• YAKHAK HOEJI
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• v.45 no.6
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• pp.650-655
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• 2001

Carvedilol is a nonselective $\beta$-blocking agent with vasodilating properties that are attributed mainly to its blocking activity at $\alpha$$^{1}$-receptors. Carvedilol is used in the treatment of mild to moderate hypertention and angina pectoris and is often used in combination with other drugs. This study was carried out to evaluate the bioequivalence and pharmacokinetics of two carvedilol 25mg tablet formulations according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty healthy volunteers are enrolled and received a single dose (25mg as carvedilol) of each drug in the fasting state, in a randomized 2-way crossover design. After oral administration, blond samples were collected for a period of 30 hours. Plasma concentrations of carvedilol were determined by a rapid and sensitive HPLC method with spectrofluorometric detection. The major pharmacokinetic parameters such as AU $C_{0-}$30hr/, AU $C_{inf}$ , $C_{max}$, $T_{max}$, $t_{1}$2 / Cl/F and V $_{\beta}$//F were calculated. ANOVA test and t-test were utilized for the statistical analysis of each parameter. The results showed that the differences in AU $C_{0-}$30hr/, $C_{max}$ and $T_{max}$ between two were ~5.66, 1.74 and 0.00%, respectively. Minimum detectable differences ($\Delta$) at $\alpha$=0.05 were less than$\pm$ 20% except $T_{max}$ (8.44, 18.36, and 33.86%, respectively). The 90% confidence intervals of all parameters were within $\pm$20% (-10.60~ -0.72, -9.00~12.49 and -19.81~19.81%, respectively). Therefore, it is concluded that the two formulations are bioequivalent for both the extent and the rate of absorption after single dose administration.ation.ion.ion.ation.ion.n.

• Journal of Veterinary Science
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• v.22 no.5
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• pp.47.1-47.10
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• 2021

Background: Due to multiple similarities in the structure and physiology of human and pig skin, the pig model is extremely useful for biological drug testing after subcutaneous administration. Knowledge of the differences between subcutaneous injection sites could have a significant impact on the absorption phase and pharmacokinetic profiles of biological drugs. Objectives: This study aimed to analyze the impact of administration site on pharmacokinetics and selected biochemical and hematological parameters after a single subcutaneous administration of ustekinumab in pigs. Drug concentrations in blood plasma were analyzed by enzyme-linked immunosorbent assay. Pharmacokinetic analyses were performed based on raw data using Phoenix WinNonlin 8.1 software and ThothPro v 4.1. Methods: The study included 12 healthy, female, large white piglets. Each group received a single dose of ustekinumab given as a 1 mg/kg subcutaneous injection into the internal part of the inguinal fold or the external part of the inguinal fold. Results: The differences in absorption rate between the internal and external parts of the inguinal fold were not significant. However, the time of maximal concentration, clearance, area under the curve calculated between zero and mean residence time and mean residence time between groups were substantially different (p > 0.05). The relative bioavailability after administration of ustekinumab into the external part of the inguinal fold was 40.36% lower than after administration of ustekinumab into the internal part of the inguinal fold. Conclusions: Healthy breeding pigs are a relevant model to study the pharmacokinetic profile of subcutaneously administered ustekinumab.

• Biomolecules & Therapeutics
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• v.23 no.2
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• pp.201-206
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• 2015

Scutellaria baicalensis is one of the most widely used herbal medicines in East Asia. Because baicalein and baicalin are major components of this herb, it is important to understand the effects of these compounds on drug metabolizing enzymes, such as cytochrome P450 (CYP), for evaluating herb-drug interaction. The effects of baicalin and baicalein on activities of ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), benzyloxyresorufin O-debenzylase (BROD), p-nitrophenol hydroxylase and erythromycin N-demethylase were assessed in rat liver microsomes in the present study. In addition, the pharmacokinetics of caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) in baicalin-treated rats were compared with untreated control. As results, EROD, MROD and BROD activities were inhibited by both baicalin and baicalein. However, there were no significant differences in the pharmacokinetic parameters of oral caffeine and its three metabolites between control and baicalin-treated rats. When the plasma concentration of baicalin was determined, the maximum concentration of baicalin was below the estimated $IC_{50}$ values observed in vitro. In conclusion, baicalin had no effects on the pharmacokinetics of caffeine and its metabolites in vivo, following single oral administration in rats.

• Korean Journal of Clinical Pharmacy
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• v.27 no.2
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• pp.63-68
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• 2017

Neonates have large inter-individual variability in pharmacokinetic parameters of many drugs due to developmental differences. The aim of this study was to investigate the factors affecting the pharmacokinetic parameters of drugs, which are commonly used in critically ill neonates. Factors that reflect physiologic maturation such as gestational age, postnatal age, postconceptional age, birth weight, and current body weight were correlated with pharmacokinetic parameters in neonates, especially preterm infants. Comorbidity characteristics affecting pharmacokinetics in critically ill neonates were perinatal asphyxia, hypoxic ischemic encephalopathy, patent ductus arteriosus (PDA), and renal dysfunction. Administration of indomethacin or ibuprofen in neonates with PDA was associated with the reduced clearance of renally excreted drugs such as vancomycin and amikacin. Therapeutic hypothermia and extracoporeal membrane oxygenation were influencing factors on pharmacokinetic parameters in critically ill neonates. Dosing adjustment and careful monitoring according to the factors affecting pharmacokinetic variability is required for safe and effective pharmacotherapy in neonatal intensive care unit.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.691-698
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• 1995

We used rats as the experimental animal for the elucidation of metabolic patterns and pharmacokinetic profiles of SMZ in the rat, by use of the urine and plasma from predetermined intervals, respectively. Information herefrom would give some insight into species differences and sex differences in the metabolism and pharamcokinetics of drugs, at least SMZ in particular. Results would be summarized as follows: 1. There were two hydorxy metabolites(5-hydroxysulfamethazine and 6-hydroxyethylsulfamethazine) and an acetyl derivative($N_4$-acetyl sulfamethazine) in the 24h-collected urine, on confirmation with each standard materials. There were also two unknown metabolites therein. 2. In the viewpoint of quantitative aspect, $N_4$-acetylsulfamethazine was the largest, hence it is assumed that the acetyl pathway is the major one in the metabolism of SMZ in the rat. 3. As regards sex difference in the rat, the male had more metabolic capacity than the female in metabolism of SMZ. 4. The concenteration-time curves of sulfamethazine(20mg/kg, po) in the plasma compartment were fitted to a one-compartment open model by use of a computer program(NONLIN). 5. There were significant differences(P<0.05) in the pharmacokinetics of sulfamethazine between two sexes in the rat, with higher disposition rate in the male. 6. The emergence of $N_4AcSMZ$ metabolized from SMZ was fast in the plasma of the rat. Half-life of $N_4AcSMZ$ was also. significantly different(P<0.05) between two sexes, suggesting differences in the eliminatory capacity of $N_4AcSMZ$.

• Korean Journal of Clinical Pharmacy
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• v.22 no.1
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• pp.21-29
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• 2012

Modern biologics are biotechnology-derived therapeutics, including recombinant therapeutic proteins like monoclonal antibodies, cytokines and tissue growth factors. Although the pharmacokinetics of therapeutic biologics should be evaluated based on the same general principles as small molecules, careful considerations should be given to bioanalytics and pharmacokinetics when designing pharmacokinetic studies of biologics during their drug development, due to their different physicochemical properties compared with small molecules. The aim of this study was to develop a draft guidance on pharmacokinetic studies of therapeutic biologics in clinical studies. All the elements outlined in the current Food and Drug Administration (FDA), European Medicinal Agency (EMEA), and International Conference on Harmonisation (ICH) guidelines and regulations, and the related literatures previously published were searched and evaluated. In this draft guidance, the specific problems related to the pharmacokinetics of therapeutic biologics that need special consideration during drug development process were addressed, and differences in pharmacokinetic characteristics between biologics and small molecules affecting the content of the development programme were presented.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.24-28
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• 1997

In the present study, a pharmacokinetic model to address the effects of the diffusional barrier between splanchnic bed and enterocytes on the extent of presystemic and systemic intestinal elimination of drugs was developed. The model is composed of five compartments, ie., gut lumen, enterocyte, splanchnic bed, liver and central compartments. The equations for various pharmacokinetic parameters important for estimating the quantitative differences between presystemic and systemic intestinal and hepatic elimination of drugs were derived. A simulation study demonstrated that the diffusions[ barrier present between splanchnic blood and enterocytes can have significant effects on oral bioavailability and systemic clearance of drugs. In conclusion, the model can be useful for a better understanding of the effects of diffusional barrier on the extent of administration-route dependent intestinal and hepatic elimination of drugs, especially those with high hydrophilicity and/or charge(s) under physiological conditions.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.310.2-311
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• 2003

The effects of differences in the rate and composition of intravenous fluid replacement for urine loss on the pharmacokinetics and pharmacodynamics of torasemide were evaluated using rabbits as the animal model. Each rabbit received 2-h constant intravenous infusion of 1 mg/kg ∼ 1 of torasemide with 0％ replacement (treatment I, n = 6), 50％ replacement (treatment II, n = 9), and 100％ replacement with lactated Ringer's solution (treatment III, n = 8) as well as with 100％ replacement with 5％ dextrose in water(D-5-W, treatment IV, n=6). (omitted)

• Korean Journal of Clinical Pharmacy
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• v.21 no.2
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• pp.74-80
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• 2011

Population pharmacokinetics for gentamicin were compared with 20 Korean patients (14 male and 6 female) and 25 Caucasian appendicitis patients (16 male and 9 female). Two to six blood specimens were collected from all patients at the following times : just before a regularly scheduled infusion and at 0.5 hour after the end of a 0.5 hour infusion. Nonparametric expected maximum(NPEM) algorithm for population modeling was used. The estimated parameters were the elimination rate constant(K), the slope(KS) of the relationship between K versus creatinine clearance(Ccr), the apparent volume of distribution (V), the slope(VS) of the relationship between V versus weight, gentamicin clearance(CL) and the slope(CS) of the relationship between CL versus Ccr and the V. The output includes two marginal probability density function(PDF), means, medians, modes, variance, skewness, kurtosis, and CV%. The mean K(KS) were$0.402{\pm}0.129hr^{-1}$ ($0.00486{\pm}0.00197[hr{\cdot}mL/min/1.73m^2]^{-1}$) and $0.425{\pm}0.137hr^{-1}$($0.00432{\pm}0.00168[hr{\cdot}mL/min/1.73m^2]^{-1}$) for Korean and Caucasian populations, respectively. The mean V(VS) were not different at $14.3{\pm}3.69L$($0.241{\pm}0.0511L/kg$) and $15.8{\pm}4.81L$($0.236{\pm}0.0531L/kg$) for Korean and Caucasian populations, respectively (P>0.2). The mean CL(CS) were $5.68{\pm}1.69L/hr$ ($0.0714{\pm}0.0222L/kg[hr{\cdot}mL/min/1.73m^2]$) and $6.29{\pm}1.84L/hr$ ($0.0629{\pm}0.0189L/kg[hr{\cdot}mL/min/1.73m^2]$) for Korean and Caucasian populations, respectively. There are no differences in gentamicin pharmacokinetics between Korean and Caucasian appendicitis patients.

• YAKHAK HOEJI
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• v.39 no.2
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• pp.103-112
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• 1995

Population pharmacokinetics for gentamicin were compared with 24 American patients (16 male and 8 female) and 16 Korean-American appendicitis patients(12 male and 4 female). Two to six blood specimens were collected from all patients at the following times: just before a regularly scheduled infusion and at 1/2 hour after the end of a 1/2 hour infusion. Nonparametric expected maximum(NPEM) algorithm for population modeling was used. The estimated parameters were the elimination rate constant(K), the slope of the relationship between K versus creatinine clearance(KS), the apparent volume of distribution(V), the slope of the relationship between V versus weight(VS), gentamicin clearance(CL) and the slope of the relationship between CL versus creatinine clearance and the VS(CS). The output includes a 3-dimensional plot of the joint probability density function(PDF), two marginal PDF, means, medians, modes, variance, skewness, kurtosis, and CV%. The mean K(KS) were 0.424$\pm$0.139(0.00429$\pm$0.00164) and 0.411$\pm$0.135 hr$^{-1}$ (0.00475$\pm$0.00180[hr.mL/min/1.73m$^{2}]^{-1}$) for American and Korean-American populations, respectively. The mean V(VS) were not different at 15.6$\pm$4.77(0.233$\pm$0.0526) and 15.1$\pm$3.84L(0.239$\pm$0.0492 L/kg) for American and Korean-American populations, respectively (P>0.2). The mean CL (CS) were 6.28$\pm$1.85(0.0634$\pm$0.0191) and 5.70$\pm$1.77 L/hr(0.0701$\pm$0.0215 L/kg[hr.mL/min/1.73m$^{2}$)] for American and Korean-American populations, respectively. There are no differences in gentamicin pharmacokinetics between American and Korean-American Appendicitis patients.