• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.421.3-422
• /
• 2002

Carvedilol is a nonselective $\beta$-adrenoblocking agent with vasodilating activities. The pharmacokinetics and pharmacodynamics of carvedilol were studied in healthy volunteers following single oral administration. After oral administration of carvedilol 25mg. blood samples were collected for a period of 30 hours. Plasma concentrations of carvedilol were determined by HPLC with spectrofluorometric detection. The effects of carvedilol on systolic and diastolic blood pressure (BP) and heart rate (HR) were measured during the same period. (omitted)

• Proceeding of EDISON Challenge
• /
• 2017.03a
• /
• pp.696-697
• /
• 2017

본 연구의 목적은 단클론항체 (mAb) 약동학적 특성을 보다 쉽게 이해하고자 문헌에 보고된 mAb의 PK 모델을 구현할 수 있도록 시뮬레이션 모델을 만드는 것이다. 본 연구결과를 바탕으로 약물의 용법/용량, 각각의 모델 파라미터의 변화에 따른 혈중농도, 수용체 점여 등의 변화를 다양하게 시뮬레이션 해볼 수 있다.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.307.1-307.1
• /
• 2003

Metfotrmin is a biguanide antihyperglycemic agent often used for the treatment of non-insulin dependent diabetics(NIDDM). Metformin lowers both fasting and postprandial plasma glucose concentrations by improving insulin sensitivity at hepatic and peripheral tissues. The pharmacokinetics and pharmacodynamics of metformin were studied in Korean healthy volunteers at fasting state over 10 hours. (omitted)

• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.4
• /
• pp.273-279
• /
• 2012

Busulfan is an antineoplastic agent with a narrow therapeutic window. A post-hoc population pharmacokinetic analysis of a prospective randomized trial for comparison of four-times daily versus once-daily intravenous busulfan was carried out to search for predictive factors of intravenous busulfan (iBu) pharmacokinetics (PK). In this study the population PK of iBu was characterized to provide suitable dosing recommendations. Patients were randomized to receive iBu, either as 0.8 mg/kg every 6 h or 3.2 mg/kg daily over 4 days prior to hematopoietic stem cell transplantation. In total, 295 busulfan concentrations were analyzed with NONMEM. Actual body weight and sex were significant covariates affecting the PK of iBu. Sixty patients were included in the study (all Korean; 23 women, 37 men; mean [SD] age, 36.5 [10.9] years; weight, 66.5 [11.3] kg). Population estimates for a typical patient weighing 65 kg were: clearance (CL) 7.6 l/h and volume of distribution (Vd) 32.2 l for men and 29.1 L for women. Inter-individual random variabilities of CL and $V_d$ were 16% and 9%. Based on a CL estimate from the final PK model, a simple dosage scheme to achieve the target $AUC_{0-inf}$ (defined as median AUC0-inf with a once-daily dosage) of 26.18 $mg/l{\cdot}hr$, was proposed: $24.79{\cdot}ABW^{0.5}mg$ q24h, where ABW represents the actual body weight in kilograms. The dosing scheme reduced the unexplained interindividual variabilities of CL and Vd of iBu with ABW being a significant covariate affecting clearance of iBU. We propose a new simple dosing scheme for iBu based only on ABW.

• Journal of Society of Preventive Korean Medicine
• /
• v.18 no.2
• /
• pp.89-100
• /
• 2014

Objective : The co-administration effects of Gongjindan (GJD) on the pharmacokinetics (PK) of sorafenib were observed as a process of the comprehensive and integrative medicine. Methods : After sorafenib treatment, GJD was administered within 5 min. The plasma were collected at 30min before administration, 30min, 1, 2, 3, 4, 6, 8 and 24hrs after end of GJD 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 : The absorption of sorafenib were significantly increased at 30min, 1, 6 and 6hrs after co-administration with GJD as compared with sorafenib single treated rats. Accordingly, the $AUC_{0-t}$ (47.20%) of sorafenib was significantly increased but $t_{1/2}$ (-30.63%) and $MRT_{inf}$ (-34.11%) in co-administered rats were non-significantly decreased. These findings are considered as direct evidences that GJD increased the oral bioavailability of sorafenib through increase of the absorption, when they co-administered within 5min. Conclusion : Based on the results, co-administration of GJD increased the oral bioavailability of sorafenib through increase of the gastrointestinal absorption. It is considered that the more detail pharmacokinetic studies should be tested to conclude the effects of GJD on the pharmacokinetics of sorafenib, when they were co-administered, like the effects after co-administration with reasonable intervals considering the $T_{max}$ of sorafenib (about 3.5hr-intervals) and after repeated co-administrations.Hence, concomitant uses of GJD with sorafenib may require close monitoring for potential drug interactions.

• Biomolecules & Therapeutics
• /
• v.17 no.3
• /
• pp.299-304
• /
• 2009

Rosiglitazone maleate (RGM) is widely used for improving insulin resistance. RGM is a moderate inhibitor of cytochrome P450 2C8 (CYP2C8) and is also mainly metabolized by CYP2C8. The aim of this study was to determine whether the effect of RGM on CYP2C8 is altered by co-treatment with other drugs, and whether amlodipine camsylate (AC) changes the pharmacokinetics (PK) of RGM. Of the 11 drugs that are likely to be co-administered with RGM in diabetic patients, seven drugs lowered the $IC_{50}$ value of RGM on CYP2C8 by more than 80%. In vitro CYP2C8 inhibitory assays of RGM in combination with drugs of interest showed that the $IC_{50}$ of RGM was decreased by 98.9% by AC. In a pharmacokinetic study, Sprague-Dawley (SD) rats were orally administered 1 mg/kg of RGM following by single or 10-consecutive daily administrations of 1.5 mg/kg/day of AC. No significant changes in the pharmacokinetic parameters of RGM were observed after a single administration of AC, but the AUC and $C_{max}$ values of RGM were significantly reduced by 36% and 31%, respectively, by multiple administrations of AC. In conclusion, RGM was found to be affected by AC by in vitro CYP2C8 inhibition testing, and multiple dosing of AC appreciably changed the pharmacokinetics of RGM. These findings suggest that a drug interaction exists between AC and RGM.

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

• Mass Spectrometry Letters
• /
• v.11 no.4
• /
• pp.71-76
• /
• 2020

While montelukast (ML), a cysteinyl-leukotriene type 1 receptor (CysLT1) antagonist is widely used to treat symptoms of rhinitis or asthma, its formulations are mainly limited to solid preparation due to its instability. Recently, there have been attempts to develop various ML dosage forms, and this situation increases the demand of sensitive and creditable methods to determine ML in various samples such as plasma. Thus, here, a simple and efficient method to determine ML in rat plasma using liquid-liquid extraction (LLE) and multiple reaction monitoring was presented. The mixture of DCM:EtOAc (25:75, v/v), the optimized extract solvent for LLE was found to be effective to extract ML without hydrophilic salts and proteins from the sample with limited volume. Also, the use of zafirlukast, instead of expensive ML-d6, as the internal standard makes the present method economical. The developed method was successfully validated in terms of selectivity, matrix effects (-14.8--6.9%), linearity (r230.998 within 0.5-500 ng/mL), sensitivity (the limit of detection and the lower limit of quantitation, ≤0.5 ng/mL), accuracy (88.4-100.6%), precision (3.0-13.3%), and recovery (80.8-86.3%) by following the FDA guidelines. Finally, the applicability of the validated method to pharmacokinetics (PK) studies was confirmed by the successful determination of PK parameters through it following oral administration of Singulair® granule in rats. Therefore, the present method can contribute to the development of new ML formulations through its performance to determine ML in rat plasma efficiently and sensitively.

• Journal of Environmental Health Sciences
• /
• v.40 no.5
• /
• pp.407-412
• /
• 2014

Objectives: The internal dose of ethyl parabens is important in order to evaluate the risk of this chemical. However, there are little PK model data for parabens to apply this. This experiment attempted PK modeling to ascertain PK values. Methods: Twenty mg/kg ethyl paraben was administered orally to Sprague-Dawley rats at the same point in time. The rats were sacrificed at times 0, 15, 30 and minutes, and 1, 2, 4, 8, 12, 24 hours after oral gavage. Blood and urine were collected and pretreated for analysis. Accuracy, precision and LOD (limit of detection) were calculated for this analysis. Ethyl paraben, detected by HPLC-MS, was applied to PK modeling using Berkeley Madonna. Results: This study showed 100.1-103.7% accuracy, 1.4-3.7% precision and a 1.0 ng/mL limit of detection. Orally administered ethyl paraben reached maximum concentration after 30 minutes of dosing in serum and urine of rats. The concentrations were 2,354 ng/mL in serum and 386,000 ng/mL in urine samples. These peak concentrations were excreted after one hour of intubation over 12 hours. For the pharmacokinetic parameters of ethyl paraben revealed using Berkeley Madonna, the absorption rate was 5.539/hour, the excretion rate was 0.048/hour, the half-life was 14.441 hours and AUC was 481,186 ng hour/mL. Conclusion: Orally administered ethyl paraben was absorbed rapidly in rats and excreted in urine. This chemical, ethyl paraben, accumulated in the body but was excreted over 12 hours after dosing.

• The Journal of Korean Medicine
• /
• v.37 no.2
• /
• pp.1-11
• /
• 2016

Objectives: The objective of this study was to elucidate the effect of Jaeumkanghwatang (JEKHT) on the plasma concentration and pharmacokinetics of tamoxifen in combination therapy as a process of the comprehensive and integrative medicine against breast cancer. Methods: After 50 mg/kg of tamoxifen treatment, JEKHT 100 mg/kg was orally administered within 5 min. The plasma were collected at 30 min before administration, 30min, 1, 2, 3, 4, 6, 8 and 24 hrs after end of JEKHT treatment, and plasma concentrations of tamoxifen were analyzed using LC-MS/MS methods. PK parameters of tamoxifen ($T_{max}$, $C_{max}$, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with tamoxifen single administered rats. Results: JEKHT did not influenced on the plasma concentrations and pharmacokinetics of tamoxifen after single oral co-administration, within 5min except for some negligible effects on plasma concentration. The $T_{max}$, $C_{max}$, AUC, $t_{1/2}$ and $MRT_{inf}$ of tamoxifen in co-administered rats were quite similar to those of tamoxifen single treated rats. Conclusions: Based on the results of the present study, JEKHT did not influenced on the oral bioavailability of tamoxifen, when they were single co-administered within 5min. However, more detail pharmacokinetic studies should be tested to conclude the possibilities that can be used as comprehensive and integrative therapy with JEKHT and tamoxifen for breast cancers, when they were co-administered, like the effects on the pretreatment of JEKHT and after repeat co-administrations.