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Determination of sumatriptan in human plasma using liquid chromatography-mass spectrometry for pharmacokinetic study in healthy Korean volunteers.

Seungil CHO ; Moonyoung JEGAL ; Boram OHK ; Bo Kyung KIM ; Mi Ri GWON ; Woo Youl KANG ; Sook Jin SEONG ; Hyun Ju KIM ; Hae Won LEE ; Young Ran YOON

Translational and Clinical Pharmacology.2017;25(2):106-111. doi:10.12793/tcp.2017.25.2.106

This study describes the development of an analytical method to determine sumatriptan levels in human plasma using high performance liquid chromatography (HPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS) and its application to a pharmacokinetic study in healthy Korean volunteers. A single 50 mg dose of sumatriptan was orally administered to twelve healthy volunteers (nine women and three men). The HPLC-MS/MS analytical method was validated with respect to its specificity, linearity, sensitivity, accuracy, precision, recovery, and stability. The calibration curve was linear over a concentration range of 0.3–100 ng/mL (r > 0.999). The lower limit of quantitation for sumatriptan in plasma was 0.3 ng/mL. The accuracy and precision of the analytical method were acceptable within 15% at all quality control levels. We compared plasma concentration-time curves as well as pharmacokinetic parameters such as the area under the curve (AUC) and maximum plasma concentration (C(max)). Both the mean AUC and C(max) of sumatriptan were 1.56 times higher in women than in men. These differences could be largely explained by the difference in body weight (44%) between women and men. The outcomes may provide insights into developing appropriate individualized treatment strategies.
Area Under Curve ; Body Weight ; Calibration ; Chromatography, Liquid ; Female ; Healthy Volunteers ; Humans* ; Male ; Methods ; Plasma* ; Quality Control ; Sensitivity and Specificity ; Spectrum Analysis* ; Sumatriptan* ; Tandem Mass Spectrometry ; Volunteers*

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Relationship between body weight and postmenstrual age in a Korean pediatric population.

Jinju GUK ; Dongwoo CHAE ; Kyungsoo PARK

Translational and Clinical Pharmacology.2017;25(2):101-105. doi:10.12793/tcp.2017.25.2.101

Weight is a covariate representative of body size and is known to influence drug disposition. Recently, with increased use of allometric scaling, this variable has become more significant in accounting for variability in pharmacokinetic parameters. In adults, weight can be considered as a time invariant covariate because physical development is complete. As a result, when weight is missing in data, the typical or median value (say, 70 kg) could be imputed. On the contrary, weight continuously changes with age in the pediatric population. In this case, it is more appropriate to consider different median weight for each age group. We constructed a prediction model for weight using postmenstrual age (PMA) with the data consisting of 83,014 Korean pediatric patients. Weight, PMA, and gender information were collected from electronic medical records. Sigmoid models multiplied by exponential or logistic function were tested for basic model structure. Covariate effects on model parameters were then investigated using selection criteria of p < 0.001. All analyses were performed using NONMEM 7.3.0 and R3.2.0. The sigmoid model multiplied by logistic function best described the data and there was a significant difference between boys and girls in model parameters. It is expected that the results obtained in this work can be used for imputation of missing weights in pediatrics when PMA is available. In addition, the developed model can be used for clinical studies in children under 12 years old whose weight change rapidly with age and for model building in dealing with time varying body weight as a covariate.
Adult ; Body Size ; Body Weight* ; Child ; Colon, Sigmoid ; Electronic Health Records ; Female ; Humans ; Patient Selection ; Pediatrics ; Weights and Measures

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Bioequivalence data analysis for the case of separate hospitalization.

Kyun Seop BAE ; Seung Ho KANG

Translational and Clinical Pharmacology.2017;25(2):93-100. doi:10.12793/tcp.2017.25.2.93

A bioequivalence study is usually conducted with the same-day drug administration. However, hospitalization is occasionally separated for logistical, operational, or other reasons. Recently, there was a case of separate hospitalization because of difficulties in subject recruitment. This article suggests a better way of bioequivalence data analysis for the case of separate hospitalization. The key features are (1) considering the hospitalization date as a random effect than a fixed effect and 2) using “PROC MIXED” instead of “PROC GLM” to include incomplete subject data.
Hospitalization* ; Statistics as Topic* ; Therapeutic Equivalency*

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Pharmacokinetic characteristics of fluticasone, salmeterol and tiotropium after concurrent inhalation.

Jung SUNWOO ; Su jin RHEE ; SeungHwan LEE ; Sang Won LEE ; Jina JUNG ; Hankil SON ; In Jin JANG

Translational and Clinical Pharmacology.2017;25(2):85-92. doi:10.12793/tcp.2017.25.2.85

Chronic obstructive pulmonary disease (COPD) is a type of progressive, obstructive lung disease characterized by long-term poor airflow. The symptoms of COPD may be relieved and its progression delayed by fluticasone (FTS), salmeterol (SM), and tiotropium (TTP). The aim of this study is to investigate pharmacokinetic (PK) characteristics of inhaled FTS, SM, and TTP after co-administration. An open-label, single-arm, three-period, simple ascending dose study was conducted in 10 healthy male subjects. A single dose of FTS/SM (250/50 µg) and TTP (18 µg) were concomitantly inhaled in period 1, and the dose of each drug was escalated to two- and three-fold in periods 2 and 3, respectively, with a 2-week washout between periods. Activated charcoal was co-administered before and after inhalation to block gastrointestinal absorption. Blood samples for PK analysis were collected up to 24 hours. PK parameters were obtained by non-compartmental analysis. FTS, SM, and TTP rapidly reached maximum plasma concentration after inhalation (0.08–3.00 h, 0.03–0.10 h and 0.03–0.10 h, respectively) and were eliminated with mean half-lives of 9.29–10.44 h, 6.09–12.39 h and 0.25–47.42 h, respectively. PK assessment of the lowest dose of TTP was limited due to relatively low systemic exposure compared to the lower limit of quantification. In conclusion, PK characteristics of FTS, SM, and TTP by pulmonary absorption were evaluated after concurrent inhalation. FTS and SM showed dose-proportional PK profiles between 250–750 µg and 50–150 µg, respectively, while TTP presented dose-proportionality in the early phase exposure between 18-54 µg.
Charcoal ; Fluticasone* ; Gastrointestinal Absorption ; Humans ; Inhalation* ; Lung Diseases, Obstructive ; Male ; Pharmacokinetics ; Plasma ; Pulmonary Disease, Chronic Obstructive ; Respiratory Tract Absorption ; Salmeterol Xinafoate* ; Tiotropium Bromide*

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Parameter estimation for sigmoid E(max) models in exposure-response relationship.

Sangmin CHOE ; Donghwan LEE

Translational and Clinical Pharmacology.2017;25(2):74-84. doi:10.12793/tcp.2017.25.2.74

The purpose of this simulation study is to explore the limitation of the population PK/PD analysis using data from a clinical study and to help to construct an appropriate PK/PD design that enable precise and unbiased estimation of both fixed and random PD parameters in PK/PD analysis under different doses and Hill coefficients. Seven escalating doses of virtual drugs with equal potency and efficacy but with five different Hill coefficients were used in simulations of single and multiple dose scenarios with dense sampling design. A total of 70 scenarios with 100 subjects were simulated and estimated 100 times applying 1-compartment PK model and sigmoid E(max) model. The bias and precision of the parameter estimates in each scenario were assessed using relative bias and relative root mean square error. For the single dose scenarios, most PD parameters of sigmoid E(max) model were accurately and precisely estimated when the C(max) was more than 85% of EC₅₀, except for typical value and inter-individual variability of EC₅₀ which were poorly estimated at low Hill coefficients. For the multiple dose studies, the parameter estimation performance was not good. This simulation study demonstrated the effect of the relative range of sampled concentrations to EC₅₀ and sigmoidicity on the parameter estimation performance using dense sampling design.
Bias (Epidemiology) ; Clinical Study ; Colon, Sigmoid*

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Metabolomic analysis of healthy human urine following administration of glimepiride using a liquid chromatography-tandem mass spectrometry.

Eun Young DO ; Mi Ri GWON ; Bo Kyung KIM ; Boram OHK ; Hae Won LEE ; Woo Youl KANG ; Sook Jin SEONG ; Hyun Ju KIM ; Young Ran YOON

Translational and Clinical Pharmacology.2017;25(2):67-73. doi:10.12793/tcp.2017.25.2.67

Glimepiride, a third generation sulfonylurea, is an antihyperglycemic agent widely used to treat type 2 diabetes mellitus. In this study, an untargeted urinary metabolomic analysis was performed to identify endogenous metabolites affected by glimepiride administration. Urine samples of twelve healthy male volunteers were collected before and after administration of 2 mg glimepiride. These samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and then subjected to multivariate data analysis including principal component analysis and orthogonal partial least squares discriminant analysis. Through this metabolomic profiling, we identified several endogenous metabolites such as adenosine 3′, 5′-cyclic monophosphate (cAMP), quercetin, tyramine, and urocanic acid, which exhibit significant metabolomic changes between pre- and posturine samples. Among these, cAMP, which is known to be related to insulin secretion, was the most significantly altered metabolite following glimepiride administration. In addition, the pathway analysis showed that purine, tyrosine, and histidine metabolism was affected by pharmacological responses to glimepiride. Together, the results suggest that the pharmacometabolomic approach, based on LC-MS/MS, is useful in understanding the alterations in biochemical pathways associated with glimepiride action.
Adenosine ; Diabetes Mellitus, Type 2 ; Histidine ; Humans* ; Insulin ; Least-Squares Analysis ; Male ; Mass Spectrometry* ; Metabolism ; Metabolomics* ; Principal Component Analysis ; Quercetin ; Statistics as Topic ; Tyramine ; Tyrosine ; Urocanic Acid ; Volunteers

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Allopurinol-induced severe cutaneous adverse reactions: A report of three cases with the HLA-B*58:01 allele who underwent lymphocyte activation test.

Eun Young KIM ; Jung Eun SEOL ; Jae Hyeog CHOI ; Na Yul KIM ; Jae Gook SHIN

Translational and Clinical Pharmacology.2017;25(2):63-66. doi:10.12793/tcp.2017.25.2.63

Allopurinol-induced severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome are reportedly associated with the HLA-B*58:01 genotype. Three patients who developed SCARs after allopurinol administration were subjected to HLA-B genotyping and lymphocyte activation test (LAT) to evaluate genetic risk and to detect the causative agent, respectively. All three patients given allopurinol to treat gout were diagnosed with DRESS syndrome. Symptom onset commenced 7-24 days after drug exposure; the patients took allopurinol (100–200 mg/d) for 2-30 days. HLA-B genotyping was performed using a polymerase chain reaction (PCR)-sequence-based typing (SBT) method. All patients had a single HLA-B*58:01 allele: HLA-B*13:02/*58:01 (a 63-year-old male), HLA-B*48:01/*58:01 (a 71-year-old female), and HLA-B*44:03/*58:01 (a 22-year-old male). Only the last patient yielded a positive LAT result, confirming that allopurinol was the causative agent. These findings suggest that patients with HLA-B*58:01 may develop SCARs upon allopurinol administration. Therefore, HLA-B genotyping could be helpful in preventing serious problems attributable to allopurinol treatment, although PCR-SBT HLA-B genotyping is time consuming. A simple genotyping test is required in practice. LAT may help to identify a causative agent.
Aged ; Alleles* ; Allopurinol ; Cicatrix ; Drug Hypersensitivity Syndrome ; Genotype ; Gout ; HLA-B Antigens ; Humans ; Lymphocyte Activation* ; Lymphocytes* ; Methods ; Middle Aged ; Polymerase Chain Reaction ; Stevens-Johnson Syndrome ; Young Adult

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Comparison of pharmacokinetic characteristics of sildenafil citrate chewable tablets and film-coated tablets in healthy male subjects.

Hyounggyoon YOO ; Sang Min CHO ; Youn Woong CHOI ; Hye Jung LEE ; Ji Hye KWON ; Soo Whan KIM ; Jae Woo KIM ; SeungHwan LEE ; Jang Hee HONG

Translational and Clinical Pharmacology.2017;25(3):153-156. doi:10.12793/tcp.2017.25.3.153

UI14SDF100CW is a chewable tablet of sildenafil citrate, which was developed to improve compliance through convenience of administration. The purpose of this study was to compare the pharmacokinetic (PK) properties of sildenafil citrate chewable tablets (UI14SDF100CW) and conventional sildenafil citrate film-coated tablets (Viagra®, Pfizer). A randomized, open-label, single dose, two-treatment, two-period, two-way crossover study was conducted in 60 healthy male volunteers. In each period, the subjects received a single oral dose of UI14SDF100CW or Viagra® (both tablets contain 140.45 mg of sildenafil citrate, which is equivalent to 100 mg of sildenafil). Serial blood samples were collected up to 24 h post-dose for PK analysis. The plasma concentration of sildenafil was determined using a validated HPLC-MS/MS assay. PK parameters of sildenafil were calculated using non-compartmental methods. The plasma concentration-time profiles of sildenafil in both formulations were similar. For UI14SDF100CW, the C(max) and AUC(last) of sildenafil were 1068.69 ± 458.25 (mean ± standard deviation) mg/L and 3580.59 ± 1680.29 h·mg/L, and the corresponding values for Viagra® were 1146.84 ± 501.70 mg/L and 3406.35 ± 1452.31 h·/L, respectively. The geometric mean ratios (90% confidence intervals) of UI14SDF100CW to Viagra® for C(max) and AUC(last) were 0.933 (0.853–1.021) and 1.034 (0.969–1.108), respectively, which met the bioequivalence criteria of Korean regulatory agency. In conclusion, UI14SDF100CW and Viagra® showed similar PK properties. Therefore, UI14SDF100CW can be an alternative to sildenafil for the treatment of erectile dysfunction, providing better compliance.
Compliance ; Cross-Over Studies ; Erectile Dysfunction ; Humans ; Male* ; Pharmacokinetics ; Plasma ; Sildenafil Citrate* ; Tablets* ; Therapeutic Equivalency ; Volunteers

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Prediction and visualization of CYP2D6 genotype-based phenotype using clustering algorithms.

Eun Young KIM ; Sang Goo SHIN ; Jae Gook SHIN

Translational and Clinical Pharmacology.2017;25(3):147-152. doi:10.12793/tcp.2017.25.3.147

This study focused on the role of cytochrome P450 2D6 (CYP2D6) genotypes to predict phenotypes in the metabolism of dextromethorphan. CYP2D6 genotypes and metabolic ratios (MRs) of dextromethorphan were determined in 201 Koreans. Unsupervised clustering algorithms, hierarchical and k-means clustering analysis, and color visualizations of CYP2D6 activity were performed on a subset of 130 subjects. A total of 23 different genotypes were identified, five of which were observed in one subject. Phenotype classifications were based on the means, medians, and standard deviations of the log MR values for each genotype. Color visualization was used to display the mean and median of each genotype as different color intensities. Cutoff values were determined using receiver operating characteristic curves from the k-means analysis, and the data were validated in the remaining subset of 71 subjects. Using the two highest silhouette values, the selected numbers of clusters were three (the best) and four. The findings from the two clustering algorithms were similar to those of other studies, classifying *5/*5 as a lowest activity group and genotypes containing duplicated alleles (i.e., CYP2D6*1/*2N) as a highest activity group. The validation of the k-means clustering results with data from the 71 subjects revealed relatively high concordance rates: 92.8% and 73.9% in three and four clusters, respectively. Additionally, color visualization allowed for rapid interpretation of results. Although the clustering approach to predict CYP2D6 phenotype from CYP2D6 genotype is not fully complete, it provides general information about the genotype to phenotype relationship, including rare genotypes with only one subject.
Alleles ; Classification ; Cluster Analysis* ; Cytochrome P-450 CYP2D6* ; Dextromethorphan ; Genotype ; Metabolism ; Phenotype* ; ROC Curve

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Caffsim: simulation of plasma caffeine concentrations implemented as an R package and Web-applications.

Sungpil HAN ; Yong Soon CHO ; Seok Kyu YOON ; Hyungsub KIM ; Kyun Seop BAE

Translational and Clinical Pharmacology.2017;25(3):141-146. doi:10.12793/tcp.2017.25.3.141

Caffeine is a naturally-occurring central nervous system stimulant found in plant constituents including coffee, cocoa beans, and tea leaves. Consumption of caffeine through imbibing caffeinated drinks is rapidly growing among children, adolescents, and young adults, who tend to be more caffeine-sensitive than the rest of the general public; consequently, caffeine-related toxicities among these groups are also growing in number. However, a quantitative and interactive tool for predicting the plasma caffeine concentration that may lead to caffeine intoxication has yet to be developed. Using the previously established population-pharmacokinetic model, we developed “caffsim” R package and its web-based applications using Shiny and EDISON (EDucation-research Integration through Simulation On the Net). The primary aim of the software is to easily predict and calculate plasma caffeine concentration and pharmacokinetic parameters and visualize their changes after single or multiple ingestions of caffeine. The caffsim R package helps understand how plasma caffeine concentration changes over time and how long toxic concentration of caffeine can last in caffeine-sensitive groups. It may also help clinical evaluation of relationship between caffeine intake and toxicities when suspicious acute symptoms occur.
Adolescent ; Cacao ; Caffeine* ; Central Nervous System ; Child ; Coffee ; Humans ; Pharmacokinetics ; Plants ; Plasma* ; Tea ; Young Adult

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