Ticagrelor in modern cardiology - an up-to-date review of most important aspects of ticagrelor pharmacotherapy

Determination of ticagrelol in rat plasma and tablets by micellar electrokinetic chromatography coupled with large volume sample stacking: Application to a pharmacokinetic study

A method using micellar electrokinetic chromatography coupled with large-volume sample stacking for the determination of ticagrelol was developed and validated. The analysis was performed in a fused silica capillary (41.5 cm effective length, 50 μm diameter) with ultraviolet detection at 195 nm. The background electrolytes were 30 mM phosphate buffer of pH 3.0 with 120 mM sodium dodecylsulfate and 10 % (v/v) acetonitrile (120 s X 50 mbar; 20°C; -18 kV) and 30 mM borate buffer of pH 8.5 with 75 mM sodium dodecylsulfate (120 s X 50 mbar; 20°C; 25 kV); under acidic and alkaline conditions, respectively. The method was found to be reliable with respect to specificity, linearity of the calibration line (R2  > 0.99), repeatability (relative standard deviation 2.56%-3.34%), and accuracy (recovery in the range 101.21%-102.67%). The limits of detection and quantitation were 0.032, 0.071, and 0.087, 0.188 μg/mL, respectively. The method was successfully applied for the determination of ticagrelol concentrations in rat plasma and tablets with good recoveries and reproducibility. The presented method proved to be suitable for monitoring ticagrelor in rat plasma.

Eptifibatide, an Older Therapeutic Peptide with New Indications: From Clinical Pharmacology to Everyday Clinical Practice

Therapeutic peptides are oligomers or short polymers of amino acids used for various medical purposes. Peptide-based treatments have evolved considerably due to new technologies, stimulating new research interests. They have been shown to be beneficial in a variety of therapeutic applications, notably in the treatment of cardiovascular disorders such as acute coronary syndrome (ACS). ACS is characterized by coronary artery wall damage and consequent formation of an intraluminal thrombus obstructing one or more coronary arteries, leading to unstable angina, non-ST elevated myocardial infarction, and ST-elevated myocardial infarction. One of the promising peptide drugs in the treatment of these pathologies is eptifibatide, a synthetic heptapeptide derived from rattlesnake venom. Eptifibatide is a glycoprotein IIb/IIIa inhibitor that blocks different pathways in platelet activation and aggregation. In this narrative review, we summarized the current evidence on the mechanism of action, clinical pharmacology, and applications of eptifibatide in cardiology. Additionally, we illustrated its possible broader usage with new indications, including ischemic stroke, carotid stenting, intracranial aneurysm stenting, and septic shock. Further research is, however, required to fully evaluate the role of eptifibatide in these pathologies, independently and in comparison to other medications.

Pharmacogenetics of Antiplatelet Therapy

Antiplatelet therapy is used in the treatment of patients with acute coronary syndromes, stroke, and those undergoing percutaneous coronary intervention. Clopidogrel is the most widely used antiplatelet P2Y12 inhibitor in clinical practice. Genetic variation in CYP2C19 may influence its enzymatic activity, resulting in individuals who are carriers of loss-of-function CYP2C19 alleles and thus have reduced active clopidogrel metabolites, high on-treatment platelet reactivity, and increased ischemic risk. Prospective studies have examined the utility of CYP2C19 genetic testing to guide antiplatelet therapy, and more recently published meta-analyses suggest that pharmacogenetics represents a key treatment strategy to individualize antiplatelet therapy. Rapid genetic tests, including bedside genotyping platforms that are validated and have high reproducibility, are available to guide selection of P2Y12 inhibitors in clinical practice. The aim of this review is to provide an overview of the background and rationale for the role of a guided antiplatelet approach to enhance patient care.

Pharmacokinetics and Pharmacodynamics of Approved and Investigational P2Y12 Receptor Antagonists

Coronary artery disease remains the major cause of mortality worldwide. Antiplatelet drugs such as acetylsalicylic acid and P2Y12 receptor antagonists are cornerstone treatments for the prevention of thrombotic events in patients with coronary artery disease. Clopidogrel has long been the gold standard but has major pharmacological limitations such as a slow onset and long duration of effect, as well as weak platelet inhibition with high inter-individual pharmacokinetic and pharmacodynamic variability. There has been a strong need to develop potent P2Y12 receptor antagonists with more favorable pharmacological properties. Prasugrel and ticagrelor are more potent and have a faster onset of action; however, they have shown an increased bleeding risk compared with clopidogrel. Cangrelor is highly potent and has a very rapid onset and offset of effect; however, its indication is limited to P2Y12 antagonist-naïve patients undergoing percutaneous coronary intervention. Two novel P2Y12 receptor antagonists are currently in clinical development, namely vicagrel and selatogrel. Vicagrel is an analog of clopidogrel with enhanced and more efficient formation of its active metabolite. Selatogrel is characterized by a rapid onset of action following subcutaneous administration and developed for early treatment of a suspected acute myocardial infarction. This review article describes the clinical pharmacology profile of marketed P2Y12 receptor antagonists and those under development focusing on pharmacokinetic, pharmacodynamic, and drug-drug interaction liability.

A Case of Intraparenchymal Hepatic Hemorrhage Due to Ticagrelor Loading Treatment in an Elderly Patient With Acute Coronary Syndrome

Ticagrelor is a potent P2Y12 inhibitor that is increasingly used in acute coronary syndrome. Although drug-related intrahepatic hemorrhages have been reported with anticoagulant drugs, no case of intrahepatic hemorrhage due to ticagrelor has been encountered in the literature. With this case, we tried to explain that potent antiaggregant drugs may cause this rare bleeding complication. Although ticagrelor is used for rapid antiaggregation effect in acute coronary syndrome, de-escalation to clopidogrel treatment in elderly patients during the hospitalization period is a more reasonable option.

Ticagrelor Does Not Protect Against Endothelial Ischemia-Reperfusion Injury in Patients With Coronary Artery Disease

BACKGROUND

Ticagrelor is a recommended P2Y₁₂ receptor inhibitor after acute coronary syndrome (ACS). Its superiority has been suggested to rely on pleiotropic effects beyond platelet inhibition. Experimental studies indicate that ticagrelor may protect from ischemia-reperfusion injury but no data are available from such studies on patients. This study aimed to determine if chronic ticagrelor treatment protects against endothelial ischemia-reperfusion injury in patients with a previous ACS.

METHODS

Patients with a previous ACS were studied with flow mediated dilatation of the left brachial artery to determine the degree of endothelial ischemia-reperfusion injury before and after discontinuation of ticagrelor treatment, which had been continuous since 1 year. Each patient underwent 3 identical examinations. The first examination (Visit A) was at the end of ticagrelor treatment and the following 2 (Visit B and C) were after cessation of this treatment with an interval of 2 to 4 weeks.

RESULTS

Ischemia and reperfusion induced significant impairment of endothelial function at all 3 occasions (absolute decline in flow mediated dilatation 3.0% ± 0.7 at Visit A (P < 0.001), 1.9% ± 0.9 at Visit B (P < 0.05) and 1.9% ± 0.4 at Visit C (P < 0.0001)). However, there was no difference in the degree of endothelial ischemia-reperfusion injury or baseline endothelial function between the visits.

CONCLUSION

Chronic ticagrelor treatment in patients 1 year after an ACS does not protect against endothelial ischaemia-reperfusion injury. Nor is it associated with better basal endothelial function compared to after discontinuation of treatment.

Antithrombotic strategies for patients with coronary and lower extremity peripheral artery diseases: a narrative review

INTRODUCTION

Patients with coexisting coronary artery disease (CAD) and peripheral artery disease (PAD) present a very high rate of cardiovascular (CV) morbidity and mortality. Several studies have demonstrated that different regimens of antithrombotic therapies may reduce adverse CV events in patients with CAD or PAD. However, data on optimal antithrombotic combination to use in these very high-risk patients are scarce and conflicting.

AREAS COVERED

This paper reviews current data on antithrombotic therapies tested in CAD patients with concomitant lower extremity PAD.

EXPERT OPINION

The antithrombotic response in lower extremity PAD patients varies based on the atherosclerotic burden. For patients with isolated stable PAD may be sufficient a less potent P2Y12 inhibitor as clopidogrel, whereas patients with lower extremity PAD and documented CAD benefit from a more intense and prolonged antithrombotic treatment.

Central apnoeas and ticagrelor-related dyspnoea in patients with acute coronary syndrome

AIMS

Dyspnoea often occurs in patients with acute coronary syndrome (ACS) treated with ticagrelor compared with other anti-platelet agents and is a cause of drug discontinuation. We aimed to explore the contribution of central apnoeas (CA) and chemoreflex sensitization to ticagrelor-related dyspnoea in patients with ACS.

METHODS AND RESULTS

Sixty consecutive patients with ACS, preserved left ventricular ejection fraction, and no history of obstructive sleep apnoea, treated either with ticagrelor 90 mg b.i.d. (n = 30) or prasugrel 10 mg o.d. (n = 30) were consecutively enrolled. One week after ACS, all patients underwent two-dimensional Doppler echocardiography, pulmonary static/dynamic testing, carbon monoxide diffusion capacity assessment, 24-h cardiorespiratory monitoring for hypopnoea-apnoea detection, and evaluation of the chemosensitivity to hypercapnia by rebreathing technique. No differences were found in baseline demographic and clinical characteristics, echocardiographic, and pulmonary data between the two groups. Patients on ticagrelor, when compared with those on prasugrel, reported more frequently dyspnoea (43.3% vs. 6.7%, P = 0.001; severe dyspnoea 23.3% vs. 0%, P = 0.005), and showed higher apnoea-hypopnoea index (AHI) and central apnoea index (CAI) during the day, the night and the entire 24-h period (all P < 0.001). Similarly, they showed a higher chemosensitivity to hypercapnia (P = 0.001). Among patients treated with ticagrelor, those referring dyspnoea had the highest AHI, CAI, and chemosensitivity to hypercapnia (all P < 0.05).

CONCLUSION

Central apnoeas are a likely mechanism of dyspnoea and should be screened for in patients treated with ticagrelor. A drug-related sensitization of the chemoreflex may be the cause of ventilatory instability and breathlessness in this setting.

Ticagrelor and preconditioning in patients with stable coronary artery disease (TAPER-S): a randomized pilot clinical trial

Background

Ticagrelor is a reversibly binding, direct-acting, oral, P₂Y₁₂ antagonist used for the prevention of atherothrombotic events in patients with coronary artery disease (CAD). Ticagrelor blocks adenosine reuptake through the inhibition of equilibrative nucleoside transporter 1 (ENT-1) on erythrocytes and platelets, thereby facilitating adenosine-induced physiological responses such as an increase in coronary blood flow velocity. Meanwhile, adenosine plays an important role in triggering ischemic preconditioning through the activation of the A1 receptor. Therefore, an increase in ticagrelor-enhanced adenosine bioavailability may confer beneficial effects through mechanisms related to preconditioning activation and improvement of coronary microvascular dysfunction.

Methods

To determine whether ticagrelor can trigger ischemic preconditioning and influence microvascular function, we designed this prospective, open-label, pilot study that enrolled patients with stable multivessel CAD requiring staged, fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI). Participants will be randomized in 1:1 ratios either to ticagrelor (loading dose (LD) 180 mg, maintenance dose (MD) 90 mg bid) or to clopidogrel (LD 600 mg, MD 75 mg) from 3 to 1 days before the scheduled PCI. The PCI operators will be blinded to the randomization arm. The primary endpoint is the delta (difference) between ST segment elevations (in millimeters, mm) as assessed by intracoronary electrocardiogram (ECG) during the two-step sequential coronary balloon inflation in the culprit vessel. Secondary endpoints are 1) changes in coronary flow reserve (CFR), index of microvascular resistance (IMR), and FFR measured in the culprit vessel and reference vessel at the end of PCI, and 2) angina score during inflations. This study started in 2018 with the aim of enrolling 100 patients. Based on the rate of negative FFR up to 30% and a drop-out rate up to 10%, we expect to detect an absolute difference of 4 mm among the study arms in the mean change of ST elevation following repeated balloon inflations. All study procedures were reviewed and approved by the Ethical Committee of the Catholic University of Sacred Heart.

Discussion

Ticagrelor might improve ischemia tolerance and microvascular function compared to clopidogrel, and these effects might translate to better long-term clinical outcomes.

Trial registration

EudraCT No. 2016–004746-28. No. NCT02701140. 

Trial status

Information provided in this manuscript refers to the definitive version (n. 3.0) of the study protocol, dated 31 October 2017, and includes all protocol amendments. Recruitment started on 18 September 2018 and is currently ongoing. The enrollment is expected to be completed by the end of 2019.

Trial sponsor

Fondazione Policlinico Universitario A. Gemelli – Roma, Polo di Scienze Cardiovascolari e Toraciche, Largo Agostino Gemelli 8, 00168 Rome, Italy.

Optimal strategy of switching from clopidogrel to ticagrelor in Chinese acute coronary syndrome patients with complicated coronary artery disease: the switching from clopidogrel to ticagrelor (SHIFT-CACS) study

BACKGROUND

The dose and time point for switching from clopidogrel to ticagrelor remain controversial, especially for Chinese acute coronary syndrome (ACS) patients with complicated coronary artery disease (CAD). Hence, the purpose of this study was to further explore the optimal dose and time point for the switching strategy to balance the increase in platelet inhibition and the decrease in adverse events in Chinese ACS patients with complicated CAD managed by percutaneous coronary intervention (PCI).

METHODS

From July 2017 to December 2017, the prospective, randomized, open-label study (the SwitcHIng from clopidogrel to ticagrelor study) assigned the eligible Chinese ACS patients with complicated CAD managed by PCI (n = 102) for 90 mg of ticagrelor at 12 h (T-90 mg-12 h), 90 mg of ticagrelor at 24 h (T-90 mg-24h) or 180 mg ticagrelor at 24 h (T-180 mg-24 h) after the last dose of clopidogrel. The primary endpoint was the comparison of maximal platelet aggregation (MPA) values at 2 h after switching strategies among the three groups. In addition, the MPA values at baseline, 8 h and before discharge and the rates of high on-treatment platelet reactivity were evaluated, the incidences of bleeding episodes and dyspnea during hospitalization and at 30-day follow-up in our study were also recorded. The MPA was measured by light transmittance aggregometry in our study. A repeated-measures analysis of variance (ANOVA) model and one-way ANOVA were used to compare data for the primary endpoint.

RESULTS

The MPA values were significantly decreased in the T-180 mg-24 h group compared with the T-90 mg-12 h group (P = 0.017) and decreased numerically compared with the T-90 mg-24 h group (P = 0.072) at 2 h. In particular, the MPA values were markedly reduced in the T-90 mg-24 h group compared with the T-90 mg-12 h group at 8 h after switching treatment (P = 0.002). There was no significant difference among the three groups in all bleedings and dyspnea events.

CONCLUSIONS

The optimal treatment strategy recommended in this study for Chinese ACS patients with complicated CAD managed by PCI is 180 or 90 mg of ticagrelor at 24 h after the last dose of clopidogrel. In addition, a negative interaction was detected in this study between the overlap for clopidogrel and ticagrelor at 12 h after the last dose of clopidogrel.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03577652; http://clinicaltrials.gov/ct2/show/NCT03577652.

Biocatalysis as Useful Tool in Asymmetric Synthesis: An Assessment of Recently Granted Patents (2014–2019)

The broad interdisciplinary nature of biocatalysis fosters innovation, as different technical fields are interconnected and synergized. A way to depict that innovation is by conducting a survey on patent activities. This paper analyses the intellectual property activities of the last five years (2014–2019) with a specific focus on biocatalysis applied to asymmetric synthesis. Furthermore, to reflect the inventive and innovative steps, only patents that were granted during that period are considered. Patent searches using several keywords (e.g., enzyme names) have been conducted by using several patent engine servers (e.g., Espacenet, SciFinder, Google Patents), with focus on granted patents during the period 2014–2019. Around 200 granted patents have been identified, covering all enzyme types. The inventive pattern focuses on the protection of novel protein sequences, as well as on new substrates. In some other cases, combined processes, multi-step enzymatic reactions, as well as process conditions are the innovative basis. Both industries and academic groups are active in patenting. As a conclusion of this survey, we can assert that biocatalysis is increasingly recognized as a useful tool for asymmetric synthesis and being considered as an innovative option to build IP and protect synthetic routes.

Progress in the development of antiplatelet agents: Focus on the targeted molecular pathway from bench to clinic

Antiplatelet drugs serve as a first-line antithrombotic therapy for the management of acute ischemic events and the prevention of secondary complications in vascular diseases. Numerous antiplatelet therapies have been developed; however, currently available agents are still associated with inadequate efficacy, risk of bleeding, and variability in individual response. Understanding the mechanisms of platelet involvement in thrombosis and the clinical development process of antiplatelet agents is critical for the discovery of novel agents. The functions of platelets in thrombosis are regulated by two major mechanisms: the interaction between surface receptors and their ligands, and the downstream intracellular signaling pathways. Recently, most of the progress made in antiplatelet drug development has been achieved with P2Y receptor antagonists. Additionally, the usage of GP IIb/IIIa receptor antagonists has decreased, because it is associated with a higher risk of bleeding and thrombocytopenia. Agents targeting other platelet surface receptors such as PARs, TP receptor, EP3 receptor, GPIb-IX-V receptor, P-selectin, as well as intracellular signaling factors, such as PI3Kβ, have been evaluated in an attempt to develop the next generation of antiplatelet drugs, reduce or eliminate interpatient variability of drug efficacy and significantly lower the risk of drug-induced bleeding. The aim of this review is to describe the pathways of platelet activation in thrombosis, and summarize the development process of antiplatelet agents, as well as the preclinical and clinical evaluations performed on these agents.

Modulation of CYP450 Activities in Patients With Type 2 Diabetes

We conducted a comprehensive in vivo study evaluating the influence of type 2 diabetes (T2D) on major cytochrome P450 (CYP450) activities. These activities were assessed in 38 T2D and 35 non-T2D subjects after a single oral administration of a cocktail of probe drugs: 100 mg caffeine (CYP1A2), 100 mg bupropion (CYP2B6), 250 mg tolbutamide (CYP2C9), 20 mg omeprazole (CYP2C19), 30 mg dextromethorphan (CYP2D6), 2 mg midazolam (CYP3As), and 250 mg chlorzoxazone (alone; CYP2E1). Mean metabolic activity for CYP2C19, CYP2B6, and CYP3A was decreased in subjects with T2D by about 46%, 45%, and 38% (P < 0.01), respectively. CYP1A2 and CYP2C9 activities seemed slightly increased in subjects with diabetes, and no difference was observed for CYP2D6 or CYP2E1 activities. Several covariables, such as inflammatory markers (interleukin (IL)-1ß, IL-6, gamma interferon, and tumor necrosis factor alpha), genotypes, and diabetes-related and demographic-related factors were considered in our analyses. Our results indicate that low chronic inflammatory status associated with T2D modulates CYP450 activities in an isoform-specific manner.

Assessment of the Risk of Rhabdomyolysis and Myopathy During Concomitant Treatment with Ticagrelor and Statins

The introduction of ticagrelor, one of the first directly-acting oral antiplatelet drugs, provided new possibilities in the prevention of thrombotic events in patients with acute coronary syndromes (ACS). Current guidelines recommend ticagrelor in dual antiplatelet therapy with aspirin over clopidogrel for prevention of stent thrombosis in patients with ACS. Moreover, in the management of ACS, lipid-lowering treatment with high-intensity statin therapy is advised for secondary prevention of cardiovascular events over the long term. Despite the apparent advantages of combined antiplatelet and lipid-lowering treatments, a possible interaction between statins and ticagrelor may lead to myopathy and rhabdomyolysis. In this review, relevant information was gathered on the ticagrelor-statin interaction that might lead to this life-threatening condition. This review focuses on the most widely used statins—simvastatin, atorvastatin, and rosuvastatin. Possible mechanisms of this interaction are discussed, including CYP3A4 isoenzymes, organic anion transporter polypeptide (OATPs), P-glycoprotein and glucuronidation. PubMed database was searched for relevant case reports and all data gathered from the introduction of ticagrelor to March 2018 are presented and discussed. In summary, co-administration of statins and ticagrelor was found to be relatively safe in routinely prescribed doses. However, caution should be exercised, especially in elder populations.

Effects of ticagrelor on the sodium/calcium exchanger 1 (NCX1) in cardiac derived H9c2 cells

Ticagrelor is a direct acting and reversibly binding P2Y₁₂ antagonist approved for the prevention of thromboembolic events. Clinical effects of ticagrelor cannot be simply accounted for by pure platelet inhibition, and off-target mechanisms can potentially play a role. In particular, recent evidence suggests that ticagrelor may also influence heart function and improve the evolution of myocardial ischemic injury by more direct effects on myocytes. The cardiac sodium/calcium exchanger 1 (NCX1) is a critical player in the generation and control of calcium (Ca²⁺) signals, which orchestrate multiple myocyte activities in health and disease. Altered expression and/or activity of NCX1 can have profound consequences for the function and fate of myocytes. Whether ticagrelor affects cardiac NCX1 has not been investigated yet. To explore this hypothesis, we analyzed the expression, localization and activity of NCX1 in the heart derived H9c2-NCX1 cells following ticagrelor exposure. We found that ticagrelor concentration- and time-dependently reduced the activity of the cardiac NCX1 in H9c2 cells. In particular, the inhibitory effect of ticagrelor on the Ca²⁺-influx mode of NCX1 was evident within 1 h and further developed after 24 h, when NCX1 activity was suppressed by about 55% in cells treated with 1 μM ticagrelor. Ticagrelor-induced inhibition of exchanger activity was reached at clinically relevant concentrations, without affecting the expression levels and subcellular distribution of NCX1. Collectively, these findings suggest that cardiac NCX1 is a new downstream target of ticagrelor, which may contribute to the therapeutic profile of ticagrelor in clinical practice.

Ticagrelor and Statin Interaction Induces Rhabdomyolysis and Acute Renal Failure: Case reports and Scoping Review

Ever since evidence about the increased risk of stent thrombosis with drug eluting stents (DES) surfaced in 2005, the Food and Drug Administration (FDA) has recommended the use of dual antiplatelet therapy (aspirin with P2Y12 inhibitor) following DES placement. The PLATO trial demonstrated lower mortality rates with the use of Ticagrelor when compared to clopidogrel (9.8% vs. 11.7%, p<0.001) when treating patients with acute coronary syndrome. Given their pleiotropic benefits, statins are today the second most prescribed drug in the United States and often co-prescribed with Ticagrelor. FDA's post market surveillance of Ticagrelor use along with statins in post-myocardial infarction care is now revealing novel and serious adverse events. We present two cases of rhabdomyolysis and acute renal failure (ARF) which develop while the patients were on statins and Ticagrelor. Case 1: A 66-year-old female presented with bilateral thigh pain for 3 days. One month prior to presentation, she was managed for non-ST segment elevation myocardial infarction (NSTEMI) and had been started on aspirin, ticagrelor and simvastatin. Laboratory values revealed creatinine kinase (CK) level at 40,000 U/L and creatinine 3.2 mg/dL suggesting rhabdomyolysis and ARF. Case 2: A 63-year-old male presented with generalized body aches and fatigue for 4 days. He had sustained STEMI two months before and received two drug eluting stents (DES) and aspirin, ticagrelor and rosuvastatin had been initiated. CK was 380,000 U/L and creatinine 7.94 mg/dL suggesting rhabdomyolysis and ARF. Both patients presented with rhabdomyolysis and acute renal failure within weeks after ticagrelor and statin were commenced. A review of the literature indicated that 11 similar cases of ticagrelor-induced ARF and rhabdomyolysis had been reported. Ticagrelor competes with statins when metabolized by cytochrome P450 (CYP) 3A4 leading to statin retention, leading to major adverse effects like rhabdomyolysis and acute renal failure. Our review is intended to alert clinicians about this important drug interaction.

Development of an LC-MS/MS method for simultaneous determination of ticagrelor and its active metabolite during concomitant treatment with atorvastatin

A combination of antiplatelet drugs with high-intensity statin therapy is a standard in patients with coronary events. Concomitant treatment with ticagrelor, a moderate CYP3A4 inhibitor, and CYP3A4-metabolized statins such as atorvastatin, might lead to an increased risk of muscle-related adverse events. Therefore, investigation of concentrations of these compounds in clinical samples is necessary. For this purpose, an LC-MS/MS method was developed for simultaneous determination of ticagrelor and its active metabolite (AR-C124910XX), as well as 2-hydroxyatorvastatin, which is the main metabolite of atorvastatin. Protein precipitation was used for sample preparation and afterwards the analytes were separated on a Kinetex XB-C18 column with an isocratic elution (water and acetonitrile with 0.1% formic acid, 57:43, v/v). Detection was performed on a triple-quadrupole MS with multiple-reaction-monitoring via electrospray ionization. The method was fully validated according to the EMA's recommendations. Determination was possible within ranges: 1.25-2000 ng/mL for ticagrelor, 1.25-1000 ng/mL for its AR-C124910XX, 1.25-50 ng/mL for atorvastatin and 1.14-45.73 for 2-hydroxyatorvastatin. Within and between-run accuracy, expressed as a relative error, was within 0.05-10.56% for all analytes, while within and between-run precision, expressed as coefficient of variation, was within 0.61-9.91%. Ticagrelor, atorvastatin and their main metabolites were found to be stable in acetonitrile stock solutions, and in plasma samples stored for 24 h at room temperature, 1 month at -25 °C, after 3 cycles of freezing and thawing, and in processed samples stored as a dry residue for 24 h at 4 °C and for 24 h in autosampler at room temperature. This simple and rapid method allowed simultaneous determination of the analytes for the first time. The procedure was applied for the pharmacokinetic study of ticagrelor, its active metabolite AR-C124910XX, and 2-hydroxyatorvastatin in patients simultaneously treated with ticagrelor and atorvastatin.

Antithrombotic P2Y12 receptor antagonists: recent developments in drug discovery

The P2Y₁₂ receptor is one of eight known P2Y receptor subtypes, and belongs to the G-protein-coupled receptor (GPCR) family. The P2Y₁₂ receptor is highly expressed on blood platelets and in the brain. Potent, selective, peripherally acting antagonists for the P2Y₁₂ receptor are used clinically as antithrombotic drugs. Several different scaffolds have been identified as P2Y₁₂ receptor antagonists, including irreversibly acting thienotetrahydropyridines (prodrugs), and reversible competitive antagonists, including adenine nucleotide analogs, piperazinyl-glutamate-quinolines, -pyridines, and -pyrimidines, and anthraquinone derivatives. Here, we provide an overview of the different scaffolds that have been developed as P2Y₁₂ receptor antagonists, some of which have become important therapeutics.