed that sunflower oil, heptadecane and paraffin were efficiently emulsified and emulsions formed with vegetable oils (olive oil, corn oil and sunflower oil) were more stable than emulsions formed with hydrocarbons.

Quantifying Asphalt Emulsion-Based Chip Seal Curing Times Using Electrical Resistance Measurements.

DOT National Transportation Integrated Search

2017-04-15

Chip sealing typically consists of covering a pavement surface with asphalt emulsion into which aggregate chips are embedded. The asphalt emulsion cures through the evaporation of water, thus providing mechanical strength to adhere to the pavement wh...

Stability of cosmetic emulsion containing different amount of hemp oil.

PubMed

Kowalska, M; Ziomek, M; Żbikowska, A

2015-08-01

The aim of the study was to determine the optimal conditions, that is the content of hemp oil and time of homogenization to obtain stable dispersion systems. For this purpose, six emulsions were prepared, their stability was examined empirically and the most correctly formulated emulsion composition was determined using a computer simulation. Variable parameters (oil content and homogenization time) were indicated by the optimization software based on Kleeman's method. Physical properties of the synthesized emulsions were studied by numerous techniques involving particle size analysis, optical microscopy, Turbiscan test and viscosity of emulsions. The emulsion containing 50 g of oil and being homogenized for 6 min had the highest stability. Empirically determined parameters proved to be consistent with the results obtained using the computer software. The computer simulation showed that the most stable emulsion should contain from 30 to 50 g of oil and should be homogenized for 2.5-6 min. The computer software based on Kleeman's method proved to be useful for quick optimization of the composition and production parameters of stable emulsion systems. Moreover, obtaining an emulsion system with proper stability justifies further research extended with sensory analysis, which will allow the application of such systems (containing hemp oil, beneficial for skin) in the cosmetic industry. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Oil-in-oil emulsions: a unique tool for the formation of polymer nanoparticles.

PubMed

Klapper, Markus; Nenov, Svetlin; Haschick, Robert; Müller, Kevin; Müllen, Klaus

2008-09-01

Polymer latex particles are nanofunctional materials with widespread applications including electronics, pharmaceuticals, photonics, cosmetics, and coatings. These materials are typically prepared using waterborne heterogeneous systems such as emulsion, miniemulsion, and suspension polymerization. However, all of these processes are limited to water-stable catalysts and monomers mainly polymerizable via radical polymerization. In this Account, we describe a method to overcome this limitation: nonaqueous emulsions can serve as a versatile tool for the synthesis of new types of polymer nanoparticles. To form these emulsions, we first needed to find two nonmiscible nonpolar/polar aprotic organic solvents. We used solvent mixtures of either DMF or acetonitrile in alkanes and carefully designed amphiphilic block and statistical copolymers, such as polyisoprene- b-poly(methyl methacrylate) (PI- b-PMMA), as additives to stabilize these emulsions. Unlike aqueous emulsions, these new emulsion systems allowed the use of water-sensitive monomers and catalysts. Although polyaddition and polycondensation reactions usually lead to a large number of side products and only to oligomers in the aqueous phase, these new conditions resulted in high-molecular-weight, defect-free polymers. Furthermore, conducting nanoparticles were produced by the iron(III)-induced synthesis of poly(ethylenedioxythiophene) (PEDOT) in an emulsion of acetonitrile in cyclohexane. Because metallocenes are sensitive to nitrile and carbonyl groups, the acetonitrile and DMF emulsions were not suitable for carrying out metallocene-catalyzed olefin polymerization. Instead, we developed a second system, which consists of alkanes dispersed in perfluoroalkanes. In this case, we designed a new amphipolar polymeric emulsifier with fluorous and aliphatic side chains to stabilize the emulsions. Such heterogeneous mixtures facilitated the catalytic polymerization of ethylene or propylene to give spherical nanoparticles of high molecular weight polyolefins. These nonaqueous systems also allow for the combination of different polymerization techniques to obtain complex architectures such as core-shell structures. Previously, such structures primarily used vinylic monomers, which greatly limited the number of polymer combinations. We have demonstrated how nonaqueous emulsions allow the use of a broad variety of hydrolyzable monomers and sensitive catalysts to yield polyester, polyurethane, polyamide, conducting polymers, and polyolefin latex particles in one step under ambient reaction conditions. This nonpolar emulsion strategy dramatically increases the chemical palette of polymers that can form nanoparticles via emulsion polymerization.

Physical stability of 20% lipid injectable emulsions via simulated syringe infusion: effects of glass vs plastic product packaging.

PubMed

Driscoll, David F; Ling, Pei-Ra; Bistrian, Bruce R

2007-01-01

The United States Pharmacopeia (USP) has proposed large-globule-size limits to ensure the physical stability of lipid injectable emulsions, expressed as the percent fat >5 microm, or PFAT(5), not exceeding 0.05%. Visibly obvious phase separation as free oil has been shown to occur in some samples if PFAT(5) is >0.4%. We recently found that lipids, newly packaged in plastic (P), exceed the proposed USP limits and seem to produce less stable total nutrient admixtures compared with those made from conventional glass (G), which do meet proposed USP standards. We tested the possible stability differences between 20% lipid injectable emulsions in either P or G in a simulated neonatal syringe infusion study. Eighteen individual syringes were prepared from each 20% lipid injectable emulsion product (n = 36) and attached to a syringe pump set at an infusion rate of 0.5 mL/hour. The starting PFAT(5) levels were measured at time 0 and after 24 hours of infusion, using a laser-based light obscuration technique as described by the USP Chapter <729>. The data were assessed by a 2-way analysis of variance (ANOVA) with Container (G vs P) and Time as the independent variables and PFAT as the dependent variable. At time 0, the starting PFAT(5) level for lipids packaged in G was 0.006% +/- 0.001% vs 0.162% +/- 0.026% for P, whereas at the end of the infusion they were 0.013% +/- 0.003% and 0.328% +/- 0.046%, respectively. Significant differences were noted overall between groups for Container, Time, and Container-Time interaction (all p < .001). Bonferroni tests showed significant differences in PFAT(5) levels between Containers at time 0 (T-0; p < .001) and T-0 vs T-24 for P-based lipids (p < .001), whereas no such differences were noted for Time for the G-based lipids. Similar results were noted for PFAT(10) levels. We confirm that presently available lipid injectable emulsions packaged in newly introduced plastic containers exceed the proposed USP <729> PFAT(5) limits and subsequently become significantly less stable during a simulated syringe-based infusion. Although modest growth (p = NS) in large-diameter fat globules was observed for the glass-based lipids, they remained within proposed USP globule size limits throughout the study. Glass-based lipids seem to be a more stable dosage form and potentially a safer way to deliver lipids via syringe infusion to critically ill neonates.

Conditions associated with Clostridium sporogenes growth as a surrogate for Clostridium botulinum in nonthermally processed canned butter.

PubMed

Taylor, R H; Dunn, M L; Ogden, L V; Jefferies, L K; Eggett, D L; Steele, F M

2013-05-01

The objective of this study was to better understand the effect of butter composition and emulsion structure on growth and survival of Clostridium sporogenes, used as a surrogate for C. botulinum in canned butter. The lack of a thermal process step in commercially available canned butter raises questions of potential safety, because it is hermetically sealed and generally exhibits anaerobic growth conditions, which are optimal for Clostridium botulinum growth. Without thermal processing, low-acid canned foods must have inhibitory factors present to prevent C. botulinum growth. Some potential intrinsic inhibitory factors, or hurdles, within butter include: reduced water activity, acidity in cultured products, elevated salt content, and the micro-droplet nature of the aqueous phase in the butter emulsion. It was hypothesized that a normal, intact butter emulsion would have sufficient hurdles to prevent C. botulinum growth, whereas a broken butter emulsion would result in a coalesced aqueous phase that would allow for C. botulinum growth. Batch-churned butter was inoculated with C. sporogenes; butter samples with varying salt contents (0, 0.8, 1.6, and 2.4% wt/wt NaCl) were prepared and stored in coated steel cans for varying times (1 or 2 wk) and temperatures (22 or 41°C) to determine temperature and emulsion structure effects on C. sporogenes growth. Samples stored at 41°C showed a significant increase in C. sporogenes growth compared with those stored at 22°C. Furthermore, NaCl addition was found to have a significant effect on C. sporogenes growth, with 0.8% NaCl promoting more growth than 0%, but with decreases in growth observed at 1.6 and 2.4%. Uninoculated control plates were also found to have bacterial growth; this growth was attributed to other anaerobic bacteria present within the cream. It was concluded that removal of the hurdle created by the micro-droplet size of the emulsion aqueous phase could result in C. botulinum growth even at elevated salt levels and, therefore, home preparation of canned butter is not advisable. It is also possible that commercially canned butter, if heat abused, could potentially allow for C. botulinum growth and, therefore, consumption is not recommended. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effect of the coexistence of sodium caseinate and Tween 20 as stabilizers of food emulsions at acidic pH.

PubMed

Perugini, Luisa; Cinelli, Giuseppe; Cofelice, Martina; Ceglie, Andrea; Lopez, Francesco; Cuomo, Francesca

2018-02-05

In the present investigation the properties of edible nanoemulsions were studied. Sodium caseinate represents a good candidate for food emulsion preparations thanks to its surface-active properties and because it is perceived as a natural product by consumers. Nevertheless, it is very sensitive to acidic pH close to its isoelectric point and, if used as emulsion stabilizer, this aspect can negatively affect the emulsion stability. In order to prevent this drawback, sodium caseinate was used in combination with a non-ionic surfactant (Tween 20) as emulsifier of oil/water nanoemulsions. For these reasons, nanoemulsions stabilized by Tween 20, sodium caseinate and by a blend of the two emulsifiers were studied and compared according to their response to pH variations. Nanoemulsions were characterized for size of the dispersed phase with variation of time and temperature, for their rheological properties, for surface charge as a function of pH and for protein fluorescence. Noticeably, it was ascertained that, at pH close to caseinate isoelectric point, emulsions stabilized with the blend of caseinate and Tween 20 were more stable, compared with emulsions stabilized only with sodium caseinate. Such behavior was explained according to the composition of the emulsifiers at the oil/water interface where, at acidic pH, the presence of Tween 20 ensured the steric stabilization thus improving the role of sodium caseinate as emulsion stabilizer. Copyright © 2018 Elsevier B.V. All rights reserved.

The development of self-emulsifying oil-in-water emulsion adjuvant and an evaluation of the impact of droplet size on performance.

PubMed

Shah, Ruchi R; Dodd, Stephanie; Schaefer, Mary; Ugozzoli, Mildred; Singh, Manmohan; Otten, Gillis R; Amiji, Mansoor M; O'Hagan, Derek T; Brito, Luis A

2015-04-01

Microfluidization is an established technique for preparing emulsion adjuvant formulations for use in vaccines. Although this technique reproducibly yields high-quality stable emulsions, it is complex, expensive, and requires proprietary equipment. For this study, we developed a novel and simple low shear process to prepare stable reproducible emulsions without the use of any proprietary equipment. We found this process can produce a wide range of differently sized emulsions based on the modification of ratios of oil and surfactants. Using this process, we prepared a novel 20-nm-sized emulsion that was stable, reproducible, and showed adjuvant effects. During evaluation of this emulsion, we studied a range of emulsions with the same composition all sized below 200; 20, 90, and 160 nm in vivo and established a correlation between adjuvant size and immune responses. Our studies indicate that 160-nm-sized emulsions generate the strongest immune responses. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

ASSESSMENT OF A STABLE COSMETIC PREPARATION BASED ON ENZYMATIC INTERESTERIFIED FAT, PROPOSED IN THE PREVENTION OF ATOPIC DERMATITIS.

PubMed

Kowalska, Malgorzata; Mendrycka, Mariola; Zbikowska, Anna; Kowalska, Dorota

2017-03-01

Atopic dermatitis is one of the most common skin disorders seen in infants, children and adults. Proper prevention might slow the atopic symptoms. The purpose of the work was a sensory analysis, an evaluation of moistening properties and stability of emulsions based on an enzymatic interesterified fat blend (mutton tallow and walnut oil) and homogenized at different revolutions and different contents of thickener. The emulsions were evaluated with respect to sensory and skin moisturizing properties by 78 respondents. Stability tests, particle size, distribution, dispersity index, morphology structure of the emulsions were determinated too. Taking into consideration all properties of the emulsions, emulsion IV (containing 0.9 g carboxymethyl cellulose and homogenized at 18000 rpm) and emulsion V (1.5 g of carboxymethyl cellulose and homogenized at 24000 rpm) were found to be of optimum composition. The emulsions exhibited good stability, were highly rated in sensory terms and displayed optimum moistening properties. It has been proven that model emulsions based on interesterified fats containing partial acylglicerols, with optimum carboxymethyl cellulose content and specific revolutions at the time of homogenization are an opportunity for developing preparations targeted at skins requiring special care (e.g., with atopic dermatitis or psoriasis). The work proved the use of enzymatic process to create the emulsifier, which represents the innovative contribution of this work. Also it showed an additional application of enzymatic interesterified fats which since has been used only in food industries.

Multi-omic profiles of hepatic metabolism in TPN-fed preterm pigs

USDA-ARS?s Scientific Manuscript database

New generation lipid emulsions comprised of fish oil or blends of soybean/fish/medium chain triglyceride/olive oil are emerging that result in favorable clinical metabolic outcomes in pediatric populations. Our aim was to characterize the lipidodomic, metabolomic, and transcriptomic profiles these ...

Intra-arterial idarubicin_lipiodol without embolisation in hepatocellular carcinoma: The LIDA-B phase I trial.

PubMed

Guiu, Boris; Jouve, Jean-Louis; Schmitt, Antonin; Minello, Anne; Bonnetain, Franck; Cassinotto, Christophe; Piron, Lauranne; Cercueil, Jean-Pierre; Loffroy, Romaric; Latournerie, Marianne; Wendremaire, Maëva; Lepage, Côme; Boulin, Mathieu

2018-06-01

Idarubicin shows high cytotoxicity against hepatocellular carcinoma (HCC) cells, a high hepatic extraction ratio, and high lipophilicity leading to stable emulsions with lipiodol. A dose-escalation phase I trial of idarubicin_lipiodol (without embolisation) was conducted in patients with cirrhotic HCC to estimate the maximum-tolerated dose (MTD) and to assess the safety, efficacy, and pharmacokinetics of the drug, and the health-related quality of life achieved by patients. Patients underwent two sessions of treatment with a transarterial idarubicin_lipiodol emulsion without embolisation. The idarubicin dose was escalated according to a modified continuous reassessment method. The MTD was defined as the dose closest to that causing dose-limiting toxicity (DLT) in 20% of patients. A group of 15 patients were enrolled, including one patient at 10 mg, four patients at 15 mg, seven patients at 20 mg, and three patients at 25 mg. Only two patients experienced DLT: oedematous ascitic decompensation and abdominal pain at 20 and 25 mg, respectively. The calculated MTD of idarubicin was 20 mg. The most frequent grade ≥3 adverse events were biological. One month after the second session, the objective response rate was 29% (complete response, 0%; partial response, 29%) based on modified Response Evaluation Criteria In Solid Tumours. The median time to progression was 5.4 months [95% confidence limit (CI) 3.0-14.6 months] and median overall survival was 20.6 months (95% CI 5.7-28.7 months). Pharmacokinetic analysis of idarubicin showed that the mean C max of idarubicin after intra-arterial injection of the idarubicin-lipiodol emulsion is approximately half the C max after intravenous administration. Health-related quality of life results confirmed the good safety results associated with use of the drug. The MTD of idarubicin was 20 mg after two chemolipiodolisation sessions. Encouraging safety results, and patient responses and survival were observed. A phase II trial has been scheduled. There is a need for transarterial regimens that improve the responses and survival of patients with unresectable HCC. In this phase I trial, we showed that two sessions of treatment with a transarterial idarubicin_lipiodol emulsion without embolisation was well tolerated and gave promising efficacy in terms of tumour control and patient survival. Copyright © 2018 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Reversed phase HPLC analysis of stability and microstructural effects on degradation kinetics of β-carotene encapsulated in freeze-dried maltodextrin-emulsion systems.

PubMed

Harnkarnsujarit, Nathdanai; Charoenrein, Sanguansri; Roos, Yrjö H

2012-09-26

Degradation of dispersed lipophilic compounds in hydrophilic solids depends upon matrix stability and lipid physicochemical properties. This study investigated effects of solid microstructure and size of lipid droplets on the stability of dispersed β-carotene in freeze-dried systems. Emulsions of β-carotene in sunflower oil were dispersed in maltodextrin systems (M040/DE6, M100/DE11, and M250/DE25.5) (8% w/w oil) and prefrozen at various freezing conditions prior to freeze-drying to control nucleation and subsequent pore size and structural collapse of freeze-dried solids. The particle size, physical state, and β-carotene contents of freeze-dried emulsions were measured during storage at various water activity (a(w)) using a laser particle size analyzer, differential scanning calorimeter, and high performance liquid chromatography (HPLC), respectively. The results showed that M040 stabilized emulsions in low temperature freezing exhibited lipid crystallization. Collapse of solids in storage at a(w) which plasticized systems to the rubbery state led to flow and increased the size of oil droplets. Degradation of β-carotene analyzed using a reversed-phase C(30) column followed first-order kinetics. Porosity of solids had a major effect on β-carotene stability; however, the highest stability was found in fully plasticized and collapsed solids.

Influence of ionic complexation on release rate profiles from multiple water-in-oil-in-water (W/O/W) emulsions.

PubMed

Bonnet, Marie; Cansell, Maud; Placin, Frédéric; David-Briand, Elisabeth; Anton, Marc; Leal-Calderon, Fernando

2010-07-14

Water-in-oil-in-water (W/O/W) double emulsions were prepared, and the kinetics of release of magnesium ions from the internal to the external water phase was followed. Different chelating agents (phosvitin and gluconate) were used to bind magnesium within the prospect of improving the ion retention in the internal aqueous droplets. Magnesium release was monitored for 1 month of storage, for each formulation, with and without chelation, at two storage temperatures (4 and 25 degrees C). Leakage occurred without film rupturing (coalescence) and was mainly due to entropically driven diffusion/permeation phenomena. The experimental results revealed a clear correlation between the effectiveness of chelating agents to delay the delivery and their binding capacity characterized by the equilibrium affinity constant. The kinetic data (percent released versus time curves) were interpreted within the framework of a kinetic model based on diffusion and taking into account magnesium chelation.

The role of lecithin degradation on the pH dependent stability of halofantrine encapsulated fat nano-emulsions.

PubMed

Haidar, Iman; Harding, Ian H; Bowater, Ian C; Eldridge, Daniel S; Charman, William N

2017-08-07

We report on the successful incorporation of the antimalarial drug, halofantrine, into laboratory based soybean oil emulsions which were designed to mimic the commercially available parenteral fat emulsion, Intralipid ® . A high pH (minimum of pH 9, preferable pH of 11) was required for the drug laden emulsion to remain stable on storage and also to resist breaking under various stresses. Ageing of lecithin samples on storage was noted to result in degradation and a decrease in pH. We argue that this is the main reason for a similar decrease in pH for lecithin based emulsions and subsequent instability in drug laden emulsions. As expected, incorporation of the drug (halofantrine) resulted in lower stability. The (intensity weighted) particle size increased from 281nm for the drug free emulsion to 550nm following a loading of 1gL -1 of halofantrine, indicative of a lowering in stability and this was reflected in a shorter shelf life. Interestingly, incorporation of even higher concentrations of drug then resulted in better stability albeit never as stable as the drug free emulsion. We also report on unusual and complex surface tension behaviour for fresh lecithin where multiple critical concentration points were observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Emulsion Composition on Pulmonary Tobramycin Delivery During Antibacterial Perfluorocarbon Ventilation

PubMed Central

Orizondo, Ryan A.; Fabiilli, Mario L.; Morales, Marissa A.

2016-01-01

Abstract Background: The effectiveness of inhaled aerosolized antibiotics is limited by poor ventilation of infected airways. Pulmonary delivery of antibiotics emulsified within liquid perfluorocarbon [antibacterial perfluorocarbon ventilation (APV)] may solve this problem through better airway penetration and improved spatial uniformity. However, little work has been done to explore emulsion formulation and the corresponding effects on drug delivery during APV. This study investigated the effects of emulsion formulation on emulsion stability and the pharmacokinetics of antibiotic delivery via APV. Methods: Gravity-driven phase separation was examined in vitro by measuring emulsion tobramycin concentrations at varying heights within a column of emulsion over 4 hours for varying values of fluorosurfactant concentration (Cfs = 5–48 mg/mL H2O). Serum and pulmonary tobramycin concentrations in rats were then evaluated following pulmonary tobramycin delivery via aerosol or APV utilizing sufficiently stable emulsions of varying aqueous volume percentage (Vaq = 1%–5%), aqueous tobramycin concentration (Ct = 20–100 mg/mL), and Cfs (15 and 48 mg/mL H2O). Results: In vitro assessment showed sufficient spatial and temporal uniformity of tobramycin dispersion within emulsion for Cfs ≥15 mg/mL H2O, while lower Cfs values showed insufficient emulsification even immediately following preparation. APV with stable emulsion formulations resulted in 5–22 times greater pulmonary tobramycin concentrations at 4 hours post-delivery relative to aerosolized delivery. Concentrations increased with emulsion formulations utilizing increased Vaq (with decreased Ct) and, to a lesser extent, increased Cfs. Conclusions: The emulsion stability necessary for effective delivery is retained at Cfs values as low as 15 mg/mL H2O. Additionally, the pulmonary retention of antibiotic delivered via APV is significantly greater than that of aerosolized delivery and can be most effectively increased by increasing Vaq and decreasing Ct. APV has been further proven as an effective means of pulmonary drug delivery with the potential to significantly improve antibiotic therapy for lung disease patients. PMID:26741303

Natural Oil-Based Emulsion Containing Allantoin Versus Aqueous Cream for Managing Radiation-Induced Skin Reactions in Patients With Cancer: A Phase 3, Double-Blind, Randomized, Controlled Trial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Raymond Javan, E-mail: email.rchan@gmail.com; School of Nursing, Queensland University of Technology, Kelvin Grove; Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove

Purpose: To investigate the effects of a natural oil-based emulsion containing allantoin versus aqueous cream for preventing and managing radiation-induced skin reactions. Methods and Materials: A total of 174 patients were randomized and participated in the study. Patients received either cream 1 (the natural oil-based emulsion containing allantoin) or cream 2 (aqueous cream). Skin toxicity, pain, itching, and skin-related quality of life scores were collected for up to 4 weeks after radiation treatment. Results: Patients who received cream 1 had a significantly lower average level of Common Terminology Criteria for Adverse Events at week 3 (P<.05) but had statistically higher averagemore » levels of skin toxicity at weeks 7, 8, and 9 (all P<.001). Similar results were observed when skin toxicity was analyzed by grades. With regards to pain, patients in the cream 2 group had a significantly higher average level of worst pain (P<.05) and itching (P=.046) compared with the cream 1 group at week 3; however, these differences were not observed at other weeks. In addition, there was a strong trend for cream 2 to reduce the incidence of grade 2 or more skin toxicity in comparison with cream 1 (P=.056). Overall, more participants in the cream 1 group were required to use another topical treatment at weeks 8 (P=.049) and 9 (P=.01). Conclusion: The natural oil-based emulsion containing allantoin seems to have similar effects for managing skin toxicity compared with aqueous cream up to week 5; however, it becomes significantly less effective at later weeks into the radiation treatment and beyond treatment completion (week 6 and beyond). There were no major differences in pain, itching, and skin-related quality of life. In light of these results, clinicians and patients can base their decision on costs and preferences. Overall, aqueous cream seems to be a more preferred option.« less

Dynamics of Unjammed Emulsions

NASA Astrophysics Data System (ADS)

Guerra, Rodrigo; Kodger, Thomas; Weitz, David

2014-03-01

Light scattering and NMR densitometry measurements of quiescent emulsions have shown that amorphous packings of soft, repulsive droplets unjam at osmotic pressures 105 times larger than the typical droplet thermal energy density: 3kB/T 4 πR3. This transition corresponds to the pressure at which the thermal fluctuations of individual droplet positions match the yield strain of the packing and drive the fluidization of the material. We use confocal microscopy to investigate the microscopic dynamics of this fluid-like phase and find them to be fundamentally different from those of conventional glass-forming liquids; cage-breaking dynamics are not evident from droplet mean squared displacements and the effective viscosity of the emulsion, though 105 larger than the background fluid, appears largely insensitive to the confining pressure.

Enhanced fish oil-in-water emulsions enabled by rapeseed lecithins obtained under different processing conditions.

PubMed

Li, Jingbo; Pedersen, Jacob Nedergaard; Anankanbil, Sampson; Guo, Zheng

2018-10-30

It is hypothesized that rapeseed lecithins may have different emulsifying and antioxidant properties in delivering fish oil compared to soy lecithin based on previous studies. The results showed that in vitro antioxidant activities of rapeseed lecithins were stronger than those of soy lecithin. Emulsions stabilized by rapeseed based lecithins and DATEM were stable over 3 months at 4 °C, whereas the creaming of emulsions containing soy lecithin started immediately after its preparation. Zeta-potential of rapeseed lecithins was higher than soy lecithin and DATEM, which partially contributed to the emulsion stability. Although the particle sizes of emulsions prepared by rapeseed lecithins increased after 14 days storage, no creaming was observed. Lipid oxidation as indicated by TBARS values suggested that DATEM was the most unfavorable, followed by soy lecithin. It is concluded that rapeseed lecithins are better than soy lecithin and DATEM in terms of emulsion stability and antioxidant capability, respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

Studies on the formation of polymeric nano-emulsions obtained via low-energy emulsification and their use as templates for drug delivery nanoparticle dispersions.

PubMed

Calderó, G; Montes, R; Llinàs, M; García-Celma, M J; Porras, M; Solans, C

2016-09-01

Ethylcellulose nanoparticles have been obtained from O/W nano-emulsions of the water/polyoxyethylene 10 oleyl ether/[ethyl acetate+4wt% ethylcellulose] system by low energy-energy emulsification at 25°C. Nano-emulsions with droplet sizes below 200nm and high kinetic stability were chosen for solubilising dexamethasone (DXM). Phase behaviour, conductivity and optical analysis studies of the system have evidenced for the first time that both, the polymer and the drug play a role on the structure of the aggregates formed along the emulsification path. Nano-emulsion formation may take place by both, phase inversion and self-emulsification. Spherical polymeric nanoparticles containing surfactant, showing sizes below 160nm have been obtained from the nano-emulsions by organic solvent evaporation. DXM loading in the nanoparticles was high (>90%). The release kinetics of nanoparticle dispersions with similar particle size and encapsulated DXM but different polymer to surfactant ratio were studied and compared to an aqueous DXM solution. Drug release from the nanoparticle dispersions was slower than from the aqueous solution. While the DXM solution showed a Fickian release pattern, the release behaviour from the nanoparticle dispersions was faster than that expected from a pure Fickian release. A coupled diffusion/relaxation model fitted the results very well, suggesting that polymer chains undergo conformational changes enhancing drug release. The contribution of diffusion and relaxation to drug transport in the nanoparticle dispersions depended on their composition and release time. Surfactant micelles present in the nanoparticle dispersion may exert a mild reservoir effect. The small particle size and the prolonged DXM release provided by the ethylcellulose nanoparticle dispersions make them suitable vehicles for controlled drug delivery applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Modulating in vitro gastric digestion of emulsions using composite whey protein-cellulose nanocrystal interfaces.

PubMed

Sarkar, Anwesha; Zhang, Shuning; Murray, Brent; Russell, Jessica A; Boxal, Sally

2017-10-01

In this study, we designed emulsions with an oil-water interface consisting of a composite layer of whey protein isolate (WPI, 1wt%) and cellulose nanocrystals (CNCs) (1-3wt%). The hypothesis was that a secondary layer of CNCs at the WPI-stabilized oil-water interface could protect the interfacial protein layer against in vitro gastric digestion by pepsin at 37°C. A combination of transmission electron microscopy, ζ-potential measurements, interfacial shear viscosity measurements and theoretical surface coverage considerations suggested the presence of CNCs and WPI together at the O/W interface, owing to the electrostatic attraction between complementarily charged WPI and CNCs at pH 3. Microstructural analysis and droplet sizing revealed that the presence of CNCs increased the resistance of the interfacial protein film to rupture by pepsin, thus inhibiting droplet coalescence in the gastric phase, which occurs rapidly in an emulsion stabilized by WPI alone. It appeared that there was an optimum concentration of CNCs at the interface for such barrier effects. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) results further confirmed that the presence of 3wt% of CNCs reduced the rate and extent of proteolysis of protein at the interface. Besides, evidence of adsorption of CNCs to the protein-coated droplets to form more rigid layers, there is also the possibility that network formation by the CNCs in the bulk (continuous) phase reduced the kinetics of proteolysis. Nevertheless, structuring emulsions with mixed protein-particle layers could be an effective strategy to tune and control interfacial barrier properties during gastric passage of emulsions. Copyright © 2017 Elsevier B.V. All rights reserved.

A comparative study on the capacity of a range of food-grade particles to form stable O/W and W/O Pickering emulsions.

PubMed

Duffus, Laudina J; Norton, Jennifer E; Smith, Paul; Norton, Ian T; Spyropoulos, Fotios

2016-07-01

Whilst literature describing edible Pickering emulsions is becoming increasingly available, current understanding of these systems still suffers from a lack of consistency in terms of the (processing and formulation) conditions within which these structures have been studied. The current study aims to provide a comparative analysis of the behaviour of different edible Pickering candidates and their ability to stabilise emulsion droplets, under well-controlled and uniform experimental conditions, in order to clearly identify the particle properties necessary for successful Pickering functionality. More specifically, an extensive investigation into the suitability of various food-grade material to act as Pickering particles and provide stable oil-in-water (O/W) and water-in-oil (W/O) emulsions was carried out. Polysaccharide and flavonoid particles were characterised in terms of their size, ζ-potential, interfacial activity and wettability, under equivalent conditions. Particles were subsequently used to stabilise 20% w/w O/W and W/O emulsions, in the absence of added surfactant or other known emulsifying agents, through different processing routes. All formed Pickering emulsions were shown to resist significant droplet size variation and remain stable at particle concentrations between 2 and 3% w/w. The main particle prerequisites for successful Pickering stabilisation were: particle size (200nm - 1μm); an affinity for the emulsion continuous phase and a sufficient particle charge to extend stability. Depending upon the employed emulsification process, the resulting emulsion formation and stability behaviour can be reasonably predicted a priori from the evaluation of specific particle characteristics. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Impact of model fat emulsions on sensory perception using repeated spoon to spoon ingestion.

PubMed

Appelqvist, I A M; Poelman, A A M; Cochet-Broch, M; Delahunty, C M

2016-06-01

Eating is a dynamic behaviour, in which food interacts with the mechanical and physiological environment of the mouth. This dynamic interaction changes the oral surfaces leaving particles of food and building up a film on the oral surfaces, which may impact on the temporal perception during the eating experience. The effect of repeated spoon to spoon ingestion of oil in water emulsion products (2%-50% w/w oil) was evaluated using descriptive in-mouth and after swallowing sensory attributes. Descriptive sensory analysis indicated that fatty mouthfeel and afterfeel perception (measured post swallowing) increased with the number of spoonfuls for emulsions containing 50% fat. This effect is likely due to the build-up of oil droplet layers deposited on the mouth surfaces. There was an enhancement of fatty afterfeel intensity for 50% fat emulsions containing the more lipophilic aroma ethylhexanoate compared to ethyl butanoate, indicating a cross-modal interaction. No increase in these attributes from spoon to spoon was observed for the low oil emulsions; since most of the oil in the emulsion was swallowed and very little oil was likely to be left in the mouth. Sweetness perception increased as fat level increased in the emulsion due to an increase in the effective concentration of sugar in the aqueous phase. However, the sweetness perceived did not change from spoon to spoon, suggesting that any oil-droplets deposited on the oral surfaces did not form a complete barrier, restricting access of the sucrose to the taste buds. This study highlights the importance of measuring the dynamic nature of eating and demonstrated change in sensory perception occurring with repeated ingestion of model emulsions, which was likely due to a change in mouth environment. Copyright © 2016 Elsevier Inc. All rights reserved.

Structurally Stable Attractive Nanoscale Emulsions with Dipole-Dipole Interaction-Driven Interdrop Percolation.

PubMed

Shin, Kyounghee; Gong, Gyeonghyeon; Cuadrado, Jonas; Jeon, Serim; Seo, Mintae; Choi, Hong Sung; Hwang, Jae Sung; Lee, Youngbok; Fernandez-Nieves, Alberto; Kim, Jin Woong

2017-03-28

This study introduces an extremely stable attractive nanoscale emulsion fluid, in which the amphiphilic block copolymer, poly(ethylene oxide)-block-poly(ϵ-caprolactone) (PEO-b-PCL), is tightly packed with lecithin, thereby forming a mechanically robust thin-film at the oil-water interface. The molecular association of PEO-b-PCL with lecithin is critical for formation of a tighter and denser molecular assembly at the interface, which is systematically confirmed by T 2 relaxation and DSC analyses. Moreover, suspension rheology studies also reflect the interdroplet attractions over a wide volume fraction range of the dispersed oil phase; this results in a percolated network of stable drops that exhibit no signs of coalescence or phase separation. This unique rheological behavior is attributed to the dipolar interaction between the phosphorylcholine groups of lecithin and the methoxy end groups of PEO-b-PCL. Finally, the nanoemulsion system significantly enhances transdermal delivery efficiency due to its favorable attraction to the skin, as well as high diffusivity of the nanoscale emulsion drops. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel submicron emulsion system loaded with vincristine–oleic acid ion-pair complex with improved anticancer effect: in vitro and in vivo studies

PubMed Central

Zhang, Ting; Zheng, Yong; Peng, Qiang; Cao, Xi; Gong, Tao; Zhang, Zhirong

2013-01-01

Background Vincristine (VCR), which is a widely used antineoplastic drug, was integrated with a submicron-emulsion drug-delivery system to enhance the anticancer effect. Methods After the formation of a VCR-oleic acid ion-pair complex (VCR-OA), the VCR-OA-loaded submicron emulsion (VCR-OA-SME), prepared by classical high-pressure homogenization, was characterized and its in vitro anticancer effects were evaluated. Results The submicron-emulsion formulation exhibited a homogeneous round shape. The mean particle size, zeta potential, and encapsulation efficiency were 157.6 ± 12.6 nm, −26.5 ± 5.0 mV and 78.64% ± 3.44%, respectively. An in vitro release study of the VCR-OA-SME revealed that 12.4% of the VCR was released within the first 2 hours (initial burst-release phase) and the rest of the drug was detected in the subsequent sustained-release phase. Compared with VCR solution, the pharmacokinetic study of VCR-OA-SME showed relatively longer mean residence time (mean residence time [0–∞] increased from 187.19 to 227.56 minutes), higher maximum concentration (from 252.13 ng/mL to 533.34 ng/mL), and greater area under the curve (area under the curve [0–∞] from 11,417.77 μg/L/minute to 17,164.34 μg/L/minute. Moreover, the VCR-OA-SME exhibited higher cytotoxicity (P < 0.05) on tumor cells by inducing cell arrest in the G2/M phase or even apoptosis (P < 0.05). Conclusion The VCR-OA-SME formulation in our study displayed great potential for an anticancer effect for VCR. PMID:23658485

Effect of molecular exchange on water droplet size analysis as determined by diffusion NMR: The W/O/W double emulsion case.

PubMed

Vermeir, Lien; Sabatino, Paolo; Balcaen, Mathieu; Declerck, Arnout; Dewettinck, Koen; Martins, José C; Guthausen, Gisela; Van der Meeren, Paul

2016-08-01

The accuracy of the inner water droplet size determination of W/O/W emulsions upon water diffusion measurement by diffusion NMR was evaluated. The resulting droplet size data were compared to the results acquired from the diffusion measurement of a highly water soluble marker compound with low permeability in the oil layer of a W/O/W emulsion, which provide a closer representation of the actual droplet size. Differences in droplet size data obtained from water and the marker were ascribed to extra-droplet water diffusion. The diffusion data of the tetramethylammonium cation marker were measured using high-resolution pulsed field gradient NMR, whereas the water diffusion was measured using both low-resolution and high-resolution NMR. Different data analysis procedures were evaluated to correct for the effect of extra-droplet water diffusion on the accuracy of water droplet size analysis. Using the water diffusion data, the use of a low measurement temperature and diffusion delay Δ could reduce the droplet size overestimation resulting from extra-droplet water diffusion, but this undesirable effect was inevitable. Detailed analysis of the diffusion data revealed that the extra-droplet diffusion effect was due to an exchange between the inner water phase and the oil phase, rather than by exchange between the internal and external aqueous phase. A promising data analysis procedure for retrieving reliable size data consisted of the application of Einstein's diffusion law to the experimentally determined diffusion distances. This simple procedure allowed determining the inner water droplet size of W/O/W emulsions upon measurement of water diffusion by low-resolution NMR at or even above room temperature. Copyright © 2016 Elsevier Inc. All rights reserved.

Microrheology and microstructure of water-in-water emulsions containing sodium caseinate and locust bean gum.

PubMed

Moschakis, Thomas; Chantzos, Nikos; Biliaderis, Costas G; Dickinson, Eric

2018-05-23

The mechanical response on the microscale of phase-separated water-in-water emulsions containing sodium caseinate (SCN) and locust bean gum (LBG) has been monitored by confocal laser scanning microscopy and particle tracking microrheology. Mixed biopolymer systems exhibiting phase-separated micro-regions were enriched in either protein or polysaccharide in the continuous or dispersed phase, depending on the weight ratio of the two biopolymers. Measurements of the tracking of charged probe particles revealed that the local rheological properties of protein-rich regions were considerably lower than that of LBG-rich domains for all the biopolymer ratios examined. At pH 7 in the absence of added salt, the viscosity of the protein-rich regions was little affected by an increase in overall LBG concentration, which is consistent with the phase separation mechanism in the mixed solution of charged (SCN) and uncharged (LBG) biopolymers being dominated by the relative entropy of the counter-ions associated with the charged protein molecules. Addition of salt was found to produce an enhancement in the level of thermodynamic incompatibility, leading to faster and more pronounced phase separation, and altering the micro-viscosity of protein-rich regions. At high ionic strength, it was also noted that there was a pronounced accumulation of incorporated probe particles at the liquid-liquid interface. The microrheological properties of the SCN-rich regions were found to be substantially pH-dependent in the range 7 > pH > 5.4. By adjusting the acidification conditions and the biopolymer ratio, discrete protein-based microspheres were generated with potential applications as a functional food ingredient.