• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.267-275
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• 2002

A self-microemulsifying drug delivery system (SMEDDS) was developed to increase the dissolution rate, solubility, and ultimately bioavailability of a poorly water soluble drug, lovastatin. SMEDDS was thε mixtures of oils, surfactants, and cosurfactants, which emulsify under conditions of gentle agitation, similar to those which would be encountered in the gastro-intestinal (GI) tract. Various types of self-emulsifying formulations were prepared using four types of oil (Capryol 90, Lauroglycol 90, Labrafil M 1944 CS and Labrafil M 2125), two surfactants (Cremophor EL and Tween 80), and three cosurfactants (Carbitol, PEG 400 and propylene glycol). Thε efficiency of emulsification was studied using a laser diffraction size analyzer to determine particle size distributions of the resultant emulsions. Optimized formulations selected for bioavailability assessment were Carpryol 90 (40%), Cremophor EL (30%) and Carbitol (30%). SMEDDS containing lovastatin (20 mg and 5 mg) were compared to a conventional lovastatin tablet $(Mevacor^{\circledR},\;20\;mg/tab)$ by the oral administration as prefilled hard gelatin capsules to fasted beagle dogs for in vivo study. The arεa under the serum concentration-time curve from time zero to the last measured time in serum, $AUC_{0{\rightarrow}24h}$, was significantly greater in SMEDDS, suggesting that bioavailability increase 130% and 192% by the SMEDDS, respectively. The self-emulsifying formulations of lovastatin afforded the improvement in absolute oral bioavailability relative to previous data of lovastatin tablet formulation. These data indicate the utility of dispersed self-emulsifying formulations for the oral delivery of lovastatin and potentially other poorly absorbed drugs.

• Journal of Pharmaceutical Investigation
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• v.29 no.2
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• pp.87-92
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• 1999

Drug delivery to the brain may be achieved by producing chimeric peptide, attaching the drug to protein 'vectors' which are transported into the brain from the blood by a receptor-mediated transcytosis through the blood-brain barrier (BBB). Since the BBB expresses high concentrations of transferrin receptor, and it was reported that anti-transferrin receptor mouse monoclonal antibody (OX26) undergoes transcytosis through the BBB, it is logical to assume that a drug delivery system via transferrin receptor-mediated transcytosis is a promising strategy. In the present study, therefore, we tested feasibility of several OX26 based vectors for the brain delivery of a model drug. Avidin-based delivery vectors such as OX26-streptavidin (OX26-SA), OX26-neutralite avidin (OX26-NLA) were chemically synthesized vectors and OX26 immunoglobulin G 3 type $C_{H}3$ fusion avidin $(OX26\;IgG3C_H3-AV)$ was genetically engineered. To improve the efficiency of producing chimeric peptide, we used avidin-biotin technology. Pharmacokinetics of $[^3H]biotin$ bound to OX26-SA, OX26-NLA and $OX26\;IgG3C_H3-AV$ was determined by intravenous injection technique, and their stabilities in plasma were analyzed using HPLC. The brain delivery of $[^3H]biotin$ bound to OX26-SA, OX26-NLA and OX26\;$IgG3C_{H}3-AV$ (expressed as %ID/g brain) was $0.22{\pm}0.01$, $0.18{\pm}0.01$ and $0.25{\pm}0.09$, respectively. The areas under the plasma concentration versus time curve (AUC) for OX26-SA, OX26-NLA, $OX26\;IgG3C_H3-AV$ from time zero to 60 min were $209{\pm}10$, $195{\pm}9$, $134{\pm}29\;%ID\;min/ml$ respectively and their total clearances $(CL_{tot})$ were $1.00{\pm}0.09$, $1.08{\pm}0.07$ and $1.54{\pm}0.29\;ml/min/kg$, espectively. These results showed that these vectors possess preferable pharmaceutical (e.g., resonable stability) and pharmacokinetics (e.g., significant brain uptake and enhanced AUC) for brain delivery. Therefore, these vectors may be broadly useful in the brain delivery of drugs that are not transported into the brain to a significant extent.

• Journal of Pharmaceutical Investigation
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• v.29 no.2
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• pp.145-149
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• 1999

Bioequivalence of two cefixime capsules, test drug ($Cepirin^R$ capsule: Cheiljedang Corp.) and reference drug ($Suprax^R$ capsule: Dong A Pharm. Com.), was evaluated according to the guidelines of Korea Food and Drug Administration (KFDA). Sixteen healthy volunteers were divided randomly into two groups and administered the drug orally at the dose of 400 mg as cefixime in a $2{\times}2$ crossover study. There was a 1-week washout period between the administrations. Blood samples were taken at predetermined time intervals for 12 hour and the plasma concentration of cefixime was determined with a HPLC method. $AUC_{0-12hr}$ (area under the plasma concentration-time curve form time zero to 12 hour), $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were estimated from the plasma drug concentrationtime data. Analysis of variance (ANOVA) revealed no difference in $AUC_{0-12hr}$, $C_{max}$ and $T_{max}$ between the formulations. The apparent differences of these parameters between the formulations were less than 20% (i.e., 8.62, 11.10 and 0.00% for $AUC_{0-12hr}$, $C_{max}$ and $T_{max}$,respectively). The powers $(1-{\beta})$ for $AUC_{0-12hr}$ $C_{max}$ and $T_{max}$ were over 0.9. Minimal detectable difference $({\Delta})$ at ${\alpha}=0.05$, $1-{\beta}=0.8$ were less than 20% (i.e., 12.84, 11.05 and 17.99% for $AUC_{0-12hr}$, $C_{max}$ and $T_{max}$, respectively). The 90% confidence intervals $({\delta})$ for these parameters were also within ${\pm}20%$ (i.e., $-0.53{\le}{\delta}{\le}17.76$, $3.23{\le}{\delta}{\le}18.97$ and $-12.81{\le}{\delta}{\le}12.81$ for $AUC_{0-12hr}$, $C_{max}$ and $T_{max}$, respectively). These results satisfied the criteria of KFDA guideline for bioequivalence, indicating the two formulations of cefixime were bioequivlent.

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.255-261
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• 2007

A bioequivalence study of $Nimegen^{TM}$ soft capsule (Medica Korea Pharma. Co., Ltd.) to $RoAccutane^{(R)}$ soft capsule (Roche Korea Ind. Co., Ltd.) was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). Thirty healthy male Korean volunteers received each medicine at the isotretinoin dose of 60 mg in a $2{\times}2$ crossover study. There was one week wash-out period between the doses. Plasma concentrations of isotretinoin were monitored by a high performance liquid chromatography (HPLC) for over a period of 48 hours after drug administration. $AUC_t$ (the area under the plasma concentration-time curve from time zero to 48 hr) was calculated by the linear trapezoidal rule method. $C_{MAX}$ (maximum plasma drug concentration) and $T_{MAX}$ (time to reach $C_{MAX}$) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t\;and\;C_{MAX}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{MAX}$ ratio for $Nimegen^{TM}/RoAccutane^{(R)}$ were $log0.860{\sim}log0.98\;and\;log0.85{\sim}log1.00$, respectively. These values were within the acceptable bioequivalence intervals of $log0.80{\sim}log1.25$. Thus, our study demonstrated the bioequivalence of $Nimegen^{TM}\;and\;RoAccutane^{(R)}$ with respect to the rate and extent of absorption.

• Journal of Pharmaceutical Investigation
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• v.39 no.2
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• pp.133-139
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• 2009

The purpose of the present study was to evaluate the bioequivalence of two pioglitazone HCl tablets, $Actos^{TM}$, tablets (Lilly Korea. Ltd., Korea) as a reference drug and $Piros^{TM}$, tablets (Reyon Pharm. Co., Ltd., Korea) as test drug, according to the guideline of Korea Food and Drug Administration (KFDA). Twenty-four healthy male Korean volunteers received one tablet containing pioglitazone HCl 15 mg in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of pioglitazone were monitored for over a period of 36 hr after administration by using a high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The area under the plasma concentration-time curve from time zero to 36 hr ($AUC_{0-36hr}$), maximum plasma drug concentration ($C_{max}$) and time to reach $C_{max}$ ($T_{max}$) were complied from the plasma concentration-time data. Analysis of variance (ANOVA) test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_{0-36hr}$ and $C_{max}$. The 90% confidence intervals of the $AUC_{0-36hr}$ ratio and the $C_{max}$ ratio for $Piros^{TM}$/$Actos^{TM}$. were log 0.8753-log 1.1286 and log 0.8669-log 1.1734, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25, recommended by KFDA. In all of these results, we concluded that the $Piros^{TM}$. tablet was bioequivalent to the $Actos^{TM}$. tablet, based on the rate and extent of absorption.

• Journal of Pharmaceutical Investigation
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• v.39 no.6
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• pp.457-463
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• 2009

The purpose of the present study was to evaluate the bioequivalence of meloxicam capsule, $Mobic^{TM}$ capsule( Boehringer Ingelheim Ltd., Korea) as a reference drug and $Meloxifen^{TM}$ capsule (Kukje Pharma Ind. Co., Ltd., Korea) as a test drug, according to the guidelines of Korea Food and Drug Administration(KFDA). Thirty two healthy male Korean volunteers received capsule containing meloxicam 7.5 mg in a $2{\times}2$ crossover study. There was a one-week above washout period between the doses. Plasma concentrations of meloxicam were monitored for over a period of 72 hr after administration by using a high performance liquid chromatography-tandem mass spectrometer(LC-MS/MS). $AUC_t$(the area under the plasma concentration-time curve from time zero to 72 hr), $C_{max}$(maximum plasma drug concentration) and $T_{max}$(time to reach $C_{max}$) were complied from the plasma concentration-time data. Analysis of variance(ANOVA) test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$ and $C_{max}$. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for $Meloxifen^{TM}/Mobic^{TM}$ were log 0.8605-log 0.9847 and log 0.9765-log 1.1503, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25, recommended by KFDA. In all of these results, we concluded that $Meloxifen^{TM}$ capsule was bioequivalent to $Mobic^{TM}$ capsule, based on the rate and extent of absorption.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.107-116
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• 1983

This paper is concerned with the permeability through a decomposed granite soil layer which is influnced by change of grain sizes and crushed soils made by varied compaction energy. The change in the content of crushed soils can be described in terms of the ratio of surface area ($S_w{^{\prime}}/S_w $). The experiments were carried out to obtain the relationships of the coefficient of permeability(K) versus the optimum moisture content($w_{opt}$) by the variable head permeability test with the samples that were preapared by compaction test. The results are found as follows; (1) By the change in compaction energy, the crush ratio increased whereas the void ratio decreased with a larger maximum dry density running in parallel with the zero air void curve. (2) The ratio of surface area was $0.33(P)^{0.96}$ in $S_w{^{\prime}}/S_w $ with no relation to the compaction energy. (3) The grain size which produced the largest crush of soil particles ranged from 0.5 to 1 millimetre (4) The relationship of K versus $e^3$/1+e appeared as a straight line on the full-log-scale paper under the optimum moisture state. (5) As the compaction energy was larger, the passing percentage of #200-sieve grains increased linearly. The increment in the surface area ratio was deemed to have been caused by the decreased in the permeability.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.5
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• pp.297-305
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• 2006

The thermal ratcheting deformation at the reactor baffle and upper internal structure of the liquid metal reactor (LMR) can occur due to movement of the hot sodium free surface. In in-service inspection of reactor internals of LMR, a new inspection technique should be developed for the detection of the thermal ratcheting damage. In this study, an inspection technique using ultrasonic guided wave is proposed for the detection of the thermal ratcheting damage of cylindrical vessels. A 316L stainless steel cylindrical shell specimen has been prepared. The thermal ratchet structural tests were cyclically performed by heat-up up to $550^{\circ}C$ with steep temperature gradients along the axial direction after cool-down by cooling water. Ultrasonic guided wave propagation has been characterized by analysis of dispersion curve of the stainless steel plate. The zero-order antisymmetric $A_0$ guided wave has been selected as the optimal mode for detection of the ratcheting deformation. It is confirmed that the thermal ratcheting deformation can be detected by the measurement of transit time difference of circumferentially propagated $A_0$ guided waves.

• International Commerce and Information Review
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• v.3 no.2
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• pp.1-16
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• 2001

This study discusses some theoretical implications for efficient utilization of the global E-commerce in a world of uncertainty by beginning with measures of risk and return for the global E-commerce, and by moving to risk and return for a efficient transaction portfolio of many risky methods of transaction. Decision rules are developed to show how individuals choose optimal transaction portfolios that maximize their expected utility of wealth. First, the individuals will generally want to allocate positive amount to the global E-commerce, which requires that the expected marginal utility of wealth equals zero. Secondly, the optimal transaction portfolio will be determined by finding the point of tangency between the efficient trading line and the hightest indifference curve in the mean-variance plane. Thirdly, if the global E-commerce is positively correlated with wealth, it must have an expected return that is higher than the risk-free transaction methods in order to compensate for its risk. Fourthly, on the other hand, if the global E-commerce is negatively correlated with wealth, it will have an expected return that is less than the risk-free transaction methods. Finally, the valuation of global E-commerce depends on the degree of individual's risk aversion and the covariance between the expected return of total wealth and the return of global E-commerce.

• Journal of Pharmaceutical Investigation
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• v.36 no.1
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• pp.59-65
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• 2006

The purpose of this study was to evaluate the bioequivalence of two amlodipine maleate tablets, SKAD tablet (SK Pharma. Co., Ltd., Seoul, Korea, reference drug) and A-PINE tablet (Daewon Pharm. Co., Ltd., Seoul, Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty-four healthy male volunteers, $22.79\;{\pm}\;1.86$ years in age and $70.08\;{\pm}\;8.68$ kg in body weight, were divided into two groups and a randomized $2\;{\time}\;2$ crossover study was employed. After a tablet containing 6.42 mg of amlodipine maleate was orally administrated, blood was taken at predetermined time intervals over a period of 144 hr and concentrations of amlodipine in plasma were monitored using LC-MS/MS. Pharmacokinetic parameters such as $AUC_t$ (the area under the plasma concentration-time curve from time zero to 144 hr), $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were calculated and analysis of variance (ANOVA) test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$ and $C_{max}$, and untransformed $T_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for A-PINE/SKAD were $log\;0.9429{\sim}log \;1.1476$ and $log\;0.9l46{\sim}log\;1.1488$, respectively. Since these values were within the acceptable bioequivalence intervals of $log\;0.80{\sim}log\;1.25$, recommended by KFDA, it was concluded that A-PINE tablet was bioequivalent to SKAD tablet, in terms of both rate and extent of absorption.