Pharmacokinetics and Pharmacodynamics of Tegoprazan Coadministered With Amoxicillin and Clarithromycin in Healthy Subjects.

This clinical trial was conducted to evaluate the pharmacokinetics and pharmacodynamics of tegoprazan when coadministered with amoxicillin/clarithromycin in healthy subjects. Cohort 1 was an open-label, randomized multiple-dose study to evaluate the mutual interaction of tegoprazan and amoxicillin/clarithromycin on the disposition of 3 tested drugs including tegoprazan M1 metabolite and 14-hydroxyclarithromycin (14-OH-clarithromycin). Cohort 2 was an open-label, randomized, active-controlled, parallel multiple-dose study to compare the intragastric pH profile after multiple oral doses of 50 or 100 mg tegoprazan coadministered with amoxicillin/clarithromycin 1000/500 mg for 7 days and pantoprazole-based triple therapy as the comparator arm. The coadministration of tegoprazan with amoxicillin/clarithromycin increased Css,max (2.2-fold) and AUCτ (2.7-fold) of tegoprazan and M1 (2.1- and 2.2-fold for Css,max and AUCτ , respectively) compared with administration of tegoprazan alone. The Css,max and AUCτ of 14-OH-clarithromycin increased by 1.7- and 1.8-fold, respectively; the disposition of amoxicillin and clarithromycin were not significantly changed. On days 1 and 7 of treatment, tegoprazan-based therapies (both 50- and 100-mg therapies) maintained pH above 6 for more than 88% of the 24-hour period, which was significantly longer compared with pantoprazole-based therapy. Tegoprazan either alone or in combination with amoxicillin/clarithromycin was well tolerated in healthy subjects. In conclusion, the exposure of tegoprazan was increased after coadministration of amoxicillin/clarithromycin, which led to increase pharmacodynamic response measured by intragastric pH compared with tegoprazan alone. Therefore, tegoprazan-based triple therapy would be effective therapeutic regimen to manage intragastric pH in terms of gastric or duodenal ulcers healing, treatment of gastroesophageal reflux disease, and Helicobacter pylori eradication.

First-in-Human, Double-Blind, Randomized Controlled Trial of an Oral Dose of GnRH Antagonist TU2670 in Healthy Women.

OBJECTIVE: To evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of TU2670, a novel orally active, nonpeptide gonadotropin-releasing hormone (GnRH) antagonist administered to healthy female participants. METHODS: This was a first-in-human, multicenter, phase 1, randomized, double-blind, placebo-controlled, single-dose ascending trial that took place in multiple medical centers. A total of 16 healthy premenopausal women (23 to 45 years of age) were randomized and received 20, 40, 80, and 160 mg TU2670 (GnRH antagonist) or placebo 7 days (±1 day) after the onset of menstrual bleeding. We performed a noncompartmental analysis for pharmacokinetic parameters and calculated relative minimum concentration values (Cmin, % Baseline) of serum pharmacodynamic (PD) markers (luteinizing hormone [LH], follicle-stimulating hormone [FSH], and estradiol). RESULTS: There were no significant differences among treatments with respect to vital signs, electrocardiography, adverse events, ovulation test results, and ultrasonography. The median Tmax of TU2670 occurred 0.75 to 1.00 hours after dosing, and concentrations then declined, with a mean apparent half-life (t1/2) of 3.0 to 5.9 hours. AUClast (17.7-417.9 ng·h/mL) and Cmax (8.1-95.4 ng/mL) increased in a dose-dependent manner. The PD analysis after a single administration of TU2670 revealed dose-dependent suppression of LH, FSH, and estradiol. Maximal suppression of the pre-dose baseline (%) was 58% to 82% at 6 to 8 hours for LH, 28% to 39% at 6 to 12 hours for FSH, and 34% to 82% at 12 to 24 hours for estradiol. CONCLUSION: The single administration of TU2670 in healthy premenopausal women was well tolerated and resulted in the dose-dependent suppression of LH, FSH, and estradiol, suggesting rapid and significant inhibition of pituitary and ovarian hormones.

A new population pharmacokinetic model for vancomycin in patients with variable renal function: Therapeutic drug monitoring based on extended covariate model using CKD-EPI estimation.

WHAT IS KNOWN AND OBJECTIVE: Although patients may have received vancomycin therapy with therapeutic drug monitoring (TDM), those treated with high-strength and long-term vancomycin therapy might have unstable and time-varying renal function. The methods used to estimate renal function should not be considered interchangeable with pharmacokinetic (PK) modeling and model-based estimation of vancomycin pharmacokinetics. While Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) for renal function estimation has been widely integrated into clinical practice, a population PK model including CKD-EPI has not been established. The study was aimed at developing a new population PK model for optimal vancomycin prediction in patients with time-varying and variable renal function to evaluate the interchangeability of estimation methods. METHODS: The most suitable population PK model was explored and evaluated using non-linear mixed-effect modelling for the best fit of vancomycin concentrations from patients who needed to maintain high trough vancomycin concentrations of >10 mg/L or >15 mg/L. Renal function was estimated using the Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD) and CKD-EPI equations. NONMEM 7.4 was used to develop the population PK model. RESULTS: A total of 328 vancomycin concentrations in 99 patients were used to develop the population PK model. Vancomycin pharmacokinetics was best described by a two-compartment model. The CKD-EPI equation for vancomycin clearance was included in the final model among the estimation methods of renal function. A new covariate model, including extended covariate parameters that explain changes in renal function from the population-predicted value and individual dosing time, provided the best explanation for vancomycin pharmacokinetics among the various models tested. WHAT IS NEW AND CONCLUSION: A new extended covariate model for vancomycin using the CKD-EPI method may afford suitable dose adjustment for high-strength and long-term vancomycin therapy that results in unstable renal function.

Prediction of the human in vivo antiplatelet effect of S- and R-indobufen using population pharmacodynamic modeling and simulation based on in vitro platelet aggregation test.

Indobufen (Ibustrin®), a reversible inhibitor of platelet aggregation, exists in two enantiomeric forms in 1:1 ratio. Here, we characterized the anti-platelet effect of S- and R-indobufen using response surface modeling using NONMEM® and predicted the therapeutic doses exerting the maximal efficacy of each enantioselective S- and R-indobufen formulation. S- and R-indobufen were added individually or together to 24 plasma samples from drug-naïve healthy subjects, generating 892 samples containing randomly selected concentrations of the drugs of 0-128 mg/L. Collagen-induced platelet aggregation in platelet-rich plasma was determined using a Chrono-log Lumi-Aggregometer. Inhibitory sigmoid Imax model adequately described the anti-platelet effect. The S-form was more potent, whereas the R-form showed less inter-individual variation. No significant interaction was observed between the two enantiomers. The anti-platelet effect of multiple treatments with 200 mg indobufen twice daily doses was predicted in the simulation study, and the effect of S- or R-indobufen alone at various doses was predicted to define optimal dosing regimen for each enantiomer. Simulation study predicted that 200 mg twice daily administration of S-indobufen alone will produce more treatment effect than S-and R-mixture formulation. S-indobufen produced treatment effect at lower concentration than R-indobufen. However, inter-individual variation of the pharmacodynamic response was smaller in R-indobufen. The present study suggests the optimal doses of R-and S-enantioselective indobufen formulations in terms of treatment efficacy for patients with thromboembolic problems. The proposed methodology in this study can be applied to the develop novel enantio-selective drugs more efficiently.

Efficacy of mitiglinide and sitagliptin, alone or in combination, on postprandial excursion and glycemic variability assessed by continuous glucose monitoring: a post hoc analysis with single-day treatment.

OBJECTIVE: To compare the efficacy of mitiglinide and sitagliptin, alone or in combination, on postprandial excursion and glycemic variability assessed by continuous glucose monitoring (CGM) in a single-day treatment setting. METHODS: This was a post hoc analysis of a randomized crossover study comparing the efficacy of sitagliptin, mitiglinide and the combination of these two drugs. Twenty-four hour CGM was performed before and after a single-day treatment with each drug alone or in combination. RESULTS: Mean glucose levels were decreased in all groups. The average of three postprandial glucose excursions AUC (average of all three 4-h postprandial periods throughout the day) (AUCpp-average) decreased in the mitiglinide and combination treatment groups, but not in the sitagliptin group. The lowering effect on AUCpp-average was greater in patients given mitiglinide (-47 mg/dl, p < 0.001) or combination treatment (-66 mg/dl, p < 0.001) compared with sitagliptin alone (-18 mg/dl). The reduction in mean amplitude of glycemic excursion was greater with mitiglinide (-29.3 mg/dl, p < 0.001) and combination treatment (-28.3 mg/dl, p < 0.01) than with sitagliptin alone (-8.9 mg/dl). CONCLUSIONS: Mitiglinide or combination treatment resulted in lower glycemic variability and postprandial glucose excursion than sitagliptin alone; however, the results of this single-day pharmacodynamics study cannot be generalized to a clinical setting.

Predicting the efficacy of an oral paclitaxel formulation (DHP107) through modeling and simulation.

PURPOSE: DHP107 is an oral paclitaxel under development. The present study characterized the pharmacokinetic properties of DHP107 and predicted the efficacy in comparison to that of intravenous paclitaxel, using modeling and simulation of data from the early phase of clinical development. METHODS: In the first-in-human study of the pharmacokinetic characteristics of DHP107 and intravenous paclitaxel, patients received DHP107 60 to 600 mg/m(2), followed by intravenous paclitaxel 175 mg/m(2). Using the pharmacokinetic model of DHP107 from the present analysis and from a previously published pharmacodynamic analysis of the association between paclitaxel concentration and neutropenia, phase I clinical trial for DHP107, with a modified Fibonacci dose escalation scheme, were simulated to predict the maximal tolerated dose (MTD). Additional simulations of paclitaxel concentration over time were conducted to compare the efficacy of DHP107 with that of intravenous paclitaxel, based on time over minimum effective concentration. FINDINGS: In the clinical trial simulation, 480 mg/m(2) was the most frequently predicted MTD of DHP107. In the simulations for efficacy, the times over minimum effective concentration with DHP107 at the predicted MTD were greater than those of intravenous paclitaxel in weekly regimens. IMPLICATIONS: The findings from this analysis suggest the possibility of efficacy of DHP107 in weekly regimens and provides a scientific rationale for further development. Based on findings from modeling and simulation, DHP107 was predicted to be more efficacious compared with intravenous paclitaxel in weekly regimens, and this finding should be confirmed in further clinical trials.

Population pharmacokinetic analysis of simvastatin and its active metabolite with the characterization of atypical complex absorption kinetics.

PURPOSE: The pharmacokinetics of simvastatin is complex with multiple peaks in the absorption phase, which cannot be adequately described by a conventional first order absorption model. The biotransformation of simvastatin into simvastatin acid, an active metabolite, is reversible. This study evaluated the pharmacokinetics of simvastatin and simvastatin acid, focusing on the absorption kinetics. METHODS: Data were collected from three bioequivalence studies, in which subjects were administered 60 mg simvastatin, and from one crossover study, in which subjects were administered two doses randomly selected from 10, 20, 30, 40 to 80 mg simvastatin with washout period. The pharmacokinetics of simvastatin was assessed in 133 healthy males. Plasma concentrations of simvastatin and simvastatin acid were measured in 2,182 and 2,130 samples, respectively, and the pharmacokinetic data were analyzed using NONMEM. RESULTS: The time course of changes in the plasma simvastatin concentration was best described by a two-compartment linear model with three parallel absorption processes, each of which consisted of mixed zero-and first order absorption. Additions of inter-occasional variability to the absorption parameters significantly improved the model's fit. The disposition parameter estimates were significantly different when different absorption models were applied, indicating the importance of the appropriate absorption modeling. Pharmacokinetic modeling preferred the inter-conversion between simvastatin and simvastatin acid. CONCLUSION: A pharmacokinetic model describing the complex, multiple peak, absorption kinetics of simvastatin was formulated using three parallel, mixed zero and first-order absorptions. This type of absorption model may be applicable to other drugs that show irregular, multiple-peak concentrations during their absorption phase.

Tolerability and pharmacokinetics of avanafil, a phosphodiesterase type 5 inhibitor: a single- and multiple-dose, double-blind, randomized, placebo-controlled, dose-escalation study in healthy Korean male volunteers.

BACKGROUND: Avanafil is a selective phosphodiesterase type 5 inhibitor being developed for the treatment of erectile dysfunction. OBJECTIVE: This study was conducted to meet Korean regulatory requirements for the marketing of avanafil. To this end, tolerability and pharmacokinetic properties of single and multiple oral doses of avanafil in healthy Korean male volunteers were assessed. METHODS: A double-blind, randomized, placebo-controlled, parallel-group, dose-escalation study was conducted at the Asan Medical Center (Seoul, Korea). Subjects were randomized to receive either drug or placebo in blocks according to each dose. Subjects were randomly allocated to receive 50-, 100-, or 200-mg tablets of avanafil or placebo once daily for 7 days (avanafil:placebo, 8:2 in each dose group). Tolerability was assessed by monitoring vital signs and results of laboratory tests, 12-lead ECGs, and color discrimination tests. Blood samples of approximately 6 mL were collected in heparinized tubes before and 0.1, 0.33, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours after drug administration on days 1 and 7. Plasma concentrations of avanafil were measured using LC-MS/MS. Pharmacokinetic parameters of avanafil on days 1 and 7 were determined by noncompartmental analysis and compared among the 3 dose groups. RESULTS: Of the 32 healthy male subjects initially enrolled, 30 completed the study. The mean (SD) age, height, and weight of the participants were 23.4 (1.7) years, 175.0 (5.4) cm, and 70.3 (8.9) kg, respectively. Adverse events were reported by 20 of 25 subjects (80%) taking avanafil and by 4 of 6 (67%) taking placebo. No serious adverse events were reported, and there were no clinically relevant changes in vital signs, ECG recordings, physical examination findings, or color discrimination test results. All the adverse events resolved spontaneously. Avanafil reached a mean T(max) at 0.33 to 0.52 hour after dosing and then declined, with a mean apparent t1/2 of 5.36 to 10.66 hours. AUC and C(max) were proportional to dose, and the mean accumulation index on day 7 after a single daily dose of avanafil was 0.98. CONCLUSION: Avanafil was generally well tolerated and had linear pharmacokinetic properties at daily doses of 50 to 200 mg over 7 days in these healthy Korean male volunteers. Korean National Study Registration Number: 3466.

Pain on injection with microemulsion propofol.

AIMS: To evaluate the incidence and severity of injection pain caused by microemulsion propofol and lipid emulsion propofol in relation to plasma bradykinin generation and aqueous free propofol concentrations. METHODS: Injection pain was evaluated in 147 patients. Aqueous free propofol concentrations in each formulation, and in formulation mixtures containing agents that reduce propofol-induced pain, were measured by high-performance liquid chromatography. Plasma bradykinin concentrations in both formulations and in their components mixed with blood sampled from six volunteers were measured by radioimmunoassays. Injection pain caused by 8% polyethylene glycol 660 hydroxystearate (PEG660 HS) was evaluated in another 10 volunteers. RESULTS: The incidence of injection pain [visual analogue scale (VAS) >30 mm] caused by microemulsion and lipid emulsion propofol was 69.7 and 42.3% (P < 0.001), respectively. The median VAS scores for microemulsion and lipid emulsion propofol were 59 and 24 mm, respectively (95% confidence interval for the difference 12.5, 40.0). The aqueous free propofol concentration of microemulsion propofol was seven times higher than that of lipid emulsion propofol. Agents that reduce injection pain did not affect aqueous free propofol concentrations. Microemulsion propofol and 8% PEG660 HS enhanced plasma bradykinin generation, whereas lipid emulsion propofol and lipid solvent did not. PEG660 HS did not cause injection pain. CONCLUSIONS: Higher aqueous free propofol concentrations of microemulsion propofol produce more frequent and severe pain. The plasma kallikrein-kinin system may not be involved, and the agents that reduce injection pain may not act by decreasing aqueous free propofol concentrations.