• 한국물환경학회지
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• 제24권5호
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• pp.603-610
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• 2008

A mathematical model was developed to understand how the presence of plants affects vertical profiles of electron acceptors, their reduced species, and trace metals in the wetland sediments. The model accounted for biodegradation of organic matter utilizing sequential electron acceptors and subsequent chemical reactions using stoichiometric relationship. These biogeochemical reactions were affected by the combined effects of oxygen release and evapotranspiration driven by wetland plants. The measured data showed that $SO_4{^{2-}}$ concentrations increased at the beginning of the growing season and then gradually decreased. Based on the measured data, it was hypothesized that the limitation of the solid phase sulfide in direct contact with the roots may result in the gradual decrease of $SO_4{^{2-}}$ concentrations. With the dynamic formulation for the limitation of the solid phase sulfide, model simulated time variable sulfate profiles using published model parameters. Oxygen release from roots produced divalent metal species (i.e. $Cd^{2+}$) as well as oxidized sulfur species (i.e. $SO_4{^{2-}}$) in the sediment pore water. Evapotranspiration-induced advection increased flux of divalent metal species from the overlying water column into the rhizosphere. The increased divalent metal species were converted to the metal sulfide with sufficient FeS around the rhizosphere, which contributed to the decrease of bioavailability and toxicity of divalent metal activity in the pore water. Since the divalent metal activity is a good predictor of the metal bioavailability, this model with a proper simulation of solid phase sulfide plays an essential role to predict the dynamics of trace metals in the wetland sediments.

• The Korean Journal of Physiology and Pharmacology
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• 제17권3호
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• pp.245-251
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• 2013

The purpose of this study was to investigate the effects of fluvastatin on the pharmacokinetics of repaglinide in rats. The effect of fluvastatin on P-glycoprotein and CYP3A4 activity was evaluated. The pharmacokinetic parameters and blood glucose concentrations were also determined after oral and intravenous administration of repaglinide to rats in the presence and absence of fluvastatin. Fluvastatin inhibited CYP3A4 activity in a concentration-dependent manner with a 50% inhibition concentration($IC_{50}$) of 4.1 ${\mu}M$ and P-gp activity. Compared to the oral control group, fluvastatin significantly increased the AUC and the peak plasma level of repaglinide by 45.9% and 22.7%, respectively. Fluvastatin significantly decreased the total body clearance (TBC) of repaglinide compared to the control. Fluvastatin also significantly increased the absolute bioavailability (BA) of repaglinide by 46.1% compared to the control group. Moreover, the relative BA of repaglinide was 1.14- to 1.46-fold greater than that of the control. Compared to the i.v. control, fluvastatin significantly increased the $AUC_{0-{\infty}}$ of i.v. administered repaglinide. The blood glucose concentrations showed significant differences compared to the oral controls. Fluvastatin enhanced the oral BA of repaglinide, which may be mainly attributable to the inhibition of the CYP3A4-mediated metabolism of repaglinide in the small intestine and/or liver, to the inhibition of the P-gp efflux transporter in the small intestine and/or to the reduction of TBC of repaglinide by fluvastatin. The study has raised the awareness of potential interactions during concomitant use of repaglinide with fluvastatin. Therefore, the concurrent use of repaglinide and fluvastatin may require close monitoring for potential drug interactions.

• Archives of Pharmacal Research
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• 제28권8호
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• pp.970-976
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• 2005

The purpose of this study was to investigate the effect of morin, a flavonoid, on the pharmacokinetics of diltiazem and one of its metabolites, desacetyldiltiazem in rats. Pharmacokinetic parameters of diltiazem and desacetyldiltiazem were determined after oral administration of diltiazem (15 mg/kg) in rats pretreated with morin (1.5, 7.5, and 15 mg/kg). Compared with the control group (given diltiazem alone), pretreatment of morin significantly increased the absorption rate constant $(K_a)$ and peak concentration $(C_{max})$ of diltiazem (p<0.05, p<0.01). Area under the plasma concentration-time curve (AUC) of diltiazem in rats pretreated with morin were significantly higher than that in the control group (p<0.05, p<0.01), hence the absolute bioavailability $(AB\%)$ of diltiazem was significantly higher than that of the control group (p<0.05, p<0.01). Relative bioavailability $(RB\%)$ of diltiazem in rats pretreated with morin was increased by 1.36- to 2.03-fold. The terminal half-life $(t_{1/2})$ and time to reach the peak concentration $(T_{max})$ of diltiazem were not altered significantly with morin pretreatment. AUC of desacetyldiltiazem was increased significantly (p<0.05) in rats pretreated with morin at doses of 7.5 and 15 mg/kg, but metabolite-parent ratio (MR) of desacetyldiltiazem was decreased significantly (p<0.05), implying that pretreatment of morin could be effective to inhibit the CYP 3A4-mediated metabolism of diltiazem. There were no apparent changes of $T_{max}$ and $t_{1/2}$ of desacetyldiltiazem with morin pretreatment. Collectively, the pretreatment of morin significantly altered pharmacokinetics of diltiazem, which can be attributed to increased intestinal absorption as well as reduced first-pass metabolism. Based on these results, dose modification should be taken into consideration when diltiazem is used concomitantly with morin or morin-containing dietary supplements in clinical setting.

• 대한가정학회지
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• 제38권12호
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• pp.59-71
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• 2000

The purpose of this study was to assess the iron nutritional status and dietary iron availability of postmenopausal women residing in Jeonju area. The anthropometric parameters, nutrient intake and biochemical status of iron were measured from 57 postmenopausal women aged 50∼74 years old. Mean values of hemoglobin(Hb), hematocrit(Hct), serum iron(Fe), total iron binding capacity(TIBC) and serum ferritin(Ferritin) concentration were 12.82${\pm}$1.03g/dl, 37.68${\pm}$2.99%, 92.60${\pm}$46.66ug/dl, 353.0${\pm}$54.48ug/dl, 86.86${\pm}$100.7ug/ιrespectively. Prevalence of iron deficiency greatly varied by indices from 14.04% when judged by Ferritin(<20ug/ι) to 40.4% by TIBC(>360${\mu}$g/dl. The anemic subjects assessed with Hct percent(36%) represented 22.8%, whereas 21.1% of the subjects possessed less than 12g/dl of Hb. Ferritin concentration showed a significantly negative correlation with TIBC(r=-0.343, p<0.01) and a positive correlation with MCHC(r=0.361, p<0.01). The mean daily intake of iron was 10.62mg and intake of heme iron was 5.3%(0.56mg) of total iron intake. Total absorbable iron caculated by the method of Monsen was 0.49mg anti bioavailability of dietary iron was 4.61%. Ferritin Concentration was positively associated with total iron intake(r=0.264, p<0.05), dietary nonheme iron(r=0.286, p<0.05) and iron of animal food (r=0.364, p<0.01). But Ferritin concentration was not correlated dietary heme iron(r=-0.137, p>0.05). Major food groups of iron intake were vegetables(20.15%), cereals(19.59%) and fishes(12.34%) in postmenopausal women. Intake of eggs was positively associated with Ferritin(r=0.473, p<0.01).

• 약학회지
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• 제39권4호
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• pp.401-410
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• 1995

Pharmacolinetic profiles of omeprazole enteric coated granules including Ramezole$^\circledR$, Losec$^\circledR$, omeprazole-Na and omeprazole-resin salt were studied using the crossover design in rats and rabbits. The absorption variance of the preparations at the altered pH condition of the gastrointestinal tract was also studied. After oral administration of four omeprazole enteric coated pellets (10mg/kg) with and without concomitant administration NaHCO$_{3}$ (5 mg/ml, 60 mM) in the rats, the differences of absorplion rate and extent were evaluated. In the NaHCO$_{3}$, administration group, the T$_{max}$ appeared to be 2~10 times shorter than water administration group, and the $C_{max}$ also increased to about 4 times, and the AUC increased to about 2.5 times. Pharmacokinetic parameters of four omeprazole enteric coated pellets in rats showed no statistical significance (ANOVA, P>0.05) in both groups. In the crossover study, the second dosed drug showed 4~5 times increased bioavailability than first dosed drug, which shows the strong carry-over effect of acid secretion of the first dosed drug. The differences of the pharmacokinetic parameters of the two test formulations (Losec$^\circledR$ and omeprazole-resin) showed no statistical significance.

• Archives of Pharmacal Research
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• 제18권4호
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• pp.237-242
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• 1995

For the vioequivalence study of two ceftriaxone injection formulations ($Rocephin{\circledR}$ ; Roche, and Triaxone ; Hanmi0, the HPLC analytical method for the analysis of ceftriaxone in plasma was used. Fourteen healthy volunteers completed the study and each subject were IM in jected signle doses (1 g) of the test and the reference formulations in a two-way crossover design with an one week drug free interval between doses. Following each administration, plasma concentrations of ceftrixone were monitored over a period of 24 h. Bioequivalence parameters $AUC_{24th}, {\;}T_{max}, {\;}C_{max}$ and MRT determined from the data obtained for the two formulations were examined by analyses of variance (ANOVA) and other criteria and tests for bioequivalence. Results of ANOVA and confidence limits of test/reference ratios of $AUC_{24th}, {\;}T_{max}, {\;}C_{max}$ and MRT, and statistical tests indicated the bioequivalence of the two formulations (i.e., test/reference ratio was within $100{\pm}20%$) except for $T_{max}$ The mean of $T_{max}$ showed only 6. 9% difference from the reference but the detection limit was 22.5% which is slightly over the 20% criteria. No pharmacokinetic parameters including Ka, Kel, Vd and Cl indicated significant difference in between the two fomulations. It was concluded that the data yielded fro the two cefriaxone formulations demonstrated that they were bioequivalent.

• Toxicological Research
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• 제35권1호
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• pp.65-74
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• 2019

Tetrahydrocurcumin (THC) is a major metabolite of curcumin, which is obtained from Curcuma longa. THC has various benefits and overcomes the bioavailability issue of curcumin. To establish it as a pharmacologically active molecule, its safety profile has to be determined. Thus, the present study aimed to determine the preclinical safety profile of THC in a 90-day subchronic and reproductive/developmental toxicity study in Wistar rats. THC at oral doses of 100, 200, and 400 mg/kg was administered daily for 90 days. Rats in the recovery group were kept for 14 days after treatment termination. The animals were observed for treatment-related morbidity, mortality, and changes in clinical signs, clinical pathology, and histopathology. In the reproductive/developmental toxicity study, THC at 100, 200, and 400 mg/kg was administered orally to rats and the reproductive/developmental parameters in adult male and female rats and pups were observed. THC at up to 400 mg/kg/day of did not have any significant effect on all parameters in male and female rats in both toxicity studies. Thus, 400 mg/kg/day can be considered as the no-observed-adverse-effect-level of THC in rats.

• 대한예방한의학회지
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• 제19권1호
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• pp.145-159
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• 2015

Objective : In the previous study, co-administration of Gongjindan-gamibang (GJD) with sorafenib increased oral bioavailability of sorafenib through augment the absorption, therefore, the effects of GJD co-administration on the pharmacokinetics of sorafenib were observed after single and 7-day repeated oral co-administration with 3.5 hr-intervals in the present study. Method : After 50 mg/kg of sorafenib treatment, GJD 100 mg/kg was administered with 3.5 hr-intervals. The plasma were collected at 30 min before administration, 30 min, 1, 2, 3, 4, 6, 8 and 24 hrs after end of first and last 7th sorafenib treatment, and plasma concentrations of sorafenib were analyzed using LC-MS/MS methods. PK parameters of sorafenib ($T_{max}$, $C_{max}$, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with sorafenib single administered rats. Results : GJD markedly inhibited the absorption of sorafenib, from 1 hr to 24 hrs after end of first 3.5 hr-interval co-administration, the $C_{max}$ (-43.27%), $AUC_{0-t}$ (-56.29%) and $AUC_{0-inf}$ (-66.70%) of sorafenib in co-administered rats were dramatically decreased as compared with sorafenib single treated rats. However, GJD significantly increased the absorption of sorafenib, from 4 hr to 8 hrs after end of last 7th 3.5 hr-interval co-administration, the $AUC_{0-t}$ (34.08%) and $AUC_{0-inf}$ (37.31%) of sorafenib in co-administered rats were dramatically increased as compared with sorafenib single treated rats. Conclusion : Although GJD decreased the oral bioavailability of sorafenib through inhibition of gastrointestinal absorptions after end of first 3.5 hr-interval co-administration, it is observed that GJD increases the oral bioavailability of sorafenib as facilitated the absorption after end of last 7th repeated co-administration. Hence, the co-administration of GJD and sorafenib should be avoided in the combination therapy of sorafenib with GJD on anticancer therapy.

• Journal of Pharmaceutical Investigation
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• 제35권2호
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• pp.117-122
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• 2005

After establishing improved HPLC analytical method of cefaclor in human plasma samples, a bioavailability study of cefaclor capsules was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). The standard calibration curve using an HPLC with UV detector was constructed in a range of $0.0324{\sim}16\;{\mu}g/ml$. The 6% perchloric acid instead of 6% trichloroacetic acid was used to precipitate plasma protein. The HPLC chromatograms were precisely and accurately resolved when spiked with human plasma spiked with cefaclor and cephalexin (internal standard). Twenty healthy male Korean volunteers received two commercial cefaclor capsules, $Neocef^{\circledR}$ capsule (Jinyang Pharm. Co., Ltd) or $Ceclor^{\circledR}$ capsule (Lilly Korea. Co., Ltd.) at the 250 mg cefaclor in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of cefaclor were monitored for 8 hours after oral drug administration. $AUC_t$ the area under the plasma concentration-time curve from time zero to 8 hr (13 points), 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 cross-over design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for $Neocef^{\circledR}/Ceclor^{\circledR}$ were $0.9049{\leq}{\delta}{\leq}1.226$, respectively. These values were within the acceptable bioequivalence intervals of 0.80-1.25. Thus, our study demonstrated the bioequivalence of $Neocef^{\circledR}/Ceclor^{\circledR}$ with respect to the extent of absorption.

• 대한수의학회지
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• 제46권1호
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• pp.7-12
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• 2006

We have studied pharmacokinetics of a new anti-human immunodeficiency virus (HIV) agent VP-0501 and its amino acid prodrug VP-0501AL which is designed to improve oral bioavailability. After oral administration at 100 mg/kg dose in rats (n = 4), VP-0501 was not detectable in plasma (<50 ng/ml), while after the administration of VP-0501AL, VP-0501 was quantitatively detected, at least for 8 hrs, with Cmax of ca. $2.5{\mu}g/ml$ and AUC of $8hr^{\ast}{\mu}g/ml$. When VP-0501 was intravenously administered at 50mg/kg, this compound appeared at a marginal level in plasma with AUC of $2hr^{\ast}{\mu}g/ml$, $t_{1/2}$ of 2 hr, $C_0$ of $0.7{\mu}g/ml$, and MRT of 3 hr. On the other hand, with intravenous VP-0501AL at the same dose, both the prodrug VP-0501AL and its metabolite VP-0501 appeared comparatively at higher level in the plasma: pharmacokinetic parameters of VP-0501AL including $Vd_{\beta}$, AUC, $t_{1/2,{\beta}}$, $C_0$, $CL_{tot}$, and MRT were ca. 2 L/kg, $70hr^{\ast}{\mu}g/ml$, 2 hr, $180{\mu}g/ml$, 0.7 L/hr/kg, and 1 hr, respectively. These results demonstrate that attachment of amino acid alanine to VP-0501 is an effective approach for improvement of its oral bioavailability. Therefore, VP-0501AL is expected to become a new highly bioavailable and potent anti-AIDS drug candidate/lead compound.