Oil Phase Concentration Research Articles

Long-term stability investigation of o/w cosmetic creams stabilized by mixed emulsifier

Polyglyceryl-3 Methylglucose Distearate (PMD, TEGO? Care 450, Evonik, Germany)is natural (vegetable), non-ionic, PEG-free emulsifier, suitable for the formulation of oil-in-water (o/w) cosmetic creams and lotions. The oil phase components can be selected from mineral oils, vegetable oils and synthetic esters, which enable different variety of application profile of these emulsions. It is possible to prepare stable emulsions using low-level concentration of the PMD (2-3%) if lotions contain 10-25%, and creams 20-40 % of oil phase. PMD forms liquid crystal structure in the presence of stearic acid, glyceryl stearate, fatty alcohols, or their combinations. The o/w type creams, stabilized by these mixed emulsifiers are complex, multiphase systems. The aim of this work was to formulate, prepare and investigate long-term stability of the o/w creams stabilized by mixed emulsifier polyglyceryl-3 methylglucose distearate/glyceryl stearate/stearyl alcohol, depending on concentration levels of PMD (2% or 3%) and oil:water phase ratio (20:80 and 30:70). The samples were prepared using hot/hot procedure. Organoleptic inspection, centrifugation test, rheological measurements, electric conductivity and pH value measurements were performed 72 h, 1, 3, 12 and 30 months after preparation. The prepared samples were apparently white and homogenous creams. The consistency and homogeneity were preserved after centrifugation of the creams after 72 h, 1, 3, 12 and 30 months storage, and no phase separation could be detected. The pH values obtained are suitable for skin application. Conductivity values (25.2-63.7 ?S cm1, 72 h after preparation) were attributed to the multiple phase o/w emulsions with high percentages of fixed water. Results of the rheological measurements have shown that the investigated creams exhibited non-Newtonian thyxotropic behavior. The concentration of emulsifier PMD and oil phase content had an influence on the rheological parameters of investigated samples. The creams prepared with higher content of emulsifiers (3%) and oil phase (30%) exhibited higher values of apparent viscosities and thyxotropic area. The observed decrease of electrical conductivity and increase of apparent viscosities values, which occurred in the creams during 3 months of storage, were probably attributed to bulk water content decreasing. These changes are mildly expressed in the samples with higher content of oil phase. The obtained results of organoleptic characteristics, pH, electric conductivity value and rheological parameters during 30 months of storage indicate good long-term stability of the o/w creams prepared with mixed emulsifier containing PMD at low concentration levels (2% or 3%). Changes during ageing, caused by structuration of creams were less expressed in samples with 30% of oil phase, however, the observed differences were not related with the PMD concentration. In this case, advantage could be given to o/w cream prepared with 30% of oil phase, stabilized by using 2% emulsifier polyglyceryl-3 methylglucose distearate.

Physico-chemical properties investigation of cisplatin loaded polybutyladipate (PBA) nanoparticles prepared by w/o/w

cis-Diamminedichloroplatinum(II) (cisplatin) is used against different kinds of cancers. Unfortunately, because of the severe side-effects like nephrotoxicity, ototoxicity, etc., they are administered in small doses at low concentrations. The purpose of this work is to improve injectional controlled release (ICR) of cisplatin that releases drug in the extended temporal periods. In order to access this aim, biodegradable polymeric nanoparticles containing cisplatin as anticancer drug of various ranges from 71 to 661nm were prepared by a w/o/w double emulsion solvent evaporation technique. Influences of process parameters such as solvent removal technique, type and concentration of polymer, volume of oil phase, volume of external aqueous phase, concentration of stabilizer, drug concentration in the internal and external aqueous phases and power of sonication on morphology, characteristics of the nanoparticles and release profile were investigated. Morphology of the nanoparticles was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and the images indicated that spherical shape of the nanoparticles can be tailored to rod-like shape by changing the reaction parameters. Size of the nanoparticles decreased as polymer concentration decreases. Volume of oil phase, power of sonication and drug concentration in the internal water phase affected the size of nanoparticles. Drug release profiles indicate that polymer concentration in the oil phase and stabilizer concentration in the external water phase have critical role in the drug release process from the nanoparticles. The in-vitro release of the encapsulated drug was observed by using the diffusion models of release from a sphere carrier and the release pattern was shown to be a complex process.

Formation and characterization of self-assembling fish oil microemulsions

The novel fish oil O/W microemulsion system is formed with food-acceptable components, Tween 80, ethyl oleate, fish oil and water. We studied the influence of fish oil proportion in the oil phase on the microemulsion regions. We investigated this system using the dynamic light scattering and transmission electron microscopy; the rheological characteristics and release effect were also explored. The obtained results indicated that the particle sizes of spherical droplets in microemulsions depend significantly on the total oil phase content, varying from 5 to 198 nm. The rheological measurements showed that all studied microemulsions followed shear thinning behavior. Well-controlled release profile of the fish oil microemulsions was found in different dialyzate solutions.

Pomegranate seed oil as a functional ingredient in beverages

Pomegranate seeds are by-products of pomegranate juice industry. Since the seeds contain valuable oil that has nutritional and medicinal properties, they can be useful for food applications (especially in juice and beverage industries) as a functional agent. In this study, the possibility of producing a stable pomegranate-seed-oil-in-water emulsion to be used as a base formula for a new functional beverage was investigated. The influence of gum Arabic (GA) concentration (10.0, 12.5, and 15.0%, w/w) with a constant oil phase content (6.0% w/w) on the turbidity loss rate, emulsion stability index, and droplet size distribution was investigated. Turbidity loss rate was inversely proportional to the GA concentration for all the formulations studied here. Compared to other emulsions, emulsion with 15.0% w/w GA did not show a discernible cream layer during 42 days of storage. Emulsion with 15.0% w/w GA indicated the smallest polydispersity index during this period. The results of this study showed that it was possible to produce a relatively stable pomegranate-seed-oil-in-water emulsion for use as a functional agent in beverages.

A microemulsion-template-interfacial-reaction route to copper sulfide hollow spheres

CuS hollow spheres have been successfully synthesized through a facile microemulsion-template-interfacial-reaction route using copper naphthenate as metal precursor and thioacetamide as the source of S2−. In this way, hollow spheres could be obtained directly since the reaction of two reactants respectively dissolved in two different phases of an oil-in-water (o/w) microemulsion only occurs at the oil/water interface. Therefore, it is a key for forming hollow spheres to optimize the interfacial reaction rate by controlling reaction conditions. Furthermore, the size of the hollow spheres can be tailored by changing the content of oil phase. In this study, the average diameter of the CuS hollow spheres can be adjusted from 110 to 280nm by changing the content of oil phase from 0.5ml to 1.5ml. In addition, the reaction temperature is a very important factor for forming CuS hollow spheres and the appropriate reaction temperature is about 50°C.

Three-Component Olive Oil-In-Water High Internal Phase Emulsions Stabilized by Palm Surfactant and Their Moisturizing Properties

In the present study, olive oil was used for the preparation of three-component high internal phase emulsions with oil volume fraction of more than 0.77 stabilized by palm-based polyoxyethylene lauryl ether for the first time. These emulsions were investigated on their morphology, structural properties, stability, and hydration efficacy. Droplet size distribution observed from the optical micrographs was in agreement with the light scattering results, which suggested that droplet size was influenced by oil phase and surfactant concentrations. Rheological results exhibiting flow curves cross-over implied structural build-up that gave rise to high stability which was supported by stable three-month storage at an elevated temperature. The hydration efficacy of the emulsion was examined in vivo using a corneometer.

Manufacture of ceramic membranes for application in demulsification process for cross-flow microfiltration

This paper describes the manufacture of tubular ceramic membranes and the study of their performance in thedemulsification of soybean oil/water emulsions. The membranes were made by iso-static pressing method andmicro and macro structurally characterized by SEM, porosimetry by mercury intrusion and determination of apparentdensity and porosity. The microfiltration tests were realized on an experimental workbench, and fluid dynamicparameters, such as transmembrane flux and pressure were used to evaluate the process relative to the oil phaseconcentration (analysed by TOC measurements) in the permeate. The results showed that the membrane withpores' average diameter of 1.36 μm achieved higher transmembrane flux than the membrane with pores' averagediameter of 0.8 μm. The volume of open pores (responsible for the permeation) was predominant in the total porosity,which was higher than 50% for all tested membranes. Concerning demulsification, the monolayer membraneswere efficacious, as the rejection coefficient was higher than 99%.

Pressure and electrokinetic injections for on‐line sample stacking neutral analytes in microemulsion electrokinetic chromatography with salt‐containing matrixes

An on-line technique for pressure and electrokinetic injections of long sample plugs with simultaneous stacking of neutral analytes (notoginsenoside R(1), ginsenoside Rg(1), ginsenoside Rf, ginsenoside Rh(1), ginsenoside Rd, ginsenoside Rg3) in microemulsion electrokinetic chromatography is presented. The effects of salt concentration, sample plug length, organic modification of the sample matrix, oil phase and SDS concentration on stacking efficiency were examined in order to optimize the two injection methods. In microemulsion electrokinetic chromatography, the effect of the type of oil and SDS content on stacking mechanism is often sophisticated. This study had demonstrated that the oil type and SDS content in microemulsion indeed markedly altered the affinity of microemulsion with analytes. Finally, in comparison with the electrokinetic injection method, the most apparent disadvantages of the pressure injection method were the relatively high LOD and poor reproducibility.

Separation and on-line preconcentration by stacking and sweeping of charged analytes in the plant by microemulsion electrokinetic chromatography with nonionic surfactants

A novel on-line technique for stacking and sweeping of long sample plugs with simultaneous determination of charged analytes in the plant (protocatechuic aldehyde, rosmarinic acid, danshensu, salvianolic acid B, and protocatechuic acid) by the nonionic microemulsion electrokinetic chromatography (MEEKC) is presented. The preconcentration efficiency provided about 9–28-fold for stacking and 7–14-fold for sweeping in the enhancements of LOD. The effects of oil phase, Brij-35 and buffer concentrations on stacking and sweeping efficiency were examined in order to optimize the two methods. In nonionic MEEKC, the effect of the type of oil and buffer contents on preconcentration mechanism is often sophisticated. This study had demonstrated that the oil type and buffer content in nonionic microemulsion indeed markedly altered the affinity of microemulsion with analytes. Finally, in comparison to the stacking method, the most apparent disadvantages of the sweeping method were the relatively high limits of detection and poor peak shapes.

Rheological characteristics of drug-loaded microemulsions and their printability in three dimensional printing systems

Rheological properties of microemulsions (MEs) and their printability in three dimensional printing (3DP) systems were investigated. A series of MEs with different contents of oil phase were prepared using sonication method with ibuprofen as model drug and soybean lecithin as emulfier. Stationary and transient rheological properties of MEs were investigated by ARES-SRF using concentric cylinders measuring systems. 3DP systems with piezoelectric drop-on-demand print heads were employed to test the printability of the MEs. Results demonstrate that the apparent viscosity and dynamic linear viscoelastic regions of the MEs are the most important parameters for continuous and stable printing of MEs by 3DP. The incorporation of drug in the MEs has little influence on the MEs’ stationary rheological behaviors and dynamic viscoelasticity, but the concentration of oil phase has a strong influence on them. The rheological property of binder liquids has a close relationship with their printability in 3DP system.

Heat resistance of Bacillus cereus emetic toxin, cereulide

The study describes the effects of heating temperature and exposure time on the thermal stability of cereulide under different conditions (pH, presence/absence of oil phase and cereulide concentration). Cereulide heat inactivation was investigated at 100, 121 and 150 degrees C under different alkaline pH values (8.6-10.6) and in the presence of oil phase (0.6-1.4%). Three different cereulide concentrations (0.5, 5 and 6 microg ml(-1)) were used. Cereulide detection was performed with computer-aided semen analyzer and with HPLC-MS. Highly alkaline pH was needed to achieve inactivation. At lower cereulide concentrations less drastic conditions were needed. Removal of alkaline buffer after the heat treatment resulted in the recovery of toxic activity. Heat stability of cereulide has been proved to be remarkable, even at highly alkaline pH values, at all temperatures tested. The loss of activity appeared to be reversible. The study demonstrates the inability of any heat treatment used in the food industry to inactivate cereulide. Food safety has to rely on prevention and cold chain maintenance. Cleaning practices also need to be adapted as cereulide may remain in its active form upon sterilization of used material.

Characterization and demulsification of produced liquid from weak base ASP flooding

Weak base alkali-surfactant-polymer (ASP) flooding technology has been applied in Daqing oilfield to enhance oil recovery. The effects of ASP on the characteristics of oil droplets in produced liquid were investigated. Surfactant can decrease interfacial tension (IFT) and zeta potential, making main contribution to the stability of oil droplets. Weak alkali (Na 2CO 3) can decrease IFT and polymer can decrease zeta potential, resulting in stable oil droplets in produced liquid. The produced liquid from weak base ASP flooding is easier to treat than that from strong base ASP flooding. A mixed demulsifier GFD410-8 was prepared and used to enhance oil–water separation in produced liquid. When the demulsifier dose of 50 mg/kg was used to demulsify the simulated produced liquid with the concentrations of alkali 2000 mg/kg, surfactant 600 mg/kg and polymer 600 mg/kg, water volume and water content after 30 min settling were less than 30% and 1000 mg/L, respectively. The demulsifier also greatly decreased water content in oil phase and oil concentration in water phase for actual produced liquid from oil well. The demulsification mechanism was also investigated in terms of IFT and zeta potential.

Effect of added oil and modified starch on rheological properties, droplet size distribution, opacity and stability of beverage cloud emulsions

Optical and rheological properties of beverage cloud emulsions as a function of water-phase and oil-phase concentrations were investigated. The specific gravity of phases, particle size distribution and creaming stability of prepared emulsions in diluted forms were evaluated. Combinations of emulsions with added starch (3.74–18.7% w/w, with oil at 3.74% w/w) and oil (7.48–18.7% w/w with starch at 11.2% w/w) were used. The specific gravity of oil phase was adjusted using a constant combination of weighing agents [sucrose acetate isobutyrate and brominated vegetable oil] and different level of coconut oil. Oil-phase concentration had a significant effect (P<0.05) on increasing the opacity of emulsion. Increase in modified starch concentration for all water phases decreased the flow behavior index while oil phase at any given concentration of coconut oil contributed to a Newtonian behavior. Raise in viscosity of emulsions was more pronounced as oil concentration increased and shear thinning behavior of oil added emulsions was associated with droplet flocculation. Creaming in acidified sugar solution of 11°Bx and pH 3 was observed when the oil-phase specific gravity decreased and sedimentation occurred at the lower viscosity of water phase. Examination of dynamic rheological properties of emulsions revealed that all oil added emulsions showed viscous behavior with the delta degree (G″/G′) greater than 74 at maximum frequency level (50rad/s) and decreased along with increasing the oil level. The solid or elastic behavior was related to those emulsions that exhibited sedimentation with the delta degree lower than 35.

Effects of formulation factors on encapsulation efficiency and release behaviour in vitro of huperzine A-PLGA microspheres

To develop a long-acting injectable huperzine A-PLGA microsphere for the chronic therapy of Alzheimer's disease, the microsphere was prepared by using o/w emulsion solvent extraction evaporation method based on a series of formulation design of the emulsion. The dialysis method was used for release analysis. The encapsulation efficiency and release amount of the microspheres were determined by UV/VIS spectrophotometry. The morphology of the microspheres was observed by scanning electron microscopy. The distribution of the drug within microspheres was observed by a confocal laser scanning microscope. The results indicated that the PLGA 15 000 microspheres possessed a smooth and round appearance with average particle size of 50 µm or so. The encapsulation percentages of microspheres prepared from PLGA 15 000, 20 000 and 30 000 were 62.75, 27.52 and 16.63%, respectively. The drug release percentage during the first day decreased from 22.52% of PLGA 30 000 microspheres to 3.97% of PLGA 15 000 microspheres, the complete release could be prolonged to 3 weeks. The initial burst release of microspheres with higher molecular weight PLGA could be explained by the inhomogeneous distribution of drug within microspheres. The encapsulation efficiency of the microspheres improved as the polymer concentration increase in oil phase and PVA concentration decreased in aqueous phase. The burst release could be controlled by reducing the polymer concentration. Evaporation temperature had a large effect on the drug release profiles. It had better be controlled under 30°C. Within a certain range of particle size, encapsulation efficiency decreased and drug release rate increased with the reducing of the particle size.

Effects of formulation factors on encapsulation efficiency and release behaviour in vitro of huperzine A-PLGA microspheres

To develop a long-acting injectable huperzine A-PLGA microsphere for the chronic therapy of Alzheimer's disease, the microsphere was prepared by using an o/w emulsion solvent extraction evaporation method based on a series of formulation design of the emulsion. The dialysis method was used for release analysis. The encapsulation efficiency and release amount of the microspheres were determined by a UV/VIS spectrophotometer. The morphology of the microspheres was observed by scanning electron microscopy. The distribution of the drug within microspheres was observed by a confocal laser scanning microscope. The results indicated that the PLGA 15 000 microspheres possessed a smooth and round appearance with average particle size of 50 µm or so. The encapsulation percentages of microspheres prepared from PLGA 15 000, 20 000 and 30 000 were 62.75%, 27.52% and 16.63%, respectively. The drug release percentage during the first day decreased from 22.52% of PLGA 30 000 microspheres to 3.97% of PLGA 15 000 microspheres, the complete release could be prolonged to 3 weeks. The initial burst release of microspheres with higher molecular weight PLGA could be explained by the inhomogeneous distribution of drug within microspheres. The encapsulation efficiency of the microspheres improved as the polymer concentration increased in the oil phase and PVA concentration decreased in the aqueous phase. The burst release could be controlled by reducing the polymer concentration. Evaporation temperature had a large effect on the drug release profiles. It had better be controlled under 30°C. Within a certain range of particle size, encapsulation efficiency decreased and drug release rate increased with the reducing of the particle size.

Optimization of chlorphenesin emulgel formulation

This study was conducted to develop an emulgel formulation of chlorphenesin (CHL) using 2 types of gelling agents: hydroxypropylmethyl cellulose (HPMC) and Carbopol 934. The influence of the type of the gelling agent and the concentration of both the oil phase and emulsifying agent on the drug release from the prepared emulgels was investigated using a 2(3) factorial design. The prepared emulgels were evaluated for their physical appearance, rheological behavior, drug release, antifungal activity, and stability. Commercially available CHL topical powder was used for comparison. All the prepared emulgels showed acceptable physical properties concerning color, homogeneity, consistency, spreadability, and pH value. They also exhibited higher drug release and antifungal activity than the CHL powder. It was found that the emulsifying agent concentration had the most pronounced effect on the drug release from the emulgels followed by the oil phase concentration and finally the type of the gelling agent. The drug release from all the emulgels was found to follow diffusion-controlled mechanism. Rheological studies revealed that the CHL emulgels exhibited a shear-thinning behavior with thixotropy. Stability studies showed that the physical appearance, rheological properties, drug release, and antifungal activity in all the prepared emulgels remained unchanged upon storage for 3 months. As a general conclusion, it was suggested that the CHL emulgel formulation prepared with HPMC with the oil phase concentration in its low level and emulsifying agent concentration in its high level was the formula of choice since it showed the highest drug release and antifungal activity.

Nanoemulsions: a new vehicle for skincare products

Nanoemulsions consist in very fine oil-in-water dispersions, having droplet diameter smaller than 100 nm. Compared to microemulsions, they are in a metastable state, and their structure depends on the history of the system. In the present work, nanoemulsions were prepared with a high shear device, which is less constraining than spontaneous emulsification procedures. Nanoemulsions are very fragile systems by nature. As they are transparent, the slightest sign of destabilisation appears visually. Two major sources of unstability were identified and extensively studied: Ostwald ripening and depletion induced floculation following the addition of thickening polymers. The control of these two mechanisms allowed the industrial production of a large variety of cosmetic products, from water-like fluids, to ringing gels obtained by increasing the oil phase content or by adding polymers. The nanoemulsions are easily valued in skin care due to their good sensorial properties (rapid penetration, merging textures) and their biophysical properties (especially their hydrating power).

Nanoemulsions: a new vehicle for skincare products

Nanoemulsions consist in very fine oil-in-water dispersions, having droplet diameter smaller than 100 nm. Compared to microemulsions, they are in a metastable state, and their structure depends on the history of the system. In the present work, nanoemulsions were prepared with a high shear device, which is less constraining than spontaneous emulsification procedures. Nanoemulsions are very fragile systems by nature. As they are transparent, the slightest sign of destabilisation appears visually. Two major sources of unstability were identified and extensively studied: Ostwald ripening and depletion induced floculation following the addition of thickening polymers. The control of these two mechanisms allowed the industrial production of a large variety of cosmetic products, from water-like fluids, to ringing gels obtained by increasing the oil phase content or by adding polymers. The nanoemulsions are easily valued in skin care due to their good sensorial properties (rapid penetration, merging textures) and their biophysical properties (especially their hydrating power).

Lecithin-based oil-in-water microemulsions for parenteral use: Pseudoternary phase diagrams, characterization and toxicity studies

Pseudoternary phase diagrams have been constructed to evaluate the phase behavior of systems containing water/lecithin/polysorbate 80/isopropyl myristate at different polysorbate 80:lecithin weight ratios (K(m)). Oil-in-water microemulsion regions were accurately determined and the influence of the K(m) on the area of existence of such disperse systems was also examined. Viscosity studies as well as particle size analysis by dynamic light scattering were carried out on oil-water microemulsions, and the influence of the oil phase content, the total amount of surfactants and K(m) on the rheological behavior, viscosity, and droplet size of such disperse systems was evaluated. All systems studied showed a water-rich isotrope region (oil-in-water microemulsion area), that was seen to be highly dependent upon the surfactant/cosurfactant weight ratio. Most of the microemulsions analyzed showed a non-Newtonian rheological behavior and both, droplet size, and viscosity of the disperse systems, were found to be much more influenced by the total content of oil phase and surfactants present in the microemulsion than by the K(m). The selected system underwent both stability and in vivo acute toxicity studies, and seemed to be highly stable, even at extreme conditions, and very low toxic according to the results obtained.

Used Motor Oil as a Source of MTBE, TAME, and BTEX to Ground Water

AbstractMethyl tert‐butyl ether (MTBE), the widely used gasoline oxygenate, has been identified as a common ground water contaminant, and BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) have long been associated with gasoline spills. Because not all instances of ground water contamination by MTBE and BTEX can be attributed to spills or leaking storage tanks, other potential sources need to be considered. In this study, used motor oil was investigated as a potential source of these contaminants. MTBE in oil was measured directly by methanol extraction and gas chromatography using a flame ionization detector (GC/FID). Water was equilibrated with oil samples and analyzed for MTBE, BTEX, and the oxygenate tert‐amyl methyl ether (TAME) by purge‐ and‐trap concentration followed by GC/FID analysis. Raoult's law was used to calculate oil‐phase concentrations of MTBE, BTEX, and TAME from aqueous‐phase concentrations. MTBE, TAME, and BTEX were not detected in any of five new motor oil samples, whereas these compounds were found at significant concentrations in all six samples of the used motor oil tested for MTBE and all four samples tested for TAME and BTEX. MTBE concentrations in used motor oil were on the order of 100 mg/L. TAME concentrations ranged from 2.2 to 87 mg/L. Concentrations of benzene were 29 to 66 mg/L, but those of other BTEX compounds were higher, typically 500 to 2000 mg/L.