• Korean Journal of Clinical Pharmacy
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• v.21 no.4
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• pp.339-346
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• 2011

Over the past few decades, drug regulatory agencies in advanced countries have been emphasizing pharmacometrics as a tool for an effective and efficient drug evaluation. Despite this international movement, the value of pharmacometrics is still poorly recognized by the Korean drug evaluation system. This study aimed to analyze the current state of utilization of pharmacometrics by foreign drug regulatory agencies and develop a road map to guide the implementation pharmacometrics into the Korean drug evaluation system. MEDLINE and foreign drug regulatory agency database were extensively searched to obtain scientific research articles, guidance, regulations and pharmacometric review reports on foreign pharmacometric drug evaluation system. A systematic roadmap comprised of 3 stages to implement pharmacometrics in Korean drug evaluation system was formulated after analyzing the collected data in tune with the current evaluation system. Pharmacometrics is an urgently required tool to achieve an efficient drug evaluation and review in Korea. The road map developed by this study is expected to aid in setting up a policy to implement and utilize pharmacometrics in Korea.

• Journal of Pharmaceutical Investigation
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• v.34 no.2
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• pp.107-114
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• 2004

External lyogels containing prostaglandin $E_1$ ethyl ester $(PGE_1-EE)$, a prodrug of prostaglandin $E_1\;(PGE_1)$ as a therapeutic agent for erectile dysfunction, were formulated to overcome the aqueous instability and enhance the percutaneous absorption. Lyogels of $PGE_1-EE$ were prepared with ethanol (EtOH)/proplyene glycol (PG) cosolvent system as a vehicle, cineol as an enhancer, and hydroxypropylcellusose as a gelling agent. In vitro percutaneous absorption studies were performed to determine the rate of $PGE_1$ absorption through rat or hairless mouse skin. The permeability of $PGE_1-EE$ lyogel with enhancer was 16-fold greater than that of lyogel without enhancer. Cosolvent produced 9-fold increase in percutaneous absorption. Pharmacodynamic effects of lyogels were evaluated in mature male cats in terms of intracavernosal pressure (ICP). Lyogels containing 0.1 % of $PGE_1-EE$ showed higher ICP compared to intraurethral preparation of $PGE_1$ (1 %) and enhancer-free control lyogel. The shelf-life $(t_{10%})$ of lyogel at refrigerated condition $(4^{\circ}C)$ was calculated as 928 days, which is 4.2 times longer than that of control hydrogel. As a result, $PGE_1-EE$ was formulated successfully to a lyogel system with a selective enhancer and cosolvent system for the topical delivery of $PGE_1$.

• Journal of Pharmaceutical Investigation
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• v.37 no.6
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• pp.369-376
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• 2007

Cyclosporine (CsA) and tacrolimus (FK506) have a narrow therapeutic range, and their pharmacokinetic (PK) characteristic varies among individual. They are also substrates for cytochrome P450 (CYP) 3A4, 3A5 genes, and P-glycoprotein, the product of the multidrug resistance 1 (MDR1). The aims were to investigate the relationship between CYP3A and MDR1 genotypes and their PK parameters among healthy subjects. We investigated the genotype for CYP3A and MDR1 gene in human using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. After oral administration of CsA and FK506 (100 mg and 1 mg, respectively), whole blood samples were taken up to 24 hours. Blood CsA and FK506 concentrations were measured by LC/MS/MS. Each PK parameters were compared using Kruskal-Wallis test according to the CYP3A and MDR1 genotype. We found that the values of AVC for CsA were significantly different among CYP3A5 and MDR1 exon 26 (C3435T) genotypes (P=0.037 and P=0.049). On the other hand, the AUC for FK506 was significantly different only among CYP3A5 genotypes (P=0.013). The results clearly demonstrate the effects of CYP3A5 and MDR1 exon 26 on Cys and FK506 disposition.

• YAKHAK HOEJI
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• v.50 no.6
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• pp.386-392
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• 2006

Pramlintide, a synthetic analogue of human hormone amylin, is the first of a new class of amylinomimetic compounds. Present study was undertaken to compile and analyze the clinical trials of pramlintide, and thereby to facilitate the design of the bridging study for the earlier introduction of the drug, which might be needed by diabetes patients in Korea. Sixty-two articles from Pubmed and MEDLINE search were used to analyze the trials of pramlintide along with prescribing information and New Drug Application packet obtained form the manufacturer. The efficacy of the new drug was attributed to three mechanisms: delay of gastric emptying time, inhibition of post-prandial glucagon secretion, and reduction of food intake by enhanced satiety. Clinical trials consistently identified the effectiveness of the drug for the treatment of type 1and type 2 diabetes who have failed to achieve glycemic control despite optimal therapy with insulin. However, the six pivotal Phase III clinical trials were peformed with mostly caucasian and some black and hispanic people. None of the trials documented the proportion of either Asian or Korean participants. Since Korean diabetes patients show different epidemiology and characteristics in their disease state, it appears that the bridging study of pramlintide should be designed in the level of full scale Phase III clinical trial along with pharmacokinetic and pbarmacodynamic studies.

• Analytical Science and Technology
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• v.34 no.2
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• pp.37-45
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• 2021

A rapid and simple LC-MS/MS analytical method in determining Jaspine B has been developed and validated in rat plasma. The standard curve value was 25 - 5000 ng/mL and the linearity, inter-day and intra-day accuracy and precision were within 15.0 % of relative standard deviation (RSD). The mean recoveries of Jaspine B ranged from 87.5 % to 91.2 % with less than 3.70 % RSD and the matrix effects ranged from 91.1 % to 108.2 % with less than 2.6 % RSD. The validated LC-MS/MS analytical method of Jaspine B was successfully applied to investigate the dose-escalated pharmacokinetic study of Jaspine B in rats following an intravenous injection of Jaspine B at a dose range of 1 - 10 mg/kg. The initial plasma concentrations and area under plasma concentration curves showed a good correlation with intravenous Jaspine B dose, indicating the dose independent pharmacokinetics of Jaspine B in rats. In conclusion, this analytical method for Jaspine B can be easily applied in the bioanalysis and pharmacokinetic studies of Jaspine B, including its administration at multiple therapeutic doses, or for making pharmacokinetic comparisons for the oral formulations of Jaspine B in small experimental animals as well as in vivo pharmacokinetic-pharmacodynamic correlation studies.

• Journal of Veterinary Clinics
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• v.36 no.3
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• pp.159-165
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• 2019

Pimobendan is an inodilator used to treat canine heart failure, and pentoxifylline is reported to be beneficial for microcirculation and heart disease. The purpose of this study was to evaluate the pharmacokinetic and pharmacodynamic profiles of a novel pimobendan-pentoxifylline liquid mixture after oral administration to dogs. Eight healthy Beagle dogs were included in the study. The dogs were divided into the control group (orally administered water; n = 4) and experimental group (orally administered pimobendan-pentoxifylline liquid mixture [pimobendan 0.25 mg/kg, pentoxifylline 15 mg/kg]; n = 4). Plasma samples were obtained and echocardiographic indices were measured for 24 hours after administration. The concentrations of pimobendan and pentoxifylline were quantified by using a liquid chromatography-mass spectrometer (LC-MS). The elimination half-life ($T_{1/2}$) was $32.96{\pm}9.80mins$ for pimobendan and $29.49{\pm}6.67mins$ for pentoxifylline. The time to reach maximum concentration ($T_{max}$) were $52.50{\pm}31.22mins$ for pimobendan and $41.25{\pm}18.87mins$ for pentoxifylline. The maximum blood concentration ($C_{max}$) was $96.92{\pm}75.64ng/mL$ for pimobendan and $7074.07{\pm}3261.1ng/mL$ for pentoxifylline. Of the echocardiographic indices, fractional shortening (FS) and left ventricular internal diameter at end systole (LVIDs) were significantly altered at 1-3 hours after the administration of pimobendan-pentoxifylline liquid mixture. The pimobendan-pentoxifylline liquid mixture was well tolerated by the dogs, with no adverse effects observed during the study.

• The Korea Journal of Herbology
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• v.33 no.6
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• pp.9-18
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• 2018

Objective : Many patients take antihypertensive drugs as well as herbal medicines at the same time in order to treat other symptoms or to keep their well-being. In this study, interactions between herbal medicines and synthetic antihypertensive drugs were analyzed. Methods : To investigate the interaction between herbal medicines and synthetic antihypertensive drugs, three electronic databases, including OASIS, Mediline and Sciencedirect were searched. Experimental and clinical studies on the interaction between herbal medicines and antihypertensive drugs were independently reviewed and included. Results : Analyzing selected studies, twenty herbs were found to interact with antihypertensive drugs. Herbs found to increase the antihypertensive effect were Panax ginseng, Carthamus tinctorius, Magnolia officinalis, Silybum marianum, Scutellaria baicalensis, Schisandra chinensis, Sophora flavescens, Piper nigrum, Curcuma longa, Ginkgo biloba, Juncus effuses and Hydrastis canadensis. In contrast, Commiphora myrrha, Rhodiola rosea, Hypericum perforatum, Eurycoma longifolia, and Daturae metel were found to inhibit the antihypertensive effect. Stephania tetrandra could increase or decrease the effect depending on the type of antihypertensive drug. Epedria sínica was suspected of pharmacodynamic interaction with antihypertensive drug. Glycyrrhiza uralensis has been reported to have serious side effects in combination with antihypertensive drugs. Conclusion : These results imply that when used in combination with herbal medicines and synthetic antihypertensive drugs, proper doses and herbs which are to avoid need to be informed to the patients. Despite concerns about interactions between herbal medicines and synthetic drugs, related research is very limited. More systematic researches are needed to give information on patient safety as well as to guide clinical practice.

• Korean Journal of Veterinary Research
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• v.51 no.4
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• pp.253-257
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• 2011

Amikacin is a semisynthetic derivative of kanamycin and primarily active against aerobic Gram-negative-pathogens with limited activity against Gram-positive bacteria. Meager study was reported on pharmacokinetic data on multi-days administration of amikacin. Hence, pharmacokinetics study was done in five clinically healthy goats (n = 5), after intravenous bolus injection of amikacin sulfate at the dose rate of 10 mg/kg body weight daily for three consecutive days. The amikacin concentrations in plasma and pharmacokinetics-parameters were analyzed by using microbiological assay technique and noncompartmental open-model, respectively. The mean peak plasma concentrations (Mean ${\pm}$ SD) of amikacin at time zero ($Cp^{0}$) was $114.19{\pm}20.78$ and $128.67{\pm}14.37{\mu}g/mL$, on day 1st and 3rd, respectively. The mean elimination half-life ($t_{1/2}ke$) was $1.00{\pm}0.28h$ on day 1st and $1.22{\pm}0.29h$ on day 3rd. Mean of area under concentration-time curve ($AUC_{0{\rightarrow}{\infty}}$) was $158.26{\pm}60.10$ and $159.70{\pm}22.74{\mu}g.h/mL$, on day 1st and 3rd respectively. The total body clearance ($Cl_{B}$) and volume of distribution at steady state (Vdss) on day 1st and 3rd were $Cl_{B}=0.07{\pm}0.02$ and $0.06{\pm}0.01L/h.kg$ and $Vdss=0.10{\pm}0.03$ and $0.11{\pm}0.05L/kg$, respectively. No-significant difference was noted in both drug-plasma concentration and pharmacokinetics-parameters, respectively. Amikacin concentration in plasma was found higher up-to 4 h and 6 h onward on down-ward trends favour to reduce toxicity. Which also support the pharmacokinetic-pharmacodynamic way of dosing of aminoglycosides and hence, amikacin may be administered 10 mg/kg intravenously daily to treat principally Gram-negative pathogens and limitedly Gram-positive-pathogens.

• Korean Journal of Clinical Pharmacy
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• v.22 no.1
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• pp.30-40
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• 2012

In Korea, elderly population aged 65 and older are about 5.0% and 10.7% in 1990 and 2009, respectively. Since elderly people may experience physiologic changes with aging and their pharmacodynamic and pharmcokinetic parameters also have been undergone changes, several adverse drug reactions can occur more frequently than young people. Especially, neuropsychiatric adverse drug reactions such as delirium and drowsiness endanger elderly patients more. The purpose of this study is to evaluate the outpatient prescriptions using drug causing delirium and drowsiness in elderly patients aged 65 and older. We retrospectively reviewed prescriptions for elderly patients collected from four community pharmacies from January 2nd to February 1st, 2010. One pharmacy was located closed to a general hospital, and others were located closed to a internal medicine or an ENT clinic. The each number of the collected prescriptions was followings; Group A (n=496) from internal medicine department of a general hospital; Group B (n=44) from ENT department of general hospital; Group C (n=144) from internal medicine clinic; Group D (n=110) from ENT clinic. In result, in Group A, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.38 In Group B, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.09 In Group C, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.51. In Group D, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.72. Especially, in Group D, the percentage of prescription that drugs causing delirium or drowsiness per Rx prescribed more than 3 is 52.73% In all the 4 groups, over the 60% of drugs causing delirium and/or drowsiness per prescription of elderly patients were prescribed. It means elderly patients take 2 drugs causing delirium and/or drowsiness among 3 drugs, which is very serious. Frequently prescribed drugs causing delirium and/or drowsiness were followings; GI agents, antitussives & expectorants, histamine H1 antagonist, analgesics, antibiotics. Among these drugs, GI agents was high raking in all the 4 groups, and pharmacists should caution elderly patients when counseling. In the internal medicine groups (Group A,C), drugs concerning chronic diseases were prescribed frequently. In conclusion, pharmacist's role is important. Pharmacists are well informed of the drugs causing delirium or drowsiness and it is important to explain about ADRs slowly and easily to the elderly patients that receive drugs causing delirium or drowsiness. And institutional device is needed. For example, when doctors prescribe drugs for the elderly patients, message is needed that supply some informations about drugs causing delirium or drowsiness.

• The Journal of Korean Medicine
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• v.38 no.2
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• pp.61-72
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• 2017

Objectives: The effects of Gamiondam-tang (GMODT) co-administration within 5min on the pharmacokinetics (PK) of tamoxifen were observed as a process of the comprehensive and integrative medicine, combination therapy of tamoxifen with GMODT to achieve synergic pharmacodynamics and reduce toxicity on the breast cancer. Methods: After 50mg/kg of tamoxifen treatment, GMODT 100mg/kg was administered within 5min. The plasma were collected at 30 min before administration, 30 min, 1, 2, 3, 4, 6, 8 and 24 hrs after end of GMODT treatment, and plasma concentrations of tamoxifen were analyzed using LC-MS/MS methods. PK parameters of tamoxifen (Tmax, Cmax, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with tamoxifen single administered rats using noncompartmental pharmacokinetics data analyzer programs. Results: Co-administration with GMODT induced increased trends of plasma tamoxifen concentrations to 1hr after end of administration, and then showed decreased trends of plasma tamoxifen concentrations, and especially significant (p<0.05) increases of plasma tamoxifen concentrations were demonstrated at 0.5hr after end of co-administration with GMODT and also related significant (p<0.05) decreases of $AUC_{0-inf}$ and $MRT_{inf}$ as compared with tamoxifen single formula treated rats, at dosage levels of tamoxifen 10 mg/kg and GMODT 100 mg/kg within 5 min, in this experiment. Conclusion: Based on the results of the present study, it is considered that single co-administration GMODT within 5min significantly inhibited the oral bioavailability of tamoxifen through variable influences on the absorption and excretion of tamoxifen, can be influenced on the toxicity or pharmacodynamic of tamoxifen.