• 멤브레인
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• 제29권4호
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• pp.231-236
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• 2019

본 연구에서는 보습오일 및 천연유화제를 포함한 하이드로젤 비드 및 고강도 하이드로젤 매트릭스로 구성된 알지네이트 기반의 하이드로젤 멤브레인을 제조하고 용출 특성을 평가하였다. 실험 결과, 하이드로젤 비드 및 고강도 하이드로젤의 조성을 조절하여 보습오일 성분의 용출 속도를 원하는 범위로 제어할 수 있음을 확인하였다. 특히 상호 침투 고분자 네트워크 구조를 가지고 있는 고강도 하이드로젤과 하이드로젤 비드를 결합함으로써 멤브레인의 물리적 안정성을 높이고 동시에 보습오일의 용출 속도를 더욱 세밀하게 제어할 수 있음을 확인하였다.

• 약학회지
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• 제31권3호
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• pp.182-188
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• 1987

Simple coacervation of bovine serum albumin was studied to prepare biodegradable microacapsule. Albumin microcapsules were prepared by using acrylonitrilestyrene polymer (M-80) resin beads and sulfamethoxydiazine as the core materials. The albumin to beads ratio was found to be 1:2.3 and the albumin to sulfamethoxydiazine ratio to be 1:2.9. The 50% release times (T$_{50%}$) of sulfamethoxydiazine and microencapsulated sulfamethoxydiazine were 6 min. and 73 min., respectively. The surface appearance of the microcapsule collected after release experiment was not different from those of the original microcapsule. In addition to slowing release of drug the microencapsulation process masked characteristic bitter taste of sulfamethoxydiazine.

• Journal of Pharmaceutical Investigation
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• 제33권3호
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• pp.179-185
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• 2003

Melatonin (MT) is an indole amide pineal hormone. It has not only very short half-life but also pH-sensitive property. The sustained release dosage form which delivers MT in a circadian fashion over 8 h is clinical value. The purpose of this study is to prepare sugar beads using multiple coating methods and enteric-coated in a sustained release to evaluate in vitro release characteristics in simulated gastric and intestinal fluids. The $Eudragit^{\circledR}$ as a polymer, sustained release membrane, and triethylcitrate (TEC) as a plasticzer were used. Multi-coated melatonin delivery system was composed of sugar, various excipients, $Eudragit^{\circledR}$ and enteric materials (e.g. hydroxy propyl methyl cellulose phthalate, HPMCP), and prepared by fluid bed coater. The dissolution test was carried out using the basket method at a stirring speed of 100 rpm at $37^{\circ}C$ in simulated gastric (pH 1.2) and intestinal fluid (pH 7.4). The released amount of MT was determined by High performance liquid chromatography method. The morhologies of surface and cross section of multi-coated beads were observed by scanning electron microscope. Size of multi-coated sugar beads was ranged over $1000{\sim}1300\;{\mu}m$. The release rate of MT from coated beads was limited in simulated gastric fluid (pH 1.2), but it was sustained in intestinal fluid (pH 7.4) during $3{\sim}8$ hours. The MT beads may provide small-intestine-targeted device for oral delivery. Studies on animal and relative experiment are in process.

• 접착 및 계면
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• 제19권2호
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• pp.68-73
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• 2018

이 연구는 에틸렌-비닐아세테이트(Ethylene-vinyl acetate, EVA) 공중합체 수지를 기본으로 하여 가교제, 발포제의 조성물과 함께 전도성을 가지는 다중벽 탄소나노튜브(Multiwall Carbon Nanotubes, MWCNT), 유리비드(glass beads)를 이용하여 전도성 EVA발포체를 제조하였다. 다중벽 탄소나노튜브의 양, 혼련시간, 유리비드의 양 및 크기에 따른 전기전도성 및 발포체의 물성을 측정하였으며, 다중벽 탄소나노튜브의 양에 따라 전기전도성이 증가하였다. 또한 유리비드의 양에 따라 전기전도성이 증가된 것을 보아 유리비드가 다중벽 탄소나노튜브의 분산성을 향상시키는 것을 알 수 있다. 유리비드를 통한 다중벽 탄소나노튜브의 에틸렌-비닐아세테이트내의 분산성 향상을 통해서 에틸렌-비닐아세테이트 전도성 발포폼을 성공적으로 만들 수 있을 것으로 기대된다.

• Macromolecular Research
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• 제15권6호
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• pp.498-505
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• 2007

This study demonstrated the in-situ functionalization with polymers of multi-walled carbon nanotubes (MWNTs) via emulsion polymerization. Polystyrene-functionalized MWNTs were prepared in an aqueous solution containing styrene monomer, non-ionic surfactant and a cationic coupling agent ([2-(methacryloyloxy)ethyl]trime-thylammonium chloride (MATMAC)). This process produced an interesting morphology in which the MWNTs, consisting of bead-string shapes or MWNTs embedded in the beads, when polymer beads were sufficiently large, produced nanohybrid material. This morphology was attributed to the interaction between the cationic coupling agent and the nanotube surface which induced polymerization within the hemimicellar or hemicylindrical structures of surfactant micelles on the surface of the nanotubes. In a solution containing MATMAC alone without surfactant, carbon nanotubes (CNTs) were not well-dispersed, and in a solution containing only surfactant without MATMAC, polymeric beads were synthesized in isolation from CNTs and continued to exist separately. The incorporation of MATMAC and surfactant together enabled large amounts of CNTs (> 0.05 wt%) to be well-dispersed in water and very effectively encapsulated by polymer chains. This method could be applied to other well-dispersed CNT solutions containing amphiphilic molecules, regardless of the type (i.e., anionic, cationic or nonionic). In this way, the solubility and dispersion of nanotubes could be increased in a solvent or polymer matrix. By enhancing the interfacial adhesion, this method might also contribute to the improved dispersion of nanotubes in a polymer matrix and thus the creation of superior polymer nanocomposites.

• 융복합기술연구소 논문집
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• 제12권1호
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• pp.13-18
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• 2022

Polyacrylonitrile was synthesized through suspension polymerization and then sieved to obtain spherical beads with a size of 200~510 ㎛. PAN was copolymerized with 2 mol% MMA monomer which is known to promote cyclization and crosslinking of nitrile group. The resonance cyclization reaction of the nitrile group in the synthesized PAN beads was observed near 170℃ with thermal analysis and FT-IR. The reaction conversion of the nitrile group in spherical beads was 23% during heat treatment, which was lower than that of the well-oriented PAN fiber used as a precursor of carbon fiber. This is because the stereo-regularity of molecular chains in the form of a random coil (spherical bead) is much lower than that of PAN fiber. It was confirmed that the compressive strength of the spherical PAN bead was greatly improved through the resonance cyclization and shrinkage according to the heat treatment, and it was also observed that the pores in PAN beads were formed after the heat treatment.

• Environmental Engineering Research
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• 제11권6호
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• pp.325-332
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• 2006

A novel series of polystyrene (PS) beads containing various sulfonamide groups was prepared, and their chemical stabilities in an aqueous solution were tested in order to determine their ability to inactivate microbes. By reacting aminomethyl polystyrene (AM PS) beads or carboxy polystyrene beads with various benzenesulfonic acid derivatives, the sulfonamide groups were introduced on the PS beads. The characteristics of the product beads were analyzed by elementary analysis after the substitution of various sulfonamide groups. Energy Dispersive Spectroscopy (EDS), and FT-IR analysis were used to analyze the elemental functional group composition, respectively. The hydrolytic stabilities of the PS beads containing various sulfonamide groups along with the relationship between the swelling ratio and their hydrophilicity were investigated. The antibacterial activity of the beads was determined by their ability to inactivate E. coli. This study reports that PS beads containing sulfonamide groups had lasting antibacterial efficacy over a satisfactory period, whilst maintaining their chemical stabilities against hydrolysis. The 8 synthesized polymer beads exhibited antibacterial ability.

• 폴리머
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• 제34권1호
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• pp.79-83
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• 2010

Poly(N-isopropylacrylamide-co-dimethylamino ethyl methacrylate)(P(NIPAM-co-DMAEMA))가 고정화된 알지네이트 비드를 제조하였다. 알지네이트와 P(NIPAM-co-DMAEMA)의 정전기적 인력을 이용하여 P(NIPAM-co-DMAEMA)로 코팅된 알지네이트 비드와 P(NIPAM-co-DMAEMA)을 함유한 알지네이트 비드를 제조하였다. P(NIPAM-co-DMAEMA)은 자유 라디칼 반응으로 제조하였고 핵자기 공명분광기를 통해 확인하였다. 비드의 온도 민감성 방출 거동을 관찰하였으며, 모델시약으로 blue dextran과 fluorescein isothiocyanate-dextran을 사용하였다. P(NIPAM-co-DMAEMA)가 고정화된 알지네이트 비드로부터의 방출 정도는 온도 의존성이 낮았고, 방출모델시약의 분자량이 작을수록 더 높았다.

• 융복합기술연구소 논문집
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• 제3권1호
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• pp.45-49
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• 2013

Spherical active carbon materials have been used for the removal of pollutants in the area of food processing, water treatment, air purification, oral administration. Moreover, they are now expected to make an epoch in the areas of electronics, life science, environmental technology, and so on due to their superior physical properties. Carbon particles should be requested for the edgeless spherical shapes in order to minimize the loss due to the abrasion during the process and/or practical use, but the carbon particles manufactured from petroleum-based pitch do not meet these needs. Nowadays, thus, the spherical active carbon particles carbonized from various spherical polymer beads are studied with thermoplastic and/or thermosetting polymers. In this paper, the synthesis of spherical phenolic beads and furan beads, which are thermosetting polymers, and their carbonization techniques are examined.

• Biomaterials and Biomechanics in Bioengineering
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• 제2권2호
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• pp.85-96
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• 2015

This study developed biodegradable bi-layered drug-eluting beads and investigated the in-vitro release of fluorouracil and cisplatin from the beads. To manufacture the drug-eluting beads, poly[(d,l)-lactide-co-glycolide] (PLGA) with lactide:glycolide ratios of 50:50 and 75:25 were mixed with fluorouracil or cisplatin. The mixture was compressed and sintered at $55^{\circ}C$ to form bi-layered beads. An elution method was employed to characterize the release characteristic of the pharmaceuticals over a 30-day period at $37^{\circ}C$. The influence of polymer type (i.e., 50:50 or 75:25 PLGA) and layer layout on the release characteristics was investigated. The experiment suggested that biodegradable beads released high concentrations of fluorouracil and cisplatin for more than 30 days. The 75:25 PLGA released the pharmaceuticals at a slower rate than the 50:50 PLGA. In addition, the bi-layered structure reduced the release rate of drugs from the core layer of the beads. By adopting the compression sintering technique, we will be able to manufacture biodegradable beads for long-term drug delivery of various anti-cancer pharmaceuticals.