Milvexian, a novel factor XIa inhibitor for stroke prevention: pharmacokinetic and pharmacodynamic evaluation.

INTRODUCTION: Antiplatelets and oral anticoagulants are commonly used to treat patients with various cardiovascular and cerebrovascular diseases. However, the primary concern for clinicians remains the risk of bleeding, thus necessitating the development of new therapies. Milvexian is a new anticoagulant that inhibits factor XIa, preventing the pathological formation of thrombi without increasing bleeding risk. AREAS COVERED: This drug evaluation examines the pharmacokinetic properties of milvexian and provides information on its pharmacodynamics and clinical efficacy in treating some cerebrovascular conditions. EXPERT OPINION: Milvexian shows a good pharmacokinetic profile with low renal elimination rates, justifying its use in patients with a high degree of renal impairment, and without relevant drug-drug interactions. In patients affected by acute non-cardioembolic ischemic stroke or high-risk transient ischemic stroke, milvexian, in addition to dual antiplatelet therapy, seems to have a positive efficacy profile without any safety concerns, especially in terms of intracranial hemorrhage. Two phase 3 trials are ongoing to investigate the efficacy and safety of milvexian for preventing cardioembolic and non-cardioembolic ischemic stroke.

An update on oral antiplatelet drug interactions with proton pump inhibitors: what are the risks?

INTRODUCTION: Aspirin and anti-P2Y12 are widely prescribed in cardiovascular patients, often in combination with proton pump inhibitors (PPIs) to limit the risk of upper gastrointestinal bleedings. The potential interaction between PPIs and antiplatelet agents has been widely discussed, but doubts remain as to whether PPIs may reduce the cardiovascular protection provided by aspirin, prasugrel, ticagrelor, and clopidogrel. AREAS COVERED: Many pharmacokinetic (PK) and pharmacodynamic (PD) studies have confirmed the interaction, especially between PPIs and clopidogrel, but with uncertain consequences on clinical outcomes. Therefore, we aimed to summarize the evidence for the widespread combined use of oral antiplatelet drugs and PPIs, to outline the current evidence supporting or opposing drug-drug interaction, and to discuss the clinical implications of such interactions. EXPERT OPINION: A large body of evidence describes the PK/PD interaction of antiplatelet drugs with PPIs and its potential role in increasing clinical cardiovascular adverse events, but no solid clinical data have confirmed these effects. In the light of the published studies, there seems to be no restriction on the choice of PPI with aspirin, prasugrel, and/or ticagrelor. The choice of a PPI with no (or minimal) interference with the hepatic cytochrome P450 2C19 is preferred in patients receiving clopidogrel.

Safety, tolerability, pharmacokinetics and pharmacodynamics of milvexian with aspirin and/or clopidogrel in healthy participants.

Milvexian, an oral activated Factor XI (FXIa) inhibitor, is in clinical studies where it may be combined with antiplatelet agents, including aspirin and/or clopidogrel, to prevent thromboembolic diseases. This phase I trial assessed safety, pharmacokinetics, and pharmacodynamics of milvexian coadministration with aspirin and/or clopidogrel in healthy participants through 3 drug-drug interaction studies using a 3-period, 3-treatment, crossover design. A total of 113 participants were randomized to receive milvexian (200 mg; twice daily for 5 days) or matched placebo coadministered with once-daily aspirin (325 mg for 5 days) and/or clopidogrel (Day 1: 300 mg; Days 2-5: 75 mg). Milvexian was safe and well tolerated, with and without aspirin and/or clopidogrel. Eight mild bleeding adverse events (AEs) were reported in 5 of 113 participants across various treatment arms. Peak and total exposures of milvexian were similar with or without clopidogrel and/or aspirin. Exposure-dependent prolongation of activated partial thromboplastin time and reduction of FXI clotting activity by milvexian were similar with coadministration of aspirin and/or clopidogrel. Milvexian, with or without coadministration of aspirin and/or clopidogrel, did not affect bleeding time or platelet aggregation. Administration of milvexian alone or with aspirin and/or clopidogrel was safe and well tolerated without increased incidence of AEs, including bleeding. Pharmacokinetic and pharmacodynamic effects of milvexian, including bleeding time, were similar with or without aspirin and/or clopidogrel.ClinicalTrials.gov Identifier: NCT03698513.

Population pharmacokinetic study and application of ticagrelor and AR-C124910XX after percutaneous coronary intervention in Chinese patients with acute coronary syndrome.

OBJECTIVES: This study aimed to understand the pharmacokinetics of ticagrelor in Chinese patients with acute coronary syndrome (ACS), identify influencing factors, and inform ticagrelor treatment optimization. MATERIALS AND METHODS: Data from 195 ACS patients, including 491 plasma ticagrelor concentration timepoints and clinical information, were analyzed using NONMEN for pharmacokinetic (PK) parameter factors. The model underwent internal validation with bootstrap methodology. RESULTS: The PK curve of ticagrelor was well delineated using a one disposition compartment model with first-order absorption rate constant, 0.67/h. When the direct bilirubin levels and white plasma cell counts increased, female patients showed decreased glomerular filtration rate, decreased ticagrelor clearance rate, and increased exposure. When the direct bilirubin levels increased and body weight and hemoglobin decreased, rs6787801 was GG compared with AA and GA, the ticagrelor metabolite clearance rate decreased and exposure increased. CONCLUSION: The study offers key insights into ticagrelor's dose-exposure relationship post-percutaneous coronary intervention in ACS patients, highlighting factors critical for personalized treatment strategies.

Comparative Bioequivalence Study of 2 Clopidogrel 75-mg Tablet Formulations in Moroccan Volunteers.

This study investigates the pharmacokinetic properties and bioequivalence of 2 formulations of clopidogrel tablets administered to a cohort of healthy Moroccan male volunteers. The primary objective was to assess the rate and extent of drug absorption from the test formulation in comparison to a reference formulation, focusing on critical parameters including maximum plasma concentration (Cmax), area under the concentration-time curve from 0 to the last measurable time (AUC0-t), and area under the concentration-time curve extrapolated to infinity (AUC0-∞). The results revealed that the geometric mean ratios of Cmax, AUC0-t, and AUC0-∞ for the test formulation relative to the reference formulation were 105.7%, 105.6%, and 105.6%, respectively. The 90% confidence intervals for these parameters fell within the predefined bioequivalence range of 80%-125%, indicating a statistically and clinically equivalent performance between the 2 formulations. This investigation sheds light on the pharmacokinetic behavior of clopidogrel in the context of the Moroccan male population, offering valuable insights into the comparability of formulations.

Association of genetic variations of 3'-UTR in clopidogrel pharmacokinetic-relevant genes with clopidogrel response in Han Chinese patients with coronary artery disease.

Dual antiplatelet therapy with aspirin and clopidogrel has reduced ischemic vascular events significantly. Genetic influence, especially those in clopidogrel pharmacokinetic-relevant genes partially accounts for interindividual pharmacodynamic variability of clopidogrel. However, most studies have concentrated on the genetic variations in introns, exons, or promoters of the candidate genes, and the association between genetic variations in 3'-UTR in clopidogrel pharmacokinetic-relevant genes and clopidogrel response is unknown. In our study, ten different algorithms were applied to pick potential miRNAs targeting the clopidogrel pharmacokinetic-relevant genes. Furthermore, the correlation between miRNA expression profiles and mRNA expression of corresponding clopidogrel pharmacokinetic-relevant genes was analyzed. Through comprehensive analysis, including bioinformatics prediction and correlation analysis of miRNA and mRNA expression profiles, miR-218-5p and miR-506-5p were supposed to regulate the expression of PON1 via binding with its 3'-UTR. Moreover, PON1 rs854551 and rs854552 were located in miRNA recognizing sequences and may serve as potential miRSNPs possibly affecting PON1 expression. The rs854552 polymorphism was genotyped and platelet reactivity index (PRI) indicative of clopidogrel response was measured in 341 Chinese coronary artery disease (CAD) patients 24 h after administration of 300 mg clopidogrel. Our results showed that PON1 rs854552 had a significant influence on PRI in CAD patients, especially in patients with CYP2C19 extensive metabolic phenotype. In conclusion, PON1 rs854552 polymorphisms may affect clopidogrel response. Bioinformatics prediction followed by functional validation could aid in decoding the contribution of unexplained variations in the 3'-UTR in drug-metabolizing enzymes on clopidogrel response.

Analysis of the effect of CYP2C19 gene properties on the anti-platelet aggregation of clopidogrel after carotid artery stenting under network pharmacology.

Antiplatelet therapy is an important factor influencing the postterm patency rate of carotid artery stenting (CAS). Clopidogrel is a platelet aggregation inhibitor mediated by the adenosine diphosphate receptor and is affected by CYP2C19 gene polymorphisms in vivo. When the CYP2C19 gene has a nonfunctional mutation, the activity of the encoded enzyme will be weakened or lost, which directly affects the metabolism of clopidogrel and ultimately weakens its antiplatelet aggregation ability. Therefore, based on network pharmacology, analyzing the influence of CYP2C19 gene polymorphisms on the antiplatelet therapeutic effect of clopidogrel after CAS is highly important for the formulation of individualized clinical drug regimens. The effect of the CYP2C19 gene polymorphism on the antiplatelet aggregation of clopidogrel after CAS was analyzed based on network pharmacology. A total of 100 patients with ischemic cerebrovascular disease who were confirmed by the neurology department and required CAS treatment were studied. CYP2C19 genotyping was performed on all patients via a gene chip. All patients were classified into the wild-type (WT) group (*1/*1), heterozygous mutation (HTM) group (CYP2C19*1/*2, CYP2C19*1/*3), and homozygous mutation (HMM) group (CYP2C19*2/*2, CYP2C19*2/*3, and CYP2C19*3/*3). High-performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS) was used to detect the blood concentration of clopidogrel and the plasma clopidogrel clearance (CL) rate in different groups of patients before and after clopidogrel treatment. The platelet aggregation rate of patients with different genotypes was measured by turbidimetry. The incidences of clopidogrel resistance (CR) and stent thrombosis in different groups after three months of treatment were analyzed. The results showed that among the different CYP2C19 genotypes, patients from the HTM group accounted for the most patients, while patients from the HTM group accounted for the least patients. Similarly, the clopidogrel CL of patients in the HMM group was lower than that of patients in the WT group and HTM group (P < 0.01). The platelet inhibition rate of patients in the HMM group was evidently inferior to that of patients in the WT group and HTM group (P < 0.01). The incidence of CR and stent thrombosis in the WT group was notably lower than that in the HTM and HMM groups (P < 0.01). These results indicate that the CYP2C19 gene can affect CR occurrence and stent thrombosis after CAS by influencing clopidogrel metabolism and platelet count.

Prognostic Impact of CYP2C19 Genotypes on Long-Term Clinical Outcomes in Older Patients After Percutaneous Coronary Intervention.

BACKGROUND: Carriers of CYP2C19 loss-of-function alleles have increased adverse events after percutaneous coronary intervention, but limited data are available for older patients. We aimed to evaluate the prognostic impact of CYP2C19 genotypes on clinical outcomes in older patients after percutaneous coronary intervention. METHODS AND RESULTS: The study included 1201 older patients (aged ≥75 years) who underwent percutaneous coronary intervention and received clopidogrel-based dual antiplatelet therapy in South Korea. Patients were grouped on the basis of CYP2C19 genotypes. The primary outcome was 3-year major adverse cardiac events, defined as a composite of cardiac death, myocardial infarction, and stent thrombosis. Older patients were grouped into 3 groups: normal metabolizer (36.6%), intermediate metabolizer (48.1%), and poor metabolizer (15.2%). The occurrence of the primary outcome was significantly different among the groups (3.1, 7.0, and 6.2% in the normal metabolizer, intermediate metabolizer, and poor metabolizer groups, respectively; P=0.02). The incidence rate of all-cause death at 3 years was greater in the intermediate metabolizer and poor metabolizer groups (8.1% and 9.2%, respectively) compared with that in the normal metabolizer group (3.5%, P=0.03) without significant differences in major bleeding. In the multivariable analysis, the intermediate metabolizer and poor metabolizer groups were independent predictors of 3-year clinical outcomes. CONCLUSIONS: In older patients, the presence of any CYP2C19 loss-of-function allele was found to be predictive of a higher incidence of major adverse cardiac events within 3 years following percutaneous coronary intervention. This finding suggests a need for further investigation into an optimal antiplatelet strategy for older patients. REGISTRATION: URL: https://clinicaltrials.gov. Identifier: NCT04734028.

Pharmacokinetic/Pharmacodynamic Assessment of the Structural Refinement of Clopidogrel Focusing on the Balance between Bioactivation and Deactivation.

The delicate balance between ischemic and bleeding risks is a critical factor in antiplatelet therapy administration. Clopidogrel and prasugrel, belonging to the thienopyridine class of antiplatelet drugs, are known for their variability in individual responsiveness and high incidence of bleeding events, respectively. The present study is centered on the development and assessment of a range of deuterated thienopyridine derivatives, leveraging insights from structure-pharmacokinetic relationships of clopidogrel and prasugrel. Our approaches were grounded in the molecular framework of clopidogrel and incorporated the C2-pharmacophore design from prasugrel. The selection of ester or carbamate substituents at the C2-position facilitated the generation of the 2-oxointermediate through hydrolysis, akin to prasugrel, thereby bypassing the issue of CYP2C19 dependency. The bulky C2-pharmacophore in our approach distinguishes itself from prasugrel's acetyloxy substituent by exhibiting a moderated hydrolysis rate, resulting in a more gradual formation of the active metabolite. Excessive and rapid release of the active metabolite, believed to be linked with an elevated risk of bleeding, is thus mitigated. Our proposed structural modification retains the hydrolysis-sensitive methyl ester of clopidogrel but substitutes it with a deuterated methyl group, shown to effectively reduce metabolic deactivation. Three promising compounds demonstrated a pharmacokinetic profile similar to that of clopidogrel at four times the dose, while also augmenting its antiplatelet activity. SIGNIFICANCE STATEMENT: Inspired by the structure-pharmacokinetic relationship of clopidogrel and prasugrel, a range of clopidogrel derivatives were designed, synthesized, and assessed. Among them, three promising compounds have been identified, striking a delicate balance between efficacy and safety for antiplatelet therapy. Additionally, the ozagrel prodrug conjugate was discovered to exert a synergistic therapeutic effect alongside clopidogrel.

Safety, Tolerability, and Pharmacodynamics of AZD3366 (Optimized Human CD39L3 Apyrase) Alone and in Combination With Ticagrelor and Acetylsalicylic Acid: A Phase 1, Randomized, Placebo-Controlled Study.

BACKGROUND: ADP and ATP are importantly involved in vascular and thrombotic homeostasis, via multiple receptor pathways. Blockade of ADP P2Y12 receptors inhibits platelet aggregation and represents an effective cardiovascular disease prevention strategy. AZD3366 (APT102), a long-acting recombinant form of an optimized CD39L3 human apyrase, has effectively reduced ATP, ADP, and platelet aggregation and provided tissue protection in preclinical models, features that could be very beneficial in treating patients with cardiovascular disease. METHODS AND RESULTS: We conducted this phase 1, first-in-human study of single ascending doses of intravenous AZD3366 or placebo, including doses added to dual antiplatelet therapy with ticagrelor and acetylsalicylic acid. The primary objective was safety and tolerability; secondary and exploratory objectives included pharmacokinetics, pharmacodynamics (measured as inhibition of platelet aggregation), adenosine diphosphatase (ADPase) activity, and ATP/ADP metabolism. In total, 104 participants were randomized. AZD3366 was generally well tolerated, with no major safety concerns observed. ADPase activity increased in a dose-dependent manner with a strong correlation to AZD3366 exposure. Inhibition of ADP-stimulated platelet aggregation was immediate, substantial, and durable. In addition, there was a prompt decrease in systemic ATP concentration and an increase in adenosine monophosphate concentrations, whereas ADP concentration appeared generally unaltered. At higher doses, there was a prolongation of capillary bleeding time without detectable changes in the ex vivo thromboelastometric parameters. CONCLUSIONS: AZD3366 was well tolerated in healthy participants and demonstrated substantial and durable inhibition of platelet aggregation after single dosing. Higher doses prolonged capillary bleeding time without detectable changes in ex vivo thromboelastometric parameters. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT04588727.

Pharmacokinetics of Edoxaban 15 mg in Very Elderly Patients with Nonvalvular Atrial Fibrillation: A Subanalysis of the ELDERCARE-AF Study.

BACKGROUND: We evaluated the pharmacokinetics (PK) of low-dose (15 mg) edoxaban in very elderly patients (≥80 years) with nonvalvular atrial fibrillation (NVAF) and high bleeding risk. METHODS: This subanalysis of the phase 3, randomized, double-blind, placebo-controlled, multicenter ELDERCARE-AF study evaluated edoxaban plasma concentrations and compared them with the Japanese population of the ENGAGE AF-TIMI 48 and Japanese severe renal impairment (SRI) studies. RESULTS: The PK analysis population included 451 patients, 53.8% of whom concomitantly used antiplatelet drugs, 41.0% had SRI, and 38.0% had low body weight. Edoxaban plasma concentrations at trough and 1 to 3 hours post-dose in ELDERCARE-AF were 17.3 ± 13.9 (n = 427) and 93.3 ± 57.8 ng/mL (n = 447), respectively. These values were slightly higher than the 15 mg group in ENGAGE AF-TIMI 48 (n = 79; 12.4 ± 12.1 and n = 115; 78.7 ± 45.0 ng/mL, respectively), lower than the ENGAGE AF-TIMI 48 high-dose reduced to 30 mg group (n = 83; 25.1 ± 36.6 and n = 111; 150 ± 91.6 ng/mL, respectively), but similar to the Japanese SRI study (n = 39; 18.4 ± 11.2 and n = 40; 96.8 ± 48.3 ng/mL, respectively). ELDERCARE-AF patients with SRI and low body weight (≤45 kg) had higher concentrations than those without, and those taking antiplatelet drugs had lower concentrations than those who were not. CONCLUSION: PK data support edoxaban 15 mg once daily for very elderly NVAF patients with high bleeding risk, with caution for patients with SRI and/or low body weight.

Utility of VerifyNow to assess the immediate pharmacodynamic response of chewed and swallowed aspirin: comparison with aggregometry.

VerifyNow (VN) test is a less laborious method to assess pharmacodynamics (PD) compared to light transmittance aggregometry (LTA). VN assay has not been used to study the immediate PD effects of acetylsalicylic acid (ASA). Ten healthy volunteers were randomly assigned to a single 162 or 650 mg dose of chewed and swallowed ASA. Pharmacodynamic and pharmacokinetic measurements were performed at baseline and serially up to 60 min after ASA administration. Onset by VN was 20 ± 7 min with 162 mg and 13 ± 7 min with 650 mg ASA (p = .07). Onset by 1 mM AA-induced PA was 13 ± 12 min with 162 mg and 7 ± 3 min with 650 mg ASA (p=NS). VN correlated with AA-induced PA (r = 0.80, p < .001) and serum TxB2 levels (r = 0.76, p < .001). 95% inhibition of serum TxB2 was achieved at 38 ± 22 min and 22 ± 8 min with the 162 and 650 mg ASA, respectively (p = .08). The onset and extent of the antiplatelet effect of 650 mg ASA is numerically faster and greater than the 162 mg dose. VN identifies the onset, extent, and dose response to ASA therapy. The ease of using VN should facilitate multicenter PD investigations of ASA.

Aspirin (acetylsalicylic acid) is an important drug widely used to prevent adverse ischemic events in patients with cardiovascular disease. Platelet aggregation and thromboxane B₂ levels in blood samples by complex laboratory methods are used to assess platelet response to aspirin. VerifyNow assay is a simple laboratory test that has not been used to assess the immediate effect of aspirin. In this study, conducted in 10 healthy volunteers, we compared the immediate platelet response to aspirin by serially assessing platelet aggregation by aggregometry and VerifyNow assay, and thromboxane B₂ levels. We also measured plasma levels of acetylsalicylic acid and salicylic acid. Our study demonstrated that the VerifyNow Aspirin test identifies the onset, extent, and dose-response to aspirin therapy. The ease of using the VerifyNow test should facilitate multicenter pharmacodynamic investigations of aspirin.

Aspirin pharmacokinetics and pharmacodynamics through gestation.

BACKGROUND: Low dose aspirin is recommended for prevention of preeclampsia, however there is not consensus on the appropriate dose. Pregnancy specific changes have the potential to impact the pharmacology of aspirin in pregnancy, however there are very limited studies on aspirin pharmacokinetics in pregnancy and none linking pharmacokinetics (PK, drug dose and drug level) to pharmacodynamics (PD, drug dose and physiologic response) in pregnancy. As a result, we do not have a good understanding of the pharmacologic response to aspirin in pregnancy, which has important implications for clinical efficacy. We sought to describe the PK and PD of aspirin through pregnancy and to identify individual covariates that impacted aspirin PK/PD. OBJECTIVE: We sought to describe the PK and PD of aspirin through pregnancy (first and third trimester), to identify covariates that significantly impact aspirin PK and to identify the relationship between aspirin PK and PD. STUDY DESIGN: This is a prospective study of patients at high risk for preeclampsia recommended to take 81 mg aspirin daily. This study involved 3 visits as follows: (1) baseline, first trimester (10-16 weeks of gestation) 6-hour PK visit, done before initiation of aspirin; (2) follow-up 1: 2 to 4 weeks after aspirin initiation; and (3) follow-up 2: third trimester 6-hour PK visit (28-32 weeks of gestation). The following were assessed at each visit: weight or body mass index, platelet function analysis-100 (Siemens), urinary thromboxane B2, serum thromboxane B2, and plasma salicylic acid. The PK visits consisted of blood work done at baseline (predose), administration of 81 mg nonenteric coated aspirin, and then plasma blood level of salicylic acid assessed at 30 minutes and then hourly 1 to 6 hours after dose. Pearson correlation and multivariable regression were used to identify associations between parameters and identify relevant covariates. Log-adjusted values were used for regression analysis. P<.05 was considered statistically significant. RESULTS: Nineteen participants were included with first trimester data, and 16 with third trimester data. There was no statistically significant change in mean PK parameters between the first and third trimester, although there was a trend to lower peak concentration in the third than in the first trimester (P=.08). In multivariable regression, baseline obesity and current body mass index as a continuous measures were negatively associated with log-adjusted peak salicylic acid concentration (-0.28 [-0.46 to -0.11], P=.003 and -0.02 [-0.03 to -0.009], P=.001, respectively) and log-adjusted plasma salicylic acid area under the curve 0 to 6 hours postdose (-0.25 [-0.45 to 0.05], P=.02, -0.04 [-0.07 to -0.01], P=.008 respectively). There was a significant decrease in urinary thromboxane 2 to 4 weeks after aspirin initiation compared with baseline, which correlated with a concomitant increase in platelet function analysis-100 closure time. In multivariable regression model, there was a strong association between plasma salicylic acid concentration (area under the curve 0-6 hours postdose) and urinary thromboxane (B=-3.12 [-5.38 to -1.04], P=.006), and with urinary thromboxane suppression and platelet inhibition, platelet function analysis-100 (-0.23 [-0.31 to -0.14], P<.001). With progressive thromboxane suppression, platelet inhibition (platelet function analysis-100 closure time) increased. Individual comorbidities, including weight, hypertension, and pregestational diabetes (Type I or II), also impacted aspirin response. CONCLUSION: We have demonstrated the relationship between individual factors, plasma concentrations of salicylic acid, thromboxane suppression, and platelet inhibition at a single dose (81 mg) of aspirin taken through pregnancy. Our findings suggest that dose modification of aspirin in pregnancy may help to achieve the optimal response. Our results may be used to facilitate computational modeling to identify optimal dosing, taking into consideration individual factors.

A pharmacokinetics interaction study of antiplatelet agents aspirin and clopidogrel combined with dl-3-n-butylphthalide in rats by liquid chromatography-tandem mass spectrometry.

A sensitive and specific high-performance liquid chromatography-tandem mass spectrometry method has been developed to determine the pharmacokinetic interactions of the antiplatelet agents aspirin and clopidogrel combined with dl-3-n-butylphthalide. For the determination of aspirin metabolite salicylic acid, clopidogrel inactive metabolite SR26334 and NBP prototype drug in rat plasma, plasma samples were prepared by precipitation of proteins using methanol containing 0.1% formic acid, followed by centrifugation. Chromatography was performed on a C18 column, eluting with a gradient of acetonitrile (with 0.1% formic acid)-water (with 0.1% formic acid). The detection adopted electrospray ion source and positive ion multiple reaction monitoring modes. The linear detection response range of salicylic acid is 80-80,000 ng/ml, and the linear detection response range of SR26334 and dl-3-n-butylphthalide is 10-10,000 ng/ml. Our study revealed that dl-3-n-butylphthalide affected the pharmacokinetics of aspirin and clopidogrel when administered to rats.

Decreased plasma exposure of clopidogrel active metabolite in rats after long-term treatment with clopidogrel.

Clopidogrel (Clop) is oxidized by cytochrome P450s (CYPs) to an active thiol metabolite, Clop-AM, to inhibit platelet activation and aggregation. As an irreversible inhibitor of CYP2B6 and CYP2C19, clopidogrel may inhibit its own metabolism after long-term administration. The study compared the pharmacokinetic profiles of clopidogrel and its metabolites in rats receiving a single or a 2 week administration of Clop. The mRNA and protein levels of hepatic clopidogrel-metabolizing enzymes and their enzymatic activities were analyzed to explore their contribution to any altered plasma exposure of Clop and its metabolites. The results showed that long-term treatment with clopidogrel significantly decreased the AUC(0-t) and Cmax values of Clop-AM in rats, accompanied with markedly impaired catalytic activities of Clop-metabolizing CYPs including CYP1A2, CYP2B6, CYP2C9, CYP2C19, and CYP3A4. It suggests that consecutive administration of Clop to rats decreases hepatic CYPs activities, which may, in turn, inhibit clopidogrel metabolism and then reduce Clop-AM plasma exposure. Therefore, long-term treatment with clopidogrel has the potential to reduce its anti-platelet activity and to increase the risk of drug-drug interaction.

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.

Pharmacokinetic and pharmacodynamic profiles of a novel phospholipid-aspirin complex liquid formulation and low dose enteric-coated aspirin: results from a prospective, randomized, crossover study.

Low dose enteric-coated aspirin (EC-ASA) is routinely used for secondary cardiovascular event prevention. However, absorption of EC tablets is poor, which can result in subtherapeutic antiplatelet effects. Phospholipid-aspirin liquid filled capsules (PL-ASA) are a novel FDA-approved immediate-release formulation designed to reduce gastrointestinal (GI) injury by limiting direct contact with the stomach lining. We compared the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of PL-ASA versus EC-ASA at a low dose. This randomized, open-label, crossover study assessed PK and PD following a single 81-mg dose of PL-ASA versus EC-ASA under fasting conditions in 36 volunteers without cardiovascular disease between 18 and 75 years of age. Volunteers were randomly assigned 1:1 to either PL-ASA then EC-ASA or vice versa with a minimum 14-day washout. Assessments included PK parameters for acetylsalicylic acid and salicylic acid, platelet aggregation in response to arachidonic acid (AA), and serum thromboxane B2 (TxB2) assessments over 24 h. PL-ASA was rapidly absorbed. PL-ASA reached Tmax 3 h earlier (1.01 vs. 4.00 h, p < 0.0001), with almost double the Cmax (720 vs. 368 ng/mL, p < 0.0001) and overall 44% higher exposure of acetylsalicylic acid (AUC0-t: 601 vs. 416 h*ng/mL, p = 0.0013) compared with EC-ASA. Within 1 h of dosing, PL-ASA achieved significantly lower residual platelet aggregation, which persisted for the full 24 h (median AA-LTA was 47% with PL-ASA vs. 80.5% with EC-ASA; p = 0.0022 at hour-24). Treatment with PL-ASA also resulted in significantly lower serum TxB2 concentrations at each time point compared with EC-ASA (all p-values < 0.05). PL-ASA resulted in faster and more complete aspirin absorption paralleled by more prompt and potent platelet inhibition compared with EC-ASA after a single 81 mg dose. PL-ASA represents an attractive novel aspirin formulation for the secondary prevention of cardiovascular events.Clinical Trial Registration ClinicalTrials.gov identifier: NCT04811625.

Interaction study of salvianolic acids for injection on pharmacokinetics of clopidogrel in rats using LC-MS/MS.

Salvianolic acids for injection (SAI) is developed from traditional Chinese medicine and approved for the treatment of cardiovascular and cerebrovascular diseases. Clopidogrel is an inhibitor of platelet aggregation, which is often prescribed for patients in combination with SAI. This present study aimed to assess the effects of SAI on the pharmacogenomics, pharmacokinetics, and pharmacodynamics of clopidogrel, thereby ensuring the safety and efficacy of coadministration. In vitro cytochrome P450 isoenzyme assays were performed in human liver microsomes using LC-MS/MS method to assess the metabolites of CYPs substrates. The effects of SAI on the pharmacokinetic and pharmacodynamic behaviors of clopidogrel were investigated in rats. The main pharmacokinetic parameters were analyzed using LC-MS/MS. Prothrombin time, activated partial thromboplastin time, bleeding time, and inhibition of platelet aggregation were measured to evaluate the effects of pharmacodynamics. Our study revealed that the clinical dose of SAI has no significant inhibitory effect on clopidogrel-related liver microsome metabolic CYP450 isoenzymes. Moreover, SAI did not affect the pharmacokinetics of clopidogrel when rats were administered both single and multiple doses. In pharmacodynamic study, SAI has no effect on platelet aggregation rate, prothrombin time, and activated partial thromboplastin time of clopidogrel but could significantly prevent the risk of bleeding caused by clopidogrel.

Ticagrelor.

Ticagrelor is one of the most recent antiplatelet agents used to inhibit platelet aggregation via blocking the ADP receptors of the subtype P2Y12. It belongs to the non-thienopyridine class. The drug was first discovered by Astra Zeneca and approved for use in 2011 by the FDA. Ticagrelor is usually used for the prevention and treatment of thromboembolism in adult patients with acute coronary syndrome. This chapter include an overview on the physical properties, chemical properties, mode of action, pharmacokinetics and common uses of ticagrelor. In addition, the reported methods of ticagrelor assay will be discussed briefly in order to help analysts to find the most convenient method for its estimation in routine analysis. The methods of synthesis used for the preparation of ticagrelor will also be covered in this chapter. Moreover, the analytical and characterization techniques used to characterize ticagrelor row material are summarized herein.