USP13 deubiquitinates p62/SQSTM1 to induce autophagy and Nrf2 release for activating antioxidant response genes.

SQSTM1/p62 (sequestosome 1) is a multifunctional protein that serves as a receptor for selective autophagy and scaffold. In selective autophagy, p62 functions as a bridge between polyubiquitinated proteins and autophagosomes. Further, p62 acts as a signaling hub for many cellular pathways including mTORC1, NF-κB, and Keap1-Nrf2. Post-translational modifications of p62, such as ubiquitination and phosphorylation, are known to determine its binding partners and regulate their intracellular functions. However, the mechanism of p62 deubiquitination remains unclear. In this study, we found that ubiquitin-specific protease 13 (USP13), a member of the USP family, directly binds p62 and removes ubiquitin at Lys7 (K7) of the PB1 domain. USP13-mediated p62 deubiquitination enhances p62 protein stability and facilitates p62 oligomerization, resulting in increased autophagy and degradation of Keap1, which is a negative regulator of the antioxidant response that promotes Nrf2 activation. Thus, USP13 can be considered a therapeutic target as a deubiquitination enzyme of p62 in autophagy-related diseases.

Comparison of Pharmacodynamics between Tegoprazan and Dexlansoprazole Regarding Nocturnal Acid Breakthrough: A Randomized Crossover Study.

Background/Aims: Tegoprazan, a novel potassium-competitive acid blocker, is expected to overcome the limitations of proton pump inhibitors and effectively control nocturnal acid breakthrough. To evaluate the pharmacodynamics of tegoprazan versus dexlansoprazole regarding nocturnal acid breakthrough in healthy subjects. Methods: In a randomized, open-label, single-dose, balanced incomplete block crossover study, 24 healthy male volunteers were enrolled and randomized to receive oral tegoprazan (50, 100, or 200 mg) or dexlansoprazole (60 mg) during each of two administration periods, separated by a 7- to 10-day washout period. Blood samples were collected for pharmacokinetic parameter analysis; gastric monitoring was performed for pharmacodynamic parameter evaluation. Results: All 24 subjects completed the study. Average maximum plasma concentration, area under the plasma concentration-time curve, and mean time with gastric pH >4 and pH >6 for tegoprazan demonstrated dose-dependent incremental increases. All the tegoprazan groups reached mean pH ≥4 within 2 hours, whereas the dexlansoprazole group required 7 hours after drug administration. Based on pharmacodynamic parameters up to 12 hours after evening dosing, 50, 100, and 200 mg of tegoprazan presented a stronger acid-suppressive effect than 60 mg of dexlansoprazole. Moreover, the dexlansoprazole group presented a comparable acid-suppressive effect with the tegoprazan groups 12 hours after dosing. Conclusions: All the tegoprazan groups demonstrated a significantly faster onset of gastric pH increase and longer holding times above pH >4 and pH >6 up to 12 hours after evening dosing than the dexlansoprazole group.

Pharmacokinetic and Pharmacodynamic Modeling and Simulation Analysis of Prasugrel in Healthy Male Volunteers.

This study evaluated the pharmacokinetics and pharmacodynamics of the antiplatelet agent prasugrel, and explored its optimal dose regimens via modeling and simulation using NONMEM. We measured platelet aggregation and the serial plasma concentrations of the inactive (R-95913) and active metabolites (R-138727) of prasugrel after a single oral dose of 10-60 mg in 20 healthy adult male volunteers. A pharmacokinetic model for R-95913 and R-138727, and a pharmacodynamic model between the concentration of R-138727 and maximal platelet aggregation measured by light transmittance were constructed. The predictability of the model for platelet aggregation was evaluated by comparing the model prediction values with the observed ones not used in the construction of the model. Pharmacokinetic data were best described by a 3-compartment models for R-95913, a 1-compartment model for R-138727 with transit compartment model for absorption delay, and first-pass metabolic conversion of R-95913 into R-138727 during absorption. The association-dissociation model between R-138727 and its receptor in platelets was applied for the inhibitory effect of prasugrel on platelet aggregation. Prasugrel rapidly inhibited platelet aggregation after oral administration, with a prolonged duration of action; however, the concentration of the active metabolite decreased rapidly, which may have been due to the slow dissociation rate of R-138727 from its target receptor in platelets. The external validation suggests that our model could be used to individualize prasugrel treatment in various clinical situations. Simulation showed rapid onset of inhibitory effect with great magnitude and consistent inhibition after therapeutic dose of prasugrel.

USP13 regulates HMGB1 stability and secretion through its deubiquitinase activity.

BACKGROUND: High mobility group box 1 (HMGB1) is a damage-associated molecular pattern (DAMP) molecule that plays a central role in innate immunity. HMGB1 acts as a late mediator of inflammation when actively secreted in response to inflammatory stimuli. Several post-translational modifications (PTMs), including acetylation, phosphorylation, and oxidation, are involved in HMGB1 secretion. However, the E3 ligases of HMGB1 and the mechanism by which DUBs regulate HMGB1 deubiquitination are not well known. METHODS: LC-MS/MS, proximity ligation assay, immunoprecipitation were used to identify ubiquitin-specific protease 13 (USP13) as a binding partner of HMGB1 and to investigate ubiquitination of HMGB1. USP13 domain mutant was constructed for domain study and Spautin-1 was treated for inhibition of USP13. Confocal microscopy image showed localization of HMGB1 by USP13 overexpression. The data were analyzed using one-way analysis of variance with Tukey's honestly significant difference post-hoc test for multiple comparisons or a two-tailed Student's t-test. RESULTS: We identified ubiquitin-specific protease 13 (USP13) as a novel binding partner of HMGB1 and demonstrated that USP13 plays a role in stabilizing HMGB1 from ubiquitin-mediated degradation. USP13 overexpression increased nucleocytoplasmic translocation of HMGB1 and promoted its secretion, which was inhibited by treatment with Spautin-1, a selective inhibitor of USP13. CONCLUSION: Taken together, we suggest that USP13 is a novel deubiquitinase of HMGB1 that regulates the stability and secretion of HMGB1.

Effect of Food on the Pharmacokinetics and Pharmacodynamics of a Single Oral Dose of Tegoprazan.

PURPOSE: Tegoprazan is a potassium-competitive acid blocker (P-CAB) that is designed to treat acid-related diseases through a fundamentally different mechanism than that of proton pump inhibitors (PPIs). Because PPIs inhibit only activated parietal cell H+/K+ adenosine triphosphatase, stimulation of parietal cells by a meal is necessary for optimal results. In contrast, P-CABs can inactivate proton pumps without acid activation and bind to both activated and inactivated adenosine triphosphatase. This study evaluates the effect of food consumption on the pharmacokinetic and pharmacodynamic properties of tegoprazan after a single oral dose in healthy men. METHODS: In this open-label, 2-period crossover study, 24 healthy men were randomized to 1 of 2 treatment sequence groups: administration of tegoprazan under the fasting condition and administration of tegoprazan under the fed condition. The dosing periods of both sequence groups were separated by a washout period of 7 days. At each dosing period, the participants received a single dose of 200 mg of tegoprazan followed by pharmacokinetic and pharmacodynamic analysis. FINDINGS: After the oral administration of 200 mg tegoprazan, the Cmax was decreased and delayed under the fed condition compared with that of the fasting condition. However, no significant differences were observed in the AUC and the time of gastric acid suppression (inhibition of integrated acidity) during 24 hours. IMPLICATIONS: The pharmacokinetic and pharmacodynamic properties of tegoprazan are independent of food effect; thus, tegoprazan could be administered regardless of the timing of food consumption in patients. ClinicalTrials.gov identifier: NCT01830309.

The risk of stroke/systemic embolism and major bleeding in Asian patients with non-valvular atrial fibrillation treated with non-vitamin K oral anticoagulants compared to warfarin: Results from a real-world data analysis.

BACKGROUND: Although randomized trials provide a high level of evidence regarding the efficacy of non-vitamin K oral anticoagulants (NOACs), the results of such trials may differ from those observed in day-to-day clinical practice. AIMS: To compare the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between NOAC and warfarin in clinical practice. METHODS: Patients with non-valvular atrial fibrillation (NVAF) who started warfarin/NOACs between January 2015 and November 2016 were retrospectively identified from Korea's nationwide health insurance claims database. Using inpatient diagnosis and imaging records, the Cox models with inverse probability of treatment weighting using propensity scores were used to estimate hazard ratios (HRs) for NOACs relative to warfarin. RESULTS: Of the 48,389 patients, 10,548, 11,414, 17,779 and 8,648 were administered apixaban, dabigatran, rivaroxaban and warfarin, respectively. Many patients had suffered prior strokes (36.7%, 37.7%, 31.4%, and 32.2% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), exhibited high CHA2DS2-VASc (4.8, 4.6, 4.6, and 4.1 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) and HAS-BLED (3.7, 3.6, 3.6, and 3.3 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) scores, had received antiplatelet therapy (75.4%, 75.7%, 76.8%, and 70.1% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), or were administered reduced doses of NOACs (49.8%, 52.9%, and 42.8% in apixaban, dabigatran, and rivaroxaban group, respectively). Apixaban, dabigatran and rivaroxaban showed a significantly lower S/SE risk [HR, 95% confidence intervals (CI): 0.62, 0.54-0.71; 0.60, 0.53-0.69; and 0.71, 0.56-0.88, respectively] than warfarin. Apixaban and dabigatran (HR, 95% CI: 0.58, 0.51-0.66 and 0.75, 0.60-0.95, respectively), but not rivaroxaban (HR, 95% CI: 0.84, 0.69-1.04), showed a significantly lower MB risk than warfarin. CONCLUSIONS: Among Asian patients who were associated with higher bleeding risk, low adherence, and receiving reduced NOAC dose than that provided in randomised controlled trials, all NOACs were associated with a significantly lower S/SE risk and apixaban and dabigatran with a significantly lower MB risk than warfarin.

First-in-Human Evaluation of the Safety, Tolerability, and Pharmacokinetics of a Neuroprotective Poly (ADP-ribose) Polymerase-1 Inhibitor, JPI-289, in Healthy Volunteers.

BACKGROUND: Poly (ADP-ribose) polymerase-1 (PARP-1) inhibitor has therapeutic potential for acute ischemic stroke by suppressing microglial activation and facilitating neuroprotection. In this first-in-human study, we investigate the safety, tolerability and pharmacokinetics (PK) of JPI-289 in healthy male volunteers. SUBJECTS AND METHODS: In single ascending dose (SAD) study, 35, 75, 150, 300, 600 mg JPI-289 or placebo was infused intravenously over 30 minutes to 40 subjects. In multiple ascending dose (MAD) study, 150, 300, 450 mg JPI-289 or placebo was infused over 1 hour every 12 hours to each of 24 subjects for 3.5 days (7 times). The plasma and urine concentrations of JPI-289 and its metabolites were determined. RESULTS: In the SAD study, AUClast and Cmax tended to increase supra-proportionally especially at higher doses in SAD study. However, Cmax showed dose-proportionality in the range of 75-600mg. JPI-289 reached a mean Tmax within 0.50 hour after dosing and a mean elimination half-life (t1/2) was 2.18 to 3.21 hours. In the MAD study, observed accumulation index ranged from 1.52 to 1.76. The effective half-life of JPI-289 was 1.88 to 3.05 hours, indicating that the plasma JPI-289 concentration rapidly reaches steady state. % recovered of JPI-289 measured in urine was 1.59-9.05%. In both studies, concentration of metabolites was less than 10% of JPI-289. Adverse events reported in the study were all mild in intensity and resolved without any sequelae. CONCLUSION: The tolerable dose ranges and pharmacokinetic characteristics of JPI-289 evaluated in these studies will be useful in further clinical development of JPI-289.

Pharmacokinetic modeling analysis of cilostazol and its active metabolites (OPC-13015 and OPC-13213) after multiple oral doses of cilostazol in healthy Korean volunteers.

Cilostazol is a selective inhibitor of phosphodiesterase III (PDE III), which is prescribed for patients with peripheral arterial disease, especially intermittent claudication. The purpose of the study was to investigate the pharmacokinetic (PK) of cilostazol and its metabolites on the immediate (IR) formulation of cilostazol in healthy Korean male volunteers by population PK modeling analysis implemented using NONMEM software.A 2 × 2 crossover study comparing multiple oral doses of IR and SR formulations of cilostazol were conducted. Serial plasma concentrations of cilostazol and its active metabolites were used in this analysis.The PK was best depicted by one-compartment model, with absorption kinetics of cilostazol having mixed first- and zero-order kinetics with a time delay at the beginning of absorption. The introduction of interoccasion variabilities into zero-order (D1), first-order (Ka), and relative bioavailability (F1) significantly improved the model fit, and total body water (TBW) was identified as a significant covariate positively affecting the clearance of cilostazol. The model validation suggested that the model constructed in this study predicted the plasma concentration of cilostazol and its two active metabolites reasonably well.The PK model we developed explored the PK characteristics of cilostazol in Korean male subjects, and may be useful for identifying optimal individual dosing regimens of cilostazol.

Pharmacokinetic and Pharmacodynamic Modeling and Simulation Analysis of CTB-001, a Recently Developed Generic of Bivalirudin.

PURPOSE: CTB-001, a recently developed generic version of bivalirudin, an FDA-approved anticoagulant used for prophylaxis and treatment of cardiovascular diseases, has shown good efficacy and safety in clinical trials. We characterized the pharmacokinetics (PK) and pharmacodynamics (PD) of CTB-001 by modeling and simulation analysis. METHODS: PK/PD data were collected from a randomized, double-blind, placebo-controlled, single-dose, dose-escalation phase 1 study conducted in 24 healthy Korean male subjects. PK/PD analysis was conducted sequentially by nonlinear mixed-effects modeling implemented in NONMEM®. Monte-Carlo simulations were conducted for PK, activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin time (TT). RESULTS: The CTB-101 PK was best described by a three-compartment linear model with a saturable binding peripheral compartment. All PD endpoints showed dose-response relationship, and their changes over time paralleled those of CTB-101 concentrations. A simple maximum effect model best described the aPTT, PT in INR, PT in seconds, and TT, whereas an inhibitory simple maximum effect model best described PT in percentages. The maximum duration of effect of CTB-001 on aPTT prolongation was 52.1 s. CONCLUSIONS: The modeling and simulation analysis well-characterized the PK and PD of CTB-001 in healthy Koreans, which will be valuable for identifying optimal dosing regimens of CBT-001.

Randomised clinical trial: safety, tolerability, pharmacokinetics, and pharmacodynamics of single and multiple oral doses of tegoprazan (CJ-12420), a novel potassium-competitive acid blocker, in healthy male subjects.

BACKGROUND: Tegoprazan (CJ-12420) is a potassium-competitive acid blocker (P-CAB) with therapeutic potential for gastro-oesophageal reflux disease (GERD) by reversibly suppressing gastric H+ /K+ -ATPase. AIMS: To investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of tegoprazan METHODS: A phase I, randomised, double-blind and placebo-controlled clinical trial was conducted in 56 healthy male subjects without Helicobacter pylori infection. In the single ascending dose study, 50, 100, 200 and 400 mg tegoprazan were administered to 32 subjects. In the multiple ascending dose study, 100 and 200 mg tegoprazan were administered every 24 hours to each of the eight subjects for 7 days. In the comparative pharmacodynamics study, 40 mg esomeprazole was administered to eight subjects every 24 hours for 7 days. The assessment included safety, tolerability, pharmacodynamics through monitoring of 24-hour gastric pH and pharmacokinetics of tegoprazan in plasma and urine. RESULTS: Tegoprazan was generally well tolerated. Most adverse events reported in the study were mild in intensity and resolved without any sequelae. Exposure to tegoprazan increased in a dose-proportional manner. Multiple dosing with tegoprazan showed no accumulation in plasma on day 7. The pharmacodynamic analysis revealed that tegoprazan showed rapid, dose-dependent gastric acid suppression. CONCLUSIONS: Tegoprazan was well tolerated and showed rapid and potent gastric acid suppression. This supports the further development of tegoprazan as a treatment for acid-related disorders.

Quantitative Modeling Analysis Demonstrates the Impact of CYP2C19 and CYP2D6 Genetic Polymorphisms on the Pharmacokinetics of Amitriptyline and Its Metabolite, Nortriptyline.

Amitriptyline is a tricyclic antidepressant that is metabolized mainly by CYP2C19 and CYP2D6 enzymes. Higher plasma levels of amitriptyline and its active metabolite, nortriptyline, are associated with an increased risk of adverse events including anticholinergic effects. The aim of this study was to evaluate the effects of CYP2C19 and CYP2D6 genetic polymorphisms on amitriptyline and nortriptyline pharmacokinetics. Twenty-four Korean healthy adult male volunteers were enrolled in the study after stratification by their CYP2C19 and CYP2D6 genotypes. Serial blood draws for pharmacokinetic analysis were made after a single oral 25-mg dose of amitriptyline was administered. Plasma amitriptyline and nortriptyline concentrations were measured by a validated liquid chromatography with tandem mass spectrometry. Population pharmacokinetic modeling analysis was conducted using NONMEM, which evaluated the effects of CYP2C19 and CYP2D6 genotypes on amitriptyline and nortriptyline pharmacokinetics. The biotransformation of amitriptyline into nortriptyline was significantly different between subjects with the CYP2C19*2/*2, *2/*3, and *3/*3 genotypes and those with the other genotypes, with an estimated metabolic clearance of 17 and 61.5 L/h, respectively. Clearance of amitriptyline through pathways other than biotransformation into nortriptyline was estimated as 18.8 and 30.6 L/h for subjects with the CYP2D6*10/*10 and *10/*5 genotypes and those with the other genotypes, respectively. This study demonstrated a quantitative effect of the CYP2C19 and CYP2D6 genotypes on amitriptyline and nortriptyline pharmacokinetics. Production of nortriptyline from amitriptyline was associated with CYP2C19 genotypes, and clearance of amitriptyline through pathways other than biotransformation into nortriptyline was associated with CYP2D6 genotypes. These observations may be useful in developing individualized, optimal therapy with amitriptyline.

Pharmacokinetic interactions and tolerability of rosuvastatin and ezetimibe: an open-label, randomized, multiple-dose, crossover study in healthy male volunteers.

PURPOSE: Rosuvastatin is a synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor that effectively reduces low-density lipoprotein cholesterol levels. However, statin monotherapy does not always achieve acceptable low-density lipoprotein cholesterol levels in patients with severe hypercholesterolemia. Ezetimibe, a selective cholesterol-absorption inhibitor, is approved for use as a monotherapy or combination therapy with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors for patients with hypercholesterolemia. The aim of this study was to examine the pharmacokinetics (PKs) of drug interactions between rosuvastatin and ezetimibe, and the tolerability of combined administration in healthy Korean male volunteers. SUBJECTS AND METHODS: Healthy subjects (n=24) were randomly allocated to 3 treatment groups: rosuvastatin (20 mg) alone, ezetimibe (10 mg) alone, and rosuvastatin (20 mg) plus ezetimibe (10 mg). The drugs were taken once every 24 hours over a period of 10 days. Blood samples were collected to analyze steady-state PKs. RESULTS: All adverse events observed during the study were mild, and the frequency was no higher for combined administration than for mono administration. For rosuvastatin, the steady-state mean ratios (90% CI) of the combined over the single dose were 1.076 (1.019-1.136) for AUCτ,ss and 1.099 (1.003-1.204) for concentration at steady-state, respectively. In the case of free and total ezetimibe, the steady-state ratios of AUCτ,ss and concentration at steady-state were 1.131 (1.051-1.218) and 1.182 (1.038-1.346), and 1.055 (0.969-1.148) and 0.996 (0.873-1.135), respectively. CONCLUSION: Combined administration of rosuvastatin and ezetimibe was well tolerated. No clinically significant PK interactions between rosuvastatin and ezetimibe were observed when the 2 drugs were administered concomitantly.

A randomized study of the efficacy and safety of parecoxib for the treatment of pain following total knee arthroplasty in Korean patients.

PURPOSE: Parecoxib is an injectable cyclooxygenase-2 inhibitor with proven postoperative analgesic efficacy in a variety of settings, including total knee arthroplasty (TKA). The effect of ethnicity on the efficacy of parecoxib for post-TKA pain has not been studied. PATIENTS AND METHODS: This was a parallel-group, double-blind, randomized, placebo- controlled study of ethnically Korean patients aged ≥18 years who had unilateral TKA. Patients who reported moderate or severe pain 6 hours after the end of postoperative opioid analgesia were randomized to receive a single intravenous dose of parecoxib sodium 40 mg or placebo. Patients were evaluated for 24 hours postdose. The primary efficacy endpoints included time-specific pain intensity difference (PID), time-specific pain relief (PR), and time to rescue medication. The incidence and nature of adverse events (AEs) assessed safety. RESULTS: Of the 116 patients randomized, 58 received parecoxib and 58 placebo. Mean (SD) PID was significantly greater for parecoxib vs placebo 1 hour postdose (0.69 [0.67] vs 0.40 [0.59], respectively; p<0.05), and for each time point up to 24 hours. Similarly, mean (SD) PR was significantly greater for parecoxib vs placebo 1.5 hours postdose (1.63 [0.85] vs 1.07 [0.90], respectively; p=0.001), and for each time point up to 24 hours. The median time (hours:minutes) to rescue medication was significantly longer for parecoxib vs placebo (21:30 vs 4:08, respectively; p<0.001). Generally, fewer AEs were reported with parecoxib than placebo, and the AE profile was consistent with previous studies. These results are comparable to the findings from a similarly designed study in a Caucasian patient population. CONCLUSION: Parecoxib 40 mg significantly improved postoperative pain vs placebo in Korean patients after TKA. The efficacy and safety of parecoxib in Korean patients is similar to that seen in Caucasian patients.

Population plasma and urine pharmacokinetics of ivabradine and its active metabolite S18982 in healthy Korean volunteers.

Ivabradine, a selective inhibitor of the pacemaker current (If ), is used for heart failure and coronary heart disease and is mainly metabolized to S18982. The purpose of this study was to explore the pharmacokinetics (PK) of ivabradine and S18982 in healthy Korean volunteers. Subjects in a phase I study were randomized to receive 2.5, 5, or 10 mg of ivabradine administered every 12 hours for 4.5 days, and serial plasma and urine concentrations of ivabradine and S18982 were measured. The plasma PK of ivabradine was best described by a 2-compartment model with mixed 0- and first-order absorption, linked to a 2-compartment model for S18982. The introduction of interoccasional variabilities and period as covariate into absorption-related parameters improved the model fit. Urine data have been applied to estimate renal and nonrenal clearance, enabling a more detailed description of the elimination process. We developed a population PK model describing the plasma and urine PK of ivabradine and S18982 in healthy Korean adult males. This model might be useful for predicting the plasma and urine PK of ivabradine, potentially helping to identify the optimal dosing regimens in various clinical situations.

Impact of CYP2D6, CYP3A5, CYP2C19, CYP2A6, SLCO1B1, ABCB1, and ABCG2 gene polymorphisms on the pharmacokinetics of simvastatin and simvastatin acid.

OBJECTIVE: The effects of various polymorphisms in cytochrome P450 (CYP) enzyme and transporter genes on the pharmacokinetics (PK) of simvastatin were evaluated in healthy Korean men. METHODS: Plasma concentration data for simvastatin and simvastatin acid were pooled from four phase I studies comprising 133 participants. The polymorphisms CYP2D6*4, CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, CYP2C19*2, CYP2C19*3, CYP2A6*7, and CYP2A6*9; SLCO1B1 rs4149056, rs2306283, and rs4149015; ABCB1 rs1128503, rs2032582, and rs1045642; and ABCG2 rs2231142 were evaluated in each participant. Noncompartmental PK results were compared by genotype. RESULTS: CYP2D6*5 and CYP2D6*14 were found to be associated with a higher area under the curve (AUC) for simvastatin, whereas the AUC of simvastatin acid was significantly increased in patients with the SLCO1B1 rs4149056, ABCG2 rs2231142, and CYP2D6*41 allele variants. Patients with the CYP2D6*41 variant showed a higher peak serum concentration (Cmax) of both simvastatin and simvastatin acid. The SLCO1B1 rs4149056 and rs4149015 polymorphisms were associated with an increased AUC ratio (i.e. ratio of simvastatin acid to simvastatin), whereas the SLCO1B1 rs4149056 and CYP2D6*5 variants were related to a higher Cmax ratio. CONCLUSION: The CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, SLCO1B1 rs4149056 and rs4149015, and ABCG2 rs2231142 genetic polymorphisms are associated with the PK of both simvastatin and simvastatin acid. This could potentially be used as a basis for individualized simvastatin therapy by predicting the clinical outcomes of this treatment.

Pharmacokinetic comparison of sustained- and immediate-release formulations of cilostazol after multiple oral doses in fed healthy male Korean volunteers.

BACKGROUND: A new extended-release form of cilostazol has recently been developed. This study was conducted to compare the pharmacokinetic characteristics of sustained-release (SR) and immediate-release (IR) formulations of cilostazol after multiple oral doses in healthy male Korean volunteers. METHODS: This was an open-label, randomized, multiple-dose, crossover study conducted in 30 healthy Korean subjects. In each treatment period, subjects received oral doses of 200 mg SR formulation every 24 hours or 100 mg IR formulation every 12 hours for 5 consecutive days in a fed state, with a washout period of 9 days. The plasma concentrations of cilostazol and its metabolites were determined using a validated liquid chromatography-tandem mass spectrometry method. The area under the plasma concentration-time curve within a dosing interval (AUC T ), the measured peak plasma concentration at steady state (C max,ss), and the time to reach C max,ss (t max,ss) were analyzed using a noncompartmental method. RESULTS: A total of 24 healthy male subjects completed the study. The mean (standard deviation [SD]) AUC T (96-120 hours) values for SR and IR were 27,378.0 (10,301.6) ng·h/mL and 27,860.3 (7,152.3) ng·h/mL, respectively. The mean (SD) C max,ss values were 2,741.4 (836.0) ng/mL and 2,051.0 (433.2) ng/mL, respectively. The median t max,ss values were 8.0 hours and 4.0 hours, respectively. The geometric mean ratios (90% confidence intervals) of the SR to IR formulations were 0.937 (0.863-1.017), 0.960 (0.883-1.043), and 0.935 (0.859-1.017) for AUC T and 0.644 (0.590-0.703), 0.586 (0.536-0.642), and 0.636 (0.577-0.702) for dose-normalized C max,ss of cilostazol, OPC-13015 (3,4-dehydro-cilostazol), and OPC-13213 (4'-trans-hydroxyl-cilostazol), respectively. All formulations were well tolerated. CONCLUSION: At steady state, the AUC T of cilostazol SR 200 mg is comparable to that of cilostazol IR 100 mg twice a day in healthy male Korean subjects. Both formulations are well tolerated.

Dose proportionality and pharmacokinetics of carvedilol sustained-release formulation: a single dose-ascending 10-sequence incomplete block study.

BACKGROUND: Carvedilol is a third-generation ß-blocker indicated for congestive heart failure and high blood pressure. The aim of this study was to investigate the dose proportionality of the carvedilol sustained-release (SR) formulation in healthy male subjects. METHODS: An open-label, single dose-ascending, 10-sequence, 3-period balanced incomplete block study was performed using healthy male subjects. In varying sequences, each subject received three of five carvedilol SR formulations (8, 16, 32, 64, or 128 mg once). The treatment periods were separated by a washout period of 7 days. Serial blood samples were collected up to 48 h after dosing. The plasma concentrations of carvedilol were determined by using validated liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters including the area under the plasma concentration-time curve (AUC) from time 0 to the last measurable time (AUClast), AUC extrapolated to infinity (AUCinf), and the measured peak plasma concentration (C max) were obtained by noncompartmental analysis. Dose proportionality was evaluated if the ln-ln plots of AUClast, AUCinf, and C max versus dose were linear and the 90% confidence intervals (CIs) of the slopes were within 0.9195 and 1.0805. Tolerability was assessed by vital signs, electrocardiogram, clinical laboratory tests, and monitoring of adverse events (AEs) throughout the study. RESULTS: A total of 31 subjects were enrolled, and 30 completed the study. The assessment of dose proportionality meets the statistical criteria; the point estimates of slope were 1.0104 (90% CI: 0.9849-1.0359) for AUClast, 1.0003 (90% CI: 0.9748-1.0258) for AUCinf, and 0.9901 (90% CI: 0.9524-1.0277) for C max, respectively. All AEs were mild, and none of the subjects dropped out due to AEs. CONCLUSION: In this study, exposure to carvedilol was proportional over the therapeutic dose range of 8-128 mg. The carvedilol SR formulation was well tolerated.

Therapeutic dosage assessment based on population pharmacokinetics of a novel single-dose transdermal donepezil patch in healthy volunteers.

PURPOSE: We performed population pharmacokinetic (PK) analysis of a novel transdermal donepezil patch in healthy subjects who participated in a phase I trial. We also studied the optimal dosage regimen with repeated patch application for achieving a therapeutic range using a PK simulation model. METHODS: This study used data from a randomized, single-dose escalation phase I clinical trial conducted in Korea. The population PK analysis was performed using NONMEM software, version 7.3. From the final PK model, we simulated repeat patch application results assuming various transdermal absorption rates. RESULTS: Based on the clinical trial data, novel donepezil patches with doses of 43.75 mg/12.5 cm(2), 87.5 mg/25 cm(2), and 175 mg/50 cm(2) were placed on each subject. A linear one-compartment, first-order elimination with sequential zero- and first-order absorption model best described the donepezil plasma concentrations after patch application. Simulated results on the basis of the PK model showed that repeat application of the patches of 87.5 mg/25 cm(2) and 175 mg/50 cm(2) every 72 h would cover the therapeutic range of donepezil and reach steady-state faster with fewer fluctuations in concentration compared to typical oral administrations. CONCLUSION: A linear one-compartment with sequential zero- and first-order absorption model was effective for describing the PKs of donepezil after application of patch. Based on this analysis, 87.5 mg/25 cm(2) or 175 mg/50 cm(2) patch application every 72 h is expected to achieve the desired plasma concentration of donepezil.

Single and multiple dose pharmacokinetics and tolerability of HX-1171, a novel antioxidant, in healthy volunteers.

BACKGROUND: HX-1171 (1-O-hexyl-2,3,5-trimethylhydroquinone) is a promising antioxidant with therapeutic potential for hepatic fibrosis. The aim of this study was to investigate the tolerability and pharmacokinetics of HX-1171 in healthy volunteers. METHODS: A randomized, single-blind, placebo-controlled, dose escalation study was conducted in 83 subjects. In the single ascending dose study, 20, 40, 80, 160, 300, 600, 1,200, 1,500 or 2,000 mg of HX-1171 was administered to 67 subjects. In the multiple ascending dose study, 500 or 1,000 mg was administered to 16 subjects for 14 days. The plasma and urine concentrations of HX-1171 were determined by using a validated liquid chromatography-mass spectrometry method. Pharmacokinetic parameters were obtained by non-compartmental analysis. Tolerability was assessed based on physical examinations, vital signs, clinical laboratory tests, and electrocardiograms. RESULTS: Adverse events reported in the study were all mild in intensity and resolved without any sequelae. HX-1171 was rapidly and minimally absorbed with a median time at maximal concentration of 0.63-1.50 hours and slowly eliminated with a terminal half-life of 21.12-40.96 hours. Accumulation index ranged from 2.0 to 2.2 after repeated dosing for 14 days. For both the single and multiple doses administrations, urinary concentrations indicated that less than 0.01% of the HX-1171 administered was excreted in urine. CONCLUSION: HX-1171 was well tolerated and minimally absorbed in healthy volunteers. The pharmacokinetic profile of HX-1171 was consistent with once-a-day dosing.

Single dose pharmacokinetics of the novel transdermal donepezil patch in healthy volunteers.

BACKGROUND: Donepezil is an acetylcholinesterase inhibitor indicated for Alzheimer's disease. The aim of this randomized, single-blind, placebo-controlled, single-dose, dose-escalation study was to investigate the safety, tolerability, and pharmacokinetics of the donepezil patch in healthy male subjects. METHODS: Each healthy male subject received a single transdermal donepezil patch (72 hours patch-on periods) of 43.75 mg/12.5 cm(2), 87.5 mg/25 cm(2), or 175 mg/50 cm(2). Serial blood samples were collected up to 312 hours after patch application. The plasma concentrations of donepezil were determined by using a validated liquid chromatography-tandem mass spectrometry method. Pharmacokinetic parameters were obtained by noncompartmental analysis. Tolerability of the patches and performance of the patches (adhesion, skin irritation, residual donepezil content in the patch) were assessed throughout the study. RESULTS: The study was completed by 36 healthy subjects. After patch application, the maximal plasma donepezil concentration (Cmax) and the area under the curve (AUC) increased in a dose-proportional manner. Median time to Cmax was ~74-76 hours (~2-4 hours after patch removal), and mean t1/2ß was ~63.77-93.07 hours. The average donepezil residue in the patch after 72 hours was ~73.9%-86.7% of the loading dose. There were neither serious adverse events nor adverse events that lead to discontinuation. Skin adhesion of the patch was good in 97.2% of the subjects. All skin irritations after patch removal were mild and were resolved during the study period. CONCLUSION: The donepezil patch appeared to be generally well tolerated and adhesive. Pharmacokinetic analysis of the donepezil patch demonstrated linear kinetics.