• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1239-1244
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• 2003

Microcapsules were prepared by coacervation method using acetone/liquid paraffin system to control the ripening of kimchi. Eudragit E100, which was soluble at below pH 5.0 in aqueous solution, was used to make microcapsules to be sensitive to acidity of kimchi. The microcapsules with Eudragit E100 containing grapefruit seed extract (GFSE) showed the highest yield of 92.13%, the size of microcapsules was decreasing as increasing the amount of aluminium stearate, a dispersing agent. Morphology of the microcapsules determined by scanning electron microscopy showed spherical forms. GFSE, encapsulated antimicrobial agents, was quickly released at acidic buffer (pH 4,5,6) within 1 storage day. However, 70% of encapsulated GFSE in Eudragit E100 microcapsules was continuously released at pH 7 till 3 days, and it was sustained till 9 days. Characteristics of kimchi containing microcapsules of GFSE were analysed with ripening period. Decease of pH in kimchi was retarded with the added GFSE microcapsules till 2 days of fermentation, but GFSE did not affect pH in kimchi after 3 days. Total numbers of microorganisms and lactic acid microorganisms in kimchi were decreased with increasing the amount of the added GFSE microcapsules, however, the effect of controlled released GFSE from pH sensitive Eudragit E100 microcapsules was hard to detect. These results suggest the possibility of pH sensitive microcapsules for high qualify of kimchi.

• YAKHAK HOEJI
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• v.34 no.3
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• pp.199-205
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• 1990

Microencapsulation of nalidixic acid using Eudragit RL, a methacrylic acid copolymer was investigated. Microcapsules were prepared by dispersing the drug solution in liquid paraffing using aluminium tristearate as dispersing agent. The preparation of the microcapsules showed high reprodulibility in particle size, shape and the drug content. The dissolution rates of Nalidixic acid from the these microcapsules considerably decreased as compared with that from Nalidixic acid powder and Nalidixic acid-Eudragit RL solid dispersions. The release of Nalidixic acid increased with increasing percentage of aluminium tristearate added to the microcapsules.

• Journal of Pharmaceutical Investigation
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• v.22 no.4
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• pp.267-279
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• 1992

Microencapsulations of amoxicillin and cephalexin, using Eudragit RS, RL, E, S and L were investigated. The microcapsules were prepared by the solvent evaporation process in liquid paraffin phase, which is based on dispersion of acetone/isopropanol containing the drug in liquid paraffin. Aluminium tristearate was used as an additive for the preparation of microcapsules. The size distribution, dissolution test and observation by SEM were examined. Good reproducibility in microcapsule preparation was observed. The microcapsules obtained were spherical and free-flowing particles. The dissolution rates of amoxicillin and cephalexin from the microcapsules were considerably decreased as compared with those from amoxicillin and cephalexin powder, respectively. As the dispersing agents (aluminium tristearate) increased, the particle size of microcapsules decreased and the dissolution rate increased. In order to control the release rate of drugs, microcapsules were prepared by mixing Eudragit RS/RL or Eudragit S/L. As Eudragit RL ratio in microcapsule of Eudragit RS/RL increased, the dissolution rate increased. As Eudragit L ratio in microcapsule of Eudragit S/L increased, the dissolution rate increased. Furthermore, the release rates of drugs from Eudragit RS/L or RS/polyelthylene glycol 1540 (PEG 1540) were examined. The dissolution rate of drugs increased with increasing of Eudragit L or PEG 1540 ratio. In conclusion, the release rates of drugs from Eudragit RS/RL or RS/PEG 1540 microcapsule could be controlled, and these microcapsules will be convenient for reducing frequency of administration.

• Food Science and Biotechnology
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• v.14 no.3
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• pp.358-362
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• 2005

Eudragit E100 microcapsules containing nisin were prepared and employed to control the ripening of kimchi. The recovery yields of microcapsules without/with nisin ranged from 93.53 to 94.61 % and 92.85 to 94.09 %, respectively. The particle size of microcapsules decreased (>200 to $100\;{\mu}m$) as the amount of aluminium tristearate increased from 6.0 to 15 %. The microcapsules were morphologically spherical and possessed rough surface. Nisin was completely released from the microcapsules within a day at pH 3.0 and within two days at pH 4.0, 5.0, and 6.0, respectively, whereas half the amount of nisin was released at pH 7.0 within two days. During fermentation of kimchi with microcapsules containing nisin, the pH decrease was retarded which resulted in a constant pH of approximately 4.2. The pH of 4.2 was optimal for ripening of kimchi for a longer period of time when compared with samples without nisin.

• Archives of Pharmacal Research
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• v.18 no.3
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• pp.183-188
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• 1995

Polymeric reinforcement and coatings of alginate beads were carried out to control the release rate of drug from alginate beads. A poorly water-soluble ibuprofen (IPF) was selected as a model drug. A commercially available $Eudragit^{\circledR}$ RS100 was also used as a polymer. Effects of polymeric contents, the presence of plasticizers and amount of drug loading on the release rate of drug were investigated. The release rate of drug from alginate beads in the simulated gastric fluid did not occur within 2 h but released immediately when dissolution media were switched to the simulated intestinal fluid. No significant difference of release rate from polymer-reinforced alginate bead without plasticizers was observed when compared to plain (simple) beads. However, the release rate of drug from polymer-reinforced alginate beads was further sustained and retarded when aluminium tristearate (AT) as a plasticizer was added to polymer. However, polyethylene glycol 400 (PEG400) did not change the release rate of drug from alginate beads although PEG400 was used to improve dispersion of polymer and sodium alginate, and plasticize $Eudragit^{\circledR}$ RS100 polymer. The presence of plasticizer was crucial to reinforce alginate gel matrices using a polymer. As the amount of drug loading increased, the release rate of drug increased as a result of decreasing effects of polymer contents in matrices. The significantly sustained release of drug from polymer-coated alginate beads occurred as the amount of polymer increased because the thickness of coated membrane increased so that cracks and pores of the outer surface of alginate beads could be reduced. The sustained and retarded action of polymer-reinforced and coated beads may result from the disturbance of swelling and erosion (disintegration) of alginate beads. From these findings, polymeric-reinforcement and coatings of alginate gel beads can provide an advanced delivery system by retarding the release rate of various drugs.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1992.05a
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• pp.64-64
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• 1992

1. Eudragit RS, RL, E, S 및 L을 이용하여 유중건조법으로 제조한 $\beta$-락탐계 항생제 (Amoxicillin, Cephalexin) 마이크로캅셀 모두가 구상 성형성과 정립성이 양호한 결과를 얻었다. 2. 분리 분산제 (aluminium tristearate)의 양을 고정시켰을 때에는 일정한 입자 분포도를 가지는 마이크로캅셀을 얻을 수 있었고, 양을 증가시켰을 때에는 입자 크기는 작아 졌으며, 용출율은 증가하였다. 3. Eudragit RS 및 S 마이크로캅셀제제로부터의 약물용출은 저조하였고, Eudragit RL 및 L 제제로부터의 약물용출은 양호하였다. 따라서 Eudragit RS/RL 마이크로캅셀제제에서는 Eudragit RL의 양을 증가시킬수록 약물의 용출율이 증가하였으며, Eudragit S/L 마이크로캅셀제제에서는 Eudragit L의 양을 증가시킬수록 약물의 용출율이 증가하였다. 약물방출 실험결과, Amoxicillin 함유Eudragit RS/RL (25/75) 마이크로캅셀, cephalxin함유 Eudragit RS/RL (75/25) 마이크로캅셀 및 Eudragit S/L (75/25) 마이크로캅셀제제는 유용한 제제로 펑가되었다. 또한 수용성 고분자인 polyethylene glycol을 혼합하어 제조하는 것에 의해 방출조절성 마이크로캅셀의 제조가 가능하였다. 유중건조법을 이용하여 본 연구방법으로 저조한 마이크로캅셀제제는 투어횟수를 줄일 수 있을 뿐만 아니라 생체에 대해 안전하고 재현성에 확보되는 유용한 제제로 판단된다. 앞으로 연구를 계속 수행하여, 특히 약물의 물리화학적 성질 및 생제내 투어 후의 생물약제학적 펑가를 엄격히 하므로써 안정성이 심히 문제시되는 다용 약물계열에 대한 조절방출성제제의 개발을 기대할 수 있다.은 해리항수의 역수이므로 해리항수가 적을수록 $\beta$ 수용체에 대한 친화력이 큰 약물이다. 시사되었으며, 이 조직에서 또한 5-$HT_2$와 5-$HT_3$ 수용체의 존재를 확인하고 각각의 기능을 분명히 했다.가 수월하게 하였고 메모리를 동적으로 관리할 수 있게 하였다. 또한 기존의 smpl에 디버깅용 함수 및 설비(facility) 제어용 함수를 추가하여 시뮬레이션 프로그램 작성을 용이하게 하였다. 예를 들면 who_server(), who_queue(), pop_Q(), push_Q(), pop_server(), push_server(), we(), wf(), printfct() 같은 함수들이다. 또한 동시에 발생되는 사건들의 순서를 조종하기 위해, 동시에 발생할 수 있는 각각의 사건에 우선순위를 두어 이 우선 순위에 의하여 사건 리스트(event list)에서 자동적으로 사건들의 순서가 결정되도록 확장하였으며, 설비 제어방식에 있어서도 FIFO, LIFO, 우선 순위 방식등을 선택할 수 있도록 확장하였다. SIMPLE는 자료구조 및 프로그램이 공개되어 있으므로 프로그래머가 원하는 기능을 쉽게 추가할 수 있는 장점도 있다. 아울러 SMPLE에서 새로이 추가된 자료구조와 함수 및 설비제어 방식등을 활용하여 실제 중형급 시스템에 대한 시뮬레이션 구현과 시스템 분석의 예를 보인다._3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하여 구한 결과 0.05 - 0.10 mm/hr 의 범위로서 이로 인한 강우손실량은 큰 의미가 없음