Preparation Of Nanoemulsions Research Articles

Development of a Novel Nano­emulsion Formulation to Improve Intestinal Absorption of Cannabidiol

Background: Cannabidiol (CBD) is highly lipophilic, and its oral bioavailability is known to be very low in humans. In this study, we developed a novel nanoemulsion preparation of CBD (CBD-NE) to improve the poor solubility and absorption of CBD. The pharmacokinetic profiles of CBD in rats were evaluated after oral administrations of CBD oil and CBD-NE, and the effect of bile secretion on CBD absorption was also evaluated. Methods: The CBD-NE formulation developed in this study consisted of vitamin E acetate, ethanol, Tween-20, and distilled water (1.7/3.8/70/24.5, w/w%). A CBD oil formulation (CBD oil, control) 100 mg/kg or CBD-NE 50 mg/kg was orally administered to rats, and the blood samples were collected over time. Moreover, the CBD oil or CBD-NE was orally administered to bile-fistulated rats, and the pharmacokinetic profiles of CBD were also evaluated. CBD concentrations in plasma were measured using LC-MS/MS. Results: The particle size of CBD-NE was 35.3 ± 11.8 nm. Mean T_max of CBD-NE was shortened significantly by the factor of 3 (from 8.00 to 2.40 h, p < 0.001) and AUC_0–_∞/dose increased by 65% (from 0.272 ± 0.045 to 0.448 ± 0.087 h L/kg) compared with CBD oil. AUC_0–_∞/dose and C_max/dose after oral administration of CBD oil were significantly reduced by the factor of 27 and 23 (p < 0.05 and p < 0.01), respectively, in bile-fistulated rats compared with the untreated rats. In contrast, all pharmacokinetic parameters after oral administration of CBD-NE were not significantly different between the untreated and bile-fistulated rats. Therefore, these results demonstrated that conventional CBD oil formulation but not CBD-NE requires bile-mediated micelle formation. Conclusions: The novel NE formulation developed in this study successfully improved the absorption of CBD regardless of bile secretion. The newly developed oral CBD-NE preparation could be useful to achieve a more stable and quicker onset of action by CBD.

Preparation of Ciprofloxacin Ocular Ophthalmic Nano Emulsion and its Physicochemical Characterization In Vitro

Preparation of Ciprofloxacin Ocular Ophthalmic Nano Emulsion and its Physicochemical Characterization In Vitro

Fatty Acids of Enteromorpha intestinalis Emulsified Drug Delivery Nanoemulsion: Evaluation of Loading Mechanism and Release Kinetics for Drug Delivery

The selection of bio-surfactants in consonance with the pharmaceutical drug in the preparation of nanoemulsion for the controlled release of drugs and bio-compatibility is still a scientific moot. We have investigated the possible mechanism of drug-surfactant interaction in this research that can iron out the surfactant identification complication. The bio-surfactants 9-Octadecenoic acid, 9-Octadeceamide and Isopropyl Myristate isolated from a marine weed Enteromorpha intestinalis were used together to stabilize the nanoemulsion. The encapsulation efficiency and release kinetics of Aspirin in nanoemulsion under different pH conditions from the nanoemulsion was studied. Nanoemulsion was prepared by the ultrasonication method and characterized by centrifugation, capillary viscometer, freeze–thaw cycle assays, dynamic light scattering analysis (DLS) and HR-TEM. The mechanism of drug surfactant interaction deduced using Spectrophotometric and ATR-FTIR analysis revealed the possible bond formations. In-vitro drug release profiles of aspirin (model drug) were evaluated by dialysis in different pH (1.2, 6.8 and 7.4) using by UV-spectrophotometry and the effective release of aspirin was observed in pH 6.8. The release kinetics was studied to identify the mode of release. The bio-surfactant based nanoemulsion of 15:6:9 composition exhibited ideal stability and controlled release in all pH conditions with linearity and time-dependent paradigm.

Binary Surfactant System for Preparation of Nano-Emulsion of Herbal Oil Mixtures

Binary Surfactant System for Preparation of Nano-Emulsion of Herbal Oil Mixtures

Preparation, Characterization and Applications of Nanoemulsions: An Insight

Nanoemulsions are defined as isotropic, thermodynamically stable, transparent or translucent; dispersions of oil and water stabilized by surfactant molecules (forms an interfacial film) having the droplet size of 20-500nm. Ease of preparation and scale-up, stability and increased bioavailability are features of these formulations which have attracted the attention of researchers. Its basic principle lies in its ability to spontaneously generate fine o/w microemulsion under mild agitation following dilution with aqueous phases. These conditions mimic the digestive motility in the GIT necessary to provide the agitation required for In vivo self emulsification. Unlike emulsions, self-nanoemulsified drug delivery systems (SNEDDS) generates microemulsion with a narrow droplet size distribution of less than 50 nm due to which these systems have also been addressed as nanoemulsions. Nanoemulsions (NE) are lipidic nanoformulations with droplet diameter in nanometer range have established tremendous attention as drug delivery formulations for lipophilic drugs due to their capability to increase solubility, permeation across biological membranes as well as their therapeutic efficiency of lipid soluble drugs due to predictable size-distribution, high drug loading and stability under biological environment. However there is still relatively narrow insight regarding preparation, characterization and applications of nanoemulsions. This limitation unfolds the premise for current review article. In this review, we attempt to explore varying intricacies, methods of preparation, characteristics, and drug delivery applications of nanoemulsions to spike interest of those contemplating a foray in this field.&#x0D; Keywords: Nanoemulsions, Novel drug delivery system, increased bioavailability.

Novel multi-phase nano-emulsion preparation for co-loading hydrophilic arbutin and hydrophobic coumaric acid using hydrocolloids

This study was designed to co-load hydrophilic arbutin and hydrophobic coumaric acid in nano-sized multi-phase emulsion (W/O/W) using hydrocolloids and examined for its various stability and bioaccessibility parameters. The creaming stability and sensory evaluation of emulsion in Lactobacillus beverage and its release kinetics in simulated oral and gastrointestinal conditions were also studied. Results revealed that multi-phase emulsion exhibited small particle size and low polydispersity index with high zeta potential. Higher encapsulation efficiency was also observed. Moreover, the multi-phase emulsion showed good storage stability under different conditions. The multi-phase emulsion also showed controlled release of arbutin and coumaric acid in simulated conditions with increasing bioaccessibility. Stability of these compounds under unfavorable conditions was also found to be increased. Moreover, high creaming stability and sensory evaluation score of the multi-phase emulsion suggested that the formulation was capable of retaining arbutin and coumaric acid in Lactobacillus beverage without affecting its sensory properties. These results indicated that the multi-phase nano-emulsion (W/O/W) could effectively co-deliver hydrophilic arbutin and hydrophobic coumaric acid and thus could be a novel delivery method for increasing bioaccessibility of these nutraceutically important phenolic compounds.

English

Nanoparticles can act as drug carriers that can modulate pharmacokinetics, increase bioavailability and target release with minimal toxic effects. The present work aimed to assess the therapeutic effect and electron microscopic changes of Nigella sativa loaded Chitosan Nanoparticles (NSLCN) on adult Schistosoma mansoni in vitro. Adult worms were removed from the portal and mesenteric veins of infected mice after 90 days, and then three to five mature worms including both sexes were cultured. Schistosoma adult was exposed to NSLCN at concentrations of (10, 20, 40, 60, 80, and 100 &mu;g/ml) for 24, and 48 h. Examination for worm viability was done after 24, and 48 h using a stereomicroscope comparing with control negative and control positive groups. The mortality rate in worms reached 88.9% in the group treated with 100 &mu;g and 80 and 84.6% in groups treated with 80 and 60 &mu;g respectively (p-value &lt;0.001). After 48 h of incubation with the same concentration, there were variable effects on motility and death of worms, the death rate reached 100% in all groups treated with nanoparticles. After 24 h incubation, the live worms have sluggish motility and reached dead score at 48 h of incubation. By (SEM) there were tegumental changes of both dead male and female in the form of loss of spines, swollen suckers and swollen inter tubercular ridges in male and loss of smooth architecture of female tegument with multiple pores. In conclusion, NSLCN appears as a new potential candidate drug against schistosomiasis. We successfully applied nanoemulsion preparation against the adult stage of S. mansoni in vitro. Key words: Schistosoma mansoni, Nigella sativa, chitosan nanoparticles, scanning electron microscope. &nbsp

Olive oil nanoemulsion preparation using high-pressure homogenization and d-phase emulsification – A design space approach

Olive oil has been extensively applied in the pharmaceutical and cosmetic industries due to its biological properties. These are attributed to monounsaturated fatty acids like oleic acid and other minor components, such as phenolics and triterpenic acids. Oil-in-water nanoemulsion may enhance the solubility of poorly water-soluble drugs, which comprise about 40% of the currently marketed ones. However, the development of vegetable oil nanoemulsions is challenging due to their complex composition. In this study, olive oil nanoemulsions were prepared using high-pressure homogenization (HPH) and d-phase emulsification (DPE), as high- and low-energy processes, respectively. DPE has the potential to overcome the drawbacks of conventional Phase Inversion Methods. Aiming to achieve a deeper understanding of HPH and DPE processes, a design of experiment approach was successfully applied. This approach allowed identifying and understanding the relationship between input factors and their associated output response, at the stage of the nanoemulsion development. Moreover, in a specific range of critical process parameters and compositions, within the design space, nanoemulsions with similar mean particle sizes of 275 nm were achieved with equal composition, regardless of the use of the HPH or DPE process.

Nanoemulsified Mentha piperita and Eucalyptus globulus oils exhibit enhanced repellent activities against Anopheles stephensi

Objective: To formulate nanoemulsion from essential oils of Mentha (M.) piperita L. and Eucalyptus (E.) globulus L. and to compare their repellant activity with normal essential oils and N,N-diethyl-m toluamide (DEET) as a standard chemical compound. Methods: In this study, protection time of essential oils and DEET was evaluated on four human subjects using test cage, and their values were determined against Anopheles stephensi. Furthermore, ED50 values for the above essential oils were determined using the ASTM E951- 94 method. The compositions of essential oils were determined using GC-MS, and droplet size and zeta potential of the nanoemulsion were measured with dynamic light scattering. Results: The results (expressed as mean±SD) showed that protection time of M. piperita 50%, M. piperita Nano 50%, E. globulus 50%, E. globulus Nano 50%, and DEET 25% was (2.89±0.45) h, (4.17±0.28) h, (0.96±0.27) h, (5.51±0.02) h, and (6.10±0.47) h, respectively. ED50 values were 29.10 (95% CI: 23.36-36.06) μg/cm2 for Mentha, 19.39 (15.35-23.99) μg/cm2 for Mentha Nano, 36.10 (28.70-48.01) μg/cm2 for Eucalyptus, 18.50 (14.65-23.23) μg/cm2 for Eucalyptus Nano, and 3.62 (2.68-4.55) μg/cm2 for DEET, respectively. E. globulus Nano and M. piperita Nano provided significantly longer protection than normal essential oils E. globulus and M. piperita (P Conclusions: The preparation of nanoemulsion from the essential oils of M. piperita and E. globulus, significantly increases the protection time and reduces ED50 values of these essential oils, hence, M. piperita Nano and E. globulus Nano can be good alternatives to DEET and other chemical compounds.

A Review on Preparation and Evaluation of Nanoemulsions

A Review on Preparation and Evaluation of Nanoemulsions

Preparation of a novel curcumin nanoemulsion by ultrasonication and its comparative effects in wound healing and the treatment of inflammation

The aim of this study was to develop and evaluate a curcumin (Cur) nanoemulsion (NE) and enhance transdermal drug delivery. The comparative effects of Cur-NE were evaluated in terms of wound healing and anti-inflammatory action. Clove oil (oil), Tween-80 (surfactant), and PEG-400 (co-surfactant) were selected on the basis of their solubility and maximum nanoemulsion region. An aqueous micro-titration method with high-energy ultrasonication was used for the preparation of Cur-NE. This method was optimized to find the best NE, followed by a five-factor, three-level, central composite design. % oil, % Smix, ultrasonication time (min), ultrasonication intensity (%), and temperature (°C) were selected and optimized as independent variables. The optimized NE had parameters of 5.0% oil, 10% Smix, ultrasonication time (10 min), 40% ultrasonication intensity and 50 °C temperature, which were applied as independent and dependent variables. On the basis of experimental data of the dependent variables, we calculated a hydrodynamic diameter of 93.64 ± 6.48 nm, transmittance of 98.64 ± 0.37%, and PDI of 0.263 ± 0.021. TEM and SEM results revealed the smooth and spherical shape of the particles in the NE, with a zeta potential of −11.67 ± 0.11, refractive index of 1.71 ± 0.034, viscosity of 37 ± 7 cp, pH of 7.4 ± 0.07, and drug content of 98.11 ± 0.16% for the optimized Cur-NE. Cur-NE optimization with clove oil, Tween-80, and PEG-400 might be useful for enhancing the skin permeation of Cur. In conclusion, Cur-NE played a significant role in wound healing and exhibited anti-inflammatory effects, demonstrating its potential as a nanoformulation for safe and nontoxic transdermal delivery.

Physicochemical Properties and Storage Stability of Food Protein-Stabilized Nanoemulsions.

This study investigated the preparation and properties of corn oil nanoemulsions stabilized by peanut protein isolate (PPI), rice bran protein isolate (RBPI), soybean protein isolate (SPI), and whey protein isolate (WPI). The mean droplet diameter of four protein-stabilized nanoemulsions prepared via ultrasound method was less than 245 nm. PPI-stabilized nanoemulsions showed better stability for 4 weeks, while the mean droplet diameter of RBPI-stabilized nanoemulsions had exceeded 1000 nm during the third week of storage. Fourier transform infrared and interfacial tension (IT) analysis showed that the higher level of disordered structure and lower IT of proteins made the stability of nanoemulsions better. Moreover, bivariate correlation analysis discovered that α-helix (p < 0.01) and β-turn (p < 0.05) of proteins were related to the mean droplet diameter of nanoemulsions, the random coil (p < 0.05) was related to the zeta potential of nanoemulsions. This study provided new idea for the relationship between the structure of protein and properties of protein-stabilized nanoemulsions.

Nanoemulsion preparation base on palm fiber mesocarp residue’s oil and its application on dry noodle

The research about nanoemulsion preparation base on palm fiber mesocarp residue’s oil and its application on dry noodle was carried out. The purposes of this research are to know the characterization of Palm Fiber Mesocarp Residue’s Oil (PFMRO), to generate nanoemulsion product and to apply nanoemulsion as well as colorness agent and carotenoid source on noodle. The method research consists of three steps: i) extraction of PFMRO with hexane solvent; ii) to generate nanoemulsion under condition: a. ratio PFMRO: water (15:82 and 20:80); b. concentration of tween 80 (2.5% and 5%) and c. homogenezier pressure (300 and 500 bar), respectively; and iii) application of nanoemulsion as colorness agent and carotenoid source on noodle. The results show that PFMRO contains oil 7.67 % (w/w), carotenoid (2549.5 ppm) and Deterioration of bleaching index (DOBI) 2.39. The nanoemulsion which was produced has diameter (150.80–202.35 nm) and average of Polidispercity index (PDI) (0.106–0.186).The conditions of best formula of nanoemulsion are rasio of PFMRO:water (20:80), amount of tween 80 (5%) and pressure of homogenizer (P) (500 bar). It is interestingly due is stable until storing for 16 days. Nanoemulsion may affect favoritecolor those are disfavorcolor (score2.5) tobefavorcolor (score 4.0 and 4.12). In addition, the concentration of carotenoid also increases on dry noodle namely undetected on dry noodle for without emulsion convert tobe 33.53ppm (crude emulsion) and 81.27 (nano emulsion). It may be concluded that crude and nanoemulsion may apply to improve the quality of dry noodle.

Development of cumin essential oil nanoemulsions and its emulsion filled hydrogels

Cumin essential oil oil-in-water nanoemulsions were formulated using non-ionic surfactants (Tween 80 and Tween 20) using an ultrasonic method. Nanoemulsion preparation was optimized for parameters such as surfactant type, surfactant concentration and sonication time to achieve minimum droplet diameter with higher physical stability. Results showed that surfactant concentration had inverse relationships with droplet diameter; however, increasing sonication time in Tween 20 and Tween 80 systems had different effects on droplets diameter. A transparent, stable nanoemulsion with droplet diameter of 70 nm was prepared with Tween 80 at a concentration of 0.75%. Thermal stability analysis showed that the nanoemulsions were stable when heated to 65 °C and then cooled to 25 °C. Before development of nanoemulsion-filled hydrogels, the brittle structure of the κ-carrageenan gel (0.25%) with the highest amount of syneresis was improved by the addition of the soluble part of gum tragacanth at a concentration of 0.6%. Optically transparent filled hydrogels were formed by incorporating cumin essential oil nanoemulsions into carrageenan-tragacanth gels. The textural properties of the mixed gels did not change noticeably after the nanoemulsion droplets were incorporated. This approach may, therefore, be useful for the incorporation of various types of lipophilic bioactive agents into functional food gels.

Preparation and characterization of nanoemulsion based β-carotene hydrogels.

The aim of this study was to develop β-carotene hydrogels using nanoemulsions, with increased β-carotene aqueous solubility, bioavailability and improved physical and chemical stabilities. The nanoemulsion of β-carotene was prepared using a solvent-displacement technique and converted into hydrogels using sodium alginate as stabilizer and calcium chloride as cross-linker. The effects of formulation parameters, mainly, the effects sodium alginate and calcium chloride concentrations on the physicochemical properties of hydrogels were evaluated using a surface response methodology. The second order polynomial equations, subsequently, were suggested to predict the changes of studied physicochemical characteristics of hydrogels, with relatively high regression of coefficients values. Based on numerical multiple optimization, it was concluded that using 4.1g/l sodium alginate and 5.7g/l calcium chloride, resulted in a hydrogel with the most desired physicochemical characteristics. No significant differences between the measured and predicted data, reconfirmed the accuracy of the models.

Improvement of physicochemical properties of nanocolloidal carrier loaded with low water solubility drug for parenteral cancer treatment by Response Surface Methodology

Nanoemulsions have been used as a drug carrier system, particularly for poorly water-soluble drugs. Sorafenib is a poorly soluble drug and also there is no parenteral treatment. The aim of this study is the development of nanoemulsions for intravenous administration of Sorafenib. The formulations were prepared by high energy emulsification method and optimized by using Response Surface Methodology (RSM). Here, the effect of independent composition variables of lecithin (1.16–2.84%, w/w), Medium-Chain Triglycerides (2.32–5.68%, w/w) and polysorbate 80 (0.58–1.42%, w/w) amounts on the properties of Sorafenib-loaded nanoemulsion was investigated. The three responses variables were particle size, zeta potential, and polydispersity index. Optimization of the conditions according to the three dependent variables was performed for the preparation of the Sorafenib-loaded nanoemulsions with the minimum value of particle size, suitable rage of zeta potential, and polydispersity index. A formulation containing 0.05% of Sorafenib kept its properties in a satisfactory range over the evaluated period. The composition with 3% Medium-Chain Triglycerides, 2.5% lecithin and 1.22% polysorbate 80 exhibited the smallest particle size and polydispersity index (43.17 nm and 0.22, respectively) with the zeta potential of −38.8 mV was the optimized composition. The fabricated nanoemulsion was characterized by the transmission electron microscope (TEM), viscosity, and stability assessment study. Also, the cytotoxicity result showed that the optimum formulations had no significant effect on a normal cell in a low concentration of the drug but could eliminate the cancer cells. The dose-dependent toxicity made it a suitable candidate for parenteral applications in the treatment of breast cancer. Furthermore, the optimized formulation indicated good storage stability for 3 months at different temperatures (4 ± 2 °C, 25 ± 2 °C and 45 ± 2 °C).

Preparation of Fenpropathrin Nanoemulsion by Phase Inversion Temperature Method and Its Study on Performance

In this study, 8% fenpropathrin nanoemulsion was prepared by phase inversion temperature (PIT) method with 8% xylene and 4% solvent oil 150# as the solvent. The characteristics of this nanoemulsion were tested and compared with emulsifiable concentrate (EC). The size of 8% fenpropathrin nanoemulsion was 62.99[Formula: see text]nm, which was much smaller than that of 20% fenpropathrin EC (459.00[Formula: see text]nm). The mixed surfactants were added in fenpropathrin nanoemulsion with DBS-Ca:LAE at 1:2 to increase the stability, and the concentration of the mixed surfactants at 10[Formula: see text]wt.% showed the highest stability and much better synergism and surface activity. The absolute zeta potential of fenpropathrin nanoemulsion was much higher than that of EC, which can effectively prevent the cohesion between particles. Field control test also revealed that the 200[Formula: see text]mg/L, 100[Formula: see text]mg/L and 50[Formula: see text]mg/L fenpropathrin nanoemulsion had higher efficacy than 100[Formula: see text]mg/L fenpropathrin EC (contrast pesticide) in 4th, 7th, 15th days, respectively. In conclusion, nanoemulsion has a great application prospective in the future.

Ultrasound-assisted oil-in-water nanoemulsion produced from Pereskia aculeata Miller mucilage

For the preparation of nanoemulsions, the correct choice of emulsifiers, together with the emulsification methods, directly influences the final product quality. The present study reports the ultrasound-assisted preparation of oil-in-water nanoemulsions produced with mucilage extracted from leaves of Pereskia aculeata Miller (ora-pro-nobis; OPN). The OPN mucilage (%) and soybean oil (%) concentration range, and the process operating parameters, ultrasonic power amplitude (%) and sonication time (min), were optimized based on the mean droplet diameter (d32). The effect of the mucilage and oil concentrations was also investigated by the response variables such as polydispersity, density, turbidity, viscosity, zeta-potential, and interfacial tension. The higher OPN mucilage concentrations (%) with lower amounts of soybean oil (%) favored nanoemulsion formations (116 ≤ d32 ≤ 171 nm) and increased polydispersity, density, and zeta-potential. On increasing OPN mucilage and soybean oil the turbidity of the dispersions increased. All colloidal systems showed Newtonian behavior, and the viscosity in the systems increased due to the greater OPN mucilage concentration in the aqueous phase at a certain oil concentration. In addition, lower values of equilibrium interfacial tension were found with increasing OPN mucilage concentrations. Finally, from the stability test, it can be pointed out that the OPN mucilage concentration should be between 1.0 and 1.5% and the oil concentration should be less than 5%, so that lower d32 values are maintained over time. Therefore, mucilage extracted from OPN and the ultrasound technique can be used in the preparation of nanoemulsions.

Preparation and characterizations of essential oil and monoterpene nanoemulsions and acaricidal activity against two-spotted spider mite (Tetranychus urticae Koch)

ABSTRACTThe present study aims at preparing nanoemulsions of two types of plant essential oils (EOs) (Callistemon viminalis and Origanum vulgare) and two monoterpenes (R-limonene and pulegone) as acaricidal agents against two-spotted spider mite, Tetranychus urticae Koch. The oil-in-water nanoemulsions (10% active ingredient) were spontaneously formed by adding dropwise an EO or monoterpene into an aqueous solution containing 20% of a surfactant (Tween 80) with continuous stirring followed by a high-energy (ultrasonication) emulsification process for 15 min. The characterizations of nanoemulsions including viscosity, pH, thermodynamic stability, droplet size, and polydispersity index (PDI) were investigated in detail. All nanoemulsions were prepared with droplet size in the range of 7.07–10.18 nm and a PDI of 0.249–0.620. Nanoemulsions exhibited high acaricidal activity against T. urticae mites with a 100% reduction at 5000 mg/L after 2–3 days of application on bean plants (Phaseolus vulgaris L.) under greenhouse conditions. No symptoms of phytotoxicity were observed in treated plants during the experiments (21 days). The stability of prepared nanoemulsions, high acaricidal activity, and the absence of organic toxic solvents make the formulations suitable as acaricidal products. The results suggest that appropriate nanoemulsions containing EOs and/or monoterpenes can be developed to control T. urticae on plants.

FORMULATION AND EVALUATION OF RED PALM OLEIN NANOEMULSION

Objective: The objective of this study is to formulate and evaluate the red palm olein (RPO) nanoemulsion using spontaneous emulsification method.Methods: Nanoemulsion formulated by spontaneous emulsification method using the comparison of surfactant (tween 80) and cosurfactant (sorbitol) concentration with the variation of RPO concentration. Evaluation of the stability of the nanoemulsion preparation includes centrifugation test, viscosity, pH, organoleptic observation (odor, color, clarity, and phase separation), and particle size measurement during 12 weeks storage at room temperature.Result: The results showed that all nanoemulsion preparations were transparent yellow, characteristic odor, type weights 1.0166–1.0641 g/ml, and stable for 12 weeks storage at room temperature. The smallest particle size was produced by the nanoemulsion preparation in a formula of the concentration of 5%, which was 67, 64 nm.Conclusion: RPO can be formulated as a nanoemulsion by spontaneous emulsification method. RPO with a 5% concentration is very stable for 12 weeks storage.