• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.263-266
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• 2000

The purified biosurfactant $3.16g/{\ell}$ was obtained after cultivation for 104hr at $25^{\circ}C$ with an optimal agitation speed of 200rpm, an aeration rate of 2vvm in a $14{\ell}$ fermenter containing $5.5{\ell}$ of LB medium and 1%(w/v) olive oil as a carbon source. For the kinetic studies, the optimal substrate concentration was analyzed on different olive oil concentrations(0.1, 0.5, 1.0, 1.5, 2.0%(w/v)) and optimal culture conditions(MLBM, 200rpm, 2vvm at $25^{\circ}C$) in a $14{\ell}$ jar fermenter. The results obtained indicate that $K_s$=0.0086 $g/{\ell}$, $q_s$= 0.664 $g/g{\cdot}h$, $q_p$= $4.2{\times}10^{-3}$ $g/g{\cdot}h$, and ${\mu}_{max}$ was determined as $0.1449h^{-1}$.

• Journal of Microbiology and Biotechnology
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• 제3권3호
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• pp.174-180
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• 1993

A strain SMF14 producing an extracellular $\beta$-lactamase was isolated from soil and identified to be a strain of Streptomyces aureofaciens. $\beta$-Lactamase was purified from the cell free culture broth through batchwise hydroxyapatite adsorption, anion exchange chromatography on DEAE Sephadex A-50, gel filtration on Sephadex G-75, and adsorption chromatography on hydroxyapatite. The molecular mass was estimated to be about 43 kDa by SDS-PAGE. The $\beta$-lactamase had substrate specificity to penicillins and it was inhibited by clavulanic acid, being classified to the group 2a of penicillinase.. The optimal reaction pH and temperature were pH 6.0~7.5 and $50^{\circ}C$. The $K_m, and V_{max}$ values of $\beta$-lactamase for penicillin G were calculated to be 1.72 mM and 5.4$\times$$10^5 \mu M \cdot min^{-1}$, respectively.

• Archives of Pharmacal Research
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• 제27권6호
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• pp.676-681
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• 2004

Acetyl-L-camitine (ALC), a naturally occurring endogenous compound, has been shown to improve the cognitive performance of patients with senile dementia Alzheimer＇s type, and to be involved in cholinergic neurotransmission. Because ALC is an endogenous compound, valida-tion of the analytical methods of ALC in the biological fluids is very important and difficult. This study was presented validation and correction for plasma ALC concentrations and pharmacok-inetics after oral administration of ALC to human volunteers. ALC concentrations in human plasma were corrected by subtracting the concentration of blank plasma from each sample. Precision and accuracy (bias %) for uncorrected ALC concentrations were below 2.6 and 6.5% for intra-days, and 4.0 and 9.4% for inter-days, respectively. Precision and accuracy (bias %)for corrected ALC concentrations were below 10.9 and 6.0% for intra-days, and 10.5 and 16.9% for inter-days, respectively. Quantitation limit was $0.1{\;}\mu\textrm{g}／mL$. After oral administration of a 500 mg ALC tablet to 8 healthy volunteers, the principle pharmacokinetic parameters were 4.2 h of the half-life$ (t_{1/2},{\beta})$, the area under the curve $(AUC_{0{\rightarrow}8){\;}of{\;}9.88{\;}\mu\textrm{g}{\cdot}h/mL$, and 3.1 h of the time ($T_{max}$) to reach $C_{max}$. This study first describes the pharmacokinetic study after oral admin-istration of a single dose of ALC in human volunteers.

• Journal of Pharmaceutical Investigation
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• 제22권3호
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• pp.229-235
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• 1992

The bioequivalence of two commercial choline magnesium trisalicylate (CMT) tablets was evaluated in 10 normal male subjects (age 21-27 yr, mean 23 yr) following single oral administrations of two products. Test product was $Trimax^{\circledR}$ tablet (Hyundai Pharm. Ind. Co., Ltd., Korea) and reference product was $Trilisate^{\circledR}$ tablet (Purdue Frederick, U.S.A.). Both products contained 500 mg salicylate. In the study, ten volunteers were administered one tablet of $Trimax^{\circledR}$ or $Trilisate^{\circledR}$ with randomized two period cross-over study. The pharmacokinetic parameters of two products were statistically compared using Student's t-test and ANOVA. When Student's t-test was applied, mean area under the curves (AUC) of $Trilisate^{\circledR}$ and $Trimax^{\circledR}$ were $388.88{\pm}74.99\; {\mu}g{\cdot}hr/ml$ and $390.63{\pm}63.02\;{\mu}g{\cdot}hr/ml$ hrlm!, respectively, which were not significantly different (p>0.05). The mean peak concentrations $(C_{max})$ and mean times to peak $(T_{max})$ of $Trilisate^{\circledR}$ and $Trimax^{\circledR}$ were $71.1{\pm}12.2$ and $72.9{\pm}10.7\;{\mu}g/ml$, and $72{\pm}33$ and $57{\pm}36min$, respectively, which were not significantly different (p>0.05). The mean terminal phase half-lives $(t_{l/2ter})$ of the two products were $2.57{\pm}0.47$ and $2.43{\pm}0.40$ hr, and also they were not significantly different (p>0.05). When ANOVA was applied, the parameters of the two products were not also significantly different each other. Based on the above results, it has been concluded that the bioavailability of $Trimax^{\circledR}$ tablet was not significantly different from that of $Trilisate^{\circledR}$ tablet.

• 한국축산식품학회지
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• 제33권2호
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• pp.155-161
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• 2013

This study developed predictive models to evaluate the kinetic behaviors of Bacillus cereus and Staphylococcus aureus in milk during storage at various temperatures. B. cereus and S. aureus (3 Log CFU/mL) were inoculated into milk and stored at $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, and $30^{\circ}C$, as well as $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$, respectively, while bacterial populations were enumerated. The growth data were fitted to the modified Gompertz model to estimate kinetic parameters, including the maximum specific growth rate (${\mu}_{max}$; Log CFU/[$mL{\cdot}h$]), lag phase duration (LPD; h), lower asymptote ($N_0$; Log CFU/mL), and upper asymptote ($N_{max}$; Log CFU/mL). To describe the kinetic behavior of B. cereus and S. aureus, the parameters were fitted to the square root model as a function of storage temperature. Finally, the developed models were validated with the observed data, and Bias (B) and Accuracy (A) factors were calculated. Cell counts of both bacteria increased with storage time. Primary modeling yielded the following parameters; ${\mu}_{max}$: 0.14-0.75 and 0.06-0.51 Log CFU/mL/h; LPD: 1.78-14.03 and 0.00-1.44 h, $N_0$: 3.10-3.37 and 2.09-3.07 Log CFU/mL, and $N_{max}$: 7.59-8.87 and 8.60-9.32 Log CFU/mL for B. cereus and S. aureus, respectively. Secondary modeling yielded a determination of coefficient ($R^2$) of 0.926.0.996. B factors were 1.20 and 0.94, and A factors were 1.16 and 1.08 for B. cereus and S. aureus, respectively. Thus, the mathematical models developed here should be useful in describing the kinetic behaviors of B. cereus and S. aureus in milk during storage.

• Biomolecules & Therapeutics
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• 제19권4호
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• pp.498-503
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• 2011

The purpose of this study was to investigate the effects of nisoldipine on the pharmacokinetics of repaglinide in rats. The effect of nisoldipine on cytochrome P450 (CYP) 3A4 activity and P-glycoprotein (P-gp) were evaluated. The pharmacokinetic parameters of repaglinide were also determined in rats after oral (0.5 $mg{\cdot}kg^{-1}$) and intravenous (0.2 $mg{\cdot}kg^{-1}$) administration of repaglinide to rats without or with nisoldipine (0.3 and 1.0 $mg{\cdot}kg^{-1}$). Nisoldipine inhibited CYP3A4 enzyme activity with a 50% inhibition concentration of 5.5 ${\mu}M$. In addition, nisoldipine significantly enhanced the cellular accumulation of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp. Compared to the oral control group, nisoldipine significantly increased the $AUC_{0-{\infty}}$ and the $C_{max}$ of repaglinide by 46.9% and 24.9%, respectively. Nisoldipine also increased the absolute bioavailability (A.B.) of repaglinide by 47.0% compared to the oral control group. Moreover, the relative bioavailability (R.B.) of repaglinide was 1.16- to 1.47-fold greater than that of the control group. Nisoldipine enhanced the oral bioavailability of repaglinide, which may be attributable to the inhibition of the CYP3A4-mediated metabolism in the small intestine and/or in the liver and to inhibition of P-gp in the small intestine rather than to reduction of renal elimination of repaglinide by nisoldipine. The increase in the oral bioavailability of repaglinide should be taken into consideration of potential drug interactions when co-administering repaglinide and nisoldipine.

• 한국수산과학회지
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• 제31권5호
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• pp.637-644
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• 1998

우리나라 근해에 많이 분포하고 있는 말똥성게 (sea urchin, Hemicentrotus pulcherrimus)의 내장으로부터 Triton X-100을 이용하여 $\beta$-galactosidase를 추출하고, $40\~80\%$ (w/v) $(NH_4)_2SO_4$, DEAE-Sephadex A-25 및 CM-Cellulose 이온교환 크로마토그래피, Con A-Sepha-rose 4B 친화성 크로마토그래피를 사용하여 분리, 정제하여 그 생화학적 특성을 조사한 결과는 다음과 같다. 정제된 $\beta$-galactosidase는 단일의 단백질로 이루어진 효소로 판명되었고, 효소의 정제도는 조효소에 비해 384.6배 증가하였고, 수율은 $1.26\%$이었다. 정제효소의 최적 pH와 온도는 각각 3.0 및 $50^{\circ}C$ 이었다. 효소의 활성은 $Ba^{2+}$와 같은 금속이온에 의해 촉진되었고, $Hg^{2+},\;Sn^{2+}$ 및 DFP에 의해 현저하게 저하되었으며, 당인 galactose 와 lactose에 의해 저하되어 기질 저해 효과가 나타남을 알 수 있었다. 효소의 분자량은 SDS-PAG 전기이동과 Sephadex G-150 겔여과를 실시한 결과 97 kDa로 나타났다. 합성기질인 PNPG를 사용하여 효소의 속도론적 상수를 측정한 결과 $K_m$은 15.0mM, $V_{max}$는 $\mu$mole/min$\cdot$mg$\cdot$protein으로 나타났다.

• 한국환경과학회지
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• 제19권5호
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• pp.647-653
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• 2010

The objectives of this research are to evaluate and compare the oxygen transfer coefficients($K_{La}$) in both a general bubbles reactor and a micro-nano bubbles reactor for effective operation in sewage treatment plants, and to understand the effect on microbial kinetic parameters of biomass growth for optimal biological treatment in sewage treatment plants when the micro-nano bubbles reactor is applied. Oxygen transfer coefficients($K_{La}$) of tap water and effluent of primary clarifier were determined. The oxygen transfer coefficients of the tap water for the general bubbles reactor and micro-nano bubbles reactor were found to be 0.28 $hr^{-1}$ and 2.50 $hr^{-1}$, respectively. The oxygen transfer coefficients of the effluent of the primary clarifier for the general bubbles reactor and micro-nano bubbles reactor were found be to 0.15 $hr^{-1}$ and 0.91 $hr^{-1}$, respectively. In order to figure out kinetic parameters of biomass growth for the general bubbles reactor and micro-nano bubbles reactor, oxygen uptake rates(OURs) in the saturated effluent of the primary clarifier were measured with the general bubbles reactor and micro-nano bubbles reactor. The OURs of in the saturated effluent of the primary clarifier with the general bubbles reactor and micro-nano bubbles reactor were 0.0294 mg $O_2/L{\cdot}hr$ and 0.0465 mg $O_2/L{\cdot}hr$, respectively. The higher micro-nano bubbles reactor's oxygen transfer coefficient increases the OURs. In addition, the maximum readily biodegradable substrate utilization rates($K_{ms}$) for the general bubbles reactor and micro-nano bubbles reactor were 3.41 mg COD utilized/mg active VSS day and 7.07 mg COD utilized/mg active VSS day, respectively. The maximum specific biomass growth rates for heterotrophic biomass(${\mu}_{max}$) were calculated by both values of yield for heterotrophic biomass($Y_H$) and the maximum readily biodegradable substrate utilization rates($K_{ms}$). The values of ${\mu}_{max}$ for the general bubbles reactor and micro-nano bubbles reactor were 1.62 $day^{-1}$ and 3.36 $day^{-1}$, respectively. The reported results show that the micro-nano bubbles reactor increased air-liquid contact area. This method could remove dissolved organic matters and nutrients efficiently and effectively.

• Journal of Pharmaceutical Investigation
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• 제38권4호
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• pp.235-240
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• 2008

A sensitive and simple method of determining the plasma levofloxacin (LFX, CAS 100986-85-4) concentrations in human volunteers by liquid-liquid extraction were developed and validated by using a high-performance liquid chromatography/diode array detector. The method was also applied to pharmacokinetic study of LFX. LFX was orally administered to 8 healthy male Korean volunteers at single lowest dose of 200 mg, compared to the published reports in which more than 500 mg of LFX was orally administered. LFX in human plasma was determined. The detection limit of LFX was $0.05\;{\mu}g/mL$. $C_{max}$ value was $2.48{\pm}0.67\;{\mu}g/mL$. $AUC_{0{\to}24\;hr$} and $AUC_{0{\to}{\infty}}$ were $14.52{\pm}3.35\;{\mu}g/mL$ and $16.00{\pm}3.66\;{\mu}g{\cdot}hr/mL$, respectively. The terminal half-life was $6.87{\pm}0.46\;hr$. Our pharmacokinetic parameters were very consistent with that previously reported, showing good correlation between LFX doses and AUC ($r^2=0.995$). This method can be useful for the pharmacokinetics and bioequivalence study with relatively low dose for reducing the main side effects of LFX.

• 약학회지
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• 제41권1호
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• pp.60-73
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• 1997

In order to design a 24 hr sustained release preparation of sulindac for oral administration, fast release pellet (FR), slow release pellet (SR) and two combined formulation (1 : 1 and 1 : 2) were prepared. The pharmacokinetic effect of such preparations has been evaluated using rabbits as a suitable in vivo model, and tested in man. Dose determination was carried out using curve fitting according to RSTPJP II program. In bioavailability test using rabbit, AUCs of sulindac in a few designed formulations were similar to each other. $C_{max}$- of RF and SR were 1.8 times and 1.2 times higher, respectively, compared to that of combined formulation (FR:SR=1:1). While plasma concentration of FR and SR decreased rapidly, that of combined formulation (FR:SR 1:1) lasted at the level close to $C_{max}$ for 24 hrs. Plasma concentration of sulfide form from the combined pellet(FR:SR=1:1) lasted for 24 hrs, and its AUC value was 1.4-fold, 2.7-fold. and 1.2-fold greater than FR pellet, SR pellet and combined pellet (FR:SR 1 : 2). Thus, the combined pellet of 1:1 ratio was found to be the most effective for oral sustained release formulation. Bioavailability test in human showed that AUC of sulfide from TSRP (1 : 1) was approximately 1.5 times greater than total AUC of Immbaron$^{\circledR}$ administered twice in a day. While $T_{max}$ of sulfide from lmmbaron$^{\circledR}$ was 4.33 +/- 1.37 hr (lst administration) and 3.33 ${pm}$ 0.82 hr (2nd administration), respectively, that of sulfide from TSRP increased to 7.17 ${pm}$ 2.86 hr. Plasma concentration of sulfide from TSRP was sustained at more, than 1.0 ${\mu}g{\cdot}$hr/ml until 24 hrs after one dose administration. In addition, TSRP may decrease local adverse reaction in the stomach, since plasma concentration of sulfide from the combined pellet was low within 2hrs in the stomach. In conclusion, it is suggested that TSRP formulation may be effective for oral 24 hr sustained release formulation of sulindac dosing 300 ~ 350mg once a day.