Factors Affecting Initial Retention of a Microencapsulated Sunflower Seed Oil/Milk Fat Fraction Blend

To study the effect of emulsion stability, particle size, emulsifier, and crystalline fat in the oil phase on initial retention of a low-trans fat encapsulated in a trehalose matrix, six emulsions were prepared. The six emulsions were formulated with 20 wt% trehalose solution as the aqueous phase, a lipid phase either with no crystalline fat, sunflower seed oil (SFO), or with a crystalline phase, a 40% SFO in high-melting fraction of milk fat (HMF) blend, and sodium caseinate (NaCas), a 50 wt% blend of the palmitic sucrose esters (SE) P-170 and P-1670, or a 50 wt% blend of NaCas/SE as stabilizers. Particle size did not change or it changed only slightly during the freeze thaw or freeze drying process when the fat phase was SFO. However, when a crystalline phase was present, the volume-weighted mean diameter (D _4,3) increased dramatically for SE and NaCas/SE stabilizers. Encapsulation properties were determined by the counteracting effects of particle size and distribution, the presence of crystalline material in the droplets and interactions between interface components, fat phase and trehalose. In addition, retention was less related to emulsion stability. The emulsions selected for this study were stable for at least 30 h which was enough for obtaining a high degree of encapsulation.     

Spray-Dried Redispersible Emulsion to Improve Oral Bioavailability of Itraconazole

Dry emulsions are powdery, lipid-based formulations from which an o/w-emulsion can be easily reconstituted in vivo or when exposed to water. The objective of this work was to prepare and characterize dry emulsion of itraconazole (ITZ) to improve its solubility and bioavailability. Dry emulsions were prepared by spray-drying liquid o/w-emulsions containing carriers like maltodextrin, sucrose, and lactose. Propylene glycol monocaprylate was selected as oil phase, and surfactant blends of vitamin E tocopherol polyethylene glycol succinate and triblock PEO–PPO–PEO copolymer as emulsifying agents. Several oil:water and carrier:water ratios were tested. An optimum formulation was selected using 3² full factorial design. The droplet size, rheological behavior, and drug release from o/w-emulsion before and after reconstitution and the micromeritic properties of spray-dried product were investigated. Maltodextrin was used as a carrier for preparing dry emulsions. The optimized dry emulsion was characterized using DSC, SEM, PXRD, and in vivo study. The SEM analysis showed that dry emulsion consisted of well-separated particles with smooth surfaces. The DSC and XRD study showed that ITZ in the dry emulsion is in the molecular dispersion state. Globule size analysis showed that dry emulsion had good reconstitution properties. The emulsions were found to be thermodynamically stable when subjected to cyclical freeze–thaw cycles and centrifugation tests. The average globule size of emulsions ranged from 0.994 to 1.668 μm. A 71.35 % increase in C _max and 114.78 % increase in AUC was evident for ITZ dry emulsion as compared to plain ITZ.     

Flow Behavior of Oleic Acid Liposomes in Sucrose Ester Glycolipid Oil-in-Water Emulsions

Liposomes have been used widely as carriers for active ingredients in cosmetics because of their ability to encapsulate both hydrophilic and hydrophobic compounds. In this work, fatty acid liposomes were prepared and introduced into olive oil-in-water emulsions stabilized by C₁₄–C₁₈ sucrose ester mixtures at pH 8.5. Light microscopy images of the emulsions showed evidence of the coexistence of oleic acid liposomes with the emulsions. As the alkyl chain length of the sucrose ester increased, the average droplet size decreased, while the zeta potential became more negative. Further decrease in droplet size was observed when borate buffer was added to the aqueous phase. The free fatty acids in the sucrose esters and olive oil are neutralized in borate buffer; consequently, fatty acid salts were produced and served as co-surfactants. The synergistic stabilization of emulsions by the mixture of sucrose esters and fatty acid salt resulted in higher stability, smaller droplet size, and lower polydispersity. The drastic increase in negative zeta potential was possibly due to the presence of free fatty acid salts in the emulsion systems. The flow curves at steady rate displayed five distinctive regions. The polydispersity of droplets enhanced the shear thickening effect at low shear rates and shear-banding effect at middle shear rates. Formation of fatty acid salts as co-surfactants caused the viscosities of the emulsions to increase by an order of magnitude. The presence of oleic acid liposome significantly reduced the viscosities of the emulsion by half an order of magnitude; this decreased viscosity helped enhance better spreadability.     

Rheological characterization of ferrous sulfate-containing water-in-oil-in-water (W1/O/W2) double emulsions

With use of response surface methodology (RSM), the W₁/O/W₂ emulsions containing ferrous sulfate as the inner phase were optimized in terms of stability (ES) and apparent viscosity (μ _app ). Curvature display of the responses around their optimal settings was appropriately described using the quadratic polynomial regression model. The non-Newtonian behavior of the test W₁/O/W₂ emulsions was characterized using the power-law model and change from non-Newtonian to Newtonian (n?1) was seen in the case of W₁/O:W₂ ratio equal 20: 80 when the level of Tween-80 was 1 v%. Results of the size distribution pattern showed 60% of the particles were less than 5 μm. Rheological properties of the test W₁/O/W₂ emulsions as the viscoelastic liquids were analyzed and the results of oscillatory experiments considering shear stress and frequency dependency of G′ and G″ moduli were discussed in terms of the internal microstructure of the emulsions.     

Catalyzed crosslinking of highly functional biobased epoxy resins

Crosslinking reactions involving epoxy homopolymerization of 100% biobased epoxidized sucrose esters (ESEs) were studied and the resulting coatings properties were compared against epoxidized soybean oil (ESO) and petrochemical-based soybean fatty acid ester resins. The low viscosity of ESE resins allowed for formulations to be developed with minimal volatile organic content. ESEs were found to have superior coatings properties, compared to ESO and the petrochemical-based soybean esters, attributable to a higher glass transition temperature (T _g) and a higher modulus. The rigid sucrose core on ESEs provided an increase in coating performance when compared to coatings from epoxidized resins synthesized with tripentaeryithritol as a core. The degree of conversion and optimization of the curing conditions were studied using differential scanning calorimetry (DSC). Thermal analysis of cured coatings was performed using DSC, dynamic mechanical analysis, and thermogravimetric analysis. In order to further enhance the coatings properties, small amounts of bisphenol A epoxy resin were added which resulted in higher moduli and T _gs.     

Freeze-Drying of Liposomes with Cryoprotectants and Its Effect on Retention Rate of Encapsulated Ftorafur and Vitamin A

Abstract

In this article, the glass transition temperature (T _g ) of liposomal suspensions, in which glucose, sucrose, mannitol, and trehalose are used as cryoprotectants, are measured by differential scanning calorimetry (DSC). The protective effect of the cryoprotectants added for liposomes during freeze-drying is investigated. Results show that the T _g of liposomal suspension with trehalose is the highest, while that with glucose is the lowest. Depending on the concentration, the vesicle size of liposomes with trehalose as cryoprotectant varies less, while the vesicle size of liposomes, with glucose as cryoprotectant varies over a wider range during the process of freeze-drying. Water-soluble ftorafur and lipid-soluble vitamin A encapsulated in liposomes were freeze-dried. The retention rates of the encapsulated pharmaceuticals inside the liposomes are measured with high performance liquid chromatography. The results indicate that the retention rate for liposomes with trehalose is the highest, and the leakage of the pharmaceutical material is less than that with glucose used as a cryoprotectant. Through a series of experimental studies, trehalose is identified as a better cryoprotectant. An optimized freeze-drying procedure for liposomes is presented.     

Polysiloxanes with Quaternary Ammonium and Polyether Groups for Silyl-Terminated Polypropylene Oxide Waterborne Emulsions

In this paper, polysiloxanes with pendant quaternary ammonium and polyether segments (EQAPS, nonionic–cationic silicone surfactant) were synthesized through hydrosilylation of poly(dimethylhydro)siloxane with allyl poly(ethylene glycol) acetic ester (M _n  = 540) and allyl glycidyl ether, followed by a ring-opening reaction of epoxide groups with diethyl amine and quaternization with benzyl chloride. The chemical structures of EQAPS and intermediate products were characterized by ¹H-NMR and FT-IR spectra. The surface activity and thermal properties of EQAPS were studied with surface tension measurement and differential scanning calorimetry analysis, respectively. The results showed that the EQAPS had a much smaller critical micelle concentration value (118 mg/L) and lower glass-transition temperature (T _g: ?57 °C). The silyl-terminated polypropylene oxide waterborne emulsions, which were substantially free from organic solvent, were prepared via a phase-inversion emulsification technique using EQAPS as single emulsifier and/or poly(ethylene glycol) (\(\bar{M}\) _n  = 400) as cosolvent. The electrical properties of the system indicated that the phase inversion was completely accomplished. The viscosity of the emulsions with different solid contents was measured, and the results showed that the most suitable solid content was about 50 wt%. The emulsions with smaller particle size (12 μm) had better storage stability (48 days at 50 °C) and freeze–thaw stability.     

Aesculus hippocastanum L. as a Stabilizer in Hemp Seed Oil Nanoemulsions for Potential Biomedical and Food Applications

Nanoemulsion systems receive a significant amount of interest nowadays due to their promising potential in biomedicine and food technology. Using a two-step process, we produced a series of nanoemulsion systems with different concentrations of hemp seed oil (HSO) stabilized with Aesculus hippocastanum L. extract (AHE). Water and commercially-available low-concentrated hyaluronic acid (HA) were used as the liquid phase. Stability tests, including an emulsifying index (EI), and droplet size distribution tests performed by dynamic light scattering (DLS) proved the beneficial impact of AHE on the emulsion’s stability. After 7 days of storage, the EI for the water-based system was found to be around 100%, unlike the HA systems. The highest stability was achieved by an emulsion containing 5% HSO and 2 g/L AHE in water, as well as the HA solution. In order to obtain the detailed characteristics of the emulsions, UV-Vis and FTIR spectra were recorded, and the viscosity of the samples was determined. Finally, a visible microscopic analysis was used for the homogeneity evaluation of the samples, and was compared with the DLS results of the water system emulsion, which showed a desirable stability. The presented results demonstrate the possible use of oil emulsions based on a plant extract rich in saponins, such as AHE. Furthermore, it was found that the anti-inflammatory properties of AHE provide opportunities for the development of new emulsion formulations with health benefits.     

Effects of emulsification variables on fuel properties of two- and three-phase biodiesel emulsions

Biodiesel has attractive fuel properties such as excellent biodegradability and lubricity, almost no emissions of sulfur oxides, PAH and n-PAH, reduced CO₂, PM and CO emission, superior combustion efficiency, etc. However, burning of biodiesel generally produces higher levels of NO_x emissions, primarily due to its high oxygen content. In this study, the emulsification technology has been considered to reduce the NO_x emission level of fossil fuel. Biodiesel, produced by means of transesterification reaction accompanied with a peroxidation process, was emulsified to form two-phase W/O and three-phase O/W/O emulsions. The effects of the emulsification variables such as hydrophilic lipophilic balance (HLB), and water content on the fuel properties and emulsion characteristics of W/O and O/W/O emulsions were investigated in this study. The experimental results show that the surfactant mixture with HLB = 13 produced the highest emulsification stability while HLB = 6 produced the lowest emulsification stability and the most significant extent of water–oil separation among the various HLB values for O/W/O biodiesel emulsion. The kinematic viscosity, specific gravity and carbon residual of the biodiesel emulsions were larger than those of the neat biodiesel. In addition, the W/O biodiesel emulsion was found to have a smaller mean droplet size, lower volumetric fraction of the dispersed phase than the O/W/O biodiesel emulsion, and the highest heating value among the test fuels, if the water content is deducted from the calculation of the heating value.     

Physical and Functional Properties of Blackberry Freeze- and Spray-Dried Powders

The aim of the present work was to develop two products from blackberry juice by freeze and spray drying with potential use as food colorants or healthy ingredients. A characterization of the physical and functional properties of the powdered juices was done. Maltodextrin or a mixture of trehalose and maltodextrin were assessed as carrier matrices. Freeze-dried, maltodextrin-containing powders presented the best retention of bioactive compounds and antiradical activity; however, they showed a narrow relative humidity range for storage in the glassy state. Spray-dried powders showed better physical properties, bearing higher glass transition temperature and lower molecular mobility than freeze-dried formulations.     

Synergistic stabilization of perfluorocarbon-pluronic F-68 emulsion by perfluoroalkylated polyhydroxylated surfactants

One of the most serious limitations of the first generation of fluorocarbon emulsions destined to serve as injectable oxygen carriers (blood substitutes) is their insufficient, stability. Considerable stabilization of such emulsions has now been achieved by using a combination of Pluronic F-68, a polyoxyethylene polyoxypropylene block polymer, and of a perfluoroalkylated polyhydroxylated surfactant (PPFS) comprising a C₆F₁₃ or C₈F₁₇ fluorophilic tail and a hydrophilic head derived from maltose or xylitol. These new surfactants are either soluble in water or dispersible in an aqueous Pluronic F-68 solution. The tensions at the surface of these solutions and dispersions and at their interface with a typical fluorocarbon, F-decalin, are discussed. A strong stabilizing effect on F-decalin emulsions was obtained when small amounts of PPFS were incorporated, the total amount of surfactant used remaining constant. For 20% w/v emulsions, the maximum stabilizing effect was reached when 20–30% of PPFS were present, resulting after one year at 25°C in an up to 10 times smaller increase in particle size than for a reference emulsion prepared with Pluronic F-68 alone. The effect is even stronger with more concentrated 50% w/v emulsions, reaching a stabilizing ratio of 17 after one year for a one-to-one PPFS/Pluronic F-68 combination. None of the PPFS, when taken alone, permitted the preparation of stable emulsions. The characteristic U-shape taken after aging, by the particle size vs PPFS/Pluronic F-68 ratio curves demonstrates a strong synergistic effect of the two surfactants. They also permitted the selection of optimal formulations for the emulsions. The evolution of the particle sizes against time for such formulations was followed for 20% and 75% w/v concentrated F-decalin emulsions at 4°C, 25°C and 50°C. The best emulsion in terms of stability was obtained with the xylitol derivative C₈F₁₇CH=CHCH₂OCH₂(CHOH)₄H; most significantly, temperature, from 4 to 50°C, had little or no effect on the aging of this emulsion over a two month period.     

Upgrading the Topical Delivery of Poorly Soluble Drugs Using Ionic Liquids as a Versatile Tool

Numerous studies are continuously being carried out in pursuit of formulations with higher performance. Problems such as poor drug solubility, which hinders drug incorporation into delivery systems and bioavailability, or limitations concerning the stability and performance of the formulations may cause difficulties, since solving all these drawbacks at once is a huge challenge. Ionic liquids (ILs), due to their tunable nature, may hypothetically be synthesized for a particular application. Therefore, predicting the impact of a particular combination of ions within an IL in drug delivery could be a useful strategy. Eight ILs, two choline amino acid ILs, two imidazole halogenated ILs, and four imidazole amino acid ILs, were prepared. Their applicability at non-toxic concentrations, for improving solubility and the incorporation of the poorly soluble, ferulic, caffeic, and p-coumaric acids, as well as rutin, into topical emulsions, was assessed. Next, the impact of the ILs on the performance of the formulations was investigated. Our study showed that choosing the appropriate IL leads to a clear upgrade of a topical emulsion, by optimizing multiple features of its performance, such as improving the delivery of poorly soluble drugs, altering the viscosity, which may lead to better sensorial features, and increasing the stability over time.     

Flow characteristics of surfactant stabilized water-in-oil emulsions

In this paper, an investigation was carried out to study the effect of water fraction and flow conditions on the flow characteristics of surfactant stabilized water-in-oil emulsion. Pressure drop measurements were conducted in 2.54-cm and 1.27-cm horizontal pipes. The influence of water fraction and the flow conditions on emulsion stability, type, conductivity, droplet size distribution, viscosity and pressure drop were reported. The results showed a significant increase in the emulsion stability, viscosity and pressure drop with increasing water fraction up to 70%. In addition, shear thinning behavior was observed for the emulsions especially at high water fractions. Furthermore, pressure drop measurements of high concentrated emulsions showed pipe diameter dependency especially at high Reynolds (Re) numbers. Moreover, drag reduction was observed with decreasing water fraction. The viscosity of surfactant-stabilized water-in-oil emulsions was modeled with a modified fluidity-additivity model.     

Effect of lipid type on water‐in‐oil‐emulsions stabilized by phosphatidylcholine‐depleted lecithin and polyglycerol polyricinoleate

Water‐in‐oil (W/O, 30:70) emulsions were prepared with phosphatidylcholine‐depleted lecithin [PC/(PI,PE) = 0.16] or polyglycerol polyricinoleate (PGPR) as emulsifying agents by means of pressure homogenization. The effect of lipid type (medium‐chain triacylglycerols, sunflower, olive, butter oil, or MCT‐oil/vegetable fat blends) was investigated in relation to particle size distribution, coalescence stability and the sedimentation of the water droplets. A significant correlation (p <0.05) was observed between the interfacial pressure caused by the addition of lecithin to the pure lipids and the specific surface area of the emulsion droplets (r_s = 0.700), and between the viscosity of the lipids used as the continuous phase (reflecting the fatty acid composition) and the specific surface area of the emulsion droplets (r_s = 0.8459) on the other hand. Blends of vegetable fat and MCT‐oil led to reduced coalescence stability due to the attachment of fat crystals to the emulsion droplets. Lecithin‐stabilized W/O emulsions showed significantly higher viscosities compared to those stabilized with PGPR. It was possible to adjust the rheological properties of lecithin‐stabilized emulsions by varying the lipid phase.     

Effect of carrier agents on the physical and thermal stability of freeze-dried passion fruit (Passiflora edulis f. flavicarpa) pulp

In this study, the physical and thermal stability of freeze-dried passion fruit (Passiflora edulis f. flavicarpa) pulp produced with different carrier agents was evaluated. Powders were produced using sucrose, fructose, ethanol, and maltodextrin as carrier agents and characterized by differential scanning calorimetry, morphology, moisture sorption curves, and sorption kinetics. The GAB (Guggenheim-Anderson-de Boer) model was suitable to mathematically describe the adsorption isotherms. The treatments that had maltodextrin as the additive exhibited reduced adsorption both in low- and in high-water activities, promoting the reduction of the moisture content in the monolayer (X_m) and enhancing the stability of the powder product. The combination of sucrose and ethanol increased the glass transition temperature of the system compared to the in natura pulp. Treatments with fructose did not improve the sorption characteristics of the powders, featuring an amorphous structure. The kinetic curves, ratio of the increase of the water content against the storage time, of the passion fruit pulp treated with 10 g of maltodextrin/100 g of pulp and with 5 g of sucrose and 10 g of maltodextrin/100 g of pulp showed reduced adsorption and similar behaviors for water activity values of 0.113, 0.529, 0.753, and 0.903.     

Preparation of high solid loading and low viscosity ceramic slurries for photopolymerization-based 3D printing

In this study, high solid loading and low viscosity cordierite slurries are successfully developed for the first time for photopolymerization-based additive manufacturing. The processability of the slurries is mainly determined by their rheological properties and photocuring parameters. The slurry preparation involves the orthogonal optimization of compositions in order to achieve suitable viscosity, stability and homogeneity. The photocuring parameters of the as-prepared slurries, including penetration depth D_p and critical exposure E_c, are also determined experimentally. Results show that viscosity increases with reduction in particle size. A higher solid-volume fraction also results in an exponential growth in viscosity. As for the dispersant amount, a concentration of 5?wt% leads to the lowest viscosity. Particle size also play an important role in the solid loading capacity of the slurries, as results suggest that smaller particles improve performance. In terms of the photocuring behaviors, the addition of 2?wt% photoinitiator generates an optimal curing process. 40?vol% solid loading leads to the thickest curing depth for all slurries with different types of particle sizes. Finally, a cordierite part with a complex hollow structure and a fine resolution is successfully fabricated. The present study offers a material basis for the polymerization-based 3D printing of porous cordierite structures.     

Fabrication and characterization of food‐grade fibers from mixtures of maltodextrin and whey protein isolate using needleless electrospinning

Food‐grade fibers were fabricated from dispersions of maltodextrin and whey protein isolate (WPI) using needleless electrospinning. Two maltodextrins (DE 2) from different starch sources were used and the maltodextrin/WPI ratio was varied. Molecular weight, intrinsic viscosity, entanglement concentration, shear stability, and electrical conductivity were studied as function of maltodextrin type and mixing ratio and correlated to fiber production rate and morphology. The results show that a high molecular weight of the maltodextrin was beneficial to its spinnability. Waxy potato starch maltodextrin (P‐MD) (M_w = 129.6 kDa) and WPI produced fibers with diameters between 1.40 and 1.67 µm at production rates up to 1.65 g/h; while the dispersions with waxy maize starch maltodextrin (M‐MD) (M_w = 85.9 kDa) showed poor spinnability and ruptured fibers. P‐MD/WPI dispersions had a higher viscosity and stronger shear thinning behavior attributed to a stronger entangled polymer network which is beneficial to electrospinning. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46328.     

Effects of TDI and FA‐703 on physico‐mechanical properties of polyurethane dispersion

A series of water dispersion polyurethanes dispersions (PUDs) were prepared by polyaddition reaction using isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), poly(oxytetramethylene) glycol (PTMG), dimethylol propionic acid (DMPA), and triol (trade name FA‐703). Various formulations were designed to investigate the effects of process variables such as TDI and FA‐703 on the physico‐mechanical properties of PUD. IR spectroscopy was used to check the end of polymerization reaction and characterization of polymer. Evolution of the particle size distribution, contact angle, T_g, molecular weight, viscosity, and mechanical properties of the emulsion‐cast films were significantly affected by variable content of TDI and FA‐703. Average particle size of the prepared polyurethane emulsions and contact angle decrease with increase of content of FA‐703 and TDI. Molecular weight, T_g, tensile strength, tear strength, hardness, viscosity and elongation at break increase with increase of content of FA‐703 and TDI. The increase of molecular weight, tensile strength, tear strength and elongation at break properties are interpreted in terms of increasing hard segments, chain flexibility, and phase separation in high content of FA‐703 and TDI‐based polyurethane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Development,rheological properties,and physical stability of d‐limonene‐in‐water emulsions formulated with copolymers as emulsifiers

This contribution reports the development of 30 wt % d ‐limonene‐in‐water emulsions formulated with a biopolymer (gellan gum) as stabilizer and prepared with a high‐pressure homogenizer. The role as emulsifiers of different ratios of amphiphilic copolymers (Atlas^TMG5000 and Atlox^TM4913) was assessed. The results indicated that the ratio of emulsifiers had significant effect on the physical stability, droplet size, viscoelasticity, and viscosity of these emulsions. The mean droplet diameters decreased as Atlas^TMG5000 concentration increased from 1 wt % to 3 wt %. The aging of emulsions resulted in an increase in the size of droplets for the emulsions containing high Atlox^TM4913 copolymer content. An increase of Atlas^TMG5000 enhanced both the G′ and G″ values and the viscosity providing higher stability to emulsions. Gellan gum caused in viscoelastic moduli weaker frequency dependence at the lower frequencies, according to the formation of a faint gel‐like matrix. All emulsions exhibited shear thinning flow properties that fitted the power‐law equation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43838.     

Mathematical expressions for calculation of oil‐polymer blends

A study of the recent literature emphasized the importance of blending polymers with oils for improving the performance characteristics (like flexibility, corrosion resistance, etc.) of adhesives, coatings and laminates. Investigation of the available data revealed that several properties of such oil‐polymer blends could be correlated by molar refraction (R_M), with reasonable accuracies. The properties of the linseed oil‐polystyrene (PS) and linseed oil‐polymethyl methacrylate (PMMA) blends studied are iodine value (IV), hydroxyl value (HV), inherent viscosity (η), melting temperature (T_M), and glass transition temperature (T_g). In the case of safflower, palm and peanut oil‐sucrose polyester formulations, the viscosity at 40 °C (η₄₀) and the melting point T_M have been correlated by R_M with the average absolute deviations (ē) of 17.8% and 3.0%, respectively. Using the orientation polarization P_O (to represent polarity) in addition to R_M, η₄₀ and T_M of oil‐polyester formulations could be calculated with ē values of 8.9% and 1.7%, compared to 17.8% and 3.0% using R_M alone. The results indicated the importance of P_O in improving the accuracy of predictions for properties.