• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.139-144
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• 2002

Two types of alginate gel beads capable of floating in the gastric cavity were prepared. The first, alginate gell bead containing olive oil(Al-Oil), is a hydrogel bead and its buoyancy is attributable to olive oil held in the alginate gel matrix. The model drug, metronidazole(MZ), contained in Al-Oil was released gradually into artificial gastric fluid. The profiles of MZ release from Al-Oil shown initial burst and after 90 min they were about 100%. The second, alginate gel bead containing curdlan microsphere(Al-C), is a gel bead with curdlan-MZ microsphere in the matrix. To sustained release rate of drug, alginate bead were prepared curdlan microsphere containing MZ. Results demonstrated that sustained delivery of MZ over 2h can be easily achieved while the bead remained float. The release properties of prepared alginate beads are applicable not only for sustained release of drugs but also for targeting the gastric mucosa.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.612-618
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• 2005

A mucoadhesive microsphere was prepared by an interpolymer complexation and solvent evaporation method, using chitosan and poly(acrylic acid) (PAA), to prolong the gastric resid ence time of the delivery system. The Fourier transform infrared results showed that microspheres were formed by an electrostatic interaction between the carboxyl groups of the PAA and the amine groups of the chitosan. X-ray diffraction and differential scanning calorimetry analysis showed that the enrofloxacin in the chitosan-PAA microsphere was molecularly dispersed in an amorphous state. Scanning electron microscopy of the surface and the quantity of mucin attached to the microspheres indicated that chitosan-PAA microspheres had a higher affinity for mucin than those of chitosan alone. The swelling and dissolution of the chitosan-PAA microspheres were found to be dependent on the pH of the medium. The rate of enrofloxacin released from the chitosan-PAA microspheres was slower at higher pH; therefore, based on their mucoadhesive properties and morphology, the chitosan-PAA microspheres can be used as a mucoadhesive oral drug delivery system.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.231.1-231.1
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• 2003

Mucoadhesive microsphere was prepared by interpo]ymer complexation of po]y(acrylic acid) (PAA) with po]y(vinyl pyrrolidone) (PVP) using solvent diffusion method. The loading efficiency of acetaminophen into the microsphere was 91.3 ${\pm}$ 6.5%. The release rate of acetaminophen from the PAA/PVP complex microspheres was slower than that from PVP microspheres at pH 2.0 and 6.8. The dissolution of microspheres made of the complex was significantly slower than those made of PVP due to H-bond between PVP and PAA. As a result, the release rate of acetaminophen from the complex microspheres was slower than that from PVP microspheres.

• Journal of Pharmaceutical Investigation
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• v.31 no.4
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• pp.241-256
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• 2001

Alginate microspheres, containing fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) or green fluorescent protein (GFP) were prepared and used as a model drug to develop the oral vaccine delivery system. The alginate microspheres were coated with poly-L-lysine or chitosan. Two methods, w/o-emulsion and spray, were used to prepare alginate microspheres. To optimize preparation conditions, effects of several factors on the particle size and particle morphology of microsphere, and loading efficiency of model antigen were investigated. In both preparation methods, the particle size and the loading efficiency were enhanced when the concentration of sodium alginate increased. In the w/o-emulsion preparation method, as the concentration of Span 80 was increased from 0.5% to 2%, the particle size was decreased, but the loading efficiency was increased. The higher the emulsification speed was, the smaller the particle size and loading efficiency were. The concentration of calcium chloride did not show any effect on the particle size and loading efficiency. In the spray preparation method, the particle size was increased as the nozzle pressure $(from\;1\;kgf/m^2\;to\;3\;kgf/m^2)$ and spray rate was raised. Increasing calcium chloride concentration (<7%) decreased the particle size, in contrast to no effect of calcium chloride concentration on the w/o-emulsion preparation method. Alginate microspheres prepared by two methods were different in the particle size and loading efficiency, the particle size of microspheres prepared by the spray method was about $2-6\;{\mu}m$, larger than that prepared by the w/o emulsion method $(about\;2{\mu}m)$, and the loading efficiency was also higher with spray method. Furthermore, drying process for the microspheres prepared by the spray was simpler and easier, compared with the w/o emulsion preparation. Therefore, the spray method was chosen to prepare alginate microspheres for further experiments. Release pattern of FITC-BSA in alginate microspheres was evaluated in simulated intestinal fluid and PBS (phosphate buffered saline). Dissolution rate of FITC-BSA from alginate/chitosan microsphere was lower than that from alginate microsphere and alginate/poly-L-lysine microsphere. By confocal laser scanning microscope, it was revealed that alginate/FITC-poly-L-lysine microspheres were present in close apposition epithelium of the Peyer's patches of rabbits following inoculation into lumen of intestine, which proved that microspheres could be taken up by Peyer's patch. In conclusion, it is suggested that alginate microsphere prepared by spray method, showing a particle size of & $10\;{\mu}m$ and a high loading efficiency, can be used as a model drug for the development of oral vaccine delivery system.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.29-32
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• 2003

특수 기능성의 심물질이 평균직경 수 마이크로의 미소한 고분자막으로 둘러싸여 있는 담체를 마이크로 캡슐이라 한다. 이러한 마이크로 캡슐의 주요한 기능은 크게 두가지로 나뉘는데, 심물질을 외부환경으로부터 보호하는 것과 심물질을 외부환경에로 방출하는 속도를 조절하는 것이다. 폴리우레탄은 제조시의 분자조성에 의해 매우 광범위한 특성을 나타낼 수 있는 흥미로운 고분자로 특히, 폴리에테르 폴리우레탄은 우수한 물성, 감염에 대한 우수한 저항성, 그리고 뛰어난 혈액 및 생체 적합성 등으로 인해 많은 연구가 되어져 왔다. (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.475-476
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• 2012

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.04a
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• pp.56-56
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• 2003

Using gel filtration chromatography (GFC), pure separation of high molecular silk fibroin was obtained and silk fibroin microsphere particles (SFMP) could be simply made by spray dryer method. Also, some of its physicochemical properties and morphology were investigated. The average molecular weight (Mw) of pure silk fibroin protein dissolved in calcium chloride is about 61, 500 g/mol as measured by gel permeation chromatography(GPC). (omitted)

• Polymer(Korea)
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• v.39 no.1
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• pp.144-150
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• 2015

Gellan gum as a natural polysaccharide has good heat resistance, acid resistance and enzymes resistance. However, one of the drawbacks of gellan gum might be the lower mechanical strength. In this work, gellan gum scaffolds were mixed with poly(lactic-co-glycolic acid) (PLGA) microsphere in order to improve mechanical properties. The gellan gum scaffolds with various contents of PLGA microsphere were prepared for the regeneration of disc tissues. To evaluate the mechanical strength of hybrid structure of gellan gum and PLGA microsphere, compression strength of the fabricated scaffolds was measured. MTT analysis, SEM observation, histological evaluation and RT-PCR were performed to confirm the effect on the cell growth and extracellular matrix secretion. As a result, it showed the best cell proliferation and extracellular matrix secretion in gellan gum sponge containing 50% PLGA microspheres. In conclusion, this study confirmed that the hybrid structure of gellan gum and PLGA microspheres was found suitable in regeneration of the intervertebral disc.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.66-70
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• 2006

Magnetite nanoparticles, which have been extensively used in many fields, were encapsulated with a natural polymer, chitosan, to improve their biocompatibility. We have synthesized magnetite $(Fe_3C_4)$ nanoparticles using chemical coprecipitation technique with sodium oleate as surfactant. Nanoparticle size can be varied from 1.2 to 7.4nm by controlling the sodium oleate concentration. Magnetite phase nanoparticles could be observed from X-ray diffraction. Magnetic colloid suspensions containing particles with sodium oleate and chitosan have been prepared. High magnetic property chitosan-microsphere particles were prepared from oleate-coated magnetite suspension using spray method. The surftce, and tile morphology of the magnetic chitosan microsphere particles were characterized using optical microscope and scanning electron microscope. Magnetic hysteresis measurement were performed using a superconducting quantum interference device (SQUID) magnetometer at room temperature to investigate the magnetic properties of the chitosan microspheres including magnetite nanoparticles. The SQUID measurements revealed superparamagnetism of nanoparticles.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.1
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• pp.25-30
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• 2019

This study was aimed to examine the synergetic effects of photochemopreventive external agents composed of inorganic ZnO and esculetin. Zinc oxide (ZnO) is widely used in sunblocks because of its excellent biostability and little toxicity. Esculetin derived from Citrus Peel has an anti-oxidative effect. We made the hollow-shaped ZnO microsphere (MS), soaked it with esculetin (EZnO). We used SKH-1 mice to measure the photodamaging effects of UVB. The mice were divided into five groups as follows; UVB nontreated group (N), vehicle (C), esculetin (E), ZnO MS (ZnO), esculetin + ZnO MS(EZno) group. Each group of samples was topically applied to the dorsal skins before the UVB irradiation. The changes of collagen fibers in the skin tissues were observed by H & E staining and Van Gieson staining. The expression of mast cells in skin tissue was observed by immunohistochemical staining of tryptase present in the mast cell granules. Expression of inflammatory cytokines such as TNF-${\alpha}$, IL-$1{\beta}$, and MMP-9, which plays an essential role in wrinkle formation, was measured by RT-PCR. Interestingly, the composition of collagen fibers was better in the EZnO applied group than in the E or ZnO group. Moreover, mast cell expression and the expression of TNF-${\alpha}$, IL-$1{\beta}$, and MMP-9 mRNA were markedly suppressed in the EZnO group, indicating that the synergetic effects of esculetin and ZnO were excellent.