Walnut Oil Nanoemulsion: Optimization of the Emulsion Capacity,Cloudiness, Density,and Surface Tension

Response surface methodology (RSM) in conjunction with central composite rotatable design (CCRD) was employed to find out the influence of preparation properties of walnut oil/water nanoemulsion namely ultrasonic time (5–15 minutes), walnut oil content (4–10% w/w) and concentration ratio of Span 80 to Tween 80 (K ₀, 0.55–0.80) on response variables including emulsion capacity, cloudiness, density and surface tension. The calculated regression models with high value of coefficient of determination (0.910–0.973) and insignificant lack of fit test indicated satisfactory agreement of empirical models with experimental observations. The results revealed linear term of walnut oil concentration was the most significant (p < 0.05) parameter on the all responses. The overall optimum region to achieve the ideal characteristics was ultrasonic time of 11.74 minutes, walnut oil content of 4.00% (w/w) and K ₀ of 0.80.     

Optimal Development of a New Stable Nutraceutical Nanoemulsion Based on the Inclusion Complex of 2-Hydroxypropyl-β-cyclodextrin with Canthaxanthin Accumulated by Dietzia natronolimnaea HS-1 Using Ultrasound-Assisted Emulsification

Solubilizing the potent anticancer pigments in nanoemulsion (NE) systems containing 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) is a novel and promising strategy to incorporate them into water-based drug formulations. The concentration effects of sunflower oil (SO, 5.61–17.39% w/w), surfactant mixture of Tween 80 (T80) and Span 20 (S20) (1:1 weight ratio, 3.95–14.05% w/w), and the inclusion complex of HP-β-CD with canthaxanthin (CTX) synthesized by Dietzia natronolimnaea HS-1 (2.61–14.39% w/w) were evaluated to formulate a stable NE using ultrasound-assisted emulsification. The NEs were evaluated regarding droplet size and polydispersity index (span), physical stability, turbidity, and loss of antioxidant activity (LAA). Response surface modeling showed that the NEs containing 12% T80/S20, 8.30% SO, and 12% CTX/HP-β-CD had the lowest droplet size (105.5 nm), span (0.394), droplet growth ratio (0.112), turbidity (0.139), and LAA (9.36%). The predicted values obtained were close to the experimental values, indicating the suitability of the constructed models. Transmission electron microscopy and confocal laser-scanning microscopy also demonstrated that the formed droplets of the NEs produced at optimal formulation were spherical in the range of 20–100 nm. A significant correlation was found between droplet size with stability (r = ?0.960, p < 0.01) and turbidity (r ² = 0.876, p < 0.01) values.     

Small-Angle Neutron Scattering Study of Nonionic Surfactant Micelles and Phase Transitions in w/o Microemulsion

The structure of micelles formed by a four component water-in-oil nonionic microemulsion surfactant polyoxyethene (20) sorbitan monoleate (Tween 80), sorbitan monolaurate (Span 20) at ethyl oleate and deuterated water interface have been probed by small-angle neutron scattering (SANS). The total surfactant concentration in each of the samples studied (Tween 80: Span 20) is fixed at 3:2. The deuterated water content is variable at 5–60% w/w. The experimental SANS data from all the seven samples are fit well by spherical micelles interacting with hard sphere potential. Increased deuterated water leads to spherical to lamellar and rod-like micelle geometry featured in the SANS scattering data. The observed change in micelle geometry supports the characterization of phase transition between the self-assembled micelles of the nonionic microemulsion.      

Minimum Evaporation Model of Dermatological Delivery Systems. Lamellar Liquid Crystal Formulations Containing Brazilian Nut (Bertholletia excelsa HBK) Vegetable Oil and Guarana Glycolic Extract

Formulations with lyotropic liquid crystals were prepared from a Brazilian nut vegetable oil, guarana extract and combination of sorbitan monooleate (Span 80) and sorbitan monolaurate ethoxylate EO 20 (Tween 20) in the ratio 1:3 (surfactant component) and their physical–chemical aspects and rheological properties were determined. Compositions with liquid crystals were found in the pseudoternary diagram in a surfactant range of 70–90% and polarized light microscopy, small-angle x-ray scattering (SAXS) showed them to be lamellar. The preparations were furthermore characterized rheologically by shear stress shear rate sweeps finding plastic and pseudoplastic behavior without thixotropy. Electric conductivity and pH measurements demonstrated a potential for future application as dermatological delivery system of the active compounds in the Bertholletia excelsa and Paullinia cupana.      

Water-in-Oil-in-Water Nanoemulsions Containing Temulawak (Curcuma xanthorriza Roxb) and Red Dragon Fruit (Hylocereus polyrhizus) Extracts

Hydrophobic curcumin in temulawak extract and hydrophilic betacyanin in red dragon fruit extract are high-value bioactive compounds with extensive applications in functional food. In this study, these extracts were encapsulated in water-in-oil-in-water (w/o/w) nanoemulsions as a delivery system using a two-step high-energy emulsification method. PGPR and Span 20 were used as lipophilic emulsifiers for the primary w/o emulsion. The most stable w/o/w formulation with the least oil phase separation of 5% v/v consisted of w/o emulsion (15% w/w) and Tween 80 (1.5% w/w) as hydrophilic emulsifier. The formulation was characterized by a 189-nm mean droplet diameter, 0.16 polydispersity index, and –32 mV zeta potential. The freeze–thaw stability may be attributed to the combination of low w/o emulsion content and high Tween 80 concentration in the outer water phase of the w/o/w nanoemulsions used in this study. The IC₅₀ values of the nanoemulsion and the red dragon fruit extract were similar. It means that the higher concentration of curcumin in the nanoemulsions and the lower IC₅₀ value of temulawak extract ensured sufficient antioxidant activities of the w/o/w nanoemulsions.     

Antioxidant Activity Degradation,Formulation Optimization,Characterization, and Stability of Equisetum Arvense Extract Nanoemulsion

Equisetum arvense supercritical CO₂ extracts (EAE) contained an initial antioxidant activity of 10.3 mM TEAC that suffered a sharp first order kinetics decay characterized by half-life time (t_1/2) of 1.05 ± 0.03 and 0.86 ± 0.03 weeks at 25 and 4°C, respectively. The aim of the present work was to develop a nanoemulsion formulation for providing EAE protection against deleterious environmental factors and extending its shelf-life functionality. The nanoemulsion area was identified by constructing pseudoternary phase diagrams and response surface methodology was used to optimize the preparation conditions. The best formulation achieved an EAE encapsulation efficiency of 97.5 ± 0.5% and antioxidant activity half-life time (t_1/2) was extended to 12.32 ± 0.40 and 14.56 ± 0.60 weeks at 25 and 4°C, respectively.      

Dynamic and Rheological Properties of Span 80 at Liquid–Liquid Interfaces

The adsorption characteristics of Span 80 at liquid/liquid interfaces were investigated. The equilibrium interfacial tension values were successfully fitted with a Langmuir isotherm resulting in the determination of a mean molecular area from 25 to 35 Å²/mol. The measured interfacial tension values and deduced adsorption parameters depend on the experimental technique used to obtain them, either Du Noüy ring or profile analysis tensiometry. Two possible explanations to such phenomenon are provided. Adsorption kinetics of Span 80 at liquid/liquid interfaces were studied, and it was concluded that the diffusion of Span 80 molecules from the bulk is the rate determining step of the adsorption. Finally the interfacial rheology properties were investigated and compared to the Lucassen–van den Tempel model. A good match was obtained when the isotherm parameters determined by profile analysis tensiometry were used.      

Kinetics of the potassium persulfate-initiated inverse emulsion polymerization of sodium acrylate solutions

The kinetics of the K₂S₂O₈-initiated inverse emulsion polymerization of aqueous sodium acrylate solutions in kerosene with Span 80 as the emulsifier has been studied. The conversion-time curves are S-shaped. The following expressions have been obtained for the maximum rate of polymerization and the molecular weight of the polymers under the experimental conditions investigated: R_max ∞ [K₂S₂O₈]^0.78[sodium acrylate]^1.5[Span 80]^0.1, (OVERLINE)M(/OVERLINE)_u ∞ [K₂S₂O₈]^−0.37[sodium acrylate]^2.9[Span 80]^−0.2. The activation energy for the maximum rate of polymerization is 94.8 kJ mol^−1. The results suggest a monomer–droplet–nucleation mechanism for the system studied. © 1996 John Wiley & Sons, Inc.     

Demulsification Efficiency of Some New Demulsifiers Based on 1,3,5-Triethanolhexahydro-1,3,5-triazine

This study mainly concentrates on the synthesis of three novel demulsifiers and the investigation of their demulsification efficiency. The demulsifiers were derived from 1,3,5-triethanolhexahydro-1,3,5-triazine, which was prepared by the reaction of monoethanol amine with formaldehyde. The 1,3,5-triethanolhexahydro-1,3,5-triazine was ethoxylated by introducing 20 units of ethylene oxide and then esterified at different molar ratios with oleic acid (1, 2, and 3) to give three demulsifiers, namely, E₂₀TO, E₂₀TO₂, and E₂₀TO₃. The chemical structures of the prepared demulsifiers were confirmed by ¹H NMR and FTIR spectrum. The demulsification efficiency of these demulsifiers was tested on the natural water-in-oil (w/o) emulsions (50% water content). From the obtained results, it has been found that the investigated demulsifiers have a great potential to break the w/o emulsions. The trioleat ester (E₂₀TO₃) exhibited the maximum demulsification efficiency (96%) after 120 minutes at 55°C.     

Preparation and Characterization of Polymeric Nanocapsules Produced by in Situ Polymerization From Nanoemulsions Produced by Direct Emulsification

Polymeric nanoparticles constitute an important drug delivery system with controlled release profile. This article describes a new way to produce polymeric nanocapsules using a vegetable oil nanoemulsion as template. The process occurs in two steps: First, a nanoemulsion was obtained with a low-energy method based on phase inversion emulsification, using 2-ethylhexyl acrylate as lipophilic monomer. The in situ polymerization of the nanoemulsion droplets is induced by the addition of polymerization catalyzers. The mean size of the polymeric nanoparticles was evaluated by photon correlation spectroscopy and atomic force microscopy. Both techniques showed the formation of polymeric nanocapsules with a mean particle size less than 300 nm.     

Nanoemulsion of Myrtus communis essential oil and evaluation of its larvicidal activity against Anopheles stephensi

PurposeExcessive use of chemical insecticides has caused environmental pollution and vector resistance. Herbal essential oils with larvicidal properties are good alternatives to synthetic insecticides.mIn this study, larvicide properties of Myrtus communis essential oil and its nanoemulsion against Anopheles stephensi were investigated.MethodsComponents of Myrtus communis essential oil were identified by GC–MS. Nanoemulsion of essential oil was made with Tween 80, Span 20, and water. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) determined particle size and morphology of nanoemulsions. The larvicide activity compared with bulk essential oil.ResultsA total of 107 M. communis essential oil compounds were discovered. The morphology of a selected nanoemulsion was spherical. LC₅₀ and LC₉₀ of M. communis essential oil were calculated as 26.1 and 46.2 µg/ml, respectively. The larvicide activity of nanoemulsion increased by 40% compared to the bulk essential oil. The nanoemulsion's larvicide activity (100%) lasted up to 3 days, while the essential oil had larvicide properties only for up to 24 h.ConclusionsMyrtus communis essential oil was found to be an effective larvicide and classified as an active larvicide. The residual efficacy of the nanoformulation of M. communis significantly increased compared with the bulk essential oil.     

Lyotropic Liquid Crystal Formed in Oleyl Polyoxyethylene Solutions by Adding Different Additives: NaDC,Tween 80, Alkyl Esters

Lyotropic liquid crystalline of oleylpolyoxyethylene(20)(AEO₂₀)/oil/water system was investigated at 25°C. The phase behavior, microstructure, and rheological properties of liquid crystalline were investigated by rheological techniques and polarizingoptical microscopy in the presence of various additives including Tween 80, sodium deoxycholate (NaDC), isoamylacetate, butyl acetate, isopropyl myristate. Diagrams show that cubic phase transforms to hexagonal phase when a shorter chain length oil is applied or NaDC or Tween 80 is added to the system.Flow experiments indicate the shear-thinning properties and a plastic behavior. The turning points of flow curves of the system AEO₂₀ and system AEO₂₀/NaDC were found. The dynamic modulus increase with increase in water content however the tendency is weaken by adding NaDC. Frequency dependence of experimental G ′ and G ′ were fitted using the multiple Maxwell model the cubic LLCs described by three relaxation times while hexagonal LLCs described by 5–8 elements. When AEO₂₀ mixes with Tween 80, the hexagonal have a monotonic decrease distribution of relaxation times without valleys.     

Micronization of Iron Oxide Particles Using Gas Antisolvent Process

Iron oxide particles were micronized by supercritical carbon dioxide (CO₂) as an antisolvent in a batch gas antisolvent (GAS) process. In the present study, the feasibility of GAS process to micronize the iron oxide particles using dimethyl sulfoxide (DMSO) as a solvent was investigated. In this direction, particle size and morphology changes were investigated with changing solution pressure (80–150 bar), temperature (308.15–328.15 K), and concentration (1.5–6 g/l). Based on the different experimental conditions, the particle size of the original iron oxide was decreased in the range of 17.25 to 4.23 µm, which shows a the success of the GAS process to reduce the particle size of the intact iron oxide particles. Simultaneously, morphology changes were observed starting from the irregular morphology for synthesized particles to more regular shapes that included fused and spherical-fused particles.     

Kinetic and Mechanistic Studies on [Zn(II)-Gly-Phe]+–Ninhydrin Reaction in Aqueous and Cationic CTAB Surfactant Micelles

The rates of reaction between metal-dipeptide complex ([Zn(II)-Gly-Phe]⁺) and ninhydrin have been determined in aqueous and aqueous–cationic micelles of cetyltrimethylammonium bromide (CTAB) at 70°C and pH 5.0. The rate data indicate that the reaction follows the template reaction mechanism in both the media. The reaction followed a first-order and fractional-order kinetics with respect to [Zn(II)-Gly-Phe]⁺ and [ninhydrin], respectively, in the excess of ninhydrin over [Zn(II)-Gly-Phe]⁺. The rate constant is affected by [CTAB] changes and maximum rate enhancement is approximately three-fold. CTAB micelles decrease the activation enthalpy and make the activation entropy less negative. Quantitative kinetic analysis of rate constant (k _ψ)–[CTAB] data was performed on the basis of pseudophase model of the micelles (proposed by Menger and Portnoy and developed by Bunton). The values of binding constants K _S for [Zn(II)-Gly-Phe]⁺ and K _N for ninhydrin with micelles are calculated with the help of observed kinetic data. The results obtained in micellar medium are treated quantitatively on the basis of pseudophase model.     

Determination of Required HLB of Capryol 90

The required hydrophilic-lipophilic balance (HLB) of an oily substance indicates the HLB of the surfactants required to prepare a stable emulsion using the oil. This study utilizes empirical method to calculate required HLB (RHLB) of Capryol 90 using surfactant blends (Span 20, Tween 20, vitamin E TPGS, Pluronic F68, Span 60, and Tween 80). The methods used were assessment of degree of creaming after centrifugation and after shelf storage for 28 days at room temperature, turbidimetric method, accelerated stability study, and droplet size analysis. The droplet size was found to be in the range of 15 to 2 µm and v/v% separation after centrifugation was found to be 0–82%. The RHLB for Capryol 90 was found to be 15. The effect of various surfactant blends was investigated. Results revealed that a blend of tocopherol polyethylene glycol succinate (TPGS) and Pluronic F68 gave the most stable emulsion for Capryol 90.