• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.260-265
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• 2013

In this study, nano-emulsions containing 0.01, 0.03, 0.05, and 0.10% ethyl acetate fraction of Hippophae rhamnoides (H. rhamnoides) leaf extracts were prepared. The particle size, particle size distribution and skin permeability of the nano-emulsions were evaluated for five weeks. Nano-emulsion was prepared by the sequential use of homogenizer and microfluidizer. Nano-emulsion containing the ethyl acetate fraction exhibited a monodispersed form. Nano-emulsion containing 0.03% ethyl acetate fraction was the most stable for five weeks. The in vitro skin permeation study of nano-emulsion containing 0.03% ethyl acetate fraction was carried out using Franz diffusion cell. The nano-emulsion showed a better skin permeability than that of O/W emulsion. These results indicate that the nano-emulsion containing the ethyl acetate fraction of H. rhamnoides leaf extract showed a remarkable stability and skin permeability than that of O/W emulsion.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.127-133
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• 2016

In this study, water-in-oil (W/O) nanoemulsions of water/Span 80-Nikkol BL 25/oil system were prepared by the PIC method at elevated temperature. This method allows the formation of finely dispersed W/O nanoemulsions with low viscosity in this system. However, macroemulsions rather than nanoemulsions were prepared by PIC method at room temperature. As a result of the significant change of interfacial tension with temperature, the emulsion droplet size decreases from $2{\mu}m$ to 100 nm with the increase in temperature from $30^{\circ}C$ to $80^{\circ}C$. The droplet size of nanoemulsions prepared at $80^{\circ}C$ was in the range of 50 ~ 200 nm and the internal phase content could reach as high as 15 wt%. The most stable nanoemulsion was formed in the vicinity of 7.0 of optimum HLB of the emulsifier mixture. The obtained nanoemulsions were stable without obvious change in droplet size in one month. This study provides valuable information for optimizing the formation of W/O nanoemulsions with low viscosity. These results suggest that W/O nanoemulsions of low viscosity could be useful for cosmetics with soft feeling.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.2
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• pp.79-89
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• 2009

The objective of this study was to find out the stable formulation of nano-emulsion containing high concentration of quercetin and to investigate the effect of an ethanol on the nano-emulsion prepared by POE (30) hydrogenated castor oil (HCO-30)/oil/quercetin/ethanol/water system. Nano-emulsion was prepared using emulsion inversion point (EIP) method as low-energy method plus homogenizer as high-energy method. To evaluate effect of ethanol and other components on the nano-emulsion, physical properties such as droplet size, morphology, and size distribution were determined. The optimal quercetin concentration was 0.2 % on the nano-emulsion. The droplet diameter was below 300 nm at the HCO-30 concentration below 2.00 %. Nano-emmulsion containing 4.75 % HCO-30 was the most stable and its mean droplet size was 172.40 nm. Finally, the size of nano-emulsion containing 4.00 % ethanol was 128.15 nm and size distribution was also narrow. The results showed that the breakdown process of this nano-emulsion could be attributed to Ostwald ripening. This study about effect of ethanol on the nano-emulsion showed that loading capacity of drug could be increased by using a small amount of ethanol. As prepared stable nano-emulsion, this study showed that these results could be applied to pharmaceutics, cosmetic including skin-care products, perfume and etc.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.1
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• pp.1-21
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• 2011

This review describes several kinds of emulsification methods for nanoemulsions and the application of nanoemulsions. Nanoemulsion droplet sizes fall typically in the range of 20 ~200 nm and show narrow size distributions. Although most of the publications on either oil-in-water (O/W) or water-in-oil (W/O) nanoemulsions have reported their formation by dispersion or high-energy emulsification methods, an increased interest is observed in the study of nano-emulsion formation by condensation or low-energy emulsification methods based on the phase transitions that take place during the emulsification process. Phase behaviour studies have shown that the size of the droplets is governed by the surfactant phase structure (bicontinuous microemulsion or lamellar) at the inversion point induced by either temperature or composition. Studies on nanoemulsion formation by the phase inversion temperature (PIT) method have shown a relation between minimum droplet size and complete solubilization of the oil in a microemulsion bicontinuous phase independently of whether the initial phase equilibrium is single or multiphase. Due to their small droplet size nanoemulsions possess stability against sedimentation or creaming with Ostwald ripening forming the main mechanism of nanoemulsion breakdown. An application of nanoemulsions is the preparation of nanoparticles using a polymerizable monomer as the disperse phase where nanoemulsion droplets act as nanoreactors, cosmetics and controlled drug delivery. In this review, we mainly focus on the cosmetics.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.417-423
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• 2015

Oil-in-water(o/w) nanoemulsions were prepared in the system of water/Span 80-Tween 80/long-chain paraffin oil via PIC method. With the increase of preparation temperature from 30 oC to 80 oC, the diameter of emulsion droplets decreased from 150 nm to 40 nm. By varying the HLB of mixed surfactants, we found that there was an optimum HLB around 13.0~14.0 corresponding to the minimum droplet size. The size of emulsion droplets increased upon increasing the ratio of oil/emulsifying agent. At $f{\leq}0.15$, the size of nanoemulsions could be kept constant more than 2 months. The increase in preparation temperature makes it possible for producing monodisperse nanoemulsions. Once the nanoemulsion is produced, the stability against Ostwald ripening is outstanding due to the extremely low solubility of the liquid paraffin oil in the continuous phase.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.369-375
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• 2015

In this study, the formation potential and the stability of nano-emulsions were evaluated according to the structure of various cosmetic oils in Tween 80/Span 80 system using PIC method at 80 oC LP 70, Isopar H and Pripure 3759 of hydrocarbons were both form a stable nano-emulsion, particle size distribution of about 40 nm. A linear structure of silicone oil formed an unstable emulsion, but cyclic or short chain oil formed was a stable nano-emulsion. In ester oils, the particle size of emulsions increases with increasing molecular weight of oils and a stable nano-emulsion could not be obtained in the molecular weight of about 450. The particle size of the nano-emulsion against required HLB value for calculating in consideration of the lipophilic and hydrophilic oil was smaller in the HLB of 8-10.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.221-226
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• 2014

IIn this study, O/W type nano-emulsions were prepared by phospholipid-nonionic surfactant mixtures and octyldodecylmyristate using the phase transition low-energy emulsification method. The nano-emulsions were formed only in the very narrow area of the concentration of mixed surfactant and oil molar ratio of around 1 : 1. The particle size of the emulsions was decreased as adding the aqueous phase into the emulsions after phase inversion point unlike the emulsions formed only with nonionic surfactant. Nano-emulsion was stable at room temperature for more than a month. Thus, the nano-emulsions containing phospholipids can be widely used as a cosmetic formulations.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.339-347
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• 2013

Nano-emulsions are submicron sized emulsions that are under extensive investigation as drug carriers for improving the delivery of therapeutic agents. The aim of this research is to investigate the stability of nano-emulsions containing polymers. Nano-emulsions containing high concentrations of Carbopol 941, Aristoflex AVC, Aronbis M, Permulen TR 2 and Aculyn 44 were unstable compared with macroemulsions with polymers. The size of emulsion droplet manufactured by adding polymer before emulsification were larger than that of emulsion manufactured by adding polymer after the emulsification. The stability of nano-emulsion containing a low concentration of polymer was also decreased, however the effect was lower than that in the high concentration of polymer. Under similar viscosity of polymer, the sequence of unstability was Aristoflex AVC < Carbopol 941 < Permulen TR2 < Carbopol 941 + Aculyn 44 < Aronbis M.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.3
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• pp.201-207
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• 2012

The influence of different dilution procedures on the properties of oil-in-water (O/W) nano-emulsions obtained by dilution of oil-in-ethanol (O/E) microemulsions with water has been studied. The system water/ethanol/nonionic surfactant/silicone oil with ethanol was chosen as model system. The dilution procedures consisted of adding water (or microemulsion) stepwise. By mixing O/E microemulsions into water, nano-emulsions with droplet diameters of 30 nm were obtained. In contrast, by mixing water into O/E microemulsion, emulsions with diameter of 400 nm were obtained The dilution methods were shown to be a key factor determining the properties of the emulsions. There were no change in diameters of nanoemulsion droplets against time, however sizes of droplets in the emulsion with larger droplets were increased with time and the mechanism of unstability was thought to be Ostwald ripening.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.29-35
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• 2016

RS White (resorcinol bis-ethylhexanoate) is used in cosmetics as a skin whitening agent. In this study, we studied the possibility of nano-emulsion formation containing whitening agent, RS White, with different types of emulsifying agents. With Tween 80, 60, HCO 60 and 40 as a hydrophilic surfactants and Span 80 as ahydrophilic surfactant, nano-emulsions were formed at appropriate concentrations, but they were not formed in the system using the Myrj 52, Montanov L, and Tegocare 450 with Span 80. The diameter of nano-emulsion sphere was smaller than 100 nm. The emulsion showed a translucent appearance and maintained stability in stability evaluation with time. In vitro skin permeation experiments showed that amounts of skin permeated nano-emulsion for 24 h were $70.84{\mu}g/cm^2$ and those of O/W emulsion were $28.97{\mu}g/cm^2$. In conclusion, a stable nano-emulsion containing the resorcinol bis-ethylhexanoate is effective for potential efficacy system as an efficient delivery system of the functional materials into skin.