Emulsion Phase Research Articles

Enhanced bactericidal effect of ceftriaxone drug encapsulated in nanostructured lipid carrier against gram-negative Escherichia coli bacteria: drug formulation, optimization, and cell culture study

BackgroundCeftriaxone is one of the most common types of antibiotics used to treat most deadly bacterial infections. One way to alleviate the side effects of medication is to reduce drug consumption by changing the ordinary drug forms into nanostructured forms. In this study, a nanostructured lipid carrier (NLC) containing hydrophilic ceftriaxone sodium drug is developed, and its effect on eliminating gram-negative bacteria Escherichia coli death is investigated.MethodsDouble emulsion solvent evaporation method is applied to prepare NLC. Mathematical modeling based on the solubility study is performed to select the best materials for NLC preparation. Haftyzer-Van Krevelen and Hoy’s models are employed for this purpose. Drug release from optimized NLC is examined under in vitro environment. Then, the efficacy of the optimized sample on eliminating gram-negative bacteria Escherichia coli is investigated.ResultsMathematical modeling reveals that both methods are capable of predicting drug encapsulation efficiency trends by chaining solid and liquid lipids. However, Haftyzer-Van Krevelen’s method can precisely predict the particle size trend by changing the surfactant types in water and oily phases of emulsions. The optimal sample has a mean particle size of 86 nm and drug entrapment efficiency of 83%. Also, a controlled drug release in prepared nanostructures over time is observed under in-vitro media. The results regarding the effectiveness of optimized NLC in killing Escherichia coli bacteria suggests that by cutting drug dosage of the nanostructured form in half, an effect comparable to that of free drug can be observed at longer times.ConclusionResults confirm that NLC structure is an appropriate alternative for the delivery of ceftriaxone drug with a controlled release behavior.

Emblicanin Rich Emblica officinalis Encapsulated Double Emulsion and its Antioxidant Stability during Storage

AbstractEmblicanin rich water‐soluble extract of Emblica officinalis (EEO) is encapsulated in the inner phase of double emulsion (DE) by using emulsifiers in different phases at different concentrations. The effects of other variables like homogenization speed, salt and herbal concentration are also investigated on various phases of DE to obtain a stable matrix. Finally, optimized EEO encapsulated DE has 2% w/w NaCl and 50% w/w EEO in inner (W1) phase, 4% w/w polyglycerol polyricinoleate (PGPR) in middle oil‐phase and 2% w/w low‐methoxy‐pectin and reverse osmosis water in outer (W2) phase. Ultra‐Turrax high shear homogenizer is employed to prepare primary emulsion (W1/O) at 20 000 rpm and DE (W1/O in W2) at 12 000 rpm. The EEO encapsulated DE has been characterized for encapsulation efficiency (>90%), viscosity (0.715 ± 0.18 Pa s), sedimentation stability, zeta potential (−32.17 ±1.17 mV), and particle size. Light and confocal laser microscopy are used for elaborating the microscopic structure of EEO encapsulated DEs. DE has shown storage stability up to 42 days and protect antioxidant activities as compared to control (herbal extract was not encapsulated in the inner phase). The present study demonstrates that the optimized DE matrix can be used to protect the bioactive properties of EEO for its use in functional food formulation.

Micellar Fd3m cubosomes from monoolein – long chain unsaturated fatty acid mixtures: Stability on temperature and pH response

HypothesisControl of the nanostructure of self-assembled systems may be achieved through manipulation of surfactant molecular packing and interfacial curvature. In order to phase engineer the inverse micellar cubosomes in some monoolein-fatty acid systems, lipids with wedge shaped molecular geometry were incorporated to promote the formation of this phase, that is of interest as potential sustained released nanocarriers. ExperimentsLiquid crystalline nanoparticle dispersions of monoolein with some cis unsaturated fatty acids were prepared and their partial temperature-composition phase diagrams and structure were established using high throughput Small Angle X-ray Scattering (SAXS) and cryogenic transmission electron microscopy (cryo-TEM). The pH responsiveness of these systems was evaluated in the presence of phosphate buffered saline (PBS). FindingsThe partial temperature-composition phase diagrams of five nanoparticle formulations containing monoolein and unsaturated fatty acids were established and identified the presence of micellar cubosomes in each of these systems. The results indicate that temperature, fatty acid concentration and structure, as well as pH all directly impact the formation and stability of this phase. Low energy inverse micellar cubic to emulsion phase transformations were identified in the monoolein with oleic acid and vaccenic acid systems at physiological temperatures that may be advantageous for staged therapeutic release strategies in nanomedicine.

Antibacterial thyme oil-loaded organo-hydrogels utilizing cellulose acetoacetate as reactive polymer emulsifier

Organo-hydrogels are widely used in various fields, due to functional organic ingredients immobilized by the gel network or stored and protected by the gels. Herein, cellulose acetoacetate (CAA) served as reactive natural polymer emulsifier to stabilize thyme oil-in-water (O/W) emulsions. Hydroxypropyl chitosan (HPCS) was added to the continuous phase in emulsions to achieve the organo-hydrogel via the enamine bonds under mild conditions. The thyme@CAA emulsion with different loadings of the inner phase (up to 50%) displayed uniform droplets distribution (3–5 μm) and favorable stability. The organo-hydrogel was systematically analyzed by Fourier transform infrared spectroscopy, optical microscope, rheology analyses. The emulsion droplets evenly dispersed in the three-dimensional network. The modulus of organo-hydrogels depended on the viscosity of precursor emulsions and the crosslinking density. The resulting organo-hydrogel displayed favorable antibacterial activity against E. coli and S. aureus. CAA, as the reactive emulsifier and crosslinking agent, was a promising alternative candidate to fabricate a series of organo-hydrogel.

Selective Attachment of Luminophore-Bearing Emulsion at Diamonds—Mechanism Analysis and Mode Selection

The authors present an efficient modification method of X-ray fluorescence separation with mineral and organic luminophores used to adjust spectral and kinetic characteristics of anomalously luminescent diamonds. The mechanism of attachment of luminophores at diamonds and hydrophobic minerals is proved, including interaction between the organic component of emulsions and the hydrophobic surface of a treated object and the concentration of insoluble luminophore grains at the organic and water interface. Selective attachment of the luminophore-bearing organic phase of emulsion at the diamond surface is achieved owing to phosphatic dispersing agents. Tri-sodium phosphate and sodium hexametaphosphate added to emulsion reduce attachment of the luminophore-bearing organic phase at the surface of kimberlite minerals. It is shown that phosphate concentration of 1.0–1.5 g/l modifies and stabilizes spectral and kinematic parameters of kimberlite mineral on the level of initial values. This mode maintains the spectral and kinematic characteristics of anomalously luminescent diamonds at the wanted level to ensure extraction of diamonds to concentrate.

Nanoemulsion production techniques upgrade bioactivity potential of nanoemulsified essential oils on Acipenser stellatus filet preserving

ABSTRACT The aim of this study was to prepare physically stable nanoemulsions containing three different essential oils (Rosemary, Cuminum, and Zataria Multiflora Boiss) by using two different nanoemulsification methods. Then microbial growth rate, antioxidant, and oxidant content of fresh fish fillet were assessed at 4°C and 10°C temperatures. Essential oils (EOs) were purified from Rosmarinus officinalis L., Zataria multiflora Boiss, and Cuminum cyminum L. and emulsified by two different methods: Ultrasonic Homogenization (USH) and Emulsion Phase Inversion (EPI). Samples of Acipenser stellatus (weight of 10 ± 1 g) were immersed in Nanoemulsified essential oils. Then antibacterial and antioxidant potential of these essential oils was analyzed by culturing in a tube and measuring PV and TBA, respectively, during 1, 3, 7, and 14 days after treatment. Cuminum cyminum L., at 4°C in the USH method reduced the growth of bacteria in the fish sample on all studied bacteria at 5% concentration compared to 3%. Also the results of Cuminum cyminum L. EO made by both methods used to emulsify the oil were better than the other two extracts. As well these results were observed for PV and TBA contents. This study showed that nanoemulsified Cuminum cyminum L. prepared by the USH method has good antioxidant potential and antibacterial effect among other essential oils and it can be used to produce novel natural antioxidants as well as flavoring agents that can be applied in different food products.

Quantification of Iodine Mass Transfer and Height of Emulsion Phase in “Emulsion-flow” Column

Quantification of Iodine Mass Transfer and Height of Emulsion Phase in “Emulsion-flow” Column

Measuring the fast oxidation kinetics of a manganese oxygen carrier using microfluidized bed thermogravimetric analysis

Oxygen carriers play critical roles in chemical looping combustion. A key task in investigating the oxygen carrier reactivity is to measure the redox kinetics in the fluidization state. However, this is still a challenge because one must perform the redox kinetics measurement in a fluidizing environment in order to simulate the strong mass and heat transfer occurring in a practical fluidized bed reactor. Herein, we report a new method, called the microfluidized bed thermogravimetric analysis (MFB-TGA), to measure the kinetics of the redox reactions, specifically the fast oxidation reaction of a manganese ore oxygen carrier. MFB-TGA is based on a real-time mass measurement of a solid sample inside a fluidized bed. The experimental data measured by MFB-TGA are interpreted with a K-L two-phase fluidized bed model to incorporate the effect of the gas concentration change in the emulsion phase. We conclude that the oxidation kinetics of this manganese ore are much faster than those of other oxygen carriers in the published works. Based on the measured oxidation reaction kinetics, the reaction time required in the air reactor is only 2.3–4 s. Therefore, a new design concept for CLC where the air reactor is operated under a dilute-phase transport regime is put forward. The new design of the air reactor has the potential to reduce cost and avoid the hot pot problem, which is a promising choice for future CLC application. In brief, this MFB-TGA method can be applied to measure the fast gas–solid reaction kinetics of any type of oxygen carriers, and thus contributes to providing reliable redox kinetics for chemical looping combustion.

Heat transfer characteristic in an external heat exchanger with horizontal tube bundle

In this research article, experimental study was carried out to obtain the heat transfer characteristics between a submerged horizontal tube bundles and a fluidized bed in a large-scale circulating fluidized bed (CFB) boiler with an external heat exchanger (EHE). Authors used operating conditions of fluidized bed heat exchanger to predict the average heat transfer coefficient (HTC) making use of an existing calculation method based on the packed renewal theory. The operational parameters in the tube EHE were measured during performance tests at variable load conditions. The heat transfer characteristics are considered in terms of heat transfer mechanisms such as emulsion phase convection, gas convection and also thermal radiation. The obtained heat transfer data exhibits a maximum value with variation mean bed particle size irrespective of pressure. The results showed that the average HTC increases with a decrease of the Sauter mean particle diameter and with the increase of the fluidizing number as a result of good mixing dynamics in emulsion phase (i.e. emulsion wall contact time, bubble fraction in the bed). Based on the heat transfer data, empirical correlations are proposed for predicting a heat transfer coefficient from fluidized bed to horizontal tube bundle. The mechanistic heat transfer model predicted the average HTC in sufficient good agreement with accessible literature data. The predictions were as accurate refer to experimental data at the examined conditions.

CaO carbonation kinetics determined using micro-fluidized bed thermogravimetric analysis

A micro-fluidized bed thermogravimetric analysis (MFB-TGA) method based on real-time mass measurement of solid sample inside a fluidized bed was developed. This technique was used to measure the fast reaction kinetics of CaO carbonation in calcium looping with similar characteristics of a strong mass and heat transfer in the fluidized bed reactor. The effects of particle size, temperature, and CO2 concentration on the fast reaction kinetics of CaO carbonation were investigated. The experimental data measured upon MFB-TGA were interpreted with a K-L two-phase fluidized bed model to evaluate the effect of gas exchange between the bubble phase and the emulsion phase on the carbonation kinetics. We concluded that the kinetics of CaO carbonation measured by MFB-TGA were faster than those measured via regular TGA. The reaction rate constant (ks) was 8.0 × 10−10 m4/(mol·s), the activation energy of the carbonation reaction was near zero, and the reaction was first order when the CO2 concentration was within 50 vol% (1 bar). This MFB-TGA method provides a new experimental idea and method for measuring gas–solid reaction kinetics occurring inside fluidized bed reactors.

Co-encapsulating CoFe2O4 and MTX for hyperthermia.

Magnetic manotheranostics can be a fascinating charm to diagnose a tumour with MRI, and treatment through hyperthermia. This study aims to synthesise and characterise magnetically responsive polymer colloids (MRPCs). Healthy tissue damage done by chemotherapy session could be minimised by MRPCs. For the colloidal formulation of MRPCs, the oil in water emulsion technique was employed with the aid of sonication and stirring. The organic phase of emulsion contained methotrexate (MTX) drug, Eudragit E100 and CoFe2O4 (synthesised by co-precipitation) in ethanol, and the aqueous phase contained tween 80 in deionised water. The emulsion was optimised by studying/adjusting two different parameters, i.e. the concentration of constituents and sonication cycles. Multiple formulations were produced at sonication amplitude of 60% at 20 kHz, followed by centrifugation and lyophilisation. Characterisation of MRPCs was done for morphology, size measurement (23-25 nm), surface charge (∼15.12), coercivity (∼1549.6 G), magnetisation (2.6 emu) and retentivity (1.34 emu). Drug release in simulating physiological environment (pH = 7.4), was observed for up to 48 h, and, to determine the best release kinetic mechanism results were compared with kinetic models. Magnetic hyperthermia studies showed that MRPCs achieved an acceptable temperature of 42°C, for hyperthermia treatments in cancer patients.

Nanoemulsions: A review on low energy formulation methods, characterization, applications and optimization technique

Nanoemulsions are emulsions with droplet size in the order of 100 nm and are kinetically stabilized dispersions formulated by combination and stabilization of two immiscible phases using a surfactant. They exhibit useful properties due to small droplet size leading to high surface area per unit volume, higher stability, optically transparent appearance, flexible fluidity and increased bioavailability of lipophilic components. Recently, interdisciplinary applications of nanoemulsions in consumer products, i.e. pharmaceuticals, pesticides, cosmetics, food, paint and environmental applications have attracted interest in its research. Various authors have focussed on preparing nanoemulsions through different methods, including high-energy and low-energy. High energy methods mainly includes microfluidization, high pressure homogenization and ultrasonication whereas, low energy methods comprise of phase transition temperature, phase inversion composition, spontaneous emulsification, micro emulsion dilution and recently developed approach such as D phase emulsification (DPE). In this review article, we address the growing usefulness of low energy method due to ease in its scale-up, less consumption of energy and increased stability in formulation of nanoemulsions. It also includes review on characterization techniques, applications of nanoemulsions and optimization studies for industrial scale up.

Diatomite-stabilized Pickering emulsion-templated synthesis of bicontinuous anti-freezing organohydrogels

Conventional hydrogels freeze and harden at sub-zero temperatures and their mechanical properties are considerably inadequate for practical load-bearing applications. These drawbacks hinder their application possibilities. In this work, we propose a new strategy based on Pickering emulsion polymerization to fabricate novel organohydrogels with antifreeze properties. Ethylene glycol (EG) is introduced into the aqueous phase of the Pickering high internal phase emulsion (HIPE) to effectively inhibit water from freezing. The resulting bicontinuous organohydrogels are prepared through simultaneous polymerization in the external and internal phases to provide enhanced mechanical properties and good hydrophilic-oleophilic properties. Furthermore, the organohydrogels are more stable than conventional hydrogels under ambient conditions and remain unfrozen and mechanically flexible down to −40 °C.

Distribution of benzalkonium chloride into the aqueous phases of submicron dispersed systems: emulsions, aqueous lecithin dispersion and nanospheres

Partitioning of benzalkonium chloride (BAC) into the aqueous phases of submicron dispersed systems such as submicron emulsions, aqueous lecithin dispersion (WLD), and suspension of nanospheres (NLC) was studied. The aqueous phases of the investigated systems were obtained by ultracentrifugation and subsequently were subjected to ultrafiltration, which procedure allowed distinguishing between the fractions of free benzalkonium chloride (w) and those incorporated in the liposomal and micellar region (wlm). The fractions present in the oily phase and in the interphase of submicron emulsions were calculated. Despite the various composition of the investigated formulations and the initial concentration of BAC, w values were very small at 0.2–8.0%. The wlm value in submicron emulsions was increased by increasing the total concentration of preservative from 29.0 to 42.0%. Using polysorbate 80 instead of lecithin resulted in a distribution of BAC to aqueous–liposomal–micellar phase that was twice as high. The very low concentration of antimicrobial active form of benzalkonium chloride was analyzed in the aqueous phase of emulsions stabilized with lecithin as well as in aqueous lecithin dispersion and nanospheres (below 3%). Replacement of lecithin with polysorbate 80 in emulsions with polysorbate significantly increase (up to 8%) the fraction of benzalkonium chloride in the aqueous phase where microbial growth occurs.

Quantum phases of canted dipolar bosons in a two-dimensional square optical lattice

We consider a minimal model to describe the quantum phases of ultracold dipolar bosons in two-dimensional (2D) square optical lattices. The model is a variation of the extended Bose-Hubbard model and apt to study the quantum phases arising from the variation in the tilt angle $\theta$ of the dipolar bosons. At low tilt angles $0^{\circ}\leqslant\theta\apprle25^{\circ}$, the ground state of the system are phases with checkerboard order, which could be either checkerboard supersolid or checkerboard density wave. For high tilt angles $55^{\circ}\apprge\theta\apprge35^{\circ}$, phases with striped order of supersolid or density wave are preferred. In the intermediate domain $25^{\circ}\apprle\theta\apprle35^{\circ}$ an emulsion or SF phase intervenes the transition between the checkerboard and striped phases. The attractive interaction dominates for $\theta\apprge55^{\circ}$, which renders the system unstable and there is a density collapse. For our studies we use Gutzwiller mean-field theory to obtain the quantum phases and the phase boundaries. In addition, we calculate the phase boundaries between an incompressible and a compressible phase of the system by considering second order perturbation analysis of the mean-field theory. The analytical results, where applicable, are in excellent agreement with the numerical results.

Flow and heat mass performances of wet particle drying process based on liquid volume-varying bridge force

Drying treatment of wet particle system is an important industrial process, involving flow and heat mass transfer multiple process. It has been widely used in many industrial processes, such as renewable energy usage and food storage. In this work, we numerically analyzed the heat mass transfer and flow behaviors of a wet particle system. Liquid volume-varying bridge force model was developed, and taking into account water evaporation. The numerical model data were validated, and we found good agreement with respect to hot particles during the cooling period. For a better explanation of the interactions among flow, heat and mass transfer, we calculated the distribution of particle Nusselt (Nup) and Sherwood (Shp) as a function of Reynolds (Rep), and interaction relationships between multiple processes were evaluated. Moreover, near the walls, lower gas velocity and higher particle volume fraction resulted in weak heat transfer characteristics. If this heat transfer coefficient is improved and addressed appropriately, emulsion phase, which accounts for major proportion as potential underlying cause of forming agglomeration structure, will be effectively avoided and kept to accepted level. This is important for the wet particle handling in actual industrial processes.

The effect of high pressure treatment on the dispersion of fat globules and the fatty acid profile of caprine milk

The effect of high pressure (200–500 MPa) on selected properties of caprine milk after high pressure- (HP-) treatment and storage (14 days, 4 °C) was determined. HP-treatment increased the particle size and protein content in the emulsion phase. Particle size increased during storage in untreated milk (P < 0.05), and high pressure minimised or prevented these changes (not significant at pressures ≥ 400 MPa). The total colour difference between untreated and HP-treated milk increased with increasing pressure (P < 0.05) and decreased during storage. HP-treatment did not induce significant differences in the fatty acid profile, excluding an increase in branched-chain fatty acids (P < 0.05). Storage did not affect the ratios of the main fatty acid groups in HP-treated milk, whereas the content of saturated fatty acids increased (not significantly), and the content of polyunsaturated fatty acids decreased in untreated milk.

An Experimental Study of Emulsion Flow in Alkaline/Solvent Coinjection with Steam for Heavy-Oil/Bitumen Recovery

SummaryWater is the dominant component in steam-injection processes, such as steam-assisted gravity drainage (SAGD). The central hypothesis in this research is that in-situ oil transport can be enhanced by generating oil-in-water emulsion, where the water-continuous phase acts as an effective oil carrier. As part of the research project, this paper presents an experimental study of how oil-in-water emulsion can improve oil transport in porous media at elevated temperatures.Diethylamine (DEA) was selected as the organic alkali that generates oil-in-water emulsions with Athabasca bitumen at a 1,000-ppm NaCl brine and a 0.5-wt% alkali concentration. This aqueous composition had been confirmed to be an optimum in terms of oil content in the water-external emulsion phase at a wide range of temperatures. Then, flow experiments with a glass-bead pack were conducted to measure the effective viscosities of emulsion samples at shear rates from 5 to 29 seconds−1 at 35 bar and temperatures from 373 to 443 K.Results show that the oil-in-water emulsions were more than 15 times less viscous than the original bitumen at temperatures from 373 to 443 K. At the shear rate of 5 seconds−1, for example, the emulsion viscosity was 12 cp at 373 K, at which the bitumen viscosity was 206 cp. The efficiency of in-situ bitumen transport was evaluated by calculating the bitumen molar flow rate under gravity drainage with the new experimental data. Results show that oil-in-water emulsion can enhance the in-situ molar flow of bitumen by a factor of 273 at 403 K and 345 at 373 K, in comparison with the two-phase flow of oil and water in conventional SAGD. At 443 K, only a fraction of bitumen is emulsified in water, but the bitumen transport by both oil-in-water emulsion and an excess oil phase in DEA-SAGD can enhance the molar flow of bitumen by a factor of 19 in comparison to SAGD. This is mainly because the mobility of the bitumen-containing phase is enhanced by the reduced viscosity and increased effective permeability. A marked difference between alkaline solvents and conventional hydrocarbon solvents is that only a small amount of an alkaline solvent enables enhancing the in-situ transport of bitumen.

Assessing the Vacuum Spray Drying Effects on the Properties of Orange Essential Oil Microparticles

The effect of using reduced pressure and absence of oxygen during the spray drying process for processing sensitive compound was investigated. Orange essential oil emulsion was atomized in the same equipment (nozzle and drying chamber) and dried under two different conditions: (a) conventional spray drying settings (airflow at ambient pressure with inlet/outlet temperatures of 190 °C/90 °C); (b) reduced-pressure conditions (10–15 kPa) for allowing water evaporation at 25–30 °C. Emulsion phase was preliminarily characterized regarding droplet size distribution, kinetic stability, microstructure, and rheological behavior in order to ensure that the formulation is able to stabilize the oil droplets. The particles recovered in both process conditions were characterized with respect to the moisture content, water activity, particle size distribution, powder morphology, encapsulation efficiency, wettability, and solubility. The particles produced by vacuum spray drying presented lower mean diameter (14.38 μm) and wettability (94 s) besides higher encapsulation efficiency (99.89%) and moisture content (6.27%) than particles resulting from the conventional process. The vacuum process employed did not affect the solubility of the samples. For both processes, most of the particles presented no apparent fissures or cracks in the structure, but some morphological changes were caused by the vacuum. The process seems to be a promising technique to produce thermo-sensitive powder and can improve technological properties.

Lipase-mediated synthesis of ricinoleic acid vanillyl ester and evaluation of antioxidant and antibacterial activity

Castor oil extracted from castor bean has antibacterial property, and has been used in various folk remedies. The major structural component of castor oil, ricinoleic acid, has actual antibacterial activity. Some phenolic compounds derived from plants have antioxidant property. Among them, vanillyl alcohol from vanilla bean has strong antioxidant activity. As vanillyl alcohol has low solubility in hydrophobic solvents and castor oil has low solubility in hydrophilic solvents, there is practical difficulty in using them. We performed lipase-mediated transesterification using vanillyl alcohol and castor oil, and synthesized ricinoleic acid vanillyl ester (RAVE). 2,2-Diphenyl-1-picrylhydrazyl assay and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) assay revealed that RAVE had a strong antioxidant activity in various organic solvents. RAVE also had antibacterial activity against some food spoilage bacteria. It showed more powerful antibacterial activity for gram positive bacteria than for gram negative bacteria. The critical micelle concentration of RAVE was measured at 7.36 μM and it partitioned exclusively into emulsion phase in water-emulsion system. Zeta potential measurement, membrane release test, and fluorescent microscopy showed that RAVE inserted itself into the bacterial cell membrane, destroyed membrane permeability, and induced cell death. As such, RAVE is a novel multi-functional compound with antioxidant and antibacterial activity, so it can be used as a functional material in the food and cosmetic industries.