Effects of itraconazole and rifampicin on the single-dose pharmacokinetics of the nonsteroidal mineralocorticoid receptor blocker esaxerenone in healthy Japanese subjects.

AIMS: To investigate the effects of the strong cytochrome P450 (CYP) 3A inhibitor itraconazole and the strong CYP3A inducer rifampicin on the pharmacokinetics of single-dose esaxerenone, a nonsteroidal mineralocorticoid receptor blocker, in healthy Japanese subjects. METHODS: Two open-label, single-sequence, crossover studies were conducted in healthy Japanese males aged 20-45 years. In Study 1 (n = 20), subjects received a single oral 2.5 mg dose of esaxerenone (Days 1, 13), with itraconazole 200 mg twice daily (Day 8) and once daily (Days 9-16). In Study 2 (n = 12), subjects received a single oral 5 mg dose of esaxerenone (Days 1, 13), with rifampicin 600 mg once daily (Days 8-16). The plasma concentration of esaxerenone and esaxerenone metabolites were measured using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated using noncompartmental analysis, and safety was assessed. RESULTS: Esaxerenone exposure increased when coadministered with itraconazole. Geometric least-square mean ratios (90% confidence interval) of peak plasma esaxerenone concentration (Cmax ), area under the plasma concentration-time curve (AUC) from zero until the last measurable concentration (AUClast ) and AUC from zero until infinity (AUCinf ) were 1.13 (1.05, 1.20) ng mL-1 , 1.47 (1.40, 1.54) ng h mL-1 and 1.53 (1.45, 1.62) ng h mL-1 , respectively. Esaxerenone exposure decreased when coadministered with rifampicin. Geometric least-squares mean ratios (90% confidence interval) of esaxerenone Cmax , AUClast and AUCinf were 0.659 (0.599, 0.724), 0.315 (0.300, 0.332) and 0.312 (0.297, 0.328), respectively. CONCLUSION: Itraconazole increased esaxerenone AUCinf by 53.1%, and rifampicin decreased esaxerenone AUCinf by 68.8%. These results suggest that caution is recommended when coadministering esaxerenone with strong inhibitors and inducers of CYP3A.

Enantioselective Bromolactonization of Trisubstituted Olefinic Acids Catalyzed by Chiral Pyridyl Phosphoramides.

Enantioselective bromolactonization of trisubstituted olefinic acids producing synthetically useful chiral lactones with two contiguous asymmetric centers has remained mainly unexplored except for the 6-exo cyclization mode. In this work, the 5-exo- and 6-endo modes of bromocyclization of trisubstituted olefinic acids were enabled for the first time using N-bromosuccinimide and a pyridyl phosphoramide catalyst. The utility of the resulting bromolactones was demonstrated by transformations harnessing reactive alkyl bromide moieties without losing stereochemical information. Optimization studies and control experiments revealed that the basicity of pyridine moieties and presence of N-H protons in the phosphoramide species strongly affected both the reactivity and enantioselectivity parameters.

Modeling of atmospheric-coupled Rayleigh waves on planets with atmosphere: From Earth observation to Mars and Venus perspectives.

Acoustic coupling between solid Earth and atmosphere has been observed since the 1960s, first from ground-based seismic, pressure, and ionospheric sensors and since 20 years with various satellite measurements, including with global positioning system (GPS) satellites. This coupling leads to the excitation of the Rayleigh surface waves by local atmospheric sources such as large natural explosions from volcanoes, meteor atmospheric air-bursts, or artificial explosions. It contributes also in the continuous excitation of Rayleigh waves and associated normal modes by atmospheric winds and pressure fluctuations. The same coupling allows the observation of Rayleigh waves in the thermosphere most of the time through ionospheric monitoring with Doppler sounders or GPS. The authors review briefly in this paper observations made on Earth and describe the general frame of the theory enabling the computation of Rayleigh waves for models of telluric planets with atmosphere. The authors then focus on Mars and Venus and give in both cases the atmospheric properties of the Rayleigh normal modes and associated surface waves compared to Earth. The authors then conclude on the observation perspectives especially for Rayleigh waves excited by atmospheric sources on Mars and for remote ionospheric observations of Rayleigh waves excited by quakes on Venus.

Achieving ZT > 1 in Cu and Ga Co-doped Ag6Ge10P12 with Superior Mechanical Performance and Its Fundamental Physical Properties toward Practical Thermoelectric Device Applications.

Recently, phosphorus-based compounds have emerged as potential candidates for thermoelectric materials. One of the key challenges facing this field is to achieve ZT > 1, which is the benchmark for thermoelectric device applications. In this study, it is demonstrated that the thermoelectric performance of environmentally friendly Ag6Ge10P12 is enhanced by co-doping Cu and Ga. The mechanical properties, coefficient of linear thermal expansion, work function, and compatibility factor are comprehensively clarified to provide guidelines for reliable device applications. The peak and average dimensionless figures of merit of Ag5.85Cu0.15Ge9.875Ga0.125P12 reach 1.04 at 723 K and 0.63 at 300-723 K, respectively, which are the highest values for phosphorus-based thermoelectric materials. The Young's modulus, Vickers microhardness, fracture toughness, and compressive strength of Ag5.85Cu0.15Ge9.875Ga0.125P12 are 132 GPa, 589, 1.23 MPa m1/2, and 219 MPa, respectively, which are superior to those of typical state-of-the-art thermoelectric materials. The remarkable thermoelectric and mechanical performance of Ag5.85Cu0.15Ge9.875Ga0.125P12 mean that it is a promising candidate for medium-temperature thermoelectric conversion. Ti, V, Rh, and Pt are suitable for electrodes without exfoliation under thermal expansion and with ohmic contacts to Ag5.85Cu0.15Ge9.875Ga0.125P12 in terms of the coefficient of linear thermal expansion and work function. Considering that the compatibility factor of Ag5.85Cu0.15Ge9.875Ga0.125P12 is approximately 2.8, half-Heusler, skutterudite, and magnesium silicide-stannide compounds are suitable n-type thermoelectric counterpart materials in thermoelectric devices. These insights will lead to the development of phosphorus-based thermoelectric materials toward practical thermoelectric device applications.

Clinical status and outcome of Japanese heart failure patients with reduced or preserved ejection fraction treated with carvedilol.

The effect of beta-blockers in treating Japanese heart failure (HF) patients with preserved left ventricular (LV) ejection fraction (EF) is unclear. This prospective observational study enrolled 1,682 Japanese HF patients who received carvedilol for the first time. Patients were followed for a mean of 1.6 years. The 1,492 patients with baseline LVEF measurements were allocated to the following groups: reduced EF (LVEF < 40%; n = 724), borderline EF (LVEF 4050%; n = 355), and preserved EF (LVEF ≥ 50%; n = 413). Baseline characteristics, New York Heart Association (NYHA) class, change in B-type natriuretic peptide (BNP) level, and long-term outcome were compared among the groups. Patients with preserved EF were more likely to be older, female, and have ischemic etiology and hypertension than patients with reduced EF. Carvedilol maintenance dosage was lower in patients with preserved EF (7.9 mg/day versus 6.6 mg/ day). NYHA class and BNP level were lower in patients with preserved EF at baseline but improved to the same level in all groups at 6 months. After adjusting for baseline characteristics, the hazard ratio for death or hospitalization due to cardiovascular disease in patients with preserved EF versus those with reduced EF was 1.031 (P = 0.847). This study elucidated the characteristics of HF patients given carvedilol in "real world" clinical settings. A comparative controlled study is necessary to elucidate whether the improvements in NYHA and BNP as well as the outcome profile observed in patients with preserved EF were caused by the favorable effects of carvedilol.

Chelating Picolinaldehyde Hydrazone Amides as Protecting Groups for Carboxylic Acids: Orthogonal Reactivities of Hydrazone Amides and Esters in Hydrolysis.

We report a chelating hydrazone amide as a protecting group for carboxylic acids. Unlike most esters, 2-picolinaldehyde hydrazone amides are stable under acidic or basic hydrolytic conditions. However, hydrazone amides can be easily converted to the corresponding carboxylic acids via Ni-mediated hydrolysis. Orthogonal reactivities of the hydrazone amides and representative protecting groups were verified by control experiments and peptide synthesis, demonstrating that chelating hydrazone amides are highly useful protecting groups.

Bioequivalence of Esaxerenone Conventional Tablet and Orally Disintegrating Tablet: Two Single-Dose Crossover Studies in Healthy Japanese Men.

We assessed the bioequivalence of a single dose of 5-mg of esaxerenone administered as an orally disintegrating tablet (ODT) with the conventional oral tablet in healthy Japanese men. This single-center, open-label, randomized, two-drug, two-stage crossover, single-dose study was conducted in two parts. In study 1, both formulations were taken with water. In study 2, only the ODT formulation was taken without water. The primary outcome was the evaluation of bioequivalence of the ODT and conventional tablet using the pharmacokinetic (PK) parameters maximum plasma concentration (Cmax ) and area under the plasma concentration-time curve to the last quantifiable time (AUClast ). Plasma concentrations were measured using a validated liquid chromatography/mass spectrometry method and PK parameters were calculated by noncompartmental analysis. The ratios of the geometric least-squares mean (2-sided 90% confidence intervals [90%CIs]) for ODT with (study 1) and without (study 2) water to the conventional tablet were 1.03 (1.00-1.07) and 1.01 (0.96-1.06) for Cmax and 1.03 (1.00-1.07) and 0.96 (0.94-0.98) for AUClast , respectively. The 90%CIs fell within the predefined bioequivalence range of 0.80-1.25. Treatment-emergent adverse events were similar between both formulations. In conclusion, esaxerenone 5-mg ODT taken with or without water was bioequivalent to a single 5-mg conventional oral tablet.

Observation and simulation of atmospheric gravity waves exciting subsequent tsunami along the coastline of Japan after Tonga explosion event.

Tsunamis are commonly generated by earthquakes beneath the ocean floor, volcanic eruptions, and landslides. The tsunami following the Tonga eruption of 2022 is believed to have been excited by atmospheric pressure fluctuations generated by the explosion of the volcano. The first, fast-traveling tsunami was excited by Lamb waves; however, it has not been clarified observationally or theoretically which type of atmospheric fluctuations excited more prominent tsunami which followd. In this study, we investigate atmospheric gravity waves that possibly excited the aforementioned subsequent tsunami based on observations and atmosphere-ocean coupling simulations. The atmospheric fluctuations are classified as Lamb waves, acoustic waves, or gravity waves. The arrival time of the gravity wave and the simulation shows that the gravity wave propagated at a phase speed of 215 m/s, coinciding with the tsunami velocity in the Pacific Ocean, and suggesting that the gravity wave resonantly excited the tsunami (Proudman resonance). These observations and theoretical calculations provide an essential basis for investigations of volcano-induced meteotsunamis, including the Tonga event.

Iron-catalyzed asymmetric epoxidation of ß,ß-disubstituted enones.

The combination of Fe(OTf)(2) and novel phenanthroline ligands enables the catalytic asymmetric epoxidation of acyclic ß,ß-disubstituted enones, which have been a heretofore inaccessible substrate class. The reaction provides highly enantioenriched α,ß-epoxyketones (up to 92% ee) that can be further converted to functionalized ß-ketoaldehydes with an all-carbon quaternary center.

Site-Selective Acylations of α- and ß-Hydroxyamides in Complex Molecules: Application of Template-Driven Acylation to Disaccharides and a Glycopeptide.

Site-selective acylations of α-and ß-hydroxyamides in complex polyols are described. The combination of a pyridine aldoxime ester and Zn(OTf)2 facilitates the acylation of two types of N-glycolyl disaccharides, namely, Gal-GlcNGc and Neu5Gc-Gal, both of which are partial structures of polysaccharides responsible for biological actions, with highly site-selective modifications achieved. Furthermore, biotinylation, one of the most important techniques in chemical biology, is used to site-selectively acylate the ß-hydroxyl group in a glycopeptide.

Effects of Repeated Oral Administration of Esaxerenone on the Pharmacokinetics of Midazolam in Healthy Japanese Males.

BACKGROUND AND OBJECTIVE: Esaxerenone showed the potential to inhibit and induce activity against cytochrome P450 (CYP) 3A in in vitro studies. We investigated whether repeated administration of 5 mg/day esaxerenone for 14 days influences the pharmacokinetics of midazolam, a sensitive CYP3A substrate, in healthy Japanese males. METHODS: This single-centre, open-label, single-sequence study had two administration periods: period 1: single oral dose of 2 mg midazolam (day 0); period 2: repeated oral doses of 5 mg/day esaxerenone for 14 days, with a single oral dose of 2 mg midazolam on day 14. Full pharmacokinetic profiles of midazolam and 1-hydroxymidazolam on days 0 and 14 and safety data were obtained. Primary pharmacokinetic endpoints for midazolam were area under the plasma concentration-time curve (AUC) from zero to time of the last measurable concentration (AUClast), AUC from zero to infinity (AUCinf), and peak plasma concentration (Cmax). RESULTS: The study included 28 male subjects. One subject was withdrawn because of a mild adverse event (increased hepatic enzyme levels) that resolved without intervention. Repeated administration of esaxerenone increased midazolam AUClast, AUCinf, and Cmax by about 1.2-fold (1.201, 1.201, and 1.224, respectively) compared with administration of midazolam alone. However, repeated administration of esaxerenone did not affect the elimination half-life of midazolam (2.86 versus 2.63 h with and without esaxerenone). There were no safety concerns associated with concomitant administration of esaxerenone and midazolam. CONCLUSIONS: Esaxerenone 5 mg/day had no clinically significant effect on midazolam pharmacokinetics and was not associated with any safety issues. Esaxerenone can be concomitantly administered with drugs of CYP3A substrates without dose adjustments. CLINICAL TRIAL REGISTRATION: JapiCTI-152832.

[Site-selective and Stereoselective Syntheses Controlled by the Electron-withdrawing Properties of Cationic Heterocycles].

This article describes our stereoselective and site-selective chemical methods for exploiting cationic heterocycles as electron-withdrawing groups (EWGs). We envisioned that the phosphoramide N-H proton of a pyridyl phosphoramide 3 would be activated by the cationic pyridinium moiety that is formed upon protonation. The resulting imide-like N-H proton and the acidic pyridinium proton of the pyridinium phosphoramide 3⋅HX cooperate together, making 3⋅HX a highly acidic dual Brønsted acid. The catalytic ability of 3⋅HX was demonstrated in the development of the first asymmetric Diels-Alder reaction between 1-amide dienes and maleimides. Focusing on the activation of N-bromosuccinimide (NBS) because of its structural similarity to maleimides, the enantioselective bromolactonization of trisubstituted olefinic acids was accomplished utilizing pyridyl phosphoramide 3f as a Brønsted base catalyst bearing an acidic N-H proton. Lastly, our strategy for the site-selective acylation of polyol compounds is described. In our system, a pyridine aldoxime ester 10, used as a mild acylating reagent, was activated by a catalytic amount of Lewis acid via the inductive effect of the cationic pyridinium moiety. The resulting metal complex preferentially attracted the alcohol with a Lewis basic site, thereby facilitating selective acylation via a template effect. This metal-template-driven strategy allowed for the site-selective acylation of diverse α-hydroxyamides, including unprotected N-glycolyl aminosugars.

Pharmacokinetics and Safety of Single-Dose Esaxerenone in Japanese Subjects with Mild to Moderate Hepatic Impairment.

INTRODUCTION: The mineralocorticoid receptor (MR) blocker esaxerenone is a new treatment for hypertension in Japan and under development for treatment of diabetic nephropathy. Hepatic impairment is known to impact the pharmacokinetics (PKs) of other MR blocking drugs. The aim of the present study was to characterise the PKs and safety of a single oral dose of esaxerenone in Japanese subjects with mild-moderate hepatic impairment. METHODS: In this open-label, parallel-group study, subjects with mild (Child-Pugh grade A) or moderate (grade B) hepatic impairment, and healthy controls with normal hepatic function matched by age and BMI (all groups n = 6), received a single 2.5-mg oral dose of esaxerenone. Plasma concentrations were measured by liquid chromatography-tandem mass spectrometry, and PK parameters were calculated using non-compartmental analysis. RESULTS: Geometric least-squares mean (GLSM) ratios (90% confidence intervals [CIs]) for area under the plasma concentration-time curve (up to the last quantifiable time, up to infinity) in subjects with mild hepatic impairment versus normal hepatic function were 0.837 (0.637, 1.099) and 0.824 (0.622, 1.092), respectively. Corresponding values for moderate hepatic impairment versus normal hepatic function were 1.078 (0.820, 1.415) and 1.098 (0.829, 1.454). GLSM ratios (90% CIs) for peak plasma concentration (Cmax) were 0.959 (0.778, 1.182) for mild hepatic impairment versus normal hepatic function and 0.804 (0.653, 0.992) for moderate hepatic impairment versus normal hepatic function. Time to Cmax and clearance values were comparable between groups. The incidence of adverse events (AEs) was 16.7% in the moderate hepatic impairment and normal hepatic function groups. One serious AE (hepatic encephalopathy) occurred in one subject with moderate hepatic impairment. CONCLUSIONS: Mild to moderate hepatic impairment had no clinically relevant effect on esaxerenone exposure. Esaxerenone dosage adjustment based on PKs is unlikely to be needed in patients with mild to moderate hepatic impairment. TRIAL REGISTRATION: JapicCTI-163339. FUNDING: Daiichi Sankyo Co., Ltd.

Pharmacokinetic interactions of esaxerenone with amlodipine and digoxin in healthy Japanese subjects.

BACKGROUND: To investigate the effects of coadministration of esaxerenone with amlodipine on the pharmacokinetics (PK) of each drug, and of esaxerenone on the PK of digoxin. METHODS: In three open-label, single-sequence, crossover studies, healthy Japanese males received single oral doses of esaxerenone 2.5 mg (Days 1, 15), with amlodipine 10 mg/day (Days 8-18) (Study 1, N = 24); single doses of amlodipine 2.5 mg (Days 1, 21), with esaxerenone 5 mg/day (Days 8-25) (Study 2; N = 20); or digoxin 0.25 mg/day (Days 1-15) with esaxerenone 5 mg/day (Days 11-15) (Study 3; N = 20). PK parameters and safety were assessed. RESULTS: Study 1: esaxerenone peak plasma concentration (Cmax) and time to Cmax were unaltered by amlodipine coadministration, but mean half-life was slightly prolonged from 18.5 to 20.9 h. Geometric least-squares mean (GLSM) ratios for Cmax, area under the plasma concentration-time curve (AUC) from zero to last measurable concentration and from zero to infinity for esaxerenone + amlodipine versus esaxerenone were 0.958, 1.154, and 1.173, respectively. Study 2: corresponding GLSM ratios for amlodipine + esaxerenone versus amlodipine were 1.099, 1.185, and 1.214. Study 3: esaxerenone did not markedly alter digoxin PK. GLSM ratios for Cmax, trough plasma concentration, and AUC during a dosing interval for digoxin versus esaxerenone + digoxin were 1.130, 1.088, and 1.072, respectively. CONCLUSIONS: No drug-drug interactions are expected during combination therapy with esaxerenone and either amlodipine or digoxin, based on a lack of any clinically relevant PK changes. TRIAL REGISTRATION: Studies 1 and 2: JapicCTI-163379 (registered on 20 September 2016); Study 3: JapicCTI-163443 (registered on 24 November 2016).

Site-Selective Esterifications of Polyol ß-Hydroxyamides and Applications to Serine-Selective Glycopeptide Modifications.

The site-selective acylations of ß-hydroxyamides in the presence of other hydroxyl groups are described. Central to the success of this modification is the metal-template-driven acylation using pyridine ketoxime esters as acylating reagents in combination with CuOTf. This strategy enables ß-hydroxyl groups to be site-selectively acylated in various derivatives, including sterically hindered secondary ß-alcohol. The utility of this methodology is showcased by the serine-selective modification of a glycopeptide with unprotected sugar.

Absolute Bioavailability of Esaxerenone and Food Effects on its Pharmacokinetics After a Single Oral Dose in Healthy Japanese Subjects: An Open-Label Crossover Study.

INTRODUCTION: To investigate the absolute bioavailability of esaxerenone and the effects of food on its pharmacokinetics (PK) after a single oral dose in healthy Japanese subjects. METHODS: Twenty-four Japanese males aged 20-45 years were randomised to six groups (each n = 4) in this single-centre, open-label, three-way, three-period crossover study. Esaxerenone (5 mg) was administered in the fasting state as a single oral dose, single intravenous infusion over 1 h, or in the postprandial state as a single oral dose. Plasma samples were taken before and during the 96 h after drug administration. Drug concentrations were measured using liquid chromatography-tandem mass spectrometry. PK parameters were calculated using noncompartmental analysis, and safety was assessed. RESULTS: After fasting intravenous administration, total body clearance was 3.69 L h-1 and volume of distribution was 92.7 L. The plasma concentration-time profile of esaxerenone was similar after fasting and postprandial administration. Absolute bioavailability of a single oral 5-mg dose of esaxerenone was 89.0% in the fasting state and 90.8% postprandially. Point estimates (1.010 and 1.019, respectively) and 90% confidence intervals for geometric least squares mean peak plasma concentrations and area under the plasma concentration-time curve ratios after postprandial versus fasting oral esaxerenone were within the prespecified range (0.80, 1.25). No severe adverse events occurred throughout the study. CONCLUSIONS: Esaxerenone has a high absolute bioavailability of approximately 90% and food has no effect on esaxerenone PK after a single oral dose of 5 mg in healthy Japanese subjects. Additionally, no safety concerns were identified. CLINICAL TRIAL REGISTRATION: JapicCTI No. 163452. FUNDING: Daiichi Sankyo Co., Ltd.

First asymmetric total syntheses of cernuane-type Lycopodium alkaloids, cernuine, and cermizine D.

The first total syntheses of two cernuane-type Lycopodium alkaloids, (-)-cernuine and (+)-cermizine D, were accomplished starting from (+)-citronellal. The syntheses involved organocatalytic alpha-amination to afford oxazolidinone, which is used for diastereoselective allylation, and asymmetric transfer aminoallylation followed by stereoselective construction of an aminal moiety as key steps.

A Method for the Isolation and Characterization of Mycosporine-Like Amino Acids from Cyanobacteria.

This report provides a broadly applicable and cost-effective method for the purification of mycosporine-like amino acids (MAAs) from cyanobacteria. As MAAs are known to have multiple bioactivities for health and beauty, a universal isolation method of MAAs from biomass is attractive. In particular, the biomass of photosynthetic microorganisms such as cyanobacteria is of interest as a natural source of useful compound production, because of their photoautotrophic property. The method presented here is applicable for the isolation of mycosporine-2-glycine (M2G), which is a rare MAA produced in a halotolerant cyanobacterium. This method also allowed for the isolation of two of the most common MAAs, shinorine (SHI) and porphyra-334 (P334). A three-step separation process using low pressure liquid chromatography yielded purified MAAs, which were characterized by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC/MS) analyses. The purified MAAs exhibited free radical scavenging activity in the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. The experimental parameters obtained in this report may allow for a scale-up of the MAA purification process for future industrial applications.

Metal Template Assisted Proximal Arrangement of a Nucleophile and an Electrophile: Site-Selective Acylation of α-Hydroxyamides in Polyols.

Site-selective acylation of α-hydroxyl groups in amides has been achieved in the presence of other primary hydroxyl groups with intrinsic high reactivity. In this methodology, a relatively stable pyridine aldoxime ester was exploited as an acyl donor to suppress undesired acylation. The catalytic activation of a pyridine aldoxime ester with a Lewis acid produced a cationic complex, which preferentially attracted the Lewis basic α-hydroxyamide via a template effect, to thus facilitate o-acylation.

Evaluation of the Pharmacokinetics and Pharmacodynamics of Prasugrel in Japanese Elderly Subjects.

BACKGROUND AND OBJECTIVE: An increased incidence in bleeding events has been reported in Western elderly patients receiving prasugrel. Therefore, doses in Japanese elderly subjects need to be carefully determined. We assessed the pharmacokinetic and pharmacodynamic effects of prasugrel at the clinical dose used in Japan in healthy Japanese elderly subjects compared with non-elderly subjects. METHODS: In an open-label parallel-group study conducted in Japan, two groups (elderly, aged >75 years; non-elderly, aged 45-65 years) received a 20-mg loading dose and a 3.75-mg maintenance dose of prasugrel for 7 days. Plasma concentration of its active metabolite, R-138727, and pharmacokinetic parameters were determined on days 1 and 7 after dosing. Pharmacodynamic response to 20 µM of adenosine diphosphate-induced platelet aggregation was measured by light transmission aggregometry. RESULTS: A total of 47 subjects were enrolled (23 elderly, 24 non-elderly). There was no statistically significant difference in pharmacokinetic parameters between groups: area under the plasma concentration-time curve up to the last quantifiable time and maximum plasma concentration were about 174-175 ng·h/mL and 134-153 ng/mL, respectively, after the loading dose; and about 25-26 ng·h/mL and 25 ng/mL, respectively, after the maintenance dose. Inhibition of platelet aggregation was higher in the elderly subjects than in the non-elderly subjects, with a statistically significant difference from 24 h after the loading dose. No serious adverse events (bleeding or non-bleeding) occurred. CONCLUSIONS: Prasugrel (20-mg loading dose; 3.75-mg maintenance dose) produced a slight increase in antiplatelet efficacy in elderly compared with non-elderly subjects, despite no statistically significant difference in the pharmacokinetics.