Formation of 1D Poly(3,4-ethylenedioxythiophene) Nanomaterials in Reverse Microemulsions and Their Application to Chemical Sensors

Yoon, H.,Chang, M.,Jang, J. Wiley - VCH Verlag GmbH & Co. KGaA 2007 Advanced Functional Materials Vol.17 No.3

<P>1D poly(3,4-ethylenedioxythiophene) (PEDOT) nanomaterials, including ellipsoidal nanoparticles, nanorods, and nanotubes, are fabricated via chemical oxidation polymerization in reverse (water-in-oil) microemulsions. The reverse cylindrical micelles are prepared with sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and aqueous FeCl<SUB>3</SUB> solution in hexane. The morphology of the final products is determined by carefully tuning the degree of oxidation potential at the micelle surface. Notably, the fabrication of gram-scale amounts of products is possible under optimized synthetic conditions, suggesting that this methodology is appropriate for the large-scale production of the corresponding nanomaterials. The as-prepared PEDOT nanomaterials are applied to the precise detection of alcohol vapors. The chemical sensors based on the PEDOT nanomaterials present excellent reversibility and reproducibility in response.</P> <B>Graphic Abstract</B> <P>Reverse micelle systems can be employed to obtain 1D nanostructures of poly(3,4-ethylenedioxythiophene) (PEDOT). Ellipsoidal, rodlike, and tubular structures (see figure) have been fabricated by varying the amount of oxidizing agent. The PEDOT nanotubes show a relatively fast response and improved sensitivity as chemical sensors for alcohol vapors. <img src='wiley_img/1616301X-2007-17-3-ADFM200600106-content.gif' alt='wiley_img/1616301X-2007-17-3-ADFM200600106-content'> </P>

Water-in-Carbon Dioxide 마이크로에멀젼에서 나노 크기의 이산화티탄 합성 및 p-니트로페놀의 광분해에 대한 연구

이만식,이근대,홍성수 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.4

CO_2에 용해 능력이 우수한 PFPE-NH_4(ammonium carboxylate perfluoro polyether) 및 PDMAEMA(poly(2-(dimethylamino)-ethyl methacrylate))-b-PFOMA(polu(1H, 1H, 2H, 2H-perfluoroocthyl methacrylate)) 계면활성제를 사용하여 W/C 마이크로에멀젼에 의해 나노 크기의 TiO_2를 제조하였다. TGA-DTA, FT-IR, XRD, TEM 등을 이용하여 나노 입자 제조시 W_0(H_2O/surfactant molar ratio)비에 따른 입자의 크기 및 결정성 등 물리적 성질을 조사하였다. 또한 제조된 TiO_2 나노 입자의 광촉매적 특성을 알아보기 위해 회분식 반응장치를 이용하여 p-니트로페놀의 광활성을 조사하였다. 제조된 TiO_2 나노 입자는 소성온도 250-450℃ 범위에서 유기물질과 수산화물이 분해 되어 450℃ 이상 비결정 구조에서 anatase 구조로 상 전이 되었다. W/C 마이크로에멀젼에서 제조된 나노 입자의 결정성 및 결정크기는 W_0 비가 증가할수록 증가하였다. p-니트로페놀의 광분해반응에서 반응성은 결정크기에 영향을 받았으며, 결정의 크기가 작을수록 반응성이 증가하였다. Titania nanoparticles were prepared by controlled hydrolysis of titanium tetraisopropoxide(TTIP) in PFPE-NH_4(ammonium carboxylate perfluoropolyether) and PDMAEMA(poly(2-(dimethylamino)ethyl methacrylate))-b-PFOMA(poly(1H, 1H, 2H, 2H-perfluoroocthyl methacrylate))/Water-in-CarbonDioxide Microemulsions. The physical properties, such as crystallite size and crystallinity according to W_0 ratio have been investigated by TGA-DTA, FT-IR, XRD and TEM. In addition, the photocatalytic degradation of p-nitrophenol has been studied by using batch reactor in the presence of UV light in order to compare the photocatalytic activity of prepared nanosized titania. The residual organic compound and hydroxyl group were completely removed in calcination temperature from the 250-450℃ and the amorphous phase changed into anatase structure above 450℃. The crystallinity and crystallite size of nanoparticles produced in water-in-carbon dioxide microemulsions increased with an increase of the W_o ratio. In the photocatalytic degradation of p-nitrophenol, the photocatalytic activity is mainly determined by the crystallite size of titania and the reaction rate increased with an decrease of crystallite size.

Synthesis of stable iron oxide nanoparticle dispersions in high ionic media

Ehsan Nourafkan,Maryam Asachi,Hui Gao,Ghulum Raza,Dongsheng Wen 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.50 No.-

A novel one-pot method was developed in this work to synthesize and disperse nanoparticles in a binarybasefluid. As an example, stable magnetite iron oxide (Fe3O4) dispersions, i.e., nanofluids, were producedin a high ionic media of binary lithium bromide-water using a microemulsion-mediated method. Theeffects of temperature and precursor concentration on morphology and size distribution of producednanoparticles were evaluated. An effective steric repulsion force was provided by the surfacefunctionalization of nanoparticles during the phase transfer, supported by the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. The formed nanoparticles exhibited a superior stability againstagglomeration in the presence of high concentrations of lithium bromide, i.e., from 20 to 50 wt.%, whichmake them good candidates for a range of novel applications.

Formulation of Microemulsion Systems for Transdermal Delivery of Aceclofenac

이재휘,Yoonjin Lee,Jongseok Kim,윤미경,최영욱 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.9

An O/W microemulsion system was developed to enhance the skin permeability of aceclofenac. 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 10~100 nm, 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 system studied is a promising tool for the percutaneous delivery of aceclofenac.

Formulation of Microemulsion Systems for Transdermal Delivery of Aceclofenac

Lee, Jae-Hwi,Lee, Yoon-Jin,Kim, Jong-Seok,Yoon, Mi-Kyeong,Choi, Young-Wook The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.9

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.

Docetaxel microemulsion for enhanced oral bioavailability: Preparation and <i>in vitro</i> and <i>in vivo</i> evaluation

Yin, Yong-Mei,Cui, Fu-De,Mu, Chao-Feng,Choi, Min-Koo,Kim, Jung Sun,Chung, Suk-Jae,Shim, Chang-Koo,Kim, Dae-Duk Elsevier 2009 Journal of controlled release Vol.140 No.2

<P><B>Abstract</B></P><P>A microemulsion system of docetaxel was prepared and evaluated for its solubilization capacity and oral bioavailability improvement. Based on a solubility study and pseudo ternary phase diagrams, microemulsions of about 30?nm in mean diameter were formulated with improved solubilization capacity towards the hydrophobic drug, docetaxel. The o/w microemulsion formulation (M-3) composed of Capryol 90 (oil), Cremophor EL (surfactant) and Transcutol (co-surfactant) enhanced the solubility of docetaxel up to 30?mg/mL, which maintained solubilization capacity for 24?h even after it was diluted 20 times with normal saline. The three formulations did not show significant difference in the <I>in vitro</I> lipid digestion study. Both the ultrafiltration and dialysis studies revealed that the release of 80% of docetaxel was released from the microemulsions within 12?h <I>in vitro</I>. Compared to the commercial product Taxotere<SUP>®</SUP> (0.025?µg/cm<SUP>2</SUP>), the apical to basolateral transport of docetaxel across the Caco-2 cell monolayer from the M-3 formulation (Capryol 90/Cremophor EL/Transcutol=29.4:24.9:12.4, w/w) was significantly improved (0.624?µg/cm<SUP>2</SUP>, <I>p</I><0.01). Moreover, the oral bioavailability of the M-3 formulation in rats (34.42%) rose dramatically compared to that of the orally administered Taxotere<SUP>®</SUP> (6.63%). This increase in bioavailability was probably due to the combined effect of the enhancement in solubility, the inhibition of P-gp efflux system and the increase in permeability. These results encourage further development of docetaxel microemulsions as an oral drug delivery system.</P> <P><B>Graphical abstract</B></P><P>Increased oral bioavailability of docetaxel in the microemulsions was observed by the combined effects of enhanced solubility, P-gp inhibition and permeability enhancing effects.</P><ce:figure></ce:figure>

Protective Effect of Clove Oil and Eugenol Microemulsions on Fatty Liver and Dyslipidemia as Components of Metabolic Syndrome

Sahar Y. Al-Okbi,Doha A. Mohamed,Thanaa E. Hamed,Amr E. Edris 한국식품영양과학회 2014 Journal of medicinal food Vol.17 No.7

In the present research, the effect of clove essential oil (CO) and its major constituent, eugenol, formulated in water-based microemulsions, was studied on fatty liver and dyslipidemia in high-fructose-fed rats. Plasma and liver lipids, oxidative stress, inflammatory biomarker, and liver function were the assessed criteria. CO dispersed in water as conventional cloudy emulsion was also subjected to the same biological evaluations for comparison with the microemulsified form of this oil. Results showed that the particle size of CO microemulsion (COM) and eugenol microemulsion (EM) was 8.0 nm and 8.9 nm, respectively. Excess dilution and incubation of these microemulsions in 1.2N HCl, that mimic stomach juice (without lipase), for 5 hours at 37 C lead to the establishment of second population of larger particles with average diameter > 100.0 nm. Biological evaluation revealed that rats of high fructose control group exhibited significant dyslipidemia, high plasma tumor necrosis factor-a, and elevated malondialdehyde. The same group of rats showed significant high liver total fat, triglycerides and cholesterol, and liver dysfunction compared to control normal rats fed balanced diet. Daily oral administration of CO conventional emulsion, COM, and EM produced significant improvement of all studied parameters. No significant change in all biochemical parameters was noticed when the groups given the different formulations were compared with each other. The study concluded that administration of CO conventional emulsion, COM, or EM produced significant improvement in fatty liver and dyslipidemia with consequent expected protection from cardiovascular diseases and other complications of fatty liver. Formulation of CO in microemulsion having particle size*8.0 nm did not enhance the protective effect compared with the same dose of CO dispersed in water as conventional macroemulsion, probably due to the ease of absorption of these bioactives in their native states. However, formulation in microemulsion provides a delivery system for oral administration of CO or eugenol in homogeneous, water-based, and thermodynamically stable dosage form during storage.

희석 방법에 따른 나노에멀젼 형성 연구

조완구 ( Wan Goo Cho ),한상길 ( Sang Gil Han ) 대한화장품학회 2012 대한화장품학회지 Vol.38 No.3

Oil-in-ethanol (O/E) 마이크로에멀젼을 물에 희석하여 얻은 O/W 나노에멀젼의 성질에 대하여 다른 희석 과정의 영향을 연구하였다. 물/에탄올/비이온성계면활성제/실리콘 오일 계를 모델 계로 선택하였다. 희석과정은 물(또는 마이크로에멀젼)을 마이크로에멀젼(또는 물)에 단계별로 첨가하는 방법으로 구성되었다. O/E 마이크로에멀젼을 물에 첨가하여 혼합하면 30 nm 정도의 입경을 가진 나노에멀젼을 얻을 수 있었다. 반면에 물을 O/E 마이크로에멀젼에 첨가하면 400 nm의 입경을 가진 에멀젼을 얻을 수 있다. 희석 방법이 얻어지는 에멀젼의 성질에 중요한 역할을 하였다. 시간에 따른 나노에멀젼의 입자 변화는 관찰되지 않았으나 입자가 큰 에멀젼은 시간에 따라 입경이 증가하였으며 불안정화 기작은 오스트왈드 라이퍼닝으로 추정되었다. 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.

Preparation and stability of fucoxanthin-loaded microemulsions

Jing Dai,김상무,신일식,김종대,이현용,신원철,김진철 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

Oil-in-water microemulsions (MEs) containing fucoxanthin were prepared. The stability of MEs stored at 4℃ was investigated for 4 weeks in terms of droplet size change and phase separation. The ME having the oil content of 2% was stable throughout the experiment. As the oil content increased to 3% and 4%, the sizes increased with time for the last 3 weeks. Further increase to 5% led to the phase separation at the 4th week. About 95% of fucoxanthin was maintained for 4 weeks once no phase separation took place soon after the preparation.

SMEDDS를 이용한 난용성 약물의 용출율 향상

김계현,이윤석,배준호,지상철,박은석 성균관대학교 약학연구소 1999 成均藥硏論文集 Vol.11 No.-

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 50nm. The microemulsion existing range is increased proportional to the ration 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.