Mi-sun Lim

Pattern Recognition Analysis for Hepatotoxicity Induced by Acetaminophen Using Plasma and Urinary 1H NMR-Based Metabolomics in Humans

Drug-induced liver injury (DILI) is currently an increasingly relevant health issue. However, available biomarkers do not reliably detect or quantify DILI risk. Therefore, the purpose of this study was to comparatively evaluate plasma and urinary biomarkers obtained from humans treated with acetaminophen (APAP) using a metabolomics approach and a proton nuclear magnetic resonance (NMR) platform. APAP (3 g/day, two 500 mg tablets every 8 h) was administered to 20 healthy Korean males (age, 20-29 years) for 7 days. Urine was collected daily before and during dosing and 6 days after the final dose. NMR spectra of these urine samples were analyzed using principal component analysis (PCA) and partial least-squares-discrimination analysis. Although the activities of aspartate aminotransferase and lactate dehydrogenase were significantly increased 7 days post-APAP treatment, serum biochemical parameters of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, γ-glutamyl transpeptidase, and lactate dehydrogenase were within normal range of hepatic function. However, urine and plasma (1)H NMR spectroscopy revealed different clustering between predosing and after APAP treatment for global metabolomic profiling through PCA. Urinary endogenous metabolites of trimethylamine-N-oxide, citrate, 3-chlorotyrosine, phenylalanine, glycine, hippurate, and glutarate as well as plasma endogenous metabolites such as lactate, glucose, 3-hydroxyisovalerate, isoleucine, acetylglycine, acetone, acetate, glutamine, ethanol, and isobutyrate responded significantly to APAP dosing in humans. Urinary and plasma endogenous metabolites were more sensitive than serum biochemical parameters. These results might be applied to predict or screen potential hepatotoxicity caused by other drugs using urinary and plasma (1)H NMR analyses.

Effect of age on the pharmacokinetics of fimasartan (BR-A-657)

Objectives: 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. Methods: 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. Results: After oral administration of 240 mg fimasartan, the mean area under the plasma concentration-time curve from time zero to infinity (AUC0→∞) 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 AUC0→∞ was 69.4% higher in older than in young subjects. The maximum plasma concentration (Cmax), time to reach Cmax and elimination half-life for fimasartan did not differ significantly between the older and young groups. Importantly, fimasartan was well tolerated during this study. Conclusions: While some PK parameters were statistically different between the two groups, the effect of age on the PK was modest (e.g., AUC increase < twofold in older subjects).

Rapid determination of finasteride in human plasma by UPLC-MS/MS and its application to clinical pharmacokinetic study

A rapid, specific, and sensitive method utilizing reversed-phase ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated to determine finasteride levels in human plasma. The plasma samples were prepared by liquid-liquid extraction with ethyl acetate, evaporation, and reconstitution. MS/MS analyses were performed on a triple-quadrupole tandem mass spectrometer by monitoring protonated parent-->daughter ion pairs at m/z 373-->305 for finasteride and m/z 237-->194 for carbamazepine (internal standard, IS). The method was validated with respect to linearity, recovery, specificity, accuracy, precision, and stability. The method exhibited a linear response from 0.1 to 30 ng/mL (r(2)>0.998). The limit of quantitation for finasteride in plasma was 0.1 ng/mL. The relative standard deviation (RSD) of intra- and inter-day measurements was less than 15% and the method was accurate within -6.0% to 2.31% at all quality-control levels. The mean extraction recovery was higher than 83% for finasteride and 84% for the IS. Plasma samples containing finasteride were stable under the three sets of conditions tested and the processed samples were stable up to 29 h in an autosampler at 5 degrees C. Detection and quantitation of both analytes within 3 min make this method suitable for high-throughput analyses. The method was successfully applied to a pharmacokinetic study of finasteride in healthy volunteers following oral administration.

Population Pharmacokinetic/Pharmacodynamic Modeling of Clopidogrel in Korean Healthy Volunteers and Stroke Patients

Population pharmacokinetic (PK) and pharmacodynamic (PD) modeling of clopidogrel was developed from pooled data from healthy volunteers (n = 44) and stroke patients (n = 35). The PK modeling used plasma concentrations of the clopidogrel metabolite (SR26334), and the PD modeling used platelet aggregation. The models were developed using NONMEM and evaluated via visual predictive check (VPC). Data were analyzed by 2‐compartment modeling with Erlangs absorption and first‐order elimination. There was no statistically significant covariate for each model parameter. The typical point estimates of PK were ktr (identical transfer rate constant) = 5.97 h−1, ke (elimination rate constant) = 0.126 h−1, kd (distribution rate constant) = 0.212 h−1, V2 (volume of central compartment) = 21.0 L, and V3 (volume of peripheral compartment) = 38.8 L. The typical point estimates of PD were kin (input rate) = 27.9 h−1, Emax (maximum effect on input rate) = 0.292 h−1, EC50 (median effective concentration) = 0.00629 ng/mL, and BASE (predose aggregation) = 66.7%. The final model was used to estimate individual parameters using patient data and showed good predictions using VPC.

Pharmacokinetics of a New Once-Daily Controlled-Release Formulation of Aceclofenac in Korean Healthy Subjects Compared with Immediate-Release Aceclofenac and the Effect of Food

AbstractBackground: A new controlled-release formulation of aceclofenac 200 mg (Clanza CR®) developed by Korea United Pharm., Inc., South Korea, for once-daily (od) dosing provides biphasic aceclofenac release consisting of immediate release of 85 mg followed by sustained release of 115 mg. Food has been known to affect the rate and extent of absorption of several drugs, in both immediate-release and controlled-release formulations. Objective: The aim of this study was to evaluate the relative bioavailability of a new controlled-release formulation of aceclofenac (200 mg od; Clanza CR®) in comparison with immediate-release aceclofenac (100 mg twice daily [bid], Airtal®) and to assess the effect of food on the pharmacokinetics of the new controlled-release aceclofenac formulation. Methods: This study was designed as a randomized, open-label, three treatment-period, crossover, single-centre study with a 1-week washout in 41 healthy adults. The three treatments consisted of immediate-release aceclofenac 100 mg bid administered under fasting conditions; controlled-release aceclofenac 200 mg od administered under fasting conditions; and controlled-release aceclofenac 200 mg od administered immediately after a standardized high-fat breakfast. Plasma concentrations of aceclofenac were determined using a highperformance liquid chromatography method. Results: In the fasted state, the 90% confidence intervals (CIs) of the least squares geometric mean ratios (GMRs) for the area under the plasma concentration-time curve from time zero to 24 hours (AUC24) and the peak plasma concentration (Cmax) of aceclofenac for the controlled-release and immediate-release formulations of aceclofenac were all within the bioequivalence criteria range of 0.8–1.25. The 90% CIs of the GMRs for the AUC24 and Cmax of aceclofenac for the controlled-release formulation of aceclofenac in the fed and fasted states were also within the bioequivalence range. Both aceclofenac formulations were well tolerated in all subjects, and no serious adverse effects were observed. Conclusion: The results demonstrate that controlled-release aceclofenac 200 mg is equivalent to immediate-release aceclofenac 100 mg when administered at the same total daily dose. Additionally, the bioavailability of controlled-release aceclofenac was not affected by high-fat foods.

Liquid chromatography–tandem mass spectrometry quantification of levosulpiride in human plasma and its application to bioequivalence study

An improved method for determining levels of levosulpiride in human plasma using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated. The protein precipitation method was used for plasma sample preparation. Levosulpiride and an internal standard (IS) were isocratically separated on a UPLC BEH C(18) column with a mobile phase of ammonium formate buffer (1mM, adjusted to pH 3 with formic acid) and acetonitrile (60:40, v/v). MS/MS detection was performed by monitoring the parent-->daughter pair of levosulpiride and the IS at m/z 342-->112 and 329-->256, respectively. The method was linear from 2.5 to 200ng/mL and exhibited acceptable precision and percent recovery. The method was successfully demonstrated in pharmacokinetic and bioequivalence studies of two levosulpiride oral formulations administered to healthy volunteers. When compared to the previous LC-MS methods, the proposed method is faster, well-validated, and uses lesser plasma volume and a similar sensitivity. The use of UPLC allowed rapid and sensitive quantification of levosulpiride, making this method suitable for high-throughput clinical applications.

Single-dose pharmacokinetics and dose proportionality of intravenous pazufloxacin mesilate in healthy Korean volunteers

Objective: The aim of this study was to investigate the pharmacokinetics and dose proportionality of a single, intravenous dose of pazufloxacin mesilate, an injectable fluoroquinolone antibiotic, in healthy Korean male volunteers. Methods: In this open-label, four-dose, parallel study, subjects were randomized to receive a single dose of pazufloxacin mesilate 300, 500, 600, and 1,000 mg (n = 6, 20, 6, and 8, respectively) administered as a 1-h intravenous infusion. Blood and urine samples were collected serially from 0 to 24 h after drug administration and analyzed using a validated HPLC method. Tolerability was assessed by monitoring clinical laboratory parameters and adverse events. Results: After single-dose intravenous administration of pazufloxacin mesilate, the mean Cmax for groups treated with 300, 500, 600, and 1,000 mg doses ranged from 5.11 to 18.06 μg/mL; the mean AUC0-t ranged from 13.70 to 58.60 μg × h/mL. Pazufloxacin exhibits lack of dose proportionality over the dose range of 300 – 1,000 mg, based on linear regression model and power model. At all four dosages studied, pazufloxacin mesilate was well tolerated. Conclusions: Our data suggest that all regimens of pazufloxacin administration were well tolerated. Pazufloxacin exhibits lack of dose proportionality over the dose range of 300 – 1,000 mg.

A Phase I study to characterize the multiple-dose pharmacokinetics, pharmacodynamics and safety of new enteric-coated triflusal formulations in healthy male volunteers

Objectives: An enteric-coated formulation of triflusal (triflusal EC), an antiplatelet agent, was developed to reduce the high incidence of gastrointestinal adverse events (AEs). The aim of this study is to compare the pharmacokinetics, pharmacodynamics and safety of triflusal EC with triflusal in healthy Korean male subjects to determine bioequivalence and non-inferiority for the purposes of marketing approval. Methods: A randomized, open-label, two-period, crossover study was conducted in 38 subjects. Either triflusal EC or triflusal was administered orally as a single 900 mg loading dose (day 1) followed by eight 600 mg/day maintenance doses on days 2 – 9, with a 13-day washout period. The plasma concentrations of 2-hydroxy-4-trifluoromethyl benzoic acid (HTB), the predominant active metabolite of triflusal, were assessed after administration of the loading dose, using HPLC/MS/MS. The platelet aggregation response to arachidonic acid was determined using turbidimetric aggregometry. Results: The 90% CIs, for the geometric mean ratios of the log-transformed AUCτ and Cmax of HTB were seen to be within the predetermined range of 0.8 – 1.25. Triflusal EC was also shown to be non-inferior in its anti-aggregatory effect. No serious AEs were reported during this study. Conclusions: The pharmacokinetic and pharmacodynamic profiles of the two triflusal formulations met the requirements for bioequivalence and non-inferiority, respectively. Both formulations were well tolerated.

Assessment of pharmacokinetic proportionality of levofloxacin and cyclosporine over a 100-fold dose range in healthy human volunteers

Objective: Levofloxacin and cyclosporine show different pharmacokinetic properties, but are known to be dose proportional within the therapeutic range. The authors evaluated the pharmacokinetic proportionality of levofloxacin and cyclosporine over a 100-fold dose range in healthy human volunteers, by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods: Two independent, randomized, crossover studies were performed. For levofloxacin, eight volunteers were randomly assigned in a 1:1 ratio to receive a low dose (7.5 mg) orally or intravenously, followed by a 1-week washout period and administration via the alternate route. After another 1-week washout period, a therapeutic dose (750 mg) was administered to all eight subjects. For cyclosporine, another eight volunteers received a low dose (2 mg) or a therapeutic dose (200 mg) orally with a 1-week washout period. Drug concentrations were determined by LC-MS/MS. Results: For levofloxacin, the mean values for dose-normalized Cmax and AUClast with the two doses were as follows: therapeutic dose, 15.2 ± 4.6 ng/ml/mg and 103.6 ± 15.5 ng·h/ml/mg, respectively; low dose, 17.1 ± 6.5 ng/ml/mg and 72.6 ± 8.7 ng·h/ml/mg, respectively. For cyclosporine, the mean values for dose-normalized Cmax and AUClast were as follows: therapeutic dose, 4.9 ± 1.5 ng/ml/mg and 15.4 ± 4.9 ng·h/ml/mg, respectively; low dose, 1.6 ± 0.6 ng/ml/mg and 9.3 ± 7.3 ng·h/ml/mg, respectively. Conclusion: In this study levofloxacin, which is completely absorbed and primarily eliminated renally without modification, showed better pharmacokinetic proportionality than cyclosporine, which is poorly absorbed and extensively metabolized.

Clinical evaluation of efficacy and tolerability of HMC05 in healthy subjects with normal and high-normal blood pressure: a pilot study.

HMC05, a formulation containing eight different herbal extracts, has been used widely for several thousand years in China, Japan, and Korea as a remedy for hypertension and headache. Although its anti-inflammatory effects in mouse monocytic cell lines and anti-atherosclerotic effects in apoE-knockout mice have been reported, the pharmacodynamic effects of HMC05 in human subjects have not yet been investigated. We evaluated the efficacy and tolerability of this drug in 14 healthy male Korean subjects with normal or high-normal blood pressure (BP) in a randomized, single-blind, crossover study with a 2-week washout period. Four 500-mg tablets of HMC05 or placebo were orally administered three times daily to nine subjects with normal BP and five subjects with high-normal BP for 4 weeks. To assess the pharmacodynamic effects of HMC05, levels of high-sensitivity C-reactive protein and homocysteine, BP, and flow-mediated vasodilation were measured before and after the 4-week medication period with evaluation of tolerability. All 14 subjects completed the study, and HMC05 was well tolerated with no significant adverse events. HMC05 did not exhibit a significant BP-lowering effect in either BP group, and there were no significant differences in other pharmacodynamic values after HMC05 or placebo administration in the two groups. Further study is needed to evaluate the efficacy and tolerability of HMC05 in an adequate number of patients with hypertension.