• 대한화장품학회지
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• 제3권1호
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• pp.27-32
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• 1973

• Journal of Microbiology and Biotechnology
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• 제18권4호
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• pp.735-741
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• 2008

In our previous study, a surfactant-coated Candida rugosa lipase immobilized in microemulsion-based organogels was exploited for the synthesis of ethyl isovalerate. In the present study, we are focusing on the effective reuse of lipase immobilized in microemulsion-based organogels (MBGs) in terms of retainment of the catalytic activity. As water is one of the co-products in esterification reactions, the removal of water becomes a priority to allow the reaction to work in the forward direction and to prevent back hydrolysis. Taking this fact into consideration, the lipase-containing microemulsion-based organogels were given pretreatment and/or several intermittent treatments with dry reverse micellar solution of AOT in organic solvent during repeated cycles of ester synthesis. The pretreated MBGs with dry reverse micellar solution exhibited lower water content and higher initial rates of esterification in comparison with untreated freshly prepared MBGs. The esterification efficiency of untreated MBGs started decreasing after 5 cycles of reuse and was almost completely lost by the end of the $8^{th}$ cycle. In contrast, pretreated MBGs exhibited a gradual decrease in esterification efficiency after 5 cycles and retained about 80% of the initial activity at the end of the $8^{th}$ cycle. The intermittent treatment of MBGs after every 3 cycles resulted in enhanced reusability of immobilized lipase for up to 9 cycles without significant loss in esterification activity, after which it resulted in a slow decrease in activity with about 27% lower activity at the end of the $12^{th}$ cycle. Furthermore, the treatment conditions such as concentration of AOT in liquid dessicant and time of treatment were optimized with respect to our system. The granulated MBGs proved to be better in terms of initial esterification rates (1.2-fold) as compared with the pelleted MBGs.

• Archives of Pharmacal Research
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• 제28권9호
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• pp.1097-1102
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• 2005

An O/W microemulsion system was developed to enhance the skin permeability of ace-clofenac. Of the oils studied, Labrafil? M 1944 CS was chosen as the oil phase: of the microemulson, as it showed a good solubilizing capacity. Pseudo-ternary phase diagrams were constructed to obtain the concentration range of oil, surfactant, Cremophor ELP, and co-surfactant, ethanol, for micoemulsion formation. Eight different formulations with various values of oil of $6-30\%$, water of $0-80\%$, and the mixture of surfactant and co-surfactant (at the ratio of 2) of $14-70\%$. The in vitro transdermal permeability of aceclofenac from the microemulsions was evaluated using Franz diffusion cells mounted with rat skin. The level of aceclofenac permeated was analyzed by HPLC and the droplet size' of the microemulsions was characterized using a Zetasizer Nano-ZS. Terpenes were added to the microemulsions at a level of $5\%$, and their effects on the skin permeation of aceclofenac were investigated. The mean diameters of the microemulsions ranged between approximately $10\~100nm$, and the skin permeability of the aceclofenac incorporated into the microemulsion systems was 5-fold higher than that of the ethanol vehicle. Of the various terpenes added, limonene had the best enhancing ability. These results indicate that the microemulsion pystem studied is a promising tool for the percutaneous delivery of aceclofenac.

• Korean Chemical Engineering Research
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• 제45권4호
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• pp.364-371
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• 2007

본 연구에서는 연속상의 종류가 AOT 계면활성제 시스템의 water-in-oil(W/O) 마이크로에멀젼을 이용한 할로겐화은 나노입자 제조에 미치는 영향에 관하여 살펴보았다. 이를 위하여 계면활성제, 연속상 오일, 무기염 수용액으로 이루어진 삼성분 시스템에 대하여 탄화수소의 연속상 종류를 변화하면서 상평형 실험을 수행한 결과, 탄화수소의 사슬 길이가 증가함에 따라 계면활성제 시스템의 친수성이 증가하여 단일상으로 존재하는 W/O 마이크로에멀젼 영역은 증가하였다. 상평형 실험결과에 의하여 결정된 단일상의 영역 내에서 W/O 마이크로에멀젼을 이용하여 할로겐화은 나노입자를 제조한 결과, 10 nm 전후의 구형에 가까운 비교적 균일한 입자가 형성되었다. 사용한 연속상 탄화수소의 사슬 길이가 증가할수록 마이크로에멀젼의 film rigidity를 감소시킴에 따라 마이크로에멀젼 사이의 교환 속도가 빨라져서 생성된 할로겐화은 나노입자의 크기는 작아지고 반면에 개수는 증가하였다. 또한 동일한 시스템에서 무기염 수용액의 조성을 증가시킴에 따라 생성된 나노입자의 크기는 증가함을 알 수 있었다.

• 청정기술
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• 제14권3호
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• pp.218-223
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• 2008

마이크로 에멀젼 수용액에 분산된 반응성 유기화합물을 전기분해를 통하여 얻을 수 있는 수산화이온 및 수소이온을 이용하여 가수분해시키고, 분해속도를 비교하는 실험을 수행하였다. 반응물질로 사용된 p-nitrophenylacetate (PNPA)의 가수분해로부터 발생하는 p-nitrophenoxide 농도 변화에 따른 흡광도 변화를 이용하여 분해속도를 얻을 수 있었다. 자체 조립한 전기분해 장치를 이용하여 전압, 반응온도, 반응물질 양에 따른 분해속도 변화를 관찰하였다. 마이크로 에멀젼 사용으로 인하여 반응물질 용해도를 증가시킬 수 있으며, 전기분해법 사용으로 인하여 반응속도 조절이 용이하며, 유지비용이 저렴하고, 기존 화학물질 투여방법에 비해 소모되는 시약 보충 및 반응 후 부산물 처리 등의 과정이 수월하다. 유기물질 분해에 대한 메커니즘 및 수처리 분야 응용에 대하여 토의하였다.

• Journal of Pharmaceutical Investigation
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• 제29권1호
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• pp.37-45
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• 1999

ABSTRACT-A self-microemulsifying drug delivery system (SMEDDS) was developed to enhance the solubility and dissolution rate of poorly water soluble drug, biphenyl dimethyl dicarboxylate, DDB. The system was optimized by evaluating the solubility of DDB and the microemulsion existence range after the preparation of microemulsions with varying compositions of triacetin and surfactant-cosurfactant mixtures (Labrasol as surfactant (S) and the combination of Transcutol, Cremophor RH 40 and Plurol oleique as cosurfactant (CoS)). SMEDDS in this study markedly improved the solubility of DDB in water up to 10 mg/ml and the size of the o/w microemulsion droplets measured by dynamic light scattering showed a narrow monodisperse size distribution with an average diameter less than 50 nm. The microemulsion existing range is increased proportional to the ratio of S/CoS, however, it decreased remarkably as the oil content was more than 20%. In vitro dissolution study of SMEDDS showed a significantly increased dissolution rate of DDB in water (> 12 fold over DDB powder), and SMEDDS also had significantly greater permeability of DDB in Caco-2 cell compared to powders.

• 약학회지
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• 제46권5호
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• pp.337-342
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• 2002

Propofol(2,6-diisopropyl phenol) is a phenol derivative that is chemically distinct from other intravenous sedative hypnotics. It has been extensively used as a short term anesthetic agent, because of the rapid onset and short duration of action. Propofol microemulsion system was prepared with different concentrations of ethyl oleate, $Solutol^{(R)}$ HS 15 and $Kollidon^{(R)}$ 17 PF. Propofol microemulsions were studied by transmittance, viscosity, particle size, in vitro release and pharmacokinetics. The range of transmittance of A group with 4% ethyl oleate and that of B group with 5% ethyl oleate were 92.6~95.1 and 91.3~94.2%, respectively. Transmittance 1~2% decreased as concentration of $Kollidon^{(R)}$ 17 PF was increased and increased 0.8~3.3% when 10 times diluted with normal saline. The viscosity of A and B group were in the range of 3.9~4.1 mPaㆍsec and 4.4~5.3 mPaㆍsec, respectively. The particle sizes of A and B group increased as amount of $Kollidon^{(R)}$ 17 PF. Also, release of propofol was slowly increased as the amount of $Kollidon^{(R)}$ 17 PF was increased. Propofol plasma concentration by i.v injection showed 2-compartment model. Pharmacokinetics of A-5 was similar to that of commercial emuision(POFOL).

• Journal of Pharmaceutical Investigation
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• 제30권4호
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• pp.273-278
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• 2000

Several topical preparations containing lidocaine, a widely used local anesthetic agent, have been developed and marketed recently for the treatment of premature ejaculation. In this study, microemulsion(ME)-based hydrogels containing lidocaine were prepared by dispersing ME to hydrogel bases such as Carbopol, sod. alginate, and sod. carboxymethylcellulose. Lidocaine-containing ME was thermodynamically stable over 6 months and had a diameter ranging from 10 to 100 nm. In vitro skin penetration of lidocaine from ME-based hydrogels followed apparent zero-order kinetics. ME-based hydrogel showed higher drug penetration during fifteen minutes after application than alcoholic hydrogel, reference preparation. Tail flick test in rat was introduced to compare in vivo local anesthetic effects of different hydrogels, and the results showed that ME-based hydrogels are superior to other hydrogels. In optical microscopy, recrystallization of lidocaine was observed within 5 min after application of reference hydrogel, but there was no change in ME-based hydrogels even after 30 minnute. These results indicated that ME-based hydrogels had some advantages in skin penetration, anesthetic effect and physical stability compared with alcoholic hydrogels. Finally it is possible to conclude that ME-based hydrogels containing lidocaine is a good topical drug delivery system for the treatment of premature ejaculation.

• 공업화학
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• 제16권5호
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• pp.677-683
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• 2005

AEO계 비이온 계면활성제를 주체로 한 세정제 시스템에서 탄화수소 용제가 단일상의 마이크로에멀젼 형성 및 세정력에 미치는 영향을 살펴보았다. 용제로 사용한 포화탄화수소의 사슬 길이가 길어질수록 마이크로에멀젼을 형성하는 온도 영역이 넓어졌으며, $35{\sim}60^{\circ}C$의 온도 조건에서 첨가한 보조계면활성제 조성에 상관없이 단일상의 ${\mu}E$이 존재하는 것을 확인할 수 있었다. 특히 본 실험에서 사용한 탄화수소 중에서 사슬 길이가 가장 큰 헥사데칸을 용제로 사용할 경우, 보조계면활성제 이소프로판올을 첨가하지 않은 경우에도 단일상의 O/W ${\mu}E$이 넓은 온도 영역에 걸쳐서 존재하였다. 상평형 실험을 통하여 선정한 단일상의 마이크로에멀젼을 주체로 한 후보 세정제 시료들은 $40^{\circ}C$에서 abietic acid에 대한 우수한 세정력을 나타내는 것을 세정 실험을 통하여 확인할 수 있었다.

• 공업화학
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• 제26권3호
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• pp.259-264
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• 2015

원유회수증진 중 하나인 화학적 공법은 원유의 특성에 맞는 화학물질들의 종류와 비율에 따라 회수되는 오일의 양이 다르기 때문에 오일 특성에 맞는 알칼리-계면활성제 용액을 제조하는 것이 중요하다. 본 연구 알칼리-계면활성제 용액과 인도네시아 A중질유와의 염도 측정 실험을 통해 마이크로에멀젼의 상 거동을 분석하여 인도네시아 A중질유와 적합한 알칼리-계면활성제 용액을 제조 및 적합한 비율을 선별하였다. 알칼리-계면활성제에 사용되는 계면활성제는 AK켐텍에서 제조된 $C_{16}-PO_7-SO_4$ 계면활성제를 사용하였고, 알칼리 물질과 조용매는 탄산나트륨, IBA 그리고 TEGBE를 사용하였다. 알칼리-계면활성제 용액과 인도네시아 A중질유를 혼합했을 때, 0.0~3.6 wt%의 염도에서 Type III의 마이크로에멀젼이 형성되었으며, 염도가 증가할 때 마이크로에멀젼은 물층(Type I)에서 중간층(Type III)에서 오일층(Type II)으로 이동하는 것을 확인할 수 있었다. 또한 Huh 방정식을 통해 A중질유와 알칼리-계면활성제 용액의 계면장력을 계산한 결과 원유회수증진을 위해 적용 가능한 계면장력 값을 갖는 것을 확인할 수 있었다. 이러한 특성들을 통해 국내산 알칼리-계면활성제를 이용한 화학적 공법의 적용 가능성을 확인하였다.