• 자원리싸이클링
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• 제23권3호
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• pp.44-50
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• 2014

본 연구에서는 기존의 cutting 분쇄방식 대신 여러 가지 문제점을 개선한 shear방식 및 2단 disk mill 방식으로 폐타이어를 미분화시켰다. 각 파쇄 또는 분쇄 단계별로 다양한 크기의 고무 칩을 얻을 수 있었다. Shear방식 및 2단 disk mill 방식은 회전 속도와 방향이 다른 두 개의 드럼형의 칼날로 이루어져 있어서 기존의 cutting 방식보다 거친 표면의 미분화 폐타이어 분말을 얻을 수 있었다. 본 연구에서는 주로 shear방식으로 미분화된 폐타이어 분말의 형상을 SEM을 통해 비교하였다. 추가적으로 적절한 크기의 폐타이어 분말이 얻어졌는지를 확인하기 위해 입도분석을 수행하였다.

• 청정기술
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• 제14권3호
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• pp.153-159
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• 2008

여드름 치료제인 트리클로산의 초임계이산화탄소에 대한 용해도를 가변부피셀(Variable volume cell)을 이용하여 온도 313.15, 323.15와 333.15 K에 대해서 10 - 40 MPa 압력범위에서 측정되었다. QLF (Quasi-chemical nonrandom lattice fluid) 상태방정식을 이용하여 측정된 용해도를 잘 계산할 수 있었고, 이 자료를 미세입자공정에 활용하였고. 입자크기에 미치는 온도와 압력의 효과를 해석하였다.

• 한국축산식품학회지
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• 제41권1호
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• pp.110-121
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• 2021

Meat industries utilize plant material such as celery in cured meat products. Extraction of valuable bioactive compounds, nitrates and nitrites often involves processes that increase cost or lack sustainability. Thus, this study investigated the effect of ball-milled celery powders (CP) on the physicochemical, antioxidant, and antimicrobial properties along with curing efficiency in comminuted meat product. Pork sausages loaded with CPs with different average particle sizes: 265 ㎛ (T1), 68 ㎛ (T2) and 7 ㎛ (T3) were compared to those added without and with sodium nitrite (150 ppm). The a⁎ values were increased for sausages with larger particle size. The L⁎ values decreased for all CPs. Residual nitrite for all particle sizes increased in the earlier stages and decreased at the end of storage period. The curing efficiency also increased for larger size particles with an increase until day 9 followed by a gradual decrease. Superfine CP had a tendency to improve the antioxidant activities. The antimicrobial activity of CPs was not comparable with nitrite added sausages. The textural parameters remained unaffected by particle size. Thus, instead of extracts or juices, micronized CPs could be used to improve the antioxidant activities and curing efficiency of label friendly reformulated meat products.

• Archives of Pharmacal Research
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• 제8권1호
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• pp.7-14
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• 1985

Membrane-coated tablet of isonicotinic acid hydrazide (INAH) which releases INAH at the zero-order kinetics was deveoped. It consisted of a soluble tablet core surrounded by a porous membrane which controls the diffusion rate. Tablet cores were prepared by compressing granules of INAH and polyvinyl chloride (PVC) dissolved in methyl ethyl ketone in which micronized sucrose were suspended. Diffusion rate of INAH from the tablet through the membrane was constant until the loaded INAH in the core was almost released. The rate was independent of pH of the dissolution medium. Water-soluble sucrose particles behaved as a poreproducing material in the water-insoluble PVC film coat. The pH independency of the rate was probably due to the high solubility of INAH in the water of wide pH range. The diffusion rate of INAH could be controlled by chnaging the composition of the membrane or the coat weight. This membrane-coated INAH tablet seemed to be a powerful candidate for the controlled release drug delivery system (DDS) of INAH or other highly watersoluble drugs.

• Journal of Pharmaceutical Investigation
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• 제6권3호
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• pp.58-69
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• 1976

It is well established that dissolution is freruently the rate limiting step in the gastrointestinal absorpton of a drug from a solid dosage from. The relationship between the dissolution rate and absorption is particularly distinct when considering drugs of low solubility. Consequently, numerous attempts have been made to modify the dissolution characteristics of poorly water soluble drugs. Since dissolution rate is directly proportional to surface area, one may increase the rate by decreasing the particle size of the drug. Levy has considered a number of methods by which a drug may be presented to the GI fludids in finely divided from. The direct method is the utilization of microcrystalline or micronized particles. A second method involves the administration of solutions from which, upon dilution with gastric fluids, the dissolved drug will precipitate in the form of very fine particles. A more unique way of obtaining microcrystalline dispersions of a drug has been ercently suggested by Sekiguchi et al. They have first proposed the formation of a eutectic mixture of a poorly water soruble drug with a physiologically inert, easily soluble carrier. When such systems are exposed to water or GI fluids, the soluble carrier will dissolve rapidly and the finely dispersed drug particles will then be released. It has been suggested by Shefter and Higuchi that the formation of crystalline solvate could be a powerful tool in affecting rapid disslution of highly insoluble substances. Goldberg et al. have noted that the formation of solid solution could reduce the particle size to a minimum and increase the dissolution rate as well as the solubility of the durgs. It has also been shown that the rates of solution of drugs were appreciably increased by coprectipitating the drug with soluble polymers. The increase was found to be sensitive to the method of preparation, the molecular weight of polymer and the particular ratio of drugs to polymer. Although several investigations have demontrated that the solubility and/or dissolution rates of drugs can be increased in this manner, little information is available in the literature related to the in vivo absorption pattern of drugs orally administered as PVP coprecipitates. Recently, however, it was demonstrated that both the rate and extent of absorption of the insoluble drug could be markedly enhanced when orally administered to rats in the form of a coprecipitate with PVP. The purpose of the present investigation was to ascertain the general appility of soluble polymer coprectation technique as a method for enhancing the in vitro dissolution rate of hydrophobic indomethacin. To accomplish this aim, the dissolution characteristics of pure indomethacin, indomethcin-polymer physical mixtures and indomethacin-polymer coprecipitates were quantitatively studied by comparing their relative dissolution rates. The solubility and dissolution behavior of these systems were also examined.

• Journal of Pharmaceutical Investigation
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• 제22권3호
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• pp.205-210
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• 1992

In order to develop a controlled-release oral drug delivery system (DDS) of theophylline (TP), microporous membrane-coated tablets were prepared and evaluated in vitro and in vivo. Rapidly water-soluble core tablets of TP (300 mg) were prepared by wet granulation and compression technique, Then the core tablets were spray-coated with polyvinylchloride (PVC) in which micronized sucrose particles were dispersed. Effect of formula compositions of coating suspensions on the pharmaceutical characteristics such as membrane strength and dissolution was investigated in vitro. The membranes remained unbroken in pH 1.2 buffer at $37^{\circ}C$ at least for 2 hours after the disintergration test. TP was released from the coated-released tablets at a zero-order rate over 8 hours. The release at pH 1.2 and 4.0 was similar in rate but a little more rapid than that at pH 6.8. The coated tablets were administered to three healthy male volunteers and their saliva profiles of TP were compared with those from the commercial sustained release TP tablets such as Slobid and Asconthin. Saliva TP concentrations from the coated tablets were successfully sustained over 48 hours after the dosing and were comparable to those of the commercial sustained-release tablets. The membrane-coating technique is very simple and does not need any sophisticated equipments. In this respect, the membrane-coated tablets may be superior to the commercial sustained-release tablets and this technique is worth adopting by the pharmaceutical industries.

• Archives of Pharmacal Research
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• 제13권2호
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• pp.151-160
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• 1990

In order to develop a controlled-release oral drug delivery system (DDS) which sustains the plasma acetaminophen (AAP) concentration for a certain period of time, microporous membrane-coated tablets were prepared and evaluated in vitro. Firstly, highly water-soluble core tablet of AAP were prepared with various formulations by wet granulation and compression technique. Then the core tablets were coated with polyvinychloride (PVC) in which micronized sucrose particles were dispersed. Effect of formula compositions of core tablets and coating suspensions on the pharmaceutical characteristics such as drug release kinetics and membrane stability of the coated tablets was investigated in vitro. AAP was released from the coated tablets as a zero-order rate in a pH-independent manner. This independency of AAP release to pH change from 1.2 to 7.2 is favorable for the controlled oral drug delivery, since it will produce a constant drug release in the stomach and intestine regardless of the pH change in the GI tract. Drug release could be extended upto 10 h according to the coating condition. The release rate could be controlled by changing the formula compositions of the core tablets and coating suspensions, coat weight per each tablet, and especially PVC/sucrose ratio and particle size of the sucrose in the coating suspension. The coated tablets prepared in this study had a fairly good pharmaceutical characteristics in vitro, however, overall evaluation of the coated tablet should await in vivo absorption study in man.