• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.154-159
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• 1998

In order to assess the susceptibility of the environmentally assisted cracking(EAC) on SA508 Cl.3 steel in primary water condition, potential step test and slow strain rate test(SSRT) were conducted in a simulated crack tip condition. In this test, anodic dissolution was dominant in the crack tip environments. Proposed simple dissolution model is a modification of Hishida's anodic dissolution model at the plastic zone. One can predict actual crack growth rate with the smooth specimen through this model.

• YAKHAK HOEJI
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• v.30 no.1
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• pp.14-23
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• 1986

This study was conducted to investigate the correlation between the dissolution rates and the bioavailabilities of commercial phenytoin products, and also the correlation between their biovailabilities in rabbits and those in humans. Dissolution test was conducted in pH 9. 0 alkaline borate buffer (0.2M) using basket method with seven phenytoin products commercially available. According to the dissolution rate, the phenytoin products were divided into three groups, such as rapid, intermediate and slow group. Three phenytoin products from each group were selected for the bioavailability test in rabbits and humans. The bioavailability test was carried out in rabbits and normal volunteers using cross over design. Single doses of 20mg/kg and 300mg/man were orally administered to rabbits and normal volunteers respectively. Average $C_{max}$, $t_{max}$ and AUC of three phenytoin products were determined from the serum concentration-time curve in rabbit and human experiments. The relative bioavailability evaluation was conducted using AUC of three phenytoin products. The correlations between the dissolution rate constants and bioavailabilities (AUC) of three phenytoin products in rabbits as well as those in humans were not found. Whereas, there was significant correlation between average AUC of three phenytoin products in humans and those in rabbits (r=0.993, p<0.1). From the results of this experiment, it can be concluded that the bioavailability of phenytoin products in humans may be predicted from the results of the rabbit experiment. Also it is assumed that the prediction of the bioavailability of phenytoin products in humans may be difficult from the only results of in vitro dissolution test.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.323-329
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• 1997

Ipriflavone is non-hormonal antiosteoporotic drug which inhibits bone resorption by reducing recruitment and/or differentiation of osteoclasts, and stimulates proliferation and differentiation of osteoblast, and also enhances calcitonin secretion in the presence of estrogen. Although some kinds of immediately-released preparation of ipriflavone are available in commercial market, in present study, we tried to formulate sustained-release tablet using coating method with hydrophobic and hydrophilic coating materials. In vitro dissolution test was applied to evaluate sustained-release patterns of several test preparations (Test tablet A, B and C) designed using different preparation method or different compositions. From the results of dissolution test, test tablet A which showed suitable dissolution profile was selected as the candidate of new product. Pharmacokinetic evaluation of test drug, ipriflavone sustained-release tablets, was conducted in 6 beagle dogs weighing $11.5{\pm}0.5\;Kg$ compared with $Theobon^{\circledR}$ tablet, immediately-released tablet (Kukjae Pharm. Co.) as reference drug. Two products were randomly administered to 6 beagle dogs, and after 1 week, cross-over study was conducted. From the present study, AUC and $T_{max}$ of test product were significantly different from those of reference product (p<0.05), respectively$(AUC\;:\;3646.28{\pm}472.56\;vs\;3646.28{\pm}472.56\;ng{\cdot}hr/ml,\;T_{max}\;:\;4.33{\pm}1.03\;vs\;1.42{\pm}0.38\;hr)$. But $C_{max}$ was not significantly different between two products (p>0.05) $(\;512.52{\pm}48.18\;vs\;443.97{\pm}140.53\;ng/ml)$. From the results of pharmacokinetic evaluations, it was noted that absorption amount of test product was increased, but absorption rate was delayed and $C_{max}$ of two products were not changed. And it was concluded that redesign of the sustained-release preparation which has a lower content of iprifavone rather than test tablet A must be considered.

• YAKHAK HOEJI
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• v.55 no.4
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• pp.324-331
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• 2011

Although the dissolution test can serve as an effective tool for quality control and predictor of in vivo performance, there are a number of drugs with no established dissolution specifications in Korean Pharmaceutical Codex (KPC). Among those commercially available, Piracetam Tablets and Fenoterol hydrobromide Tablets were selected to develop the dissolution testing method. The dissolution condition was determined based on the "Guidelines on Specifications of Dissolution tests for Oral dosage forms" of Korea Food & Drug Administration (KFDA). The dissolution test for Piracetam Tablets was carried out under sink condition with distilled water as dissolution medium, paddle rotation speed at 50 rpm and medium volume of 900 ml. More than 80% of its label claim was released within 30 min. In case of Fenoterol hydrobromide Tablets, distilled water was also found to be suitable to ensure sink condition. The rotation speed of 50 rpm and 900 ml of dissolution medium were used to evaluate the dissolution profile. The dissolution rate of fenoterol hydrobromide was over 90% in 15 min. The HPLC analysis methods were validated in terms of accuracy, precision, specificity, linearity, quantitation limit and range. The results suggested that the analytical methods used are simple and suitable to measure the dissolution rate of piracetam and fenoterol hydrobromide. Therefore, the analysis methods could be utilized in setting dissolution specifications of Piracetam Tablets and Fenoterol hydrobromide Tablets in the revised version of KPC.

• Journal of Pharmaceutical Investigation
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• v.22 no.2
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• pp.105-113
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• 1992

To improve the solubility and dissolution rate of trimethoprim (TMP), which is slightly soluble drug, its inclusion complexes were prepared and studied in this experiment. Inclusion complexes of TMP with ${\beta}-cyclodextrin$ and ${\beta}-cyclodextrin$ polymer (CDPS) were prepared according to Fenyvesi method. These were compared with TMP and its physical mixture with CDPS. Water, diluted hydrochloric acid and phosphate buffer solution were used as dissolution media. And accelerated stability test was studied at $50,\;70\;and \;80^{\circ}C$. It was found that solubility and dissolution rate of inclusion complexes were increased in water. Especially, the solubility and dissolution rate of TMP was found to be markedly increased by inclusion complexation with CDPS. In stability test, ${\beta}-cyclodextrin$ inclusion complexes were more or less stable than TMP alone. This tendency was not led in CDPS. Consequently, CDPS was useful in increasing dissolution rate and stability of TMP.

• Journal of Pharmaceutical Investigation
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• v.27 no.3
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• pp.213-217
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• 1997

The present sustained-release terfenadine-pseudoephedrine HCl dosage form was the core tablet composed of outer (fast-release) layer containing 60 mg of terfenadine and l0mg of pseudoephedrine HCl, and inner (sustained-release) layer containing 110 mg of pseudoephedrine HCl. The purpose of this study was to investigate the possibility of formulating the terfenadine-pseudoephedrine HCl double-layered tablet which was bioequivalent to the core tablet. Its sustained-release and fast-release layer were formulated with disintegrating agents and polymers, respectively, varying with their kinds and amounts. The comparative dissolution test of double-layered and core tablet was carried out at pH 1.2, 4.0 and 6.8, leading to select composite of double-layered tablet whose dissolution pattern was similar to that of core tablet. It was composed of fast-release layer containing 60mg of terfenadine. 10 mg of pseudoephedrine HCl, sodium bicarbonate, microcrystalline cellulose and sodium starch glycolate, and sustained-release layer containing 110 mg of pseudoephedrine HCl and ethylcellulose/hydroxypropyl methylcellulose) (110/30 mg/tablet).

• Archives of Pharmacal Research
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• v.18 no.5
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• pp.314-319
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• 1995

Antacid granules were prepared by agglomeration and powder method in high speed agitation type granulator. The copmositions of the test antacids were sodium bicarbonate nad magnesium carbonate nad a coating material was powder of polyvinylacetal diethyl-aminocacetate (AEA) and an additive material was talc powder. The dissolution characteristics of base from the antacid granules were investigated to evaluate neutralization capacity of hydrochloric profile of base and neutralization behavior, the following results were obtained : The prepared granules showed a pH-dependent dissolution pattern of a base. The dissolution profile of a base was varied with addition of talc powder as well as coating amount of AEA. The relationship between the ratio of dissolution retarded time for 20% and 10% AEA. The relationship between the ratio of dissolution retarded time for 20% AEA coated granules $\theta_{20}/\theta_{10}$ and the diameter reduction of the granules was explained by the rate process of neutralization of hydrochloric acid.

• Journal of Pharmaceutical Investigation
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• v.17 no.3
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• pp.135-139
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• 1987

This study was attempted to investigate the dissolution rate and the bioavailability of commercially available sulfamethoxazole and trimethoprim (SMX-TM) tablets in rabbits. The dissolution test was conducted in artificial gastric juice by basket method with eight SMX-TM tablets which were chemically equivalent. According to the dissolution rate, SMX-TM tablets were divided into four groups, such as rapid, intermediate, slow and very slow groups for the bioavailability test in rabbits. The results were as follows: 1) The dissolution rate of brand A was most rapid but brand H was most slow in artificial gastric juice. 2) Area under the blood concentration curve was larger in the order of brand A > C > E > H in rabbits. 3) There was a little difference in pharmacokinetic parameters such as biological half life, absorption rate constant and $t_{max}$. 4) The relationship between the dissolution rate and relative bioavailability was significant in brand A, C, E and H. From the results of this experiment, the bioavailability of SMX-TM tablets in rabbits may be predicted from the results of dissolution rate studies.

• Journal of Pharmaceutical Investigation
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• v.19 no.3
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• pp.155-161
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• 1989

Coprecipitates of chlorpropamide (CPA)-sodium deoxycholate (DC-Na) were prepared at various ratios of CPA to the DC-Na. The X-ray diffraction and DSC measurements indicated that CPA in 1:1 and 1:3 w/w CPA-DC-Na coprecipitates did not exist in amorphous form, but the others were amorphous. The dissolution rate of CPA from the CPA-DC-Na coprecipitates increased in distilled water and KP V 2nd disintegration test fluid (pH 6.8), but decreased extremely in KP V 1st disintegration test fluid (pH 1.2). The dissolution rates of CPA-DC-Na coprecipitates were compared with those of CPA alone and CPA-DC-Na physical mixtures. Especially, it was found that the dissolution rate of CPA markedly increased in the case of 1:5 CPA-DC-Na coprecipitate. The concentration of CPA dissolved from CPA-DC-Na coprecipitate reached a plateau within 5-10 min, and thereafter gradually decreased, indicating that CPA released from the coprecipitate was recrystallized.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.335-340
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• 2005

The forward dissolution rate of a borosilicate waste glass was determined as an interlaboratory study(ILS) testing program for the evaluation of precision in the measurement of the dissolution rate or a waste glass using a single-pass flow-through(SPFT) test, whose conducting practice has been written for standardization through American Society for Testing and Materials (ASTM). A simulated low-activity waste glass powder with a size of 100/200 mesh was dissolved by lithium buffer solution (pH=10) at 70? under Ar atmosphere. By plotting the dissolution rates as a function of silicon and boron concentration in eluate, the forward dissolution rate of the glass was obtained as about $2.7\times10^{-5}g{\cdot}m{\cdot}s^{-1}$ in our laboratory.