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GM-CSF induces proinflammatory macrophages, but the underlying mechanisms have not been studied thus far. In this study, we investigated the mechanisms of how GM-CSF induces inflammatory macrophages. First, we observed that GM-CSF increased the extent of LPS-induced acute glycolysis in murine bone marrow–derived macrophages. This directly correlates with an inflammatory phenotype because glycolysis inhibition by 2-deoxyglucose abolished GM-CSF–mediated increase of TNF-α, IL-1β, IL-6, and IL-12p70 synthesis upon LPS stimulation. Increased glycolytic capacity is due to de novo synthesis of glucose transporter (GLUT)-1, -3, and -4, as well as c-myc. Meanwhile, GM-CSF increased 3-hydroxy-3-methyl-glutaryl-CoA reductase, which is the rate-limiting enzyme of the mevalonate pathway. Inhibition of acute glycolysis or 3-hydroxy-3-methyl-glutaryl-CoA reductase abrogated the inflammatory effects of GM-CSF priming in macrophages. Finally, mice with inflamed colons exposed to dextran sodium sulfate containing GLUT-1high macrophages led to massive uptake of [18F]-fluorodeoxyglucose, but GM-CSF neutralization reduced the positron-emission tomography signal in the intestine and also decreased GLUT-1 expression in colonic macrophages. Collectively, our results reveal glycolysis and lipid metabolism created by GM-CSF as the underlying metabolic constructs for the function of inflammatory macrophages.

Namyi Gu,1,2 Joo-Youn Cho,3 Kwang-Hee Shin,4 In-Jin Jang,3 Moo-Yong Rhee2,5 1Department of Clinical Pharmacology and Therapeutics, 2Clinical Trial Center, Dongguk University College of Medicine and Ilsan Hospital, Goyang, 3Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, 4Pharmacotherapy & Translational Research Lab., College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, 5Cardiovascular Center, Dongguk University College of Medicine and Ilsan Hospital, Goyang, Republic of Korea Abstract: A low sodium diet enhances the hemodynamic effect of renin–angiotensin system blockers. It was suggested that the substrates of P-glycoprotein or cytochrome P450 3A4 were reduced on a high sodium diet. This study aimed to investigate the influence of high sodium diet on the pharmacokinetics and pharmacodynamics of fimasartan, which is a substrate of cytochrome P450 3A4 but not P-glycoprotein. The study design was a two-diet, two-period, two-sequence, randomized, open-label, and crossover with 1-week washout for diet. Eligible subjects were fed with either low sodium (50 mEq/day) diet or high sodium diet (300 mEq/day) for 7 days in the first hospitalization period and the other diet in the second period. On the seventh morning of each period, subjects received a single dose of fimasartan 60 mg in a fasted state. The serial plasma concentrations of fimasartan, serum aldosterone concentration (SAC), and plasma renin activity (PRA) were measured for pharmacokinetic–pharmacodynamic analysis. Sixteen subjects completed the study satisfying the compliance test for diets. Although the mean systemic exposure of fimasartan is slightly (≈10%) decreased on a high sodium diet, the difference was not statistically or clinically significant (P>0.05). The SAC and PRA after fimasartan administration were highly dependent on their baseline levels. The dietary sodium content influenced the baseline of SAC and PRA, but did not influence the ratio change of SAC and PRA after fimasartan treatment. The ratio change of SAC after fimasartan treatment was correlated to the systemic exposure of fimasartan (P0.05). In conclusion, the pharmacokinetics of fimasartan and ratio changes of SAC and PRA after fimasartan treatment were not significantly influenced by dietary sodium content. Keywords: aldosterone, renin activity, angiotensin receptor blocker, aldosterone, renin, cytochrome P450 3A4, P-glycoprotein, healthy, sodium diet

Su-jin Rhee,1,* SeungHwan Lee,1,2,* Seo Hyun Yoon,1 Joo-Youn Cho,1 In-Jin Jang,1 Kyung-Sang Yu1 1Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, 2Clinical Trials Center, Seoul National University Hospital, Seoul, Republic of Korea *These authors contributed equally tothis work Abstract: A new fixed-dose combination formulation of evogliptin 5 mg and metformin extended-release (XR) 1,000 mg (FDC_EVO5/MET1000) was developed to improve medication adherence for type 2 diabetes mellitus. The pharmacokinetics of FDC_EVO5/MET1000 was compared to the corresponding loose combination in a randomized, open-label, crossover study in 36 healthy male subjects (Part 1), and the food effect on FDC_EVO5/MET1000 was assessed (under fasted or fed conditions) in a randomized, open-label, crossover study in 28 healthy male subjects (Part 2). Serial blood samples for pharmacokinetic analysis were collected up to 72 hours,and pharmacokinetic parameters of evogliptin and metformin were calculated using non-compartmental methods. The geometric mean ratios (fixed-dose combination to loose combination) and 90% confidence intervals of pharmacokinetic parameters for evogliptin and metformin were all within 0.800–1.250, suggesting bioequivalent pharmacokinetic. After a single oral dose of FDC_EVO5/MET1000, food did not significantly affect evogliptin pharmacokinetic while systemic exposure of metformin was increased about 47.5% under the fed condition, which is consistent with the already established food effect on metformin XR. FDC_EVO5/MET1000 was generally well tolerated without any drug-related serious adverse events. In conclusion, FDC_EVO5/MET1000 can be substituted for the loose combination of FDC_EVO5/MET1000, providing better compliance with convenient administration. Keywords: pharmacokinetics, bioequivalence, food effect, fixed-dose combination, evogliptin, metformin XR

Prolongation of the QT interval on an ECG is a surrogate marker for predicting the proarrhythmic potential of a drug under development. The aim of this study was to evaluate the QTc prolongation potential of two neuropsychiatric drugs, quetiapine immediate release (IR) and escitalopram, in healthy individuals. This was a randomized, open-label, 4×4 Williams crossover study, with four single-dose treatments [placebo, 400 mg moxifloxacin (positive control), 20 mg escitalopram, and 100 mg quetiapine IR], conducted in 40 healthy volunteers. Serial blood samples for pharmacokinetics and ECG were collected. Individually, RR-corrected QTc intervals (QTcI) and placebo-adjusted changes from baseline values of QTcI (ΔΔQTcI) were evaluated. Lower-bound values of the one-sided 95% confidence interval for ΔΔQTcI of moxifloxacin with more than 5 ms confirmed the sensitivity of the assay. The maximum upper bound 95% confidence interval for the ΔΔQTcI of quetiapine IR and escitalopram was 13.7 and 10.5 ms, with mean estimates of 10.2 and 6.9 ms, respectively. Peak effects of moxifloxacin and quetiapine IR on ΔΔQTcI were observed at approximately time to maximum concentration (Tmax), whereas that of escitalopram was observed 3 h after Tmax. The concentration-ΔΔQTcI relationships of quetiapine IR and escitalopram were relatively flat, as compared with that of moxifloxacin. The results demonstrated the validity of trial methodology and that quetiapine IR and escitalopram caused QT prolongation in healthy individuals. In addition, hysteresis of escitalopram-induced QTc prolongation. These results indicate that higher doses of these drugs could lead to greater QT prolongation in a dose-response manner.

Endogenous metabolites of cytochrome P450 (CYP3A) are useful in predicting drug-drug interactions between in vivo CYP3A inhibitors and inducers for clinical applications of CYP3A substrate drugs. This study aimed to develop predictable markers of the magnitude of hepatic CYP3A induction and inhibition in healthy female subjects using pharmacometabolomics. Twelve female subjects received midazolam during three study phases: 1 mg midazolam (control phase), 1 mg midazolam after pretreatment with 400 mg ketoconazole once daily for 4 days (CYP3A inhibition phase), and 2.5 mg midazolam after pretreatment with 600 mg rifampicin once daily for 10 days (CYP3A induction phase). Throughout the study, blood samples were collected 24 h after midazolam administration and urine samples at 12-h intervals during the 24 h before and after midazolam administration for the analysis of endogenous steroid metabolites. A statistical model was generated to predict midazolam clearance using measurements of endogenous metabolites associated with the inhibition and induction of CYP3A. Mean midazolam clearance decreased to ∼20% of control levels during the inhibition phase and increased more than 2-fold during the induction phase. Of the urine and plasma metabolites measured, the 6β-hydroxycortisol/cortisol ratio was most significantly correlated with midazolam clearance during hepatic CYP3A inhibition and induction. Our results suggest that the urinary 6β-hydroxycortisol/cortisol ratio is the best predictor of hepatic CYP3A activity under both maximal inhibition and maximal induction. Furthermore, the predictive model including 6β-hydroxycortisol/cortisol as a covariate could be applied to predict the magnitude of CYP3A-mediated drug interactions.

Few data are available on whether adjusting the dose of posaconazole syrup is effective in patients receiving anti-cancer chemotherapy. The aim of this prospective study was to analyse the impact of increasing the frequency of posaconazole administration on optimal plasma concentrations in adult patients with haematological malignancy. A total of 133 adult patients receiving chemotherapy for acute myeloid leukaemia or myelodysplastic syndrome who received posaconazole syrup 200 mg three times daily for fungal prophylaxis were enrolled in this study. Drug trough levels were measured by liquid chromatography-tandem mass spectrometry. In 20.2% of patients (23/114) the steady-state concentration of posaconazole was suboptimal (500 ng/mL) on Day 8. In these patients, the frequency of posaconazole administration was increased to 200 mg four times daily. On Day 15, the median posaconazole concentration was significantly increased from 368 ng/mL [interquartile range (IQR), 247-403 ng/mL] to 548 ng/mL (IQR, 424-887 ng/mL) (P = 0.0003). The median increase in posaconazole concentration was 251 ng/mL (IQR, 93-517 ng/mL). Among the patients with initially suboptimal levels, 79% achieved the optimal level unless the steady-state level was200 ng/mL. This study shows that increasing the administration frequency of posaconazole syrup is effective for achieving optimal levels in patients with haematological malignancy undergoing chemotherapy.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Atenolol is an antihypertensive drug, of which negligible amounts are metabolized. • Fruit juices may decrease the oral absorption of drugs by inhibiting intestinal drug transporters, as demonstrated in vitro and in vivo. WHAT THIS STUDY ADDS • The pharmacokinetic characteristics of atenolol were determined according to the SLCO2B1 genotype after apple juice administration in healthy Korean volunteers. • Apple juice ingestion markedly reduced the systemic exposure to atenolol, but genetic variations in SLCO2B1 were unlikely to contribute substantial variability to the pharmacokinetics of atenolol. AIM Fruit juice reduces the plasma concentrations of several β-adrenoceptor blockers, likely by inhibiting OATP2B1-mediated intestinal absorption. The aim of this study was to investigate the effects of apple juice on the pharmacokinetics of atenolol. METHODS Twelve healthy Korean volunteers with genotypes of SLCO2B1 c.1457C> T (*1/*1 (n= 6) and *3/*3 (n= 6)) were enrolled in this study. In a three-phase, one-sequence crossover study, the pharmacokinetics (PK) of atenolol was evaluated after administration of 50 mg atenolol. Subjects received atenolol with either 300 ml water, 1200 ml apple juice or 600 ml apple juice. RESULTS Apple juice markedly reduced the systemic exposure to atenolol. The geometric mean ratios (95% confidence intervals) of apple juice : water were 0.18 (0.13, 0.25, 1200 ml) and 0.42 (0.30, 0.59, 600 ml) for the AUC(0,tlast). In this study, the PK parameters of atenolol responded in a dose-dependent manner to apple juice. CONCLUSIONS Apple juice markedly reduced systemic exposure to atenolol. The genetic variation of SLCO2B1 c.1457C>T had a minimal effect on the pharmacokinetics of atenolol when the drug was administered with water or apple juice.

OBJECTIVE Fesoterodine is a pro-drug of the active metabolite 5-hydroxymethyl tolterodine (5-HMT), a muscarinic receptor antagonist. This study aimed to evaluate the safety profile and pharmacokinetic characteristics of multiple oral doses of sustained-release fesoterodine (fesoterodine SR) in healthy Korean males. METHODS A randomized, double-blind, placebo-controlled, multiple-dose study with two oral doses (4 mg and 8 mg) was conducted in healthy Korean male participants. The study drug was administered once daily for 5 days. The plasma concentration of 5-HMT was measured up to 72 hours after the last drug administration. The CYP2D6 genotype was analyzed using polymerase chain reaction (PCR) methods to assess the effect of genetic polymorphisms on the pharmacokinetic parameters. RESULTS 20 participants completed the study. The mean (SD) areas under the plasma concentration-time curves during the dosing interval (AUCτ) of the 4 mg and 8 mg dose groups were 26.1 (8.0) and 64.2 (30.5) μg·h/ml and the mean peak concentrations (Cmax) were 2.6 (0.7) and 6.0 (2.0) μg/ml, respectively, at steady-state. The mean AUCτ and Cmax of 5-HMT increased in approximately the same proportion as the dose increased. Fesoterodine SR was well tolerated without any serious adverse events or abnormal clinical laboratory findings. CONCLUSION Systemic 5-HMT exposure showed dose-proportional characteristics in the 4 mg to 8 mg dose range in healthy Korean males. Thus, 4 mg or 8 mg doses of fesoterodine SR taken once-daily were tolerable in healthy Korean males.

The plasma concentrations of valproic acid (VPA) are known to decrease during the concomitant administration of carbapenem antibiotics, such as meropenem, imipenem, and ertapenem. This study summarizes 6 cases of drug-drug interactions between VPA and carbapenem antibiotics.To investigate the onset and severity of the reductions in the concentration of VPA in patients with or without the coadministration of carbapenem antibiotics, the authors performed a retrospective evaluation of therapeutic drug monitoring (TDM) reports that described a decrease in the serum concentrations of VPA during the concomitant use of carbapenem antibiotics from January 2008 to December 2010 in the Seoul National University Hospital. The evaluated TDM reports included 6 cases. The decrement ratio of the VPA serum concentration was calculated from the TDM reports, and the change in the half-life of the VPA was also estimated.Six cases presented with changes in the VPA serum concentration before and after the administration of carbapenem antibiotics. (Three cases were treated with meropenem, 2 were treated with ertapenem, and 1 was treated with imipenem.) The VPA concentrations reduced by (mean ± SD) 88.7 ± 5.3% (3 cases of meropenem), 74.0 ± 9.8% (2 cases of ertapenem), and 73.3% (1 case of imipenem), respectively, and the half-life of VPA reduced by 80.1 ± 9.0%, 64.4 ± 24.2%, and 50.6%, respectively.The interaction between VPA and carbapenem antibiotics caused decreases in the VPA serum concentrations; the extent of this decrease was greater in the meropenem-treated patients than in the imipenem-treated or ertapenem-treated cases. Because the therapeutic effect of VPA depends on its serum concentration, it should be recognized that there may be a loss of seizure control in patients using VPA with carbapenem antibiotics.

Lobeglitazone as a thiazolidinedione antihyperglycemic agent activates peroxisome proliferator-activated receptor (PPAR) γ and may be suitable as monotherapy or in combination with other antihyperglycemic agents. The primary objective of this study was to investigate potential pharmacokinetic interactions between lobeglitazone and metformin in healthy Korean subjects.A randomized, open-label, multiple-dose, three-treatment, three-period, three-sequence, crossover study was conducted in 24 healthy Korean male volunteers. Serial blood samples were collected after lobeglitazone (0.5 mg/day) and metformin (1000 mg/day) were administered alone or concomitantly for 5 days in each period, and drug concentrations were determined by liquid chromatography-tandem mass spectrometry. CLINICAL TRAIL REGISTRATION NUMBER: NCT01005160.The steady-state maximum plasma concentrations (C(max, ss); mean ± standard deviation) of lobeglitazone and metformin alone were 29.38 ± 5.25 ng/mL and 1661.84 ± 471.88 ng/mL, respectively; the C(max, ss) during co-administration were 27.15 ± 5.75 ng/mL and 1779.92 ± 405.20 ng/mL, respectively. The steady-state areas under the concentration-time curves during the dose interval (AUC(τ, ss); mean ± standard deviation) of sole administration of lobeglitazone and metformin were 277.53 ± 65.25 ng*h/mL and 9650.27 ± 2089.81 ng*h/mL, respectively. When lobeglitazone and metformin were administered concomitantly, the AUC(τ, ss) were 257.29 ± 60.61 ng*h/mL and 10600.58 ± 1960.40 ng*h/mL, respectively. The geometric mean ratios (90% confidence interval) of co-medication to lobeglitazone alone were 0.92 (0.87-0.97; C(max, ss)) and 0.93 (0.87-0.99; AUC(τ, ss)), and those for co-medication to metformin monotherapy were 1.09 (0.99-1.19; C(max, ss)) and 1.11 (1.04-1.19; AUC(τ, ss)). Both monotherapies and combination therapy were well tolerated; 52 self-resolving, non-serious adverse events were reported from 17 subjects.Lobeglitazone did not significantly affect the pharmacokinetics of metformin or vice versa when both drugs were co-administered. Lobeglitazone can be co-administered with metformin without dose adjustment for either agent. Therefore further patient studies are needed to corroborate these results.

Fimasartan is an angiotensin II receptor antagonist used to treat hypertension.The aim of this study was to evaluate the effects of fimasartan on the pharmacodynamics and pharmacokinetics of warfarin in healthy volunteers to meet regulatory requirements for drug marketing and labeling in Korea.An open-label, 1-sequence, 2-treatment, 2-period crossover study was conducted in healthy male volunteers. The subjects were administered a single-dose of warfarin 25 mg on day 1. After a 7-day washout period, once-daily fimasartan 240 mg was administered every morning from day 8 to day 16. On day 11, warfarin 25 mg was administered concomitantly with fimasartan. Serial blood samples were collected for 144 hours after each warfarin dose. The plasma concentrations of R- and S-warfarin were analyzed by using HPLC-MS/MS, and the pharmacokinetic parameters were estimated by using noncompartmental analysis. The maximal international normalized ratio (INR) and the AUC-INR curve were evaluated to assess warfarin pharmacodynamics. Tolerability was assessed via vital sign measurements, physical examinations, ECGs, clinical laboratory tests, and adverse events.A total of 15 healthy Korean men aged 20 to 39 years (mean [SD], 26.7 [5.1] years) and weighing 60.2 to 85.7 kg (mean, 71.4 [8.3] kg) participated in the study; 12 completed the study. The geometric mean ratios (GMRs [90% CIs]) of C(max) and AUC(0-last) for R-warfarin were 1.06 (0.97-1.16) and 1.07 (1.03-1.12), respectively. For S-warfarin, the GMRs (90% CIs) of C(max) and AUC(0-last) were 1.02 (0.94-1.11) and 0.99 (0.94-1.04). The INR values reached 1.93 (0.31) and 1.96 (0.37) at 36 hours and decreased to1.2 at 144 hours after warfarin treatment alone and coadministered with fimasartan, respectively. The GMRs (90% CIs) of the maximal INR and AUC-INR curve were 1.01 (0.97-1.05) and 0.98 (0.96-1.01). One (7.7%) of the 13 subjects reported epistaxis during treatment with warfarin alone, and 2 (16.7%) of 12 subjects receiving the combination treatment experienced headache, skin erosion, and an increase in blood creatine phosphokinase. No subjects had an elevated INR4 or reported any symptoms related to hypotension, including fainting or dizziness.Multiple doses of fimasartan did not seem to alter the pharmacodynamics or pharmacokinetics of warfarin in this small, select population of healthy male volunteers.

A simple, rapid and sensitive LC–MS/MS method in positive ion mode was developed and validated to determine CKD-501, lobeglitazone, in human plasma and urine using glipizide as an internal standard (IS). Lobeglitazone is a novel thiazolidinedione (TZDs)-based peroxisome proliferator-activated receptor (PPAR) agonist, used for the management of type-2 diabetes. After mixing the IS, dissolved in acetonitrile, with a plasma or urine sample containing lobeglitazone, 10 μL of supernatant was injected into the LC–MS/MS system. Quantification was performed in the multiple reaction monitoring (MRM) mode using transition of 481.5 → 152.2 (m/z) for lobeglitazone and 446.1 → 321.2 (m/z) for the IS. The method showed good linearity over concentration ranges of 0.5–1,000 ng mL−1 for plasma and 0.2–250 ng mL−1 for urine (r 2 ≥ 0.9996). The mean percent extraction recovery of lobeglitazone was 90.8 % for plasma and 87.3 % for urine, while the recoveries of the IS were greater than 86.4 % for both. The intra-day and inter-day precision of plasma ranged from 1.1 to 3.7 and 2.5 to 3.3 % (RSD), respectively, and the intra- and inter-day precision of urine ranged from 1.5 to 2.7 and 3.2 to 3.5 %, respectively. This method is simple, sensitive, and applicable for the pharmacokinetic study of lobeglitazone in human plasma. Most of the urine concentrations of lobeglitazone were below the LLOQ because the lobeglitazone is extensively metabolized.

HM30181 is an oral P-glycoprotein (P-gp) inhibitor developed to enhance the oral bioavailability of P-gp substrate drugs.The objective of this study was to investigate the tolerability and pharmacokinetic properties of HM30181 after single and multiple oral administrations to healthy Korean male volunteers. The study was performed to meet regulatory criteria for marketing the test product in South Korea.A dose-block-randomized, double-blind, placebo-controlled, dose-escalation study was performed in 180-, 360-, 600-, and 900-mg single-dose groups and 60-, 180-, and 360-mg multiple-dose groups with 10 subjects (8 active; 2 placebo) per group. In the single-dose study, blood and urine samples were collected for up to 120 hours after drug administration. In the multiple-dose study, subjects received the study drug or placebo orally once daily for 5 days. Blood samples were collected up to 624 hours after the last dose, and up to 24 hours after the first dose to evaluate the accumulation index. Urine samples were collected up to 120 hours after the last dose. Pharmacokinetic analysis was performed using noncompartmental methods. Adverse events were collected by the spontaneous reporting of the subjects or when subjects were asked general health-related questions.Thirty and 70 healthy male volunteers completed the single- and multiple-dose studies, respectively. Mean (SD) age and body weight of subjects in the single administration group were 24.0 (1.8) years and 68.8 (7.4) kg, respectively, and those of the multiple administration group were 24.5 (2.6) years and 67.6 (7.7) kg, respectively. The plasma concentrations peaked at 14 to 42 hours and declined with t(½) of 75.7 to 169.3 hours after single administration, and peaked at 5.5 to 8.0 hours and declined with t(½) of 153.5 to 215.2 hours after multiple administrations. C(max) and area under the concentration curve within dosing intervals (AUC(τ)) increased dose dependently after single administration; however, dose-dependent increases in C(max) and AUC(τ) were not observed after multiple administrations. The fraction of drug excreted unchanged in urine was minimal, with values0.01% in all dose groups. HM30181 accumulated after multiple administrations with an accumulation index of 4.0 to 7.4. All adverse events reported were mild in intensity; there were no serious adverse events reported. The most frequently reported adverse event was gastrointestinal disorder.HM30181 was well tolerated after oral administration within the dose range evaluated, with the exception of the repeated administration of 360 mg, for which gastrointestinal disorders were frequently reported. The systemic exposure of HM30181 was relatively low, and dose proportional properties of HM30181 were not observed.

Fimasartan is a selective angiotensin II receptor blocker. Hydrochlorothiazide (HCTZ), which is used to treat hypertension and edematous conditions, is coadministered with many antihypertensive agents.An open-label, randomized, multiple-dosing, 2-arm, 1-sequence, 2-period study was conducted to assess the effects of fimasartan (240 mg) on HCTZ (25 mg) or vice versa in 18 and 14 healthy male volunteers, respectively. During each drug administration period, drugs were given once daily for 7 days, with a 7-day washout period between the 2 administration periods.The respective geometric mean ratios of fimasartan for AUC τ,ss and C max,ss with HCTZ were 1.30 [90% confidence interval (CI), 0.84-2.01] and 1.17 (90% CI, 0.93-1.47) compared with fimasartan alone. The respective geometric mean ratios of HCTZ for AUC τ,ss and C max,ss with fimasartan were 0.94 (90% CI, 0.84-1.04) and 0.88 (90% CI, 0.80-0.97) compared with HCTZ alone. Plasma renin activity indicated no significant differences between fimasartan monotherapy and coadministered treatment.Fimasartan administered alone or in combination with HCTZ was well tolerated at the described dosages. Coadministration of fimasartan increased the urinary excretion of HCTZ and urine volume, but these observations are unlikely to have any clinical relevance.

The rapid achievement of effective levels of antiepileptic drugs (AEDs) is required in patients with epilepsy who have a higher risk of seizures, and oral loading of AEDs may be an important consideration in these patients. We performed the present study to investigate the efficacy and tolerability of oral loading of oxcarbazepine in patients with recurrent seizures, or after temporary discontinuation of AEDs for diagnostic or presurgical evaluation of epilepsy. Forty adult patients were studied and oxcarbazepine was administered orally at a single loading dosage of 30 mg/kg. The plasma levels of oxcarbazepine and its active metabolite, 10,11-dihydro-10-hydroxy-carbazepine (monohydroxy derivative, MHD), were measured, and clinical assessment of adverse events was performed at 2, 4, 6, 8, 10, 12, 16, and 24 h after oral loading of oxcarbazepine. Approximately two-thirds of patients reached effective levels of MHD 2 h after receiving the oral loading, and all patients reached effective levels 4 h after oxcarbazepine administration. Most patients maintained therapeutic MHD levels for at least 16 h. Almost half of the patients experienced adverse events, but all were mild to moderate in severity and resolved spontaneously within 24 h. Our study shows that oral loading of oxcarbazepine is an effective and well-tolerated method for rapidly achieving therapeutic levels of MHD in patients with epilepsy, and is a useful option in selected patients with recurrent seizures, or after temporary discontinuation of AEDs.

BACKGROUND Sertraline is a naphthalenamine derivative which has the effect of selective serotonin reuptake inhibition. It has been used for major depression, and obsessive compulsive disorder. This study was performed to evaluate the pharmacokinetic (PK) characteristics after the administration of low dose sertraline for the purpose of exploring an application of microdosing methods in PK studies. METHODS An open-label, three-period, single-sequence, dose-escalation study was performed in 6 healthy Korean male volunteers. Subjects were administered a single dose of 5 mg, 25 mg and 50 mg sertraline orally in each period, with 1 week washouts between periods. Blood samples were obtained up to 96 h after drug administration. Plasma concentrations were determined using high performance liquid chromatography-tandem mass spectrometry. PK parameters of sertraline were analyzed using non-compartmental methods. RESULTS A total of 6 subjects completed the study. After the administration of sertraline at 5 mg, 25 mg and 50 mg, the median tmax were 6.0, 6.0 and 4.0 h and the mean (SD) elimination half-lives were 31.9 (6.5), 27.2 (6.7) and 28.0 (6.6) h, respectively. The AUC and Cmax increased dose-dependently. The dose-normalized mean (SD) AUC and Cmax were different in each dosing group (p < 0.01) with 2.0 (0.8), 5.3 (1.2) and 6.0 (1.9) mg × hr/l/mg in the 5 mg, 25 mg and 50 mg groups for dose-normalized AUC, and 0.07 (0.01), 0.18 (0.05) and 0.21 (0.08) mg/l/mg in the 5 mg, 25 mg and 50 mg groups for dose-normalized Cmax, respectively, which indicates a lack of dose proportionality. CONCLUSION A lack of dose proportional properties was shown in the 5 mg dose relative to the 25 mg and 50 mg doses of sertraline. This shows that the PK parameters for low-dose sertraline could be different from those in clinical concentrations.

Background Lobeglitazone, a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist with partial PPAR-α affinity, was developed to treat type 2 diabetes mellitus. Objective This study's aim was to evaluate the tolerability and pharmacokinetic (PK) properties of lobeglitazone to satisfy regulatory requirements for marketing approval in Korea. Methods A block-randomized, double-blind, placebo-controlled, single- and multiple-dose study was conducted in healthy subjects. In the pilot study, 4 subjects were administered 0.5 mg, including 1 receiving a placebo. Then, the single-dose study was conducted with 1, 2, 4, and 8 mg doses (8 subjects in each group, including 2 receiving placebos), followed by the multiple-dose study with 1, 2, and 4 mg doses (once daily for 7 days; 8 subjects in each group, including 2 receiving placebos). Serial samples of blood and urine were collected and drug concentrations were determined by high turbulence liquid chromatography-LC/MS/MS. Tolerability assessments were performed throughout the study. Adverse events (AEs) were determined from general health-related questions and self-reports. Results Thirty-six (mean [SD]; age, 23.6 [2.7] years; weight, 70.0 [6.9] kg) and 25 Korean male subjects (age, 23.5 [3.1] years; weight 69.4 [9.4] kg) were enrolled in the single- and multiple-dose studies, respectively. The data from subjects administered lobeglitazone who completed the study (27, single; 18, multiple) was included in the PK analyses. In the single-dose study, the AUC and C max of lobeglitazone increased with the dose. After repeated dosing for 7 days, the accumulation ratio ranged from 1.1 to 1.4. A total of 25 AEs were reported by 11 (30.6%) and 8 subjects (33.3%) in the single- and multiple-dose studies, respectively. All AEs were mild in intensity and not serious. Conclusions Lobeglitazone was well tolerated in this small, selected group of healthy male Korean volunteers. The AUC and C max of lobeglitazone increased in a dose-proportional manner from 1 to 4 mg.

Background The combination of glimepiride and metformin is used for glycemic control in patients with diabetes mellitus. A fixed-dose combination of glimepiride/metformin 2/500 mg slow-release (SR) formulation was developed to improve compliance in polymedicated patients. To accommodate the various dosing regimens of glimepiride, a glimepiride/metformin 1/500 mg SR tablet was also developed. Objective The goal of this study was to compare the pharmacokinetic properties of SR fixed-dose combinations of glimepiride/metformin 2/500 mg and the newly developed glimepiride/metformin 1/500 mg formulation to meet the regulatory requirements for marketing in Korea. Methods An open-label, randomized, 2-treatment, 2-period, 2-sequence crossover study was conducted with healthy male volunteers. Eligible subjects were randomly assigned to receive a single dose of glimepiride/metformin 1/500 mg SR (test) or glimepiride/metformin 2/500 mg SR (reference) followed by a 1-week washout period and then administration of the alternate treatment. Serial blood samples were collected immediately before and after dosing for 30 hours, and plasma concentrations were determined by using LC-MS/MS with validated methods. Adverse events were assessed by subjects' self-report and interviews addressing general health-related issues. Safety profiles were evaluated throughout the study. Results Thirty-three subjects were enrolled (mean [SD] age: 27.9 [4.95] years [range, 21–40 years]). Safety profiles were assessed for all 32 subjects who were administered the study drugs, and pharmacokinetic characteristics were evaluated in the 30 subjects who completed the study. The geometric mean ratios (90% CIs) of test to reference for the dose-normalized C max and AUC 0–last of glimepiride were 0.98 (0.90–1.07) and 1.06 (0.98–1.14), respectively. In the case of metformin, the geometric mean ratios (90% CIs) of test to reference for C max and AUC 0–last were 1.06 (0.98–1.15) and 1.04 (0.97–1.12), respectively. Nine adverse events were reported. Among them, loose stool, abdominal pain, and headache were considered to be likely related to the study drug. All reported adverse events were mild in intensity. Conclusions Dose-proportional characteristics of glimepiride and comparable pharmacokinetic properties of metformin were observed between the SR fixed-dose combinations of glimepiride/metformin 1/500 mg and 2/500 mg. A single dose of either treatment was well tolerated, and the safety profiles of the 2 treatments were comparable in this small, selected all-male group of healthy Korean volunteers. ClinicalTrials.gov identifier: NCT00934323.

The aim of this study was to compare the pharmacokinetics (PK) and safety of fimasartan (BR-A-657), an angiotensin II receptor antagonist, between healthy young (19 - 45 years) and older (≥ 65 years) male subjects.To assess the effect of age on PK and safety, fimasartan was administered as a single 240 mg tablet to 12 young and 10 older male subjects, followed by serial blood sampling over 48 h. Plasma concentrations of fimasartan were analyzed using validated HPLC-MS/MS. Clinical and laboratory adverse events were assessed.After oral administration of 240 mg fimasartan, the mean area under the plasma concentration-time curve from time zero to infinity (AUC(0→∞)) was 2899.0 ng/ml/h in the older, which was significantly greater than in young subjects (1767.4 ng/ml/h; p = 0.03). The geometric mean AUC(0→∞) was 69.4% higher in older than in young subjects. The maximum plasma concentration (C(max)), time to reach C(max) and elimination half-life for fimasartan did not differ significantly between the older and young groups. Importantly, fimasartan was well tolerated during this study.While some PK parameters were statistically different between the two groups, the effect of age on the PK was modest (e.g., AUC increasetwofold in older subjects).

Epoxyeicosatrienoic acid (EET) regulates the functional integrity of the endothelium. It is hypothesized that the activity of epoxide hydrolase ( EPHX2), which determines EET concentration through hydrolysis, may affect the progression of glomerulonephritis. Here, we evaluated the relationship between genetic variations, the in vivo activity of EPHX2, and progression of IgA nephropathy (IgAN). Three single-nucleotide polymorphisms (SNPs) [rs41507953 (K55R), rs751141 (R287Q), and rs1042032] were traced in 401 IgAN patients and 402 normal healthy controls. The in vivo activity of EPHX2 was assessed by measuring substrates/metabolites of the enzyme. None of the polymorphism frequencies differed significantly between patients and controls. However, patients carrying the variant allele (A) of rs751141 possessed better kidney survival than those with the wild-type allele (G; P < 0.001). This association remained significant after adjustment for several risk factors (hazard ratio 1.83, 95% confidence interval 1.13–2.96, P = 0.014). Vascular damage was more prominent in kidney biopsies from patients carrying the G allele of rs751141. The in vivo activity of EPHX2, assessed by the epoxyoctadecenoic acid/dihydroxyoctadecenoic acid ratio using liquid chromatography/mass spectrometry analysis, was elevated in patients with the G allele. The expression of EPHX2 in the human kidney was independent of the sequence variation of the rs751141 allele. Variant rs41507953 was not present in this cohort, and rs1042032 was not associated with progression. Thus the specific measures which regulate EPHX2 activity should be designed for potential therapeutics.

Lithocholic acid (LCA) is an endogenous compound associated with hepatic toxicity during cholestasis. LCA exposure in mice resulted in decreased serum lysophosphatidylcholine (LPC) and sphingomyelin levels due to elevated lysophosphatidylcholine acyltransferase (LPCAT) and sphingomyelin phosphodiesterase (SMPD) expression. Global metabolome analysis indicated significant decreases in serum palmitoyl-, stearoyl-, oleoyl-, and linoleoyl-LPC levels after LCA exposure. LCA treatment also resulted in decreased serum sphingomyelin levels and increased hepatic ceramide levels, and induction of LPCAT and SMPD messenger RNAs (mRNAs). Transforming growth factor-β (TGF-β) induced Lpcat2/4 and Smpd3 gene expression in primary hepatocytes and the induction was diminished by pretreatment with the SMAD3 inhibitor SIS3. Furthermore, alteration of the LPCs and Lpcat1/2/4 and Smpd3 expression was attenuated in LCA-treated farnesoid X receptor-null mice that are resistant to LCA-induced intrahepatic cholestasis. Conclusion: This study revealed that LCA induced disruption of phospholipid/sphingolipid homeostasis through TGF-β signaling and that serum LPC is a biomarker for biliary injury. (HEPATOLOGY 2011;)

A simultaneous simple, rapid, and sensitive LC–MS–MS method was developed and validated for the determination of HM30181A, [2-(2-{4-[2-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-ethyl]-phenyl}-2H-tetrazol-5-yl]-4,5-dimethoxy-phenyl]amide, as a P-glycoprotein inhibitor and its two metabolites, M1 and M2, in human plasma using docetaxel as an internal standard (IS). The analytes were extracted from 200 μL of biological sample by liquid–liquid extraction using 1 mL of methyl-t-butyl ether. Chromatographic separation was carried on a Luna C8 column at 30 °C with mobile phase consisting of distilled water with 0.1% formic acid and acetonitrile (75:25, v/v) at a flow rate of 0.7 mL min−1 for human plasma samples. The method was linear over concentration ranges of 0.5–50, 0.1–10, and 0.1–10 ng mL−1 for HM30181A, M1, and M2, respectively, in human plasma. The values of coefficient variation for the assay precision were

Background Bicalutamide is an oral nonsteroidal antiandrogenic drug used in the treatment of prostate cancer. A new generic 50-mg tablet formulation of bicalutamide has recently been developed. Objective This study evaluated the relative bioavailability and tolerability of the new generic formulation of bicalutamide 50-mg tablets (test) and the currently marketed formulation (reference) in healthy Korean male subjects. The study was conducted to meet Korean regulatory requirements for authorization to market the generic formulation. Methods This was a randomized-sequence, open-label study in which healthy Korean male subjects (aged 20–55 years) received single doses of the test and reference formulations in a 2-period crossover fashion, with a 6-week washout period between doses. Blood samples for the determination of plasma bicalutamide concentrations were obtained at regular intervals over 672 hours after dose administration. Pharmacokinetic parameters were determined using noncompartmental methods. Relative bioavailability was evaluated by comparing the log-transformed C max and AUC 0–672 of the 2 formulations; Korean regulatory requirements for the assumption of bioequivalence were met if the 90% CIs fell within the range of 0.80 to 1.25. Tolerability was assessed based on physical examinations, vital signs, clinical laboratory tests, electrocardiograms (ECGs), and adverse events (AEs) (spontaneously reported or observed by investigators). Results Of 47 volunteers screened for inclusion, 38 were enrolled and 32 completed the study (mean [SD] age, 24.9 [3.7] years; mean height, 173.8 [6.2] cm; mean weight, 66.1 [7.1] kg). Median T max was 24 hours for both formulations. The C max of the test and reference formulations was 1176.2 (191.6) and 1118.9 (209.5) μg/L, respectively. The corresponding values for AUC 0–672 were 277,503 (66,865) and 271,961 (75,597) μg · h/L. The 90% CIs for the geometric mean ratios of log-transformed C max and AUC 0–672 were 1.00 to 1.11 and 0.99 to 1.07, respectively. Thirty-three AEs were reported, including 17 events in 9 subjects who received the test formulation and 16 events in 12 subjects who received the reference formulation. All AEs were mild, and no subjects discontinued the study because of AEs. Conclusions In this single-dose study in healthy Korean male subjects, the pharmacokinetic parameters of the new generic formulation of bicalutamide 50-mg tablets did not differ significantly from those of the reference formulation. The new generic formulation met Korean regulatory criteria for the assumption of bioequivalence to the currently marketed formulation. Both formulations were well tolerated. Korea Food and Drug Administration registration number: PSPD 3057.

We investigated genetic polymorphisms in the pregnane X receptor (NR1I2) in Korean individuals (n = 83) and the effects of NR1I2 genotypes on rifampin-mediated induction of bupropion hydroxylation. The pharmacokinetics of bupropion and hydroxybupropion were evaluated after an oral dose of bupropion (150 mg) administered before and after rifampin treatment for 7 days in 35 healthy subjects. The area under the time-concentration curve (AUC) ratio of hydroxybupropion to bupropion in CYP2B6*6 carriers was significantly lower than that in CYP2B6*6 noncarriers in both the basal and rifampin-induced states (p = 0.012). Among the CYP2B6*6 carriers (n = 13), the NR1I2 TGT (-25385T + g.7635G + g.8055T) carriers exhibited a significantly lower AUC ratio, representing the CYP2B6 hydroxylation activity, compared with the TGT noncarriers, in the induced state (11.9 versus 20.3, p = 0.045). The percent difference in the AUC ratio between the basal and induced states was also significantly different (212% versus 58.8%, p = 0.006). However, no significant difference was observed among the NR1I2 TGT genotypes for the CYP2B6*6 noncarriers (n = 22). In conclusion, it is suggested the NR1I2 TGT genotype decreases the bupropion hydroxylation induced by treatment with rifampin, particularly in CYP2B6*6 carriers.

Objective: This study compared the bioavailability and tolerability of a fixed-dose combination (FDC) tablet of glimepiride/metformin 2/500 mg and glimepiride 2-mg + metformin 500-mg tablets administered separately in healthy Korean subjects. Methods: In this single-dose, open-label, 2-period crossover study, healthy Korean volunteers were randomly assigned to receive, in 1 of 2 randomized sequences, an FDC tablet of glimepiride/metformin 2/500 mg (test) and glimepiride 2-mg + metformin 500-mg tablets administered separately (reference), with a 1-week washout period between treatments. Plasma concentrations of glimepiride and metformin were measured using LC/MS-MS. Pharmacokinetic parameters were analyzed using noncompartmental methods. Bioequivalence was concluded if the 90% CIs of the geometric mean test/reference ratios (GMRs) of the logarithm-transformed C max , AUC from 0 to 30 hours (AUC 0–30 ), and AUC 0−∞ values were within the predetermined regulatory range of 80% to 125%. Tolerability was assessed using physical examination and laboratory analysis. Results: A total of 32 subjects were enrolled (16 men [mean (SD) age, 21.8 (2.7) years (range, 18–26 years); weight, 68.9 (8.3) kg (range, 55.5–85.0 kg)]; 16 women [age, 23.5 (4.5) years (range, 20–38 years); weight, 51.7 (3.5) kg (range, 46.8–58.0 kg)]). The GMRs (90% CI) of glimepiride C max , AUC 0–30 , and AUC 0−∞ were 1.01 (0.91–1.11), 0.98 (0.92–1.03), and 0.97 (0.93–1.04), respectively. For metformin, these values were 0.96 (0.87–1.06), 0.96 (0.90–1.03), and 0.96 (0.90–1.03). A total of 49 adverse events (AEs) were reported in 10 subjects (31.3%) with the FDC and in 13 subjects (40.6%) with the separate tablets. The most commonly reported AEs with the test and reference treatments were dizziness (6 [19%] and 7 [22%]) and sweating (4 [13%] and 7 [22%]), respectively. The severity of all of the AEs was considered to be mild, and there were no significant differences in the prevalences of AEs between the 2 formulations. Conclusions: In this study in healthy Korean subjects, the requirements for bioequivalence of the glimepiride/metformin 2/500-mg FDC and coadministration of separate tablets of each drug were met. Both formulations were generally well tolerated.

Farnesoid X receptor (FXR) is a nuclear receptor that regulates genes involved in synthesis, metabolism, and transport of bile acids and thus plays a major role in maintaining bile acid homeostasis. In this study, metabolomic responses were investigated in urine of wild-type and Fxr-null mice fed cholic acid, an FXR ligand, using ultra-performance liquid chromatography (UPLC) coupled with electrospray time-of-flight mass spectrometry (TOFMS). Multivariate data analysis between wild-type and Fxr-null mice on a cholic acid diet revealed that the most increased ions were metabolites of p-cresol (4-methylphenol), corticosterone, and cholic acid in Fxr-null mice. The structural identities of the above metabolites were confirmed by chemical synthesis and by comparing retention time (RT) and/or tandem mass fragmentation patterns of the urinary metabolites with the authentic standards. Tauro-3alpha,6,7alpha,12alpha-tetrol (3alpha,6,7alpha,12alpha-tetrahydroxy-5beta-cholestan-26-oyltaurine), one of the most increased metabolites in Fxr-null mice on a CA diet, is a marker for efficient hydroxylation of toxic bile acids possibly through induction of Cyp3a11. A cholestatic model induced by lithocholic acid revealed that enhanced expression of Cyp3a11 is the major defense mechanism to detoxify cholestatic bile acids in Fxr-null mice. These results will be useful for identification of biomarkers for cholestasis and for determination of adaptive molecular mechanisms in cholestasis.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • The importance of efficient drug development using biomarkers has been increasingly emphasized, from preclinical studies to clinical trials. • However, as yet few ‘validated’ or ‘qualified’ biomarkers are used in early-stage drug development in terms of clinical pharmacology and disease pathophysiology. WHAT THIS STUDY ADDS • This first-time-in-human study provides evidence of the pharmacological activity of LC15-0444 in humans, by using dipeptidyl peptidase IV activity and active glucagon-like peptide-1 concentrations. • LC15-0444 possesses pharmacokinetic and pharmacodynamic characteristics that support a once-daily dosing regimen. AIMS LC15-0444 is a selective and competitive inhibitor of dipeptidyl peptidase (DPP) IV with potential for the treatment of Type 2 diabetes. The aim was to investigate the pharmacokinetic (PK) and pharmacodynamic (PD) profiles after multiple oral ascending doses of LC15-0444 in healthy male subjects. METHODS A dose block-randomized, double-blind, placebo-controlled, parallel group study was performed in three groups with 10 subjects (eight for active drug; two for placebo) per group; each group received 200, 400 or 600 mg of LC15-0444 once daily for 10 days. Blood and urine samples were collected up to 24 h after the first dosing and up to 72 h after the last dosing. RESULTS The LC15-0444 concentration–time profiles exhibited characteristics of multicompartment disposition. No dose- or time-dependent change in PK parameters was observed. Mean elimination half-life was in a range 16.6–20.1 h in the dose groups. Mean renal clearance and fraction of unchanged drug excreted in urine was 18.6–21.9 and 0.40–0.48 l h−1, respectively. In the steady state, mean accumulation ratios by dose groups were between 1.22 and 1.31. More than 80% inhibition of DPP IV activity from baseline was sustained for >24 h in all dose groups. CONCLUSIONS This study provides evidence of the pharmacological activity of LC15-0444 in humans. LC15-0444 possesses PK and PD characteristics that support a once-daily dosing regimen.

Background: Coadministration of glimepiride and metformin has been used to achieve glucose control. Because compliance with a multiple medication regimen can be difficult for some patients, combination tablets of glimepiride + metformin might be a suitable alternative for these patients. Objective: This study was conducted to compare the pharmacokinetics of test and reference formulations of glimepiride + metformin fixed-dose combination tablets under fasting conditions to meet the regulatory requirements for marketing approval of a new drug in Korea. Methods: This was a single-dose, randomized, open-label, 2-period, 2-way crossover study conducted between March 2007 and May 2007. Healthy fasting Korean men were randomized to 1 of 2 dosing sequences: a single oral administration of a fixed-dose glimepiride 1-mg + metformin 500-mg combination tablet (test) followed by single oral administration of a fixed-dose glimepiride 2 mg + metformin 500 mg combination tablet (reference), separated by a 1-week washout period between doses; or a single oral administration of a fixed-dose glimepiride 2-mg + metformin 500-mg combination tablet followed by single oral administration of a fixed-dose glimepiride 1 mg + metformin 500-mg combination tablet, separated by a 1-week washout period between doses. Serial samples of blood were collected up to 24 hours after oral administration, and drug concentrations in plasma were determined by HPLC-MS/MS. Tolerability was assessed based on adverse events and changes in clinical parameters. Serious adverse events included those that resulted in death, a life-threatening condition, congenital anomaly or birth defect, or required hospitalization or prolongation of existing hospitalization. Results: A total of 30 healthy male subjects (mean age, 25.6 years [range, 20–36 years]; weight, 69.5 kg [range, 58.2–90.7 kg]) participated in the study. After administration of the test and reference formulations, glimepiride was rapidly absorbed, reaching C max with a median T max of 1.75 and 2.0 hours, respectively, and then declined exponentially with an average t½ of 8.2 and 8.5 hours. The individual C max and AUC last of glimepiride were observed to be proportionally increased according to the administered glimepiride dose. The mean (SD) dose-normalized Cmax values of glimepiride 1 and 2 mg were 168.2 (54.9) and 149.9 (47.4) ng/mL/mg, respectively; the mean dose-normalized AUC last values of glimepiride 1 and 2 mg were 681.5 (190.3) and 635.8 (194.1) ng · h/mL/mg. Individual plots of dose-normalized C max and AUC last values identified a similarity between the 2 groups but no significant between-group differences. A total of 25 adverse events (12 after the test dose and 13 after the reference dose) were reported by 13 of the 30 subjects. All adverse events were considered mild. Twenty-one adverse events were considered related to the study drug (8 after the test dose and 13 after the reference dose). Adverse events believed to be related to the test formulation were diarrhea (4 cases), dizziness (1), headache (1), tingling sensation (1), and weakness (1). Adverse events believed to be related to the reference formulation were diarrhea (6 cases), headache (3), cold sweats (1), dyspepsia (1), epigastric discomfort (1), and lethargy (1). There were no clinically significant findings in the laboratory test results or vital sign monitoring during the study. There were no serious adverse events reported. Conclusions: The C max and AUC last of glimepiride increased proportionally according to the administered glimepiride dose in this study of healthy, fasting Korean men. The safety profiles of the 2 combination tablets were comparable.

Three kinds of herbal medicines, commonly used in Korea, Angelicae tenuissima radix, Angelicae dahuricae radix and Scutellariae radix were studied to evaluate their effect on cytochrome P450 (CYP) activities in healthy volunteers. A total of 24 healthy male volunteers were assigned to one of three parallel herbal treatment groups, each consisting of eight volunteers. A cocktail of probe drugs for CYP enzymes was orally administered before and after multiple administrations of herbal medicines, three times a day for 13 days. Probe drugs used to measure CYP activities were caffeine (CYP1A2), losartan (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), chlorzoxazone (CYP2E1) and midazolam (CYP3A4). The probe drugs and their metabolites were quantified in plasma or urine using HPLC or LC-MS/MS. Changes in each CYP activity was evaluated by metabolic ratio of the probe drug (concentration ratio of metabolite to parent form at reference time point) following the herbal medication period, compared to the baseline values. A. dahuricae radix significantly decreased CYP1A2 activity to 10% of baseline activity (95% CI: 0.05-0.21). S. radix also showed significant changes in CYP2C9 and CYP2E1 activities. Compared to baseline values, the metabolic activities of losartan were decreased to 71% (0.54-0.94). In addition, S. radix showed a 1.42-fold (1.03-1.97) increase in chlorzoxazone metabolic activity. However, CYP activities were not meaningfully influenced by A. tenuissima radix. Changes in certain CYP activities were observed after the administration of S. radix and A. dahuricae radix in healthy volunteers. Therefore, herbal medicines containing S. radix or A. dahuricae radix are candidates for further evaluation of clinically significant CYP-mediated herb-drug interactions in human beings.

Background : LC15-0444 is a selective inhibitor of dipeptidyl peptidase (DPP) IV under investigation in Korea for the treatment of type 2 diabetes. Objective : The aim of this study was to investigate the pharmacokinetic (PK), pharmacodynamic (PD), and tolerability profiles of a single dose of LC15-0444 in healthy male subjects. Methods : A dose—block-randomized, double-blind, placebo-controlled, ascending single-dose, Phase I study was performed in healthy Korean male subjects assigned to receive 25, 50, 100, 200, 400, or 600 mg of LC15-0444 capsules. Blood and urine samples were collected up to 72 hours after administration. Plasma and urine drug concentrations were determined by tandem mass spectrometry coupled with high-performance liquid chromatography. DPP IV activity was measured by continuous spectrophotometric assay. An additional food effect study was performed in the 100-mg dose group; changes in PK and PD parameters after highfat diet were evaluated. Adverse events (AEs) were detected through investigator inquiries, spontaneous reports, and clinical evaluations such as physical examinations, vital sign measurements, 12-lead electrocardiography, clinical laboratory tests (eg, hematology, blood chemistry, coagulation, urinalysis), and computerized impedance cardiography. Results : Sixty Korean men (mean age, 25.3 years [range, 19-39 years]; weight, 68.3 kg [range, 53.6-84.9 kg]) were enrolled, providing 10 subjects for each dose group. After administration, LC15-0444 reached T max at 0.5 to 5.1 hours, and was eliminated with a t ½ of 16.7 to 21.3 hours. The mean fraction of unchanged drug excreted in urine ranged from 0.21 to 0.34 and mean renal clearance was 15.5 to 23.6 L/h. The dose-normalized AUC exhibited dose-linearity over the range of 50 to 400 mg. All doses of LC15-0444 =200 mg were found to inhibit 80% of DPP IV activity for 24 hours. High-fat diet did not significantly influence the AUC of LC15-0444. LC15-0444 was generally well tolerated. None of the subjects developed any serious clinical or laboratory AEs or discontinued the study due to an AE. All AEs were mild or moderate, and no dose-related trends were observed. Fortysix AEs were reported in 18 subjects (30.0%). AEs considered to be related to the study drug were headache (6 cases), dizziness (2), nausea (1), epistaxis (1), and increased heart rate (1). All AEs resolved spontaneously. Conclusions : A single dose of LC15-0444 exhibited linear PK properties over the range of 50 to 400 mg in these healthy Korean male subjects. PK characteristics were not significantly influenced by food. In addition, doses ≥200 mg of LC15-0444 inhibited plasma DPP IV activity by >80% over a 24-hour dosing interval, and a 600-mg dose increased active glucagon-like peptide-1 levels after a standardized meal. LC15-0444 was generally well tolerated.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • The phosphodiesterase (PDE) type 5 inhibitor is a widely used agent that facilitates penile erection. • Udenafil is newly developed as a PDE-5 inhibitor. WHAT THIS STUDY ADDS • This is the first study to determine the safety, tolerability and pharmacokinetics of udenafil in healthy subjects. • Udenafil was safe and well tolerated in healthy Korean subjects. • The AUC and Cmax of udenafil increased supraproportionally with increasing dose upon single administration, but there was no significant drug accumulation upon multiple administrations. AIM To evaluate the safety, tolerability and pharmacokinetics (PK) of udenafil, a novel phosphodiesterase type 5 inhibitor. METHODS A double-blind, randomized, placebo-controlled, dose-rising, parallel-group, single- and multiple-dose study was conducted in healthy Korean subjects. The subjects were allocated to single-dose groups of 25, 50, 100, 200 or 300 mg (eight subjects in each dose group, including two placebos), or to multiple-dose groups of 100 or 200 mg (once-daily dosing for 7 days; nine subjects in each dose group, including three placebos). Serial samples of blood and urine were collected after oral administration and the drug concentrations in plasma and urine were determined by high-performance liquid chromatography. Safety and tolerability were evaluated by monitoring clinical laboratory parameters and adverse events. RESULTS Udenafil reached peak plasma concentrations at 0.8–1.3 h, and then declined mono-exponentially with a terminal half-life of 7.3–12.1 h in the single-dose study. The area under the time–concentration curves (AUC) and maximum plasma concentrations (Cmax) increased supraproportionally with increasing dose in the single-dose study. During multiple dosing, a steady state was reached at 5 days and little accumulation occurred after repeated dosing for 7 days. Udenafil was generally well tolerated in these healthy subjects, and no serious adverse events occurred. CONCLUSIONS Udenafil was safe and well tolerated in healthy volunteers. The AUC and Cmax of udenafil increased supraproportionally with increasing dose upon single administration, but there was no significant drug accumulation upon multiple administrations.

This study was carried out to determine whether polymorphisms of organic anion-transporting polypeptide 1B1 (OATP1B1) have an effect on rosuvastatin pharmacokinetics in Koreans. Among 200 subjects genotyped for OATP1B1 c.388A>G, and c.521T>C, 30 subjects were selected for the rosuvastatin pharmacokinetic study. The area under the concentration-time curve for 0 to infinity (AUC(0-infinity)) of rosuvastatin for group 1 (*1a/*1a, *1a/*1b, *1b/*1b), group 2 (*1a/*15, *1b/*15), and group 3 (*15/*15) were 111+/-49.3, 126+/-45.2, and 191+/-31.0 ng h/ml, respectively, with significant differences among the three groups (P=0.0429) and between *15/*15 and the other groups (P=0.0181). The maximum plasma concentration (Cmax) also showed a significant difference between *15/*15 and the other groups (P=0.0181). There were no significant differences in rosuvastatin-lactone pharmacokinetics among the three groups. The pharmacokinetic exposure of rosuvastatin was higher in the OATP1B1*15/*15 subjects than the others, suggesting a potential association between the OATP1B1 genetic polymorphisms and altered rosuvastatin pharmacokinetics in Korean populations.

The aim of this study was to develop a population pharmacokinetic (PK) model of udenafil and its active metabolite, DA-8164, in healthy subjects and patients with hepatic impairment (HI) and to estimate the optimal dosing recommendations for patients with HI.An open label, three parallel group, age and weight matched control study was conducted in 18 volunteers, six healthy subjects (n = 6) and patients with mild (Child-Pugh class A, n = 6) and moderate HI (Child-Pugh class B, n = 6). Serial blood samples were collected for up to 72 h after a single administration of udenafil 100 mg. A population PK model was developed using non-linear mixed effects modelling (nonmem, ver. 7.2). The simulated data from the final PK model and original data of healthy subjects were compared to identify the optimal dose for patients with HI.A two compartment model for both udenafil and DA-8164 best described the data. Prothrombin time on metabolic clearance of udenafil to DA-8164 was included in the final model as a covariate. Compared with the AUC(0,tlast ) value after administration of udenafil 100 mg to healthy subjects, the geometric mean ratios (95% confidence interval) after 100 mg and 75 mg udenafil administration were 1.21 (1.10, 1.32) and 0.74 (0.67, 0.81) in patients with mild HI, respectively. Meanwhile, those were 1.55 (1.43, 1.67) and 1.02 (0.92, 1.12) in patients with moderate HI, respectively.This study suggests that the recommended doses of udenafil are 100 mg and 75 mg in patients with mild and moderate HI, respectively.

Hyewon Chung,1,* Howard Lee,1,2,* HyeKyung Han,1 Hyungmi An,1 Kyoung Soo Lim,1,3 YongJin Lee,4 Joo-Youn Cho,1 Seo Hyun Yoon,1 In-Jin Jang,1 Kyung-Sang Yu1 1Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea; 2Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea; 3Department of Clinical Pharmacology and Therapeutics, CHA University School of Medicine and CHA Bundang Medical Center, Seongnam, Republic of Korea; 4Medical and Regulatory Affairs Team, Samyang Biopharmaceuticals Corporation, Seoul, Republic of Korea *These authors contributed equally tothis work Purpose: SYP-1018 is a lyophilized polymeric nanoparticle formulation of voriconazole that is under development for intravenous dosing. This study compared the pharmacokinetic and tolerability profiles of SYP-1018 with those of Vfend®, the marketed formulation of voriconazole. The effect of CYP2C19 polymorphism on the voriconazole pharmacokinetics was also evaluated. Methods: An open-label, two-treatment, two-period, two-sequence crossover study was conducted in 52 healthy male volunteers, who randomly received a single intravenous infusion of either of the two voriconazole formulations at 200 mg. Blood samples were collected up to 24 hours after drug administration for pharmacokinetic analysis. The plasma concentrations of voriconazole were determined using liquid chromatography with tandem mass spectrometry, and the pharmacokinetic parameters were estimated using a noncompartmental method. CYP2C19 genotype was identified in 51 subjects. Results: The geometric mean ratio (90% confidence interval) of SYP-1018 to Vfend® was 0.99 (0.93–1.04) for the maximum plasma concentrations (Cmax) and 0.97 (0.92–1.01) for the area under the concentration–time curve (AUC) from dosing to the last quantifiable concentration (AUClast). Nineteen homozygous extensive metabolizers (EMs, *1/*1), 19 intermediate metabolizers (IMs, *1/*2 or *1/*3), and ten poor metabolizers (PMs, *2/*2, *2/*3, or *3/*3) were identified, and the pharmacokinetic comparability between SYP-1018 and Vfend® was also noted when analyzed separately by genotype. The systemic exposure to voriconazole was greatest in the PM group, followed by the IM, and then the EM groups. Furthermore, the intrasubject variability for Cmax and AUClast was greater in IMs and PMs than in EMs. No serious adverse event occurred, and both treatments were well tolerated. Conclusion: SYP-1018 had comparable pharmacokinetic and tolerability profiles to Vfend® after a single intravenous infusion. CYP2C19 genotype affected not only the pharmacokinetics of voriconazole, but its intrasubject variability. SYP-1018 can be further developed as a clinically effective alternative to Vfend®. Keywords: voriconazole, pharmacokinetics, pharmacogenetics, CYP2C19

Background: Clopidogrel is a prodrug requiring metabolism by cytochrome P450 3A (CYP3A) isoenzymes, including CYP3A5, in order to be active. It is controversial whether clopidogrel interacts with CYP3A inhibitors. We investigated the influence of CYP3A5 polymorphism on the drug interaction of clopidogrel. Methods: In phase 1 of the study, we administered clopidogrel to 16 healthy volunteers who had the CYP3A5 non-expressor genotype (*3 allele) and 16 who had the CYP3A5 expressor genotype (*1 allele) with and without pretreatment with itraconazole, a potent CYP3A inhibitor. A platelet aggregation test was performed at baseline, 4 hours, 24 hours and 6 days after clopidogrel administration. In phase 2, we compared clinical outcomes of 348 patients treated with clopidogrel after successful coronary angioplasty with bare-metal stent implantation according to their CYP3A5 genotype; the primary end point was a composite of atherothrombotic events (cardiovascular death, myocardial infarction and non-hemorrhagic stroke) within 1 and 6 months after stent implantation. Results: In phase 1, the change in platelet aggregation after clopidogrel administration and pretreatment with itraconazole was greater among the subjects with the CYP3A5 expressor genotype than among those with the non-expressor genotype: 24.9% (standard deviation [SD] 13.9%) v. 6.2% (SD 13.5%) at 4 hours ( p p p p = 0.023). Multivariable analysis showed that the CYP3A5 polymorphism was a predictor of atherothrombotic events in clopidogrel users. Interpretation: People with the CYP3A5 non-expressor genotype are vulnerable to drug interactions between clopidogrel and CYP3A inhibitors. This phenomenon may be associated with worse outcomes in patients with the non-expressor genotype who are given clopidogrel after coronary angioplasty and implantation of bare-metal stents.

The aim of the present study was to evaluate the effects of polymorphisms in dopamine D2 receptor (DRD2) and cytochrome P450 (CYP) 2D6 genes on delta EEG power response to aripiprazole in healthy male volunteers. Seventeen volunteers were recruited according to the DRD2 Taq1A genotype, and separated into the following groups: homozygous wild-type (A2/A2, n = 7), heterozygous (A2/A1, n = 5) and homozygous variant-type (A1/A1, n = 5) groups. After enrollment in this study, they were genotyped for CYP2D6. The volunteers received single 10 mg oral doses of aripiprazole, in accordance with an open-label parallel group study design. Plasma levels of aripiprazole and its metabolite were determined and EEGs were obtained simultaneously. The pharmacodynamic parameter was absolute delta power in the Cz channel. The changes of delta power were not different according to DRD2 Taq1A genotypes. As to the CYP2D6 allele, the subjects had the following CYP2D6 genotypes: *10/*10 (n = 4), *1/*10 (n = 5), *1/*5 (n = 2), *1/*1 (n = 3), *2/*41 (n = 1), *2/*2 (n = 1), *2N/*10 (n = 1). Subjects exhibiting the *1/*5 and *1/*10 genotypes showed a trend toward high area under the plasma aripiprazole concentration-time curve (AUC), which was linearly related to area under the EEG response-time curve (AUEC). Our results demonstrate a need for further evaluation of the CYP2D6 genotypic effect on the pharmacodynamics of aripiprazole.

Background Pitavastatin is a potent, newly developed 3-hydroxy-3-methylglutaryl–coenzyme A reductase inhibitor for the treatment of hyperlipidemia. We characterized the effects of organic anion transporting polypeptide 1B1 (OATP1B1) alleles *1a, *1b, and *15 on the pharmacokinetics of pitavastatin. Methods Twenty–four healthy Korean volunteers who had previously participated in a pharmacokinetic study of pitavastatin (single oral dose, 1–8 mg) were further investigated. Subjects were grouped according to OATP1B1 genotype. Dose–normalized area under the plasma concentration–time curve (AUC) and peak plasma concentration (Cmax) values were analyzed, because different dosages were administered to subjects, whereas the pharmacokinetics showed linear characteristics. Results Dose-normalized pitavastatin AUCs for *1b/*1b (group 1), *1a/*1a or *1a/*1b (group 2), and *1a/*15 or *1b/*15 (group 3) were 38.8 ± 13.3, 54.4 ± 12.4, and 68.1 ± 16.3 ng · h · mL−1 · mg−1 (mean ± SD), respectively, with significant differences between all 3 groups (P = .008) and between subjects carrying and those not carrying the *15 allele (P = .004). Dose-normalized pitavastatin Cmax values were 13.2 ± 3.3, 18.2 ± 5.7, and 29.4 ± 9.6 ng · mL−1 · mg−1 in groups 1, 2, and 3, respectively, and also showed significant differences (P = .003) in a manner similar to that shown by AUC. No significant differences were found between the genotype groups in terms of dose-normalized AUC or Cmax values of pitavastatin lactone. Conclusion OATP1B1 variant haplotypes were found to have a significant effect on the pharmacokinetics of pitavastatin. These results suggest that the *15 allele is associated with decreased pitavastatin uptake from blood into hepatocytes and that OATP1B1 genetic polymorphisms have no effect on the pharmacokinetics of pitavastatin lactone. Clinical Pharmacology & Therapeutics (2005) 78, 342–350; doi: 10.1016/j.clpt.2005.07.003

Objective Our objective was to investigate the effect of the uridine 5′-diphosphate-glucuronosyltransferase (UGT) 2B15 genetic polymorphism on the pharmacokinetics and pharmacodynamics of lorazepam in basal, inhibited, and induced metabolic states in healthy normal volunteers. Methods Twenty-four healthy subjects were enrolled and grouped into UGT2B15*1/*1 or UGT2B15*2/*2 genotype groups. The pharmacokinetic and pharmacodynamic profiles of intravenous lorazepam were characterized before and after inhibition with 600 mg valproate once daily for 4 days and after induction with rifampin (INN, rifampicin) pretreatment (600 mg once daily for 10 days), with a washout period of 10 days between. The plasma concentrations of lorazepam and lorazepam glucuronide were analyzed before and at 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, and 48 hours after lorazepam administration by liquid chromatography-tandem mass spectrometry. Visual analog scale assessments and psychomotor coordination tests were administered before and up to 12 hours after drug administration. Results The UGT2B15*2/*2 group showed 0.58-fold (95% confidence interval, 0.43–0.72; P

Background and Objectives There have been considerable disagreements regarding the influence of MDR1 (ABCB1) polymorphisms on the disposition of P-glycoprotein (P-gp) substrates. We speculated that the unknown function of the A allele of exon 21 G2677T/A (Ala893Ser/Thr) provides one of the reasons for the contradictory results. This study was performed to clarify the effects of major MDR1 gene polymorphisms, including a variant A allele in exon 21, on fexofenadine pharmacokinetics. Methods We investigated the occurrence of 3 high-frequency single-nucleotide polymorphisms (SNPs) in exons 12 (C1236T), 21 (G2677T/A), and 26 (C3435T) of the MDR1 gene in 232 healthy Koreans, using a polymerase chain reaction-restriction fragment length polymorphism method, and performed haplotype analysis on these 3 SNPs. A single oral dose of 180 mg fexofenadine hydrochloride was administered to 33 healthy Korean male volunteers, who were divided into 6 groups based on the MDR1 genotype for the G2677T/A polymorphism in exon 21 and the C3435T polymorphism in exon 26. Results A strong linkage disequilibrium was observed among the 3 SNPs. The frequencies of the 4 major haplotypes, 1236C-2677A-3435C, C-G-C, T-G-C, and T-T-T, were 16.4%, 18.6%, 21.6%, and 32.2%, respectively. Fexofenadine disposition varied considerably among the groups. In the 2677AA/3435CC genotype group (n = 3), the values of area under the concentration-time curve from time 0 to 24 hours [AUC(0–24)] were significantly lower (P = .014) than those of the other 5 genotype groups (GG/CC, GT/CT, TT/TT, GA/CC, and TA/CT). As compared with the 2677GG/3435CC subjects, the AUC(0–24) values were 17% lower in the 2677AA/3435CC subjects and 47% higher in the 2677TT/3435TT subjects (GG/CC versus AA/CC versus TT/TT, 4017 ± 1137 ng · h/mL versus 3315 ± 958 ng · h/mL versus 5934 ± 2,064 ng · h/mL; P = .018). By stratification for genotypes at position 3435, homozygous 3435TT subjects were found to have significantly higher AUC(0–24) (P = .024) and maximum plasma concentration (P = .040) values than CC subjects [AUC(0–24), 5934 ± 2064 ng · h/mL versus 3998 ± 1241 ng · h/mL; maximum plasma concentration, 958 ± 408 ng/mL versus 673 ± 242 ng/mL]. Conclusions The plasma concentrations of fexofenadine after a single oral administration were lower in 2677AA/3435CC subjects than in subjects with the other 5 genotype combinations of the SNPs of G2677T/A and C3435T. These findings confirm the importance of analyzing MDR1 haplotypes and provide a plausible explanation for the conflicting results regarding the effect of MDR1 polymorphisms on the disposition of P-gp substrates. Clinical Pharmacology & Therapeutics (2004) 76, 418–427; doi: 10.1016/j.clpt.2004.08.002

Objective Our objective was to investigate the effect of the CYP3A5 genotype on the systemic clearance of midazolam in constitutive, inhibited, and induced metabolic conditions. Methods Nineteen healthy volunteers were grouped with regard to the CYP3A5*3 allele, into homozygous wild-type (CYP3A5*1/*1, n = 6), heterozygous (CYP3A5*1/*3, n = 6), and homozygous variant-type (CYP3A5*3/*3, n = 7) subject groups. The pharmacokinetic profile of intravenous midazolam was characterized before and after itraconazole administration (200 mg once daily for 4 days) and also after rifampin (INN, rifampicin) pretreatment (600 mg once daily for 10 days), with a washout period of 2 weeks in between. Results The pharmacokinetic profiles of midazolam and of its hydroxy metabolites did not show differences between the genotype groups under basal and induced metabolic conditions. However, during the inhibited metabolic state, the CYP3A5*3/*3 group showed a greater decrease in systemic clearance than was seen in the CYP3A5*1/*1 group (8.5 ± 3.8 L · h−1 · 70 kg−1 versus 13.5 ± 2.7 L · h−1 · 70 kg−1, P = .027). The 1′-hydroxymidazolam–to–midazolam area under the plasma concentration–time curve ratio was also significantly lower in the CYP3A5*3/*3 group (0.58 ± 0.35 versus 1.09 ± 0.37 for the homozygous wild-type group, P = .026). Conclusions The CYP3A5 genotype did not affect the pharmacokinetics of intravenous midazolam in the basal or induced states. However, during cytochrome P450 (CYP) 3A inhibition by itraconazole, individuals carrying the CYP3A5*1 allele were found to be less susceptible to changes in systemic clearance and showed higher 1′-hydroxymidazolam–to–midazolam area under the plasma concentration–time curve ratios, probably resulting from the relatively CYP3A4-specific inhibition caused by itraconazole. Clinical Pharmacology & Therapeutics (2004) 76, 104–112; doi: 10.1016/j.clpt.2004.03.009

A sensitive high-performance liquid chromatographic (HPLC) method with ultraviolet absorption detection (292 nm) was developed and validated for the determination of the new phosphodiesterase V inhibitor, DA-8159 (DA), in human plasma and urine. A single step liquid–liquid extraction procedure using ethyl ether was performed to recover DA and the internal standard (sildenafil citrate) from 1.0 ml of biological matrices combined with 200 μl of 0.1 M sodium carbonate buffer. A Capcell Pak C18 UG120 column ( 150 mm ×4.6 mm I.D., 5 μm) was used as a stationary phase and the mobile phase consisted of 30% acetonitrile and 70% 20 mM potassium phosphate buffer (pH 4.5) at a flow rate of 1.0 ml/min. The lower limit for quantification was 5 ng/ml for plasma and 10 ng/ml for urine samples. Within- and between-run accuracy and precision were ≤15 and ≤10%, respectively, in both plasma and urine samples. The recovery of DA from human plasma and urine was greater than 70%. Separate stability studies showed that DA is stable under the conditions of analysis. This validated assay was used for the pharmacokinetic analysis of DA during a phase I, rising dose study.

To evaluate the effect of the CYP2D6 genotype on the pharmacokinetics of tropisetron in healthy Korean subjects. A single 5-mg capsule of tropisetron was administered orally to 13 healthy subjects. Plasma concentrations were determined by validated HPLC procedures and data were analyzed by using noncompartmental linear PK methods. Four alleles, CYP2D6*1, CYP2D6*2 ×2, CYP2D6*5, and CYP2D6*10, were identified by PCR. Thirteen subjects, consisting of two homozygous carriers of the wild type allele (*1/*1), four heterozygous carriers of poor metabolizer (PM)-associated allele (*1/*10), six homozygous carriers of PM-associated alleles (four with *10/*10 and two with *5/*10), and one carrier of a duplicated allele *1/*2 ×2. All tested pharmacokinetic parameters (AUCinf, AUCinf NL70, Cmax, CmaxNL70, T1/2, and Tec) were significantly different among four different genotypic groups. The mean AUCs of carriers with the heterozygous PM-associated allele and the homozygous PM-associated allele were 1.9- and 6.8-higher than those of carriers with the wild type allele, respectively. In contrast, the mean AUC of carriers with a duplicated allele was 0.5-fold lower than that of those carriers with the wild type allele. The presence of CYP2D6*5, CYP2D6*10, and CYP2D6*2 ×2 has an important impact on the pharmacokinetics of tropisetron, which may influence clinical response to tropisetron therapy.

Metformin is a first-line drug for treating type 2 diabetes. Although metformin is known to phosphorylate AMP-activated protein kinase (AMPK), it is unclear how the glucose-lowering effect of metformin is related to AMPK activation. The aim of this study was to identify the urinary endogenous metabolites affected by metformin and to identify the novel underlying molecular mechanisms related to its anti-diabetic effect. Fourteen healthy male subjects were orally administered metformin (1000 mg) once. First morning urine samples were taken before and after administration to obtain metabolomic data. We then further investigated the anti-diabetic mechanism of metformin in vitro and in vivo. The fluctuation of the metabolite cortisol indicated that the neuroendocrine system was involved in the anti-diabetic effect of metformin. Actually we found that metformin induced AMPK/liver X receptor α (LXRα) phosphorylation, followed by pro-opiomelanocortin (POMC) suppression in rat pituitary cells. We confirmed this result by administering metformin in an animal study. Given that cortisol stimulates gluconeogenesis, we propose the anti-hyperglycemic effect of metformin is attributed to reduced POMC/adrenocorticotropic hormone (ACTH)/cortisol levels following AMPK/LXRα phosphorylation in the pituitaries.

In the field of nanomedicine, long term accumulation of nanoparticles (NPs) in the mononuclear phagocyte system (MPS) such as liver is the major hurdle in clinical translation. On the other hand, NPs could be excreted via hepatobiliary excretion pathway without overt tissue toxicity. Therefore, it is critical to develop NPs that show favorable excretion property. Herein, we demonstrated that micelle encapsulated 64Cu-labeled upconverting nanoparticles (micelle encapsulated 64Cu-NOTA-UCNPs) showed substantial hepatobiliary excretion by in vivo positron emission tomography (PET) and also upconversion luminescence imaging (ULI). Ex vivo biodistribution study reinforced the imaging results by showing clearance of 84% of initial hepatic uptake in 72 hours. Hepatobiliary excretion of the UCNPs was also verified by transmission electron microscopy (TEM) examination. Micelle encapsulated 64Cu-NOTA-UCNPs could be an optimal bimodal imaging agent owing to quantifiability of 64Cu, ability of in vivo/ex vivo ULI and good hepatobiliary excretion property.

Aims The pharmacokinetics of omeprazole and its metabolites in healthy subjects were evaluated to determine if a single dose of moclobemide inhibited CYP2C19 activity. Methods Sixteen volunteers, of whom eight were extensive metabolizers (EM) and eight were poor metabolizers for CYP2C19, participated in two studies. Venous blood samples were collected for 24 h after oral ingestion of 40 mg omeprazole with or without 300 mg moclobemide coadministration. The pharmacokinetic change of omeprazole, omeprazole sulphone and 5-hydroxyomeprazole concentrations were assessed to test for an interaction between omeprazole and moclobemide. Results The coadministration of moclobemide in EMs approximately doubled the mean AUC (from 1834 to 3760 ng ml−1 h) and Cmax (from 987 to 1649 ng ml−1) of omeprazole, and increased the AUC of omeprazole sulphone without changing AUC ratio of omeprazole to omeprazole sulphone. Moclobemide coadministration more than doubled the AUC ratio of omeprazole to 5-hydroxyomeprazole (from 2.5 to 5.3) in EMs, too. There was a significant decrease in Cmax and AUC of 5-hydroxyomeprazole in PMs but no significant changes were seen in the results for omeprazole and omeprazole sulphone AUCs. Conclusions A single dose of moclobemide resulted in significant suppression of CYP2C19 activity in EMs. We conclude that physicians prescribing moclobemide should pay attention to its pharmacokinetic interactions even on the first day of coadministration with CYP2C19 substrates.

Yu-Jung Cha,1,* Kyoung Soo Lim,2,* Min-Kyu Park,1 Stephen Schneider,3 Brian Bray,3 Myung-Chol Kang,3 Jae-Yong Chung,1 Seo Hyun Yoon,1 Joo-Youn Cho,1 Kyung-Sang Yu11Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, South Korea; 2Department of Clinical Pharmacology and Therapeutics, CHA University School of Medicine and CHA Bundang Medical Center, Seongnam, South Korea; 3Kainos Medicine USA Inc., Morrisville, NC, USA *These authors contributed equally to this workBackground: KM-023 is a new second-generation nonnucleoside reverse-transcriptase inhibitor that is under development for the treatment of human immunodeficiency virus (HIV) type 1 infection. Objective: This study determined KM-023 tolerability and pharmacokinetic characteristics in healthy subjects. Materials and methods: A randomized, double-blinded, placebo-controlled, dose-escalation study was conducted in 80 healthy South Korean male volunteers. The subjects were allocated to single- or multiple-dose (once daily for 7 days) groups that received 75, 150, 300, or 600 mg drug or placebo in a 4:1 ratio. Safety and pharmacokinetic assessments were performed during the study. Plasma and urine concentrations were quantified using liquid chromatography–tandem mass spectrometry. Results: The average maximum concentration (Cmax) and area under the concentration–time curve from time 0 to infinity (AUC∞) values of KM-023 for the 75–600 mg doses in the single-dose study ranged from 440.2 ng/mL to 1,245.4 ng/mL and 11,142.4 ng • h/mL to 33,705.6 ng • h/mL, respectively. Values of the mean Cmax at a steady state and AUC within the dosing interval ranged from 385.1 ng/mL to 1,096.7 ng/mL and 3,698.9 ng • h/mL to 10,232.6 ng • h/mL, respectively, following 75–600 mg doses in the multiple-dose study. Dose proportionality was not observed for KM-023. KM-023 showed a 0.6-fold accumulation after multiple doses in the 600 mg dose group. The mean half-life values ranged between 20.7 and 31.2 hours. KM-023 was generally well tolerated without serious adverse events. Conclusion: KM-023 demonstrated dose- and time-dependent nonlinear pharmacokinetic characteristics after single or multiple doses over a dose range (75–600 mg) in healthy subjects. KM-023 showed favorable tolerability in this study. This Phase I clinical trial information can be used to design further clinical studies appropriately to evaluate KM-023 in patients with HIV-1 infection. Keywords: KM-023, HIV-1, nonnucleoside reverse-transcriptase inhibitor, pharmacokinetics, tolerability, healthy subjects

Interethnic differences in genetic polymorphism in genes encoding drug-metabolizing enzymes and transporters are one of the major factors that cause ethnic differences in drug response. This study aimed to investigate genetic polymorphisms in genes involved in drug metabolism, transport, and excretion among Korean, Japanese, and Chinese populations, the three major East Asian ethnic groups.The frequencies of 1936 variants representing 225 genes encoding drug-metabolizing enzymes and transporters were determined from 786 healthy participants (448 Korean, 208 Japanese, and 130 Chinese) using the Affymetrix Drug-Metabolizing Enzymes and Transporters Plus microarray. To compare allele or genotype frequencies in the high-dimensional data among the three East Asian ethnic groups, multiple testing, principal component analysis (PCA), and regularized multinomial logit model through least absolute shrinkage and selection operator were used.On microarray analysis, 1071 of 1936 variants (50% of markers) were found to be monomorphic. In a large number of genetic variants, the fixation index and Pearson's correlation coefficient of minor allele frequencies were less than 0.034 and greater than 0.95, respectively, among the three ethnic groups. PCA identified 47 genetic variants with multiple testing, but was unable to discriminate ethnic groups by the first three components. Multinomial least absolute shrinkage and selection operator analysis identified 269 genetic variants that showed different frequencies among the three ethnic groups. However, none of those variants distinguished between the three ethnic groups during subsequent PCA.Korean, Japanese, and Chinese populations are not pharmacogenetically distant from one another, at least with regard to drug disposition, metabolism, and elimination.

Kyungho Jang, Seonghae Yoon, Sung-Eun Kim, Joo-Youn Cho, Seo Hyun Yoon, Kyoung Soo Lim, Kyung-Sang Yu, In-Jin Jang, Howard LeeDepartment of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of KoreaBackground: Megestrol acetate is an effective treatment for improving appetite and increasing body weight in patients with cancer-associated anorexia. However, Megace® oral suspension (OS), a micronized formulation of megestrol acetate, has low bioavailability in the fasting state. To overcome this limitation, a nanocrystal formulation has been developed. This study was performed to evaluate the pharmacokinetics and tolerability of the nanocrystal formulation and to compare them with those of Megace® OS in the fed and fasting states.Methods: A randomized, open-label, two-treatment, two-period, two-sequence, crossover study was performed in three parts in 93 healthy subjects. A single 625 mg/5 mL oral dose of a nanocrystal formulation was administered in the fasting and fed states (part I). In parts II and III, a single 625 mg/5 mL oral dose of the nanocrystal formulation or Megace® OS 800 mg/20 mL was given in the fed and fasting states, respectively. Blood samples were collected for up to 120 hours post dose for pharmacokinetic analysis. Tolerability was evaluated throughout the entire study period.Results: The nanocrystal formulation of megestrol acetate was rapidly absorbed in both the fed and fasting states. In the fed state, systemic exposure was comparable between the nanocrystal formulation of megestrol acetate and Megace® OS. In the fasting state, however, the peak plasma concentration and area under the plasma concentration-time curve to the last measurable concentration of megestrol acetate was 6.7-fold and 1.9-fold higher, respectively, for the nanocrystal formulation than for Megace® OS. No serious adverse events were reported.Conclusion: Systemic exposure to megestrol acetate is less affected by lack of concomitant food intake when it is administered using the nanocrystal formulation. The nanocrystal formulation of megestrol acetate could be more effective in treating patients with cachexia or anorexia.Keywords: megestrol acetate, nanocrystal formulation, food, anorexia