• 전기화학회지
• /
• 제18권2호
• /
• pp.75-80
• /
• 2015

방향족 친핵성 치환반응을 이용하여 멀티블록형 sulfonated poly(arylene ether sulfone)(SPAES) 공중합체를 합성하였다. 서로 다른 말단(F- 또는 OH-말단)을 가지는 친수성 및 소수성 올리고머를 합성한 후 이를 이용하여 고분자 전해질 막을 합성하였다. 각기 다른 말단이 블록공중합체의 분자량에 미치는 영향을 분석하였고, 서로 다른 친수성구조가 블록고분자의 특성에 어떠한 영향을 미치는지 분석하였다. 합성된 멀티블록고분자는 70%이상의 습도에서 나피온 막과 비슷하거나 우수한 이온전도도를 나타내었고, 특히 SPAES 9의 경우 전습도 영역에서 SPAES 10보다 높은 이온전도도를 보였는데, 이는 친수성 블록내의 술폰산기의 부분 농도가 높아짐에 따라 친수성-소수성 간의 상분리가 발달되어 이온전도도가 향상된 것으로 보인다.

• 생약학회지
• /
• 제17권2호
• /
• pp.178-183
• /
• 1986

It was our working hypothesis that introduction of 11-keto groups to 12-oleanene/ursene series of triterpenoids should endow them with corticoid-like activities, since pharmacological actions of glycyrrhetinic acid (GA) are known to be caused by inhibition on $corticoid-{\delta}^4-reductase$. 11-Keto-triterpenoids derived artificially in these studies, such as 11, 19-diketo-18, 19-secoursolic acid methyl ester(I), $11-keto-{\beta}-boswellic$ acid derivatives (IIa-IIc), 11-Keto-presenegenin dimethyl ester (III), II-keto-oleanolic acid derivatives (IVa-IVd) and 11-keto-hederagenin (V) possess the fundamental functions of ${\alpha},\;{\beta}-unsaturated$ ketone on C-11 and hydroxyl group on C-3, as like GA (VI). Additionally, they involve the carboxyl groups on rings A (II, III), D (I, III, IV, V) and E (VI), and the hydroxyl groups on rings A (III, V) and C (III). All the compounds competitively inhibited $corticoid-5{\beta}-reductase$, and the highest inhibitory potency appeared in I. All of them except $3,\;11-diketo-{\beta}-boswellic$ acid methyl ester (IIc) were more effective about five times to twice than GA. On carrageenin-induced edema test, compounds I and IVa-IVd showed anti-inflammatory activities, but III enhanced rather edema. Structure-activity relations were found in the aspects of hydrophilicity of ring A and hydrophobicity of rings C/D. The more they were hydrophilic in ring A and hydrophobic in rings C/D, the more they inhibited the enzyme. And the more they were hydrophobic in rings C/D, the more they exhibited antiiflammatory activities. However, the increased hydrophilicity in ring A resulted in increasing edema, probably due to a nonspecific inhibition on $aldosterone-5{\beta}-reductase$.

• 폴리머
• /
• 제28권2호
• /
• pp.154-161
• /
• 2004

폴리(4-비닐피리딘)의 질소 원자에 메틸기를 부착시켜 4차아민화시켜서 부분적으로 개질된 폴리(4-비닐피리딘)을 얻었고, 부분 개질된 폴리(4-비닐피리딘)의 구조를 수용액상에서 레이저 광산란 및 형광법 등을 이용하여 조사한 결과, 자기 응집현상에 의하여 핵-껍질 구조를 가지고 있는 것으로 나타났다. 즉 사슬의 소수성 부분은 상호작용에 의하여 중심부에 모여있고, 4차화된 아민의 양전하를 가진 친수성 부분은 바깥 껍질을 형성하고 있었다. 이 고분자 수용액에 음이온 계면활성제인, 도데실 황산 소듐을 첨가하면 이들 사이에 임계 응집 농도가 존재하며, 이 임계 응집 농도는 특히 NaCl 농도 0.1 M 이상에서는 급격히 감소하는 경향을 보여주었다. 또한 계면활성제의 첨가에 따라 생성된 고분자-계면활성제의 복합 응집체의 입자크기 변화 등을 동적 광산란으로 측정 분석하였다.

• 공업화학
• /
• 제17권1호
• /
• pp.12-15
• /
• 2006

본 연구의 목적은 물유리에 의해 제조된 실리카 미립자의 평균입도와 입도분포에 미치는 반응조건, 용매 및 계면활성제의 영향을 조사하는 것이다. 실리카 미립자는 다양한 종류의 계면활성제와 분산용매를 사용하는 에멀젼법에 의해 제조하였다. 계면활성제로는 비이온성인 Span 20, Span 40, Span 60 및 Span 80을 사용하였으며, 분산용매로는 알킬그룹인 n-Hexane, n-Heptane, iso-Octane 및 n-Decane을 사용하였다. 실험결과에 의하면 유화교반속도에 따른 실리카 미립자의 평균 입경은 교반속도가 증가함에 따라 감소하였으며, 일정한 입경의 에멀젼을 형성하기 위한 최적의 유화교반시간은 약 6 min임을 알 수 있었다. 생성된 실리카 미립자의 평균입경은 사용된 용매의 분자량이 증가함에 따라 감소하며, 사용한 계면활성제의 hydrophobic lipophilic balance(HLB) 값이 감소함에 따라 증가하였다.

• Journal of Pharmaceutical Investigation
• /
• 제41권3호
• /
• pp.173-178
• /
• 2011

Injectable chitosan hydrogels have attracted great potential due to sustained-release property and safety. Here, palmityl-acylated glycol chitosan (Pal-GC) was used to generate physically cross-linked hydrogels by virtue of hydrophobic attraction of linear fatty carbons. Glycol chitosan was chemically modified with N-hydroxysuccinimide-activated palmitic acid in dimethylsulfoxide (DMSO) containing dimethylaminopyridine. Through a series of preparation steps of (i) dialysis with DMSO, (ii) addition of palmityl-acylated exendin-4 (Ex4-C16), and (iii) dialysis with water, Pal-GC was self-assembled to form physically cross-linked hydrogels entrapped with Ex4-C16. The Pal-GC derivative was analyzed by using 1H NMR, and the surface morphology of Pal-GC hydrogels formed was examined by scanning electron microscopy. Also, the hypoglycemic effect induced by Pal-GC hydrogels containing Ex4-C16 (250 nmol/kg) was evaluated in non-fasted type 2 diabetic db/db mice and compared with GC hydrogels containing native Ex4 at the same dose. Results showed that palmityl group was successfully conjugated with the amines of glycol chitosan, and that Pal-GC efficiently generated the hydrogels formation. Moreover, Pal-GC hydrogels containing Ex4-C16 was found to greatly prolong the hypoglycemia duration (~ 4 days). This was due to the dual-functions of the palmityl groups present in both GC and exendin-4 such as hydrophobic attraction and plasma albumin-binding. We consider this new type of self-assembled GC hydrogels loaded with Ex4-C16 would be a promising long-acting sustained-release system with anti-diabetic property.

• 한국응용과학기술학회지
• /
• 제8권2호
• /
• pp.115-122
• /
• 1991

Four novel amphoteric surfactants of N-(2-alkylamidoethyl)-N, N-dimethyl ammonioacetates were synthesized. The each reaction between four saturated fatty acids containing 10, 12, 14 and 16 carbon atoms and N, N-dimethylethylene diamine permitted to give the intermediate products, N-(2-alkylamidoethyl)-N, N-dimethylamines. Quaterinzation of these intermediates was permitted to form N-(2-alkylamidoethyl)-N, N-dimethyl, ammonioacetates, whose sturctures were identified by CC, TLC, elemental analysis, IR pectrophotometry and $^1$HNMR spectrometry. The products yielded from 48% to 58%. The isoelectric points were shown in the range of $4.30{\sim}6.64$. It showed a tendency to learn to the acidic site and its range was broadened as increase of the hydrophobic group length. Surface tensions of the aqueous solution in the $10^{-6}{\sim}10^{-1}$mol/l of amidobetaines were measured. and the critical micell concentration(cmc) were shown in the range of $8.37{\times}10^{-6}{\sim}8.96{\times}10^{-2}$mol/l, and ${\Gamma}_{cmc}$ were reduced to 32.3~38.2 dyne/cm. A linear relationship between log cmc and the number of carbon in the hydrophobic alkyl chain was presented by the formula of log cmc=2.38-0.5n, and the contribution-rate of n on the standard free energy change in micellization ${\partial}({\Delta}G^0$$_m)/{\partial}n$, was calulated as -0.5RT.

• 한국응용과학기술학회지
• /
• 제8권2호
• /
• pp.105-114
• /
• 1991

In relation to the preparation of Langmuir-Blodgett thin film, four kinds of N-alkylpyridiniurn bromide were synthesized. The values of surface tensions of these materials, measured with a Traube stalagmometer, gave the relationship between the critical micells hydrophobic radical and between CMC and temperature. Values of thermodynamic properties(${\Delta}H^0_m,\;{\Delta}S^0_m,\;{\Delta}G^0_m,$) for the formatoin of micelle were also obtained. Experiments gave the following results; at the temperature range between 40 and 60$^{\circ}C, CMC of Hexadecyl-, Octadecyl-, Eicosyl-, and Docosyl-Pyridinium Bromide were $7.64{\times}10^{-4}{\sim}9.13{\times}10^{-4},\;3.85{\times}10^{-4}{\sim}4.60{\times}10^{-4},\;2.00{\times}10^{-4}{\sim}2.39{\times}10^{-4},\;and\;1.07{\times}10^{-4}{\sim}1.28{\times}10^{-4}$ mol/l, respectively. Surface tension, ${\Gamma}_{CMC}$, of those were 33.49${\sim}$36.00, 34.78${\sim}$37.61, 35.49${\sim}$37.61 and 38.76${\sim}$55.80 dyne/cm, respectively, The relationship between CMC and the mumber of carbon atoms in the hydrophobic radical, N was expressed as follows : Log(CMC)=A-BN where A and B are constants. At the temperature range between 40 and 60$^{\circ}C$, the change of Gibbs evergy (${\Delta}G_m$) for one methylene group ($-CH_2-$) were -0.65RT, respectively, The minus values of enthalpy change (${\Delta}H_m$) suggest that the formation of micelle is exothermic. Additionally, the overall increase in the entropy change (${\Delta}S_m$) with respect to the temperature increase suggests that the formation of micelle is attained by a exothermic enthalpy directed process.

• Preventive Nutrition and Food Science
• /
• 제1권1호
• /
• pp.87-92
• /
• 1996

This study describes a stable and simple method for the measurement of cholesteryl ester transfer protein(CETP) activities using reconstituted HDL and LDL as substrates. Apolipoproteins (apo) A-I and -B were purified from hog plasma by a new strategy without ultracentrifugation and delipidation. a simple two-step column chromatography was administered. In the first step of phenyl-sepharose CL-4B column chro-matography, hydrophobic plasma proteins were isolated. The most hydrophobic proteins bound to the column appeared to be A-I and apo-B. Contaminat proteins were efficiently eliminated from the sample by washing the column with 0.3M NaCI containing buffer after loading the plasma on the column. Two pure proteins showing each single band on SDS-PSGE of apo A-I and apo-B were individually obtained by a subsequent gel filtration column chromatography(Sephadex G-200). This two-step purification was simple and inexpensive compared to the ultracentrifugation and/or delipidation method that are most commonly used. Reconstituted hight-density lipoproteins(HDL) and low-density lipoproteins(LDL) were prepared using the purified apo A-I and-B, respectively. When these artificially prepared HDL and LDL were used in the assays for CETP as the cholesteryl ester(CE) donor and acceptor respectively, the specific transfer of CE increased up to two fold compared to that used the native HSL and LDL.

• Bulletin of the Korean Chemical Society
• /
• 제22권5호
• /
• pp.467-475
• /
• 2001

A triblock copolymer based on $poly(\varepsilon-caprolactone)$ (PCL) as the hydrophobic part and poly(ethylene glycol) (PEG) as the hydrophilic portion was synthesized by a ring-opening mechanism of ${\varepsilon}-caprolactone$ with PEG containing a hydroxyl group at bot h ends as an initiator. The synthesized block copolymers of PCL/PEG/PCL (CEC) were confirmed and characterized using various analysis equipment such as 1H NMR, DSC, FT-IR, and WAXD. Core-shell type nanoparticles of CEC triblock copolymers were prepared using a dialysis technique to estimate their potential as a colloidal drug carrier using a hydrophobic drug. From the results of particle size analysis and transmission electron microscopy, the particle size of CEC core-shell type nanoparticles was determined to be about 20-60 nm with a spherical shape. Since CEC block copolymer nanoparticles have a core-shell type micellar structure and small particle size similar to polymeric micelles, CEC block copolymer can self-associate at certain concentrations and the critical association concentration (CAC) was able to be determined by fluorescence probe techniques. The CAC values of the CEC block copolymers were dependent on the PCL block length. In addition, drug loading contents were dependent on the PCL block length: the larger the PCL block length, the higher the drug loading content. Drug release from CEC core-shell type nanoparticles showed an initial burst release for the first 12 hrs followed by pseudo-zero order release kinetics for 2 or 3 days. CEC-2 block copolymer core-shell type nanoparticles were degraded very slowly, suggesting that the drug release kinetics were governed by a diffusion mechanism rather than a degradation mechanism irrelevant to the CEC block copolymer composition.

• 폴리머
• /
• 제33권4호
• /
• pp.389-395
• /
• 2009

저분자량수용성 키토산(LMWSE)을 소수성 항진균제 전달체로 응용하기 위하여, 데옥시콜릭산(deoxycholic acid, DA)을 이용하여 LMWSE를 화학적으로 개질하였다. DA가 결합된 LMWSC 나노입자(WSEDA)의 특성은 동적 광산란기, 투과전자현미경을 이용하여 그 특성을 분석하였다. 제조되어진 나노입자의 크기는 $250{\sim}350\;nm$로 DA의 치환도가 증가함에 따라 입자의 크기가 증가하였다. 항진균제인 이트라코나졸(itraconazole)이 봉입된 WSEDA 나노입자(WSEDA-ITCN)는 소수성 상호작용을 이용한 용매 증발법으로 제조하였다. UV 분광광도계를 이용하여 약물의 함량 및 담지 효율을 측정한 결과 약물의 담지 효율은 $61{\sim}68%$로 우수한 담지 효율을 보였다. 약물방출 거동에서 이트라코나졸이 봉입된 나노파티클의 DA의 함량이 많아질수록 약물이 천천히 방출되었다. 이상의 결과로부터 본 연구에서 제조한 DA가 결합된 저분자량 수용성 키토산 나노파티클이 항진균제 전달체로서 매우 높은 응용 가능성을 나타내고 있음을 확인하였다.