• Korean Membrane Journal
• /
• 제9권1호
• /
• pp.1-11
• /
• 2007

To prepare chemically stable asymmetric microporous membranes with a hydrophilic surface, which would be expected to have better antifouling properties, poly(vinylidene fluoride) (PVDF) blend membranes were prepared by the phase inversion process. PVDF mixture solutions in N-methylpyrrolidone (NMP) blended with several polar potential ionic polymers such as polyacrylonitrile (PAN), poly(methylmethacrylate) (PMMA) and poly(N-isopropylacrylamide) (NIPAM) were used for the formation of the PVDF blend membranes. They were then characterized with several analytical methods such as FESEM, FTIR, contact angle measurement, pore size distribution and permeability measurement. Regardless of different polar polymers blended, they all showed a finger-like structure with more hydrophilic surface than the pristine PVDF membrane. For all the PVDF blend membrane, due to the polar potential ionic polymers used, the flux of those was improved. Especially the PVDF blend membrane with NIPAM showed the highest flux among the membranes prepared. Also antifouling property of the PVDF membrane was improved by the use of the polar polymers.

• 폴리머
• /
• 제26권5호
• /
• pp.670-679
• /
• 2002

1, 3-bis[2-chloroethyl]-1-nitrosourea (BCNU, carmustine)는 악성 뇌종양 치료를 위하여 화학요법적 임상에서 널리 사용되는 약물이다. 또한, poly(D,L-lactide-co-glycolide) (PLGA, 분자량: 20000 g/mole, 락타이드와 글리콜라이드 몰비 75 : 25)는 약물전달시스템을 위한 약물 전달체로써 사용되어지는 잘 알려진 생분해성 초분자이다. 본 연구에서 폴리비닐피롤리돈 (PVP) 또는 폴리에틸렌옥사이드 (PEO)를 함유하고 있는 BCNU 함유 PLGA 웨이퍼들의 BCNU 방출거동과 웨이퍼에 포접된 친수성 고분자의 효과를 조사하였다. 친수성 고분자의 첨가 또는 첨가 없이 BCNU 함유 PLGA 미분말은 분사건조법에 의해 제조하였으며, 제조된 BCNU 함유 PLGA 미분말은 압축성 형법에 의해 웨이퍼형태고 제조하였다. 친수성 고분자가 첨가된 BCNU 함유 PLGA 미분말의 포접율은 85∼97%였고, PLGA에 포접된 BCNU의 결정성은 현저히 감소하였다. 약물 방출 경향과 분해 거동에서 친수성 고분자의 함량이 증가할수록 BCNU의 초기방출량과 방출속도는 증가됨을 확인하였다. 방출시험 기간동안 웨이퍼의 형태변화와 무게변화를 측정함으로써 친수성 고분자의 함량이 증가할수록 PLGA의 수차와 분해가 촉진됨을 관찰하였다.

• 마이크로전자및패키징학회지
• /
• 제8권1호
• /
• pp.53-59
• /
• 2001

Surfaces of PTFE and PVDF were modified by ion-assisted reaction (IAR) in which 1 keV $Ar^{+}$ ions were irradiated on the surface of the polymer with varying ion dose in an oxygen gas environment, and Cu, Pt, Al and Ag thin films were deposited on the modified polymers. Wettability of the modified polymers was largely improved by the formation of hydrophilic groups due to chemical reaction between polymer surface and the oxygen gas during IAR. The change in wettability in the modified polymers was also related to the change in surface morphology and roughness. Adhesion between metal films and polymers modified by IAR was significantly improved, so that no detachment was possible in the $Scotch^{TM}$ tape test. The increase of adhesion strength between the metal film and the modified PVDF was mainly attributed to the formation of hydrophilic groups, which interacted with the metal film. In the case of the modified PTFE, the enhanced adhesion to metal film could be explained by the change in surface morphology together with the formation of hydrophilic groups. The electrical properties of the metal films on the modified polymers were also investigated.

• Membrane and Water Treatment
• /
• 제1권2호
• /
• pp.103-120
• /
• 2010

Surface modification of microfiltration and ultrafiltration membranes has been widely used to improve the protein adsorption resistance and permeation properties of hydrophobic membranes. Several surface modification methods for converting conventional membranes into low-protein-binding membranes are reviewed. They are categorized as either physical modification or chemical modification of the membrane surface. Physical modification of the membrane surface can be achieved by coating it with hydrophilic polymers, hydrophilic-hydrophobic copolymers, surfactants or proteins. Another method of physical modification is plasma treatment with gases. A hydrophilic membrane surface can be also generated during phase-inverted micro-separation during membrane formation, by blending hydrophilic or hydrophilic-hydrophobic polymers with a hydrophobic base membrane polymer. The most widely used method of chemical modification is surface grafting of a hydrophilic polymer by UV polymerization because it is the easiest method; the membranes are dipped into monomers with and without photo-initiators, then irradiated with UV. Plasma-induced polymerization of hydrophilic monomers on the surface is another popular method, and surface chemical reactions have also been developed by several researchers. Several important examples of physical and chemical modifications of membrane surfaces for low-protein-binding are summarized in this article.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
• /
• pp.9-15
• /
• 2004

The copolymerization of HEMA with different hydrophilic and hydrophobic co-monomers allows for the manipulation of their intrinsic properties. 2-Hydroxyethylmethacrylate (HEMA)-based hydrogels thus are of great interest due to their outstanding physico-mechanical properties and chemical stability. The idea to use HEMA in order to create thermo-sensitive polymers was based on our assumption that thermal-sensitivity comes from a suitable hydrophilic-hydrophobic balance of macromolecules. In this work we have chosen N-vinyl pyrrolidone as a hydrophilic co-monomer with the relatively hydrophobic HEMA due to its good polymerizing properties as well as its non-toxicity in a polymer state and deserved recognition as a biocompatible material. As a result, copolymerization of NVP and HEMA was successful in obtaining new types of thermo-sensitive polymers composed of hydrophilic and hydrophobic monomers.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 1991년도 제2차 학술발표초록집
• /
• pp.71-71
• /
• 1991

• Journal of Pharmaceutical Investigation
• /
• 제38권4호
• /
• pp.241-247
• /
• 2008

Paclitaxel is a taxane diterpene amide, which was first extracted from the stem bark of the western yew, Taxus brevifolia. This natural product has proven to be useful in the treatment of a variety of human neoplastic disorders, including ovarian cancer, breast and lung cancer. Paclitaxel is a highly hydrophobic drug that is poorly soluble in water. It is mainly given by intravenous administration. Therefore, The pharmaceutical formulation of paclitaxel ($Taxol^{(R)}$; Bristol-Myers Squibb) contains 50% $Cremophor^{(R)}$ EL and 50% dehydrated ethanol. However the ethanol/Cremophor EL vehicle required to solubilize paclitaxel in $Taxol^{(R)}$ has a pharmacological and pharmaceutical problems. To overcome these problems, new formulations for paclitaxel that do not require solubilization by $Cremophor^{(R)}$ EL are currently being developed. Therefore this study utilized a supercritical fluid antisolvent (SAS) process for cremophor-free formulation. To select hydrophilic polymers that require solubilization for paclitaxel, we evaluated polymers and the ratio of paclitaxel/polymers. HP-${\beta}$-CD was used as a hydrophilic polymer in the preparation of the paclitaxel solid dispersion. Although solubility of paclitaxel by polymers was increased, physical stability of solution after paclitaxel/polymer powder soluble in saline was unstable. To overcome this problem, we investigated the use of surfactants. At 1/20/40 of paclitaxel/hydrophilic polymer/ surfactant weight ratio, about 10 mg/mL of paclitaxel can be solubilized in this system. Compared with the solubility of paclitaxel in water ($1\;{\mu}g/mL$), the paclitaxel solid dispersion prepared by SAS process increased the solubility of paclitaxel by near 10,000 folds. The physicochemical properties was also evaluated. The particle size distribution, melting point and amophorization and shape of the powder particles were fully characterized by particle size distribution analyzer, DSC, SEM and XRD. In summary, through the SAS process, uniform nano-scale paclitaxel solid dispersion powders were obtained with excellent results compared with $Taxol^{(R)}$ for the physicochemical properties, solubility and pharmacokinetic behavior.

• 공업화학
• /
• 제32권4호
• /
• pp.371-378
• /
• 2021

고체 표면의 박테리아 부착억제를 목적으로 고분자를 이용한 친수성 표면 개질 연구가 주목을 받고 있다. 부착억제기능은 세포독성이 아닌 작용으로 바이오필름 형성의 초기단계 방지를 목적으로 하며 친수성 또는 이온성 고분자가 도입된 고체 표면은 단백질, 박테리아 등 생물 개체의 부착방지에 효과적이다. 이는 표면에서의 친수층 형성으로 인한 표면 장벽 형성, 고분자 사슬에 의한 반발력과 삼투압성 응력 작용, 그리고 이온성 고분자와 세포 표면의 정전기적 상호작용에 기인한다. 부착억제를 위한 고분자의 표면 도입은 주로 표면 기능기와의 결합을 이용한 접합 방식과 자연모방 접착 기능기를 활용한 침적 방식으로 이루어지고 있다. 본 총설에서는 표면 도입 시 부착억제 기능을 보이는 대표적인 고분자의 종류, 코팅방법, 및 항균 특성을 소개하고 향후 공공시설, 산업 등으로의 대면적 응용을 위한 고려사항들을 다루고자 한다.

• Journal of Pharmaceutical Investigation
• /
• 제18권2호
• /
• pp.55-59
• /
• 1988

The size of furosemide was reduced by the recrystallization method in order to increase the dissolution rate of the drug. Surfactants or hydrophilic polymers were used to suppress the aggregation in the crystal formation-growth process of microparticles by dispersing action. Dissolution rate of microparticles increased remarkably due to the size reduction of microparticle. The particle size decreased with increasing the concentration of the drug and the dispersing agents, i.e., surfactants or hydrophilic polymers. No polymorphic transition occurred during the microcrystallization process, but the habit of crystal formation was altered in the case of anionic surfactant.

• Journal of Pharmaceutical Investigation
• /
• 제23권4호
• /
• pp.187-206
• /
• 1993

Since the advent of recombinant DNA technology coupled with other biotechnology a variety of therapeutically effective proteins and peptides have been extensively invesitigated and many of them are now on clinical trial. They, however, suffer from some problems such as immunogenicity, antigenicity, instability and short half-life in circulation due to their proteinous natures. These drawbacks can be overcome successfully by conjugating proteins and peptides with hydrophilic polymers such as polyethylene glycol (PEG), albumin or dextran. The resulting soluble conjugates showed reduced antigenicity and immunogenicity, increased circulatory half-life, enhanced stability against proteolytic degradation. Comparing with the unmodified proteins and peptides, the therapeutic potential of conjugates is greatly enhanced. Clinical applications of these conjugates have shown promising results for the future use.