• Korean Journal of Clinical Pharmacy
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• v.20 no.2
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• pp.99-106
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• 2010

Drugs mostly represent an efficacy or an adverse effect according to their dosage and/or plasma concentrations. Therefore, to investigate the pharmacokinetic behavior of drugs including herbal medicines is necessary both to maximize the drug action and to minimize the adverse effect. To date, pharmacokinetic studies of herbal medicines have been conducted by some experts in this field on the bases of science and knowledge in Korea. On the other hand, in advanced countries, a typical series of pharmacokinetic studies has been conducted by using a harmonized guidance established. Consequently, an administrative support on these studies has to be needed in Korea as well. This study aimed to establish a draft guidance on pharmacokinetic studies of herbal medicines in non-clinical and clinical studies. Literatures previously published as well as guidances in the US, Europe and Japan were summarized for the present guidance. Effect of herbal medicines was listed on the proteins in charge of drug metabolism and transportation, as well as on the pharmacokinetics of chemical drugs. The present suggestion might be helpful to proceed pharmacokinetic studies of herbal medicines efficiently, and further polish should be needed in terms of an administrative point of view.

• Journal of Ginseng Research
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• v.43 no.3
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• pp.354-360
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• 2019

Ginsenosides, the major active ingredients of ginseng and other plants of the genus Panax, have been used as natural medicines in the East for a long time; in addition, their popularity in the West has increased owing to their various beneficial pharmacological effects. There is therefore a wealth of literature regarding the pharmacological effects of ginsenosides. In contrast, there are few comprehensive studies that investigate their pharmacokinetic behaviors. This is because ginseng contains the complicated mixture of herbal materials as well as thousands of constituents with complex chemical properties, and ginsenosides undergo multiple biotransformation processes after administration. This is a significant issue as pharmacokinetic studies provide crucial data regarding the efficacy and safety of compounds. Moreover, there have been many difficulties in the development of the optimal dosage regimens of ginsenosides and the evaluation of their interactions with other drugs. Therefore, this review details the pharmacokinetic properties and profiles of ginsenosides determined in various animal models administered through different routes of administration. Such information is valuable for designing specialized delivery systems and determining optimal dosing strategies for ginsenosides.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.749-754
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• 2008

To increase the solubility of sibutramine freebase, the solid dispersion was prepared using a fluid-bed granulator. The solid dispersion containing sibutramine freebase was characterized by differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). After filling the sibutramine solid dispersion in the gelatin hard capsule, we performed in vitro dissolution test, the stability test under accelerated conditions and pharmacokinetic study in beagle dogs. The DSC and XRD data showed that sibutramine solid dispersion would be amorphous state. The dissolution rate of sibutramine solid dispersion was significantly increased about 70% than sibutramine freebase. The stability of sibutramine solid dispersion capsules was equivalent or above to commercial product of sibutramine. In beagle dogs, the sibutramine solid dispersion showed equivalent pharmacokinetic behavior with commercial product of sibutramine hydrochloride. In conclusion, the solid dispersion system provided a possible way to overcome the low solubility of sibutramine freebase, and the sibutramine solid dispersion can be a bioequivalent with the commercial product in humans.

• Archives of Pharmacal Research
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• v.26 no.9
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• pp.763-767
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• 2003

The differences in pharmacokinetic behavior and tissue distribution of verapamil and its enantiomers were investigated in rats. In high-performance liquid chromatographic method, an achiral ODS column (150 mm $\times$ 4.6 mm i.d.) with the mobile phase consisting of methanol-water (73:30, v/v) was used for the determination of the concentration for racemic verapamil, and a Chiralcel OJ column (250 mm$\times$4.6 mm i.d.) with the mixture of n-haxane-ethanol-triethylamine (85:15:0.2, v/v/v) as mobile phase was used to determine the concentrations of verapamil enantiomers. A fluorescence detector in the analytical system was set at excitation and emission wavelengths of 275 nm and 315 nm. The differences between enantiomers were apparent in the pharmacokinetics in rats. The area under the concentration-time curve (AUC) of S-(-) verapamil was higher than that of R-(+) verapamil. The half-distribution time ($T_{1/2(\alpha)}$) of S-(-) verapamil which distributing to tissue from blood was shorter than that of R-(+) verapamil, but the elimination half-time ($T_{1/2(\beta)}$) was longer in rat following oral administration of racemic verapamil. At 1.3 h after oral administration of racemic verapamil, however, there were no significant differences between enantiomers for the distributions in major tissues such as heart, cerebrum, cerebellum, liver, spleen and kidney.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.225.1-225.1
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• 2003

Purpose. Paclitaxel has demonstrated significant activity in clinical trials against a wide variety of tumors. The clinical application of Taxol$\^$\ulcorner/, a commercial product of solubilized paclitaxel with co solvents of ethanol and Cremophor, however, has been limited largely by hypersensitivity of the excipient. The aim of this study was to formulate paclitaxel-loaded lipid nanodispersions (Px-LN) for i.v. administration without toxic excipients, and to evaluate in vitro characteristics and in vivo pharmacokinetic behaviors. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.410.2-411
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• 2002

Ketoprofen (KP), a potent analgesic and non-steroidal anti-inflammatory drug, has some disadvantages such as gastro-intestinal irritation. short half-life (1.5-4 hour) in plasma and low solubility in aqueous solution. In order to minimize these disadvantages. we have recently prepared a KP prodrug, KP-polyethylene glycol conjugate (KPEG750, PEG Mw=750), and investigated its pharmacokinetic behavior. anti-inflammatory and analgesic effect. (omitted)

• YAKHAK HOEJI
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• v.30 no.6
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• pp.301-305
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• 1986

Dose-dependent pharmacokinetics of acetaminophen was studied in the rat. Acetaminophen was injected intravenously at doses of 10, 30, 50, 100 and 200mg/kg to the adult male rats. The well-known dose-dependent pharmacokinetic behavior was found even at 30mg/kg dose. It implies that metabolism of acetaminophen in the liver, probably sulfation, is saturated at very low concentration of acetaminophen. Dosage regimen establishment based on this characteristics would be necessary even at usual does level (300-600mg/day/body).

• Journal of Pharmaceutical Investigation
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• v.35 no.6
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• pp.397-402
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• 2005

The purpose of this study was to investigate the effect of probencid on the pharmacokinetics of oral pranoprofen in rats. Pranoprofen (5 mg/kg) was coadministered with 5, 10 or 20 mg/kg of probenecid orally. Coadministration of probenecid significantly altered the pharmacokinetics of pranoprofen at 10 and 20 mg/kg. Compared with the control group, probenecid significantly (p<0.05) increased the absorption rate constant $(K_{a})$, the peak concentrations $(C_{max})$ and accordingly the area under the plasma concentration-time curve (AUC) of pranoprofen at the dose level of 10 mg/kg and 20 mg/kg of probenecid. The relative bioavailability (RB%) of pranoprofen was 1.64- to 1.82- fold increased. Furthermore, 10 and 20 mg/kg probenecid induced the decreased elimination constants $(K_{el})$ and the prolonged half-lives $(t_{1/2})$ of pranoprofen with significance (p<0.05). Coadministration of 10 and 20 mg/kg of probenecid lowered the excreted amounts of pranoprofen in the urine by 21.3-22.5% compared to the control. Overall, probenecid enhanced the bioavailability of pranoprofen and decreased its elimination rate to a greater degree at higher dose. Based on the effect of probenecid on the pharmacokinetic behavior of pranoprofen, the dosage regimen of pranoprofen should be taken into consideration when pranoprofen is administered with probenecid in the clinical setting to the patients especially with peptic ulcer or renal failure.

• Journal of Pharmaceutical Investigation
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• v.39 no.5
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• pp.359-366
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• 2009

In this study, paclitaxel-loaded lipid nanosuspension (PxLN) was prepared and the in vivo profiles after intravenous administration in rats were investigated. We compared the manufacturing processes depending on the temperature: PxLN-H for a hot homogenization process and PxLN-C for solidification of lipid-drug mixtures by liquid nitrogen. Both formulations showed submicron size distribution and the similar drug loading efficiency of about 70%. In vitro release of PxLNs and Taxol$^{(R)}$ performed by a dialysis diffusion method showed similar pattern for PxLN-H and Taxol$^{(R)}$, but the reduced release profile for PxLN-C. PxLN or Taxol$^{(R)}$ was intravenously administered to the rats at a dose of 5 mg/kg as paclitaxel. The drug in blood samples were assayed by the HPLC/MS/MS method. The AUC$_t$ of PxLN-H was 3.4-fold greater than that of Taxol$^{(R)}$. PxLN-H gave higher biodistribution in all tissues than did Taxol$^{(R)}$. In addition, it maintained the higher drug concentration for 12 h. This lipid nanosuspension might be a promising candidate for an alternative formulation for the parenteral delivery of poorly water-soluble paclitaxel.

• Journal of Pharmaceutical Investigation
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• v.27 no.2
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• pp.109-117
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• 1997

In order to elucidate the effect of phenobarbital (PB) on the nonlinear pharmacokinetic behavior of naproxen (NAP), we compared the dose dependent hepatic intrinsic clearance, biliary excretion and protein binding of NAP in control rats to those in the PB-pretreated rats which were intraperitoneally pretreated with PB sodium (75 mg/kg) once a day for four days. NAP was injected via femoral (1.5 mg/kg) and portal(0.25, 0.5, 1.5, 15 and 30 mg/kg) vein to the control and PB-pretreated rats, respectively. And also, we measured the plasma free fraction of NAP with the equilibrium dialysis method and the biliary excreted total amounts of NAP in both rats. Plasma free fraction of NAP was decreased in lower concentration than $150\;{\mu}g/ml$ of NAP due to PB pretreatment. In higher concentration, however, plasma free fraction was increased. These in vitro results suggest that the total protein concentration was increased but the total binding capacity of NAP to protein was decreased by PB-pretreatment. The total plasma clearance and the hepatic intrinsic clearance of NAP had similar values in both groups, respectively. And, both clearances of NAP were significantly increased by PB-pretreatment. Even though the plasma free fractions of NAP in both groups were constantly remained within the concentration range according to the increase of administration dose, the hepatic intrinsic clearances of NAP were significantly increased in both groups with the increased dose. And, the biliary excreted total amounts of NAP were significantly increased by PB-pretreatment at the lower dose, but decreased at the higher dose. These in vivo results suggest that NAP represents the uncommon nonlinear pharmacokinetic behavior that the hepatic intrinsic clearance was enhanced with the increased dose, and that PB enhances further the hepatic intrinsic clearance of NAP with the increased dose due to its enzyme induction effect.