• Archives of Pharmacal Research
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• v.19 no.1
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• pp.30-35
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• 1996

Poly(l-lactic acid)(PLLA) microspheres loaded with ampicillin sodium (AMP-Na_, .betha.-lactam antibiotic, were prepared by a w/o/w multiple emulsion-solvent evaporation method. The amounts of each component in three phases (inner water phase, organic phase, and outer water phase) wre carefully examined in the preparation of PLLA microspheres. The stirring rate, another preparation parameter, was also investigated for study on the effect of mechanical stress on the drug loading and morphology of PLLA microspheres. Most of the preparation parameters had a great influence on the drug loading, surface morphology and size distribution of PLLA microspheres. PLLA microspheres with 15.89 w/w% drug loading were subjected to the in vitro release experimet. The release of ampicillin sodium was constant at a rate of 1.68 $mug/ml/day$ per 1 mg of microspheres for 18 days initial burst effect.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.809-813
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• 1999

D phase emulsification has been developed and elucidated the emulsification mechanism by using phase diagrams. The process of D phase emulsification begins with the formation of isotropic surfactant solution, follows by formation of oil-in-surfactant (O/D) gel emulsion by dispersion of octamethylcyclotetra siloxane(OMCS) in the surfactant solution. Polyols were essential components for this experiments. To understand the function of polyols, the solution behaviors of nonionic surfactant/oil/water/polyol systems were investigated by the ternany phase diagrams of polyoxyethylene oleyl ether/OMCS/propylene glycol(PG) aqueous solutions. The solubility of oil in the isotropic surfactant phase was increased with the addition of PG. D phase emulsion was formed in the range of 70~90% of OMCS and 2.0~3.0 dyne/cm of interfacial tension and the structure was homogenious spherical and O/W type and its diameter was about $10{\mu}m$.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.4 s.34
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• pp.75-95
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• 1999

A colloid refers to dispersed particles of a solid or liquid having the diameter of about $10^{-5}-10^{-7}cm$. Such colloidal silver is produced by electrolysis. In this paper, colloidal silvers of various concentrations according to charge amount and time are produced, and their anti-microbial activities are measured. And optimum conditions for emulsion are measured by varying the concentration of colloidal silvers. Further, stability of the emulsion is measured with a Zeta potential, chrome meter by applying colloidal silvers to creams (W/Si, O/W, MLV).

• Proceedings of the SCSK Conference
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• 1999.10a
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• pp.75-95
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• 1999

A colloid refers to dispersed particles of a solid or liquid having the diameter of about $10^{-5}$ - $10^{-7}$. Such colloidal silver is produced by electrolysis. In this paper. colloidal silvers of various concentrations according to charge amount and time are produced, and their anti-microbial activities are measured. And optimum conditions for emulsion are measured by varying the concentration of colloidal silvers. Further, stability of the emulsion is measured with a Zeta potential. chrome meter by applying colloidal silvers to creams (W/Si. O/W, MLV).

• Analytical Science and Technology
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• v.11 no.2
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• pp.79-87
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• 1998

Consumers have recently preferred to purchase extensive UV intercepting products, which are waterproof and free from side effects on skin. During the testing of cytotoxicity (in-vitro) in neutral red (NR) method, cell survival ratio of UV-B interceptors decreased to just above 0.08 w/v%, and it was observed that the UV-A interceptors the ratio also decreased to just above 0.06 w/v%. In addition patch-tests of inorganic UV interceptors resulted in no skin irritation even below 10.0 and 11.25. In absorption curves, UV-B was most suitable for octyl methoxycinnamate (OMC) and UV-A for butyl methoxy dibenzoylmethane (BMDM). For this reason, $Nylonpoly^{TM}$ UVA/UVB the material of OMC and BMDM coated with Nylon & polyethylene, was used as the organic UV interceptor. Zinc oxide (ZnO) and titanium dioxide ($TiO_2$) was used as inorganic UV interceptors. The appropriate mixture ratio of ZnO and $TiO_2$ was 6 to 4:6% of ZnO, 4% of $TiO_2$ and 5% of $Nylonpoly^{TM}$ UVA/UVB were all combined and added to our sunscreen cream. The SPF value of in-vitro was 38.9. In practical application, each sun protection factor (SPF) duration of oil-in-water (O/W) emulsion and water-in-silicone (W/S) emulsion containing sunscreen cream of the same content showed that W/S type of sunscreen cream was 5 times as durable as the other. Therefore, this product is fit for use in swimming, climbing or skiing. This research is to minimize skin trouble caused by UV interceptors and to make one with proper softness, skin safety and UV intercepting efficiency.

• Tribology and Lubricants
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• v.5 no.1
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• pp.51-56
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• 1989

The Lubricational characteristics of O/W Emulsions of beef tallow and mineral oil based lubricants are studied in a roller on disk apparatus. It is revealed that the coefficients of friction with both emulsion lubricants exhibit essentially similar behavior; that is, they rapidly decrease to 0.1% concentration and after they constants with increasing oil concentration, and that, with oil in water emulsions of a concentrations as low as 5wt% practically forms a elastohydrodynamic film. One hand, surface temperature effect on lubricants has virtually no severe, and that, the minimum EHL film chickness estimated that it begins to increase at a concentration of several percent; the effect of particle diameter becomes maked there after.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.261-267
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• 1998

We have investigated the stability of macroemulsions of AOT prepared from Winsor systems. The emulsion system was prepared from heptane+aqueous NaCl+AOT. As the concentration of NaCl increases, the stability of the emulsion increases, reaches a maximum, and then decreases. At low salt concentration the creaming occurred due to density difference of oil and aqueous phases. We developed a model for the creaming. Behavior of the emulsions containing low salt could be described very well by the model, however, at high salt concentration the electrostatic repulsion decreased due to screening and droplets started to attract each other and the stability of the emulsion decreased.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.20 no.1
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• pp.37-51
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• 1994

Empty cross-linked chitosan microcapsule was prepared by chemical cross-linking reaction using glutaraldehyde(GA). Chitosan bead was also prepared by coacervation method using sodium hydroxide. The technique involves the formation of a chitosan solution in the discontinuous phase of W/O emulsion. The factors influencing the emulsion stability have been examined to establish optimum conditions Chitosan microcapsules were useful for encapsulation of biological materials, and chitosan bead was useful to prepare the biologically active peptide-bound polysaccharide. As a model compound Gly-His-Lys, cell growth factor, was successfully coupled to chitosan bead.

• 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.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.380-386
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• 2005

Separation of fructose and glucose was performed using emulsion liquid membranes with a mixture of an organoboronic acid and a quaternary ammonium salt as a carrier in a batch reactor. In order to find a carrier and an optimal experimental condition suitable to the sugar separation, extraction of each sugar was carried out independently. The effect of various experimental variables, such as initial concentration of sugar in the feed phase, type of organoboronic acids, and w/o ratio, on the sugar separation was investigated, and the concentrations of sugars in each aqueous phase were analyzed. The ratio of degree of extraction of fructose to that of glucose was very high, but the concentration of fructose in the receiving phase was not too high. Therefore, a stronger stripping agent in the receiving phase was required for development of a practical ELM system suitable to the sugar separation.