• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.24-38
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• 1997

Using the all-trans-retinol which is double-capsulated with matrix, we investigated its stability and the change of the epidermal thickness. The proprietary MDC comprise two steps of capsulation of retinol, i.e., primary microcapsulation with collagen and then secondary capsulation with gellan gum. We compared the activity of all-trans-retinol in various forms such as (1) simply in O/W, (2) in W/O emulsion, (3) in primary capsulted form in O/W emulsion, or (4) in MDC in O/W emulsion. After storage at 45$^{\circ}C$ for 4 weeks, retinol in MDC in O/W emulsion retained 92% of the activity compared to the standard material upon HPLC analysis, whereas the primary capsule gave 70%, the O/W emulsion form 47% and the W/O emulsion 78%. The retinol in MDC in O/W induced the siginificant increase in epidermal thickness compared to the vehicle.

• Journal of the Korean Applied Science and Technology
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• v.17 no.2
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• pp.67-75
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• 2000

Cosmetic industries have recently developed sun-block products, which are composed of W/O or O/W emulsion system. It was very difficult for waterproofing product to show the stability in W/O emulsion with $TiO_{2}$. To enhance the stability of W/O emulsion, it needs to be combined with the water and oil soluble components as the gelling agents. The emulsifiers used in W/O were 3.0% of cetyl dimethicone copolyol, 2.0% of sorbitan sesquioleate as the basic emulsifiers, and 0.6% of quaternium-18 bentonite and 1.5% of dextrin palmitate as stabilizer were used. The content of titanium dioxide was optimized up to 8.0%. Titanium dioxide was used as the UV scattering powder coated with $Al_{2}O_{3}$(UV-sperse T40/TN). The sunscreen cream prepared with W/O emulsion system by using QB and DP showed higher stability than that of W/O emulsion system by using each QB and DP. W/O emulsion from Formula 3 for passing one year was very durable more than F1 and F2. Within W/O emulsion by observing F1, F2 and F3 for one year, F3 was more excellent than F2 and F3 when they were observed at RT, $4^{\circ}C$, $40^{\circ}C$, because F3 used the mixed QB and DP in W/O emulsion. The zeta potential for F1, F2, and F3 after one year were 21, 30 and 43, respectively. From these result F3 was found best stable emulsion. The in-vitro SPF value for F3 was 35 for the initial product at room temperature and also, the in-vitro SPF values of F3 was 32 for after one year. Finally, the mean in-vivo SPF value of 10 volunteers for F3 was 27.3 by the Korea cosmetic association made the rules of SPF.

• 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 Korean Applied Science and Technology
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• v.21 no.1
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• pp.31-36
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• 2004

Liquid crystalline phases were formed from acylglutamate; polyglyceryl-10 myristate and glycerine mixture and they were used as a base material for preparing an O/W emulsion. When an oil phase is added into the liquid crystalline phases, it was inserted into the dispersed liquid crystal droplets rather than stayed outside the liquid crystals, which can be known by the fact that the size of liquid crystal droplets increases with the increasing oil phase content. Along with the increase in the droplet size, the complex modulus increases from 100 to 350 pascals and the loss angle decreases from 60 to 24 degrees, from which it can be known that the increase in the internal phase volume results in the increase in the elastic property of oil in liquid crystalline-phases (O/LC). When the water phase was lastly added into the O/LC phase, the emulsification occurred to form a O/W emulsion and the averaged particle size of the O/W emulsion changes from 22.5nm to 538nm with the addition of water phase. The results from the droplet size measurements and stability tests under accelerated conditions such as high temperature show that the obtained O/W emulsion is very consistent with time.

• Korea-Australia Rheology Journal
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• v.15 no.3
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• pp.125-130
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• 2003

The emulsion stability of cosmetic creams based on the water-in-oil (W/O) high internal phase emulsions (HIPEs) containing water, squalane oil and cetyl dimethicone copolyol was investigated with various compositional changes, such as electrolyte concentration, oil polarity and water phase volume fraction. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The slope change of complex modulus versus water phase volume fraction monitored in the linear viscoelastic region could be explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsions: the greater the increase of complex modulus was, the more the coalescence occurred and the less consistent the emulsions were. Emulsion stability was dependent on the addition of electrolyte to the water phase. Increasing the electrolyte concentration increased the refractive index of the water phase, and thus decreased the refractive index difference between oil and water phases. This decreased the attractive force between water droplets, which resulted in reducing the coalescence of droplets and increasing the stability of emulsions. Increasing the oil polarity tended to increase emulsion consistency, but did not show clear difference in cream hardness among the emulsions.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.237-246
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• 2014

Multiple emulsions, called multiphase emulsions, include water-in-oil-in-water (W/O/W) type and oil-in-water-in-oil (O/W/O) type emulsions. In cosmetic industry, they are used to stabilize active ingredients but the applicability of the multiple emulsions is limited because of low stability and difficulty of manufacturing. In this study, we investigated a two-step emulsification process for a W/O/W type emulsion. We also investigated the change of stability using different emulsifiers and oil polarity. The results suggested that polyglyceryl-10 stearate, as a main emulsifier, played an important role in the stability and the formation of the multiple emulsions.

• The Korea Journal of Herbology
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• v.25 no.4
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• pp.145-149
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• 2010

Objectives : Since cosmetics have been one of the help of life, unlike medicine, natural products have been used for cosmetics, generally giving the image of safety and relief compared to synthetic products. Among them, Houttuynia cordata has been known as a useful herbal medicine with antibiotic, anti-inflammatory and anti-oxidative activities. In this study, we were to use Houttuynia cordata extract on formulation of cosmetic emulsions. Methods : The effects of Houttuynia cordata extract on emulsion stability and viscoelastic properties of emulsion were measured using turbiscan and rheometer. And we assessed the anti-oxidative and antibiotic activities of Houttuynia cordata extract. Results : 1. The results of this investigation for emulsion stability showed that the stability emulsion containing Houttuynia cordata extract was decreased depending on concentration of Houttuynia cordata extract. 2. Super oxide dismutase activity was strongly dependents on concentration of Houttuynia cordata extract. 3. Houttuynia cordata extract showed good anti-microbial activity against Staphylococcus aureus. Conclusions : Houttuynia cordata extract can be effectively used in cosmetic emulsions when the relation between natural product extracts and formulation of cosmetics is elucidated.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.1
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• pp.48-73
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• 1998

Colloid refers to dispersed particles of solid or liquid having diameters of $10^{-5}$ to $10^{-7}$cm, among which colloidal silver is produced by electrolysis. Colloidal silver of various concentrations according to charge and time were formed, antimicrobial activity of colloidal silver was measured. And, the optimum conditions for emulsion were determined by changing the concentration of coloidal silver. Also, the stability of the emulsion was measured by zeta potential and chroma meter by applying colloidal silver to creams(W/S, O/W, MLV)

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.294-302
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• 2003

Unstable cosmetic active ingredients could be degraded rapidly by chemical and photochemical process. Particularly, some of active ingredients like retinol are known to cause skin irritation when applied on the skin excessively. Therefore, it has become a very important issue to encapsulate cosmetic actives for the stabilization and skin protection. This study was performed in order to prepare a chitosan microcapsule containing liposoluble cosmetic actives and to investigate the stabilization effect of actives when chitosan microcapsule was applied in cosmetic formulation. Chitosan, deacetylated form of chitin, has been of interest in the industrial applications due to its biocompatibility, biodegradability, non-toxicity, antimicrobial activity and also used as a wall material of capsule. Retinol was used as a core material and was stabilized by a wall of chitosan and antioxidants. The chitosan microcapsule containing retinol(CMR) was prepared by using coacervation method and W$_1$/O/W$_2$ emulsification techniques. The CMR has 0.5~10.0 ${\mu}{\textrm}{m}$ size distribution and a long-term stability of more than an year inside the cosmetic formulation(O/W). Remaining retinol percentages at 45$^{\circ}C$ after 8 weeks in the CMR dispersion were 15.6%(pH 4.0), 59.8%(pH 6.0) and 65.0%(pH 6.0 with antioxidant) respectively. Retinol stability when added CMR inside a ONV emulsion was better than that of ONV emulsion added non-capsulated retinol. As a result, remaining retinol at 45$^{\circ}C$ after 8 weeks in O/W emulsion added non-capsulated retinol and O/W emulsion containing CMR was 12.7%, 70.5% respectively. It appeared that chitosan treated microcapsule may be used for a potential encapsulation method of unstable active ingredients.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.4 s.59
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• pp.209-217
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• 2006

Emulsion is a dispersion system among liquids which are not miscible together. There are numerous cosmetic raw materials which have different physicochemical properties. Therefore, emulsion technology is very useful in cosmetics. With the development of emulsifier, several emulsification technologies have been developed. Since HLB method by Griffin in 1950's, PIT method, gel method, and D-phase methods, etc, have been developed. Recently, the application of natural emulsifier and polymeric emulsifier increases in cosmetics in order to achieve enhanced safety and biocompatibility. Besides nano-emulsion, multiple-emulsion, liquid crystal emulsion, and Pickering emulsion have been developed and applied as means of differentiating appearance and texture of products and achieving enhanced delivery of active ingredients. Meanwhile, the application studies of nano-dispersed structural system such as liposome or cubosome are on progress. Liposome is a bi- or multi-lamella layer dispersion system composed of amhiphilic molecules - phospholipids which are main components of plasma membrane. Cubosome also is a nano-sized dispersion system composed of a specific molecule like glyceryl monoloeate derived from natural products. And it has a cubic bicontinuous structure in water due to its unique molecular structure. Incorporating compounds (active materials) into such nano-particles can increase biocompatibility and delivery efficiency of target compounds. Manufacturing process and application of cosmetic emulsions and nano-particles are briefly introduced in this paper.