• Journal of Pharmaceutical Investigation
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• 제22권2호
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• pp.133-137
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• 1992

A novel oral controlled release tablet which may offer more uniform drug level in the body than simple zero-order was developed. The tablet is composed of three layers; outer film layer, middle part compression-coated hydroxypropylmethylcellulose (HPMC) matrix layer, and inner core layer. Each layer contains nicardipine HCl as a model drug. In vitro dissolution test showed that the tablet released the drug in clear three steps; a rapid initial release, followed by a constant rate of release, and then a second phase of fast release of drug. The dissolution characteristics could be modified easily by changing the grade of HPMC, thickness of matrix layer, content of methylcellulose in matrix layer, content of active ingredient in each layer. The pH of dissolution medium did not affect the release profile. This three-step release system is expected to raise the blood concentration rapidly to effective level and to maintain effective blood level longer than simple slow-release systems.

• Journal of Pharmaceutical Investigation
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• 제5권4호
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• pp.17-23
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• 1975

복용량이 비교적 적고, 난용성 의약품(醫藥品)으로 antirheumatism에 사용되고 있는 phenylbutazone을 macromolecule polymer로서 water soluble carrier인 polyvinylpyrrolidone과 solvent method로 1:1, 1:5, 및 1:9(w/w)의 coprecipitate를 형성(形成)시켰으며, 이들 coprecipitate의 용출 속도를 Pure drug 및 coprecipitate 형성 용매인methanol에서 재결정한 recrystallized pure drug의 그것과 측정 비교(比較)하였다. 1:1,1:5 및 1:9(w/w)의 coprecipitate는 recrystallized pure phenylbutazone보다 약 4.5배의 용출의 증가를 보였고, 이들 1:1,1:5,1:9(w/w)에서의 그 carrier의 양(量)에 따른 용출에의 영향은 거의 없었다. 시간(時間)에 대(對)한 log probit를 plot하여 구(求)한 dissolution half life, $T_{50%}$는 coprecipitate ratio 1:1(w/w)에서는 5.5분, 1:5에서는 10분, 1:9에서는 12.5분이었다.

• 한국유체기계학회 논문집
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• 제12권6호
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• pp.47-53
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• 2009

Ozone is a strong oxidant and a powerful disinfectant. In general, it has been used in drinking water treatment during last 100years. Ozone dissolution features are defined by the two categories of ozone contactors, bubble-diffuser and sidestream ozone contactor. Currently, sidestream-injection systems are gaining in popularity but operating cost might be slightly higher. Sidestream ozone system dissolve ozone into a sidestream flow via an injection setup or in the main process flow stream in some sidestream arrangements. The sidestream flow is subsequently mixed with the main process flow stream, which is directed to a reation tank or pipeline for oxidation and disinfection reactions. The purpose of this study is to suggest optimal operating pressure, to figure out the static-mixer effect and to understand the microbubble characteristics of ozone to improve dissolution efficiency.

• Journal of Pharmaceutical Investigation
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• 제13권2호
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• pp.73-87
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• 1983

The matrix affects the dissolution of furosemide, which is almost insoluble in the dissolution medium. In order to understand the effect of the matrix on the dissolution of furosemide, lactose, starch, $Avicel\;^{\circledR}pH\;101$, $Avicel\;^{\circledR}pH\;301$, $SiO_2$ and talc were used as the matrix and the solvent deposition method were used. The dissolution characteristics of four dissolution medium were compared to each other using various ratio of drug-to-matrix. The results are as follows: 1) Lactose was shown to be superior and talc was to be inferior to the other matrixes investigated. 2) A maximum dissolution rate and dissolution amount of furosemide were observed in 1 : 10 ratio of the drug-to-matrix. 3) $T_{80%}$ of 1 : 10 ratio of the drug-to-matrix in pH 7.2 was 1 min. from FM-lactose and 30 min. from FM-talc. $T_{50%}$ in pH 4.2 is 2 min. from furosemide-lactose and 150 min. from furosemide-talc. Total amount of furosemide in pH 1.2 at 30 min. were enhanced 13.3 fold in furosemide-lactose and 3.5 fold in furosemide-talc compared to the control. Diuretic action of those furosemide-lactose and furosemide-talc was also evaluated by monitoring changes in urinary excretion of sodium, potassium and urine volume in rat. The accumulated urine volume were enhanced 1.7 fold in furosemide-lactose (1.5) compared to the furosemide.

• 신재생에너지
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• 제4권2호
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• pp.12-20
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• 2008

Calculations for the dissolution behavior of liquid CO2 droplets released in the East Sea and the Clipperton Clarion from a moving ship and a fixed pipeline have been carried out in order to estimate the CO2 dissolution characteristics in the ocean. The results show that the injection of liquid CO2 from a moving ship in a high temperature point is an effective method for dissolution. Also, it is noted that the ultimate plume generated from CO2 bubbles repeatsand shrinking due to the peeling from a fixed pipeline, and the presence of hydrate layer on a liquid CO2 droplet acts as a resistant layer in dissolving liquid CO2.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.597-601
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• 2008

Calculations for the dissolution behavior of liquid $CO_2$ droplets released in the East Sea and the Clipperton Clarion from a moving ship and a fixed pipeline have been carried out in order to estimate the $CO_2$ dissolution characteristics in the ocean. The results show that the injection of liquid $CO_2$ from a moving ship in a high temperature point is an effective method for dissolution. Also, it is noted that the ultimate plume generated from $CO_2$ bubbles repeatsand shrinking due to the peeling from a fixed pipeline, and the presence of hydrate layer on a liquid $CO_2$ droplet acts as a resistant layer in dissolving liquid $CO_2$.

• Journal of Pharmaceutical Investigation
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• 제33권1호
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• pp.61-65
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• 2003

Silybin is the main component of Cardus marianus extracts originated from Silybum marianum and has a hepato-protective effect. It is a water-insoluble compound and poorly absorbed from the gastrointestinal tract, resulting in very low oral bioavailability(BA). Polymeric mixed-micelle precursor formulation was made to enhance the dissolution rate of silybin, showing the results of pH-independent release profile with increased dissolution. Oral BA of different preparations in rats was evaluated, revealing that the new formulation showed increased BA more than 2-fold and 4-fold compared to the marketed product and Cardus marianus extracts itself, respectively.

• Journal of Pharmaceutical Investigation
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• 제17권3호
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• pp.127-133
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• 1987

Dissolution characteristics and urinary excreted amount of commercially available three brands of sulfisoxazole tablets were investigated in order to elucidate the in vitro-in vivo correlations and relative bioavailability in humans. All the tablets tested met the K.P. IV and the USP XXI specifications for tablet weight variation, content uniformity, disintegration and dissolution. The disintegration and dissolution rate constants of sulfisoxazole tablets in pH 2.0 HCl-KCl buffer were reduced more significantly (p<0.05) than those in diluted HCl $(1{\rightarrow}12.5)$ and pH 6.5 phosphate buffer. It seemed to be attributed to the pH dependent solubility of sulfisoxazole. We could see that the relative bioavailability of brand B to sulfisoxazole powder was about 90% and that its value was higher than those of other two brands from the urinary excretion data obtained from eight healthy male volunteers by means of Latin square cross over design. No useful correlation was observed between the in vitro and in vivo studies in this experiment.

• 한국세라믹학회지
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• 제35권4호
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• pp.319-324
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• 1998

Sol-gel derived phosphate water-sioluble glasses containing Cu were prepared. Powder-shape of glasses were added in D.I water used polyethylene bottle. After solution contained glass powder were submerged in water bath on 25$^{\circ}C$ their dissolution behavior/characteristics bactericidal effect and cytotoxicity test were evaluated. The maximum amount of Cu(35 mol%) via sol-gel method was more 5 mol% increased than that with melting process. The stage of total dissolution was more dominant than that of selective leaching dur-ing dissolution due to dissolved amount of glasses increased linearly with time. The ratio of Cu+ to {{{{ {Cu }^{2+ } }} was 3:7 so that the structure of glasses is more predominant 2-dimension chain structure than 3-dimenshion po-lymeric structue. The stage of total dissolution was more dominant than that of selective leaching during dissolution. Bactericidal effect against all bacteria showed that solutions which contained 40 ppm and 100 ppm of Cu killed 80 percentages of bacteria within 2 hours and 100 percentages of those within 12 hours. The results of cytotoxicity test for L929 cells showed no cytotoxicity were observed within 96 hours for dis-solved solution that contains 40 ppm and 100 ppm of Cu.

• Journal of Pharmaceutical Investigation
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• 제26권1호
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• pp.23-28
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• 1996

The dissolution characteristics of DDB were markedly enhanced by preparing solid dispersions of drug with polyethylene glycol 6000. Solid dispersions of various weight fraction were formed by a melting method. And various tablets$(A{\sim}E)$ were prepared from these solid dispersions with excipients (lactose, com starch, Avicel and PVP) by wet granulation method. There were no significant differences in dissolution rates between physical mixture and DDB alone. But dissolution rates of solid dispersions were $1.4{\sim}2.0$ times greater than that of DDB alone and $1.2{\sim}1.8$ times greater than those of a commercial tablet.