Determination of ticagrelor and two metabolites in plasma samples by liquid chromatography and mass spectrometry

Evaluation of the effects and plasma concentration of the platelet inhibitor ticagrelor, after crushed and non-crushed intake, after cardiac arrest and after semi-urgent coronary artery bypass surgery

BACKGROUND

Ticagrelor, used in acute coronary syndrome (ACS), can be administered via nasogastric tube when oral intake is impossible. We investigated platelet inhibition and pharmacokinetics in resuscitated ACS patients and those undergoing semi-urgent coronary artery bypass graft (CABG) surgery. Our study aimed to assess platelet inhibition with use of the Platelet Function Analyser (PFA) and measured plasma concentrations of ticagrelor and its active metabolite in these ACS patients.

METHODS

We included resuscitated cardiac arrest patients (STEMI/NSTEMI) and semi-urgent CABG patients. Crushed ticagrelor tablets were administered using a nasogastric tube. PFA closure time (CT) was determined with CT longer than 113 s as reference range. Plasma concentrations of ticagrelor and its active metabolite were measured after protein precipitation, by using liquid chromatography with mass spectrometry detection.

RESULTS

In 20 resuscitated patients, 89% showed platelet inhibition at 24 h and 92% at day 4. For semi-urgent CABG patients, 85% exhibited platelet inhibition at 24 h and 84% at day 4. For ticagrelor in resuscitated patients, the median time to peak plasma concentration (Tmax) was 100 h [8; 100] for a median maximal concentration (Cmax) of 615.5 ng/mL [217.5; 1385.0]. For AR-C124910XX median Tmax was 100 h [8; 100] for a Cmax of 131.0 ng/mL [52.1; 177.7]. Among 20 patients undergoing semi-urgent CABG, Tmax for ticagrelor was 100 h [100; 100] for a median Cmax of 857.0 ng/ml [496.8; 1157.5]. For AR-C124910XX, median Tmax was 100 h [43; 100] for a Cmax of 251.0 ng/ml [173.0; 396.5].

CONCLUSION

Crushed ticagrelor via nasogastric tube achieved targeted platelet inhibition. Pharmacokinetics aligned with previous studies.EudraCT number: 2013-004191-35; Study protocol code: AGO/2013/011; EC/2014/1061; ClinicalTrial.gov identifier: NCT02341729.

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.

Sample pretreatment and HPLC determination of antiplatelet drug ticagrelor in blood plasma from patients with acute coronary syndromes

A simple HPLC method was developed for the determination of antiplatelet drug ticagrelor (TCG) in blood. Sample preparation and extraction conditions were investigated and optimized. The preparation of blood plasma was investigated by protein precipitation using perchloric acid, methanol, acetonitrile (ACN), and trifluoroacetic acid. Protein precipitation using ACN was found to be the most suitable. Chromatographic separation of TCG was performed on a C18 column with a mobile phase consisting of ACN and 15 mM ammonium acetate buffered at pH 8.0. The method was applied to determine TCG in blood plasma of patients who had a heart attack. Blood samples were collected 1.5 h after the administration of the initial loading dose of the antiplatelet drug. The average concentration of TCG was found to be 0.97 ± 0.53 μg/ml. The developed method proved to be very selective, without interferences from other endogenous substances and the influences of possible coadministered drugs. The limits of detection and quantification estimated by the signal-to-noise ratio in real samples were 0.24 and 0.4 μg/ml, respectively. The developed method is simple and can be easily applied in clinics and emergency cardiac situations after the initial loading dose of TCG in the first few hours of a heart attack.

Impact of renal function on Ticagrelor-induced antiplatelet effects in coronary artery disease patients

Background

Chronic renal failure (CKD) is associated with the presence of increased platelet reactivity and lower clinical benefit of clopidogrel. Ticagrelor has a more favorable pharmacodynamic and pharmacokinetic profile compared to clopidogrel, which has translated into better clinical outcomes in patients with acute coronary syndrome (ACS). We conducted a prospective mechanistic cohort study in order to investigate the impact of renal failure on the pharmacokinetics and pharmacodynamics of ticagrelor in patients with acute ACS.

Methods

Patients were divided into two groups based on their estimated renal clearances (eGFR ≥ 60 mL/min and eGFR < 60 mL/min). Platelet function was determined using the VerifyNow system at baseline, after the ticagrelor loading dose and at discharge. In addition, levels of ticagrelor and its active metabolite (AR-C124910XX) were determined in the first hour after loading dose.

Results

48 patients were recruited (eGFR ≥ 60 mL/min: 35 and eGFR < 60 mL/min: 13). There were no significant differences between the groups in terms of platelet inhibition after the loading or after 7 days of treatment (p = 0.219). However, the levels of ticagrelor and its active metabolite were lower in subjects with normal renal function than in CKD, especially at 4 (p = 0.02 and 0.04 respectively) and 6 h of loading (p = 0.042 and 0.08 respectively).

Conclusion

No differences in platelet inhibition were observed after treatment with ticagrelor in patients with different renal function, although patients with renal impairment showed higher levels of ticagrelor and AR-C124910XX after 4 h of the loading dose.

Integrated Pharmacokinetics/Pharmacodynamics Model and Simulation of the Ticagrelor Effect on Patients with Acute Coronary Syndrome

BACKGROUND

Data available for pharmacokinetics (PK)/pharmacodynamics (PD) of ticagrelor and significant endogenous/exogenous factors or biomarkers related to bleeding events in both healthy and clinical patients are limited.

OBJECTIVE

Based on PK and PD data from multicenter healthy subjects and patients, we aimed to establish an integrated approach towards population PK (pop PK) and the PD model of ticagrelor.

METHODS

This study was conducted as a multicenter, prospective clinical registration study involving both healthy subjects and clinical patients. The integrated Pharmacokinetic/pharmacodynamic (PK/PD) models were characterized based on PK/PD [ticagrelor concentration, aggregation baseline (BASE), P2Y12 response unit (PRU) and inhibition rate (INHIBIT)] data from 175 healthy volunteers. The model was corrected by sparse PD (BASE, PRU and INHIBIT) data from 208 patients with acute coronary syndrome (ACS). The correlations between PD biomarkers and clinically relevant bleedings in 1 year were explored.

RESULTS

A one-compartment, linear model with first-order absorption was adopted as PK model. Food status (FOOD) and body weight (WT) significantly influenced clearance and improved the fitting degree of the PK model, while SEX was selected as the covariates of the PD model. For patients taking ticagrelor 90 mg, the peak value [mean (95% CI)] of PRU was 355.15 (344.24-366.06) and the trough value was 3.64 (3.14-4.15). The PRU mean parameters were basically within the expected range (80-200) of the literature suggestions.

CONCLUSION

A fixed dose of ticagrelor, without adjusting the dosing regimen other than covariates of FOOD/WT/SEX, could be used in patients with acute coronary syndromes, and the standard regimen could be used in Chinese patients from the perspective of exposure.

Effect of Genetic Polymorphism Including NUP153 and SVEP1 on the Pharmacokinetics and Pharmacodynamics of Ticagrelor in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVE

The search for potential gene loci that affect the pharmacodynamics and pharmacokinetics of ticagrelor is a matter of broad clinical interest. The objective of this study was to investigate the effect of genetic polymorphisms on the pharmacokinetics and pharmacodynamics of ticagrelor in healthy Chinese subjects.

METHODS

This is a multi-center study in China, including three hospitals from Beijing, Nanchang, and Changsha. Healthy Chinese subjects aged 18-45 years with unknown genotypes were included. All subjects received a single oral dose of 90 mg of ticagrelor. Platelet aggregation and the area under the concentration-time curve for ticagrelor and its major active metabolite in plasma samples were assessed. Genome-wide association studies and candidate gene association analysis related to ticagrelor were performed.

RESULTS

One hundred and seventy-five native Chinese subjects were enrolled and completed the study. According to the p value, the threshold of ticagrelor population was 6.57 × 10^-7 (0.05/76106), one single-nucleotide polymorphism chr6:17616513 of gene NUP153 (p = 2.03 × 10^-7) related to the area under the concentration-time curve for plasma concentration at time zero versus the last measurable timepoint, and one single nucleotide polymorphism rs17204533 of gene SVEP1 (p = 3.96 × 10^-7) related to P2Y12 reaction unit_12h of ticagrelor was identified. In addition, L1TD1, CETP, CLEC2A, CHSY1, PDZRN3, CTU2, PIEZO1, APOBEC1, SEMA6A, KAZN, and FASN polymorphisms might influence the pharmacokinetics of ticagrelor, while PARP10, TRIB1, CYP2C19, and UGT2B7 might affected its pharmacodynamics.

CONCLUSIONS

Genetic variation affects the pharmacokinetics and pharmacodynamics of ticagrelor in healthy individuals. The detection of NUP153, SVEP1 gene variation will be helpful for pharmacodynamic prediction and evaluation, and the regulation of these genes may be the target of new drug development. Further studies are required to confirm the results and explore whether these single-nucleotide polymorphisms are associated only with platelet activity or also with cardiovascular events and all-cause mortality.

CLINICAL TRIAL REGISTRATION

NCT03161002.

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.

Gut microbiota induces high platelet response in patients with ST segment elevation myocardial infarction after ticagrelor treatment

Background:

Ticagrelor is a first-line drug for the treatment of acute ST elevation myocardial infarction (STEMI). However, approximately 20% STEMI patients taking ticagrelor exhibited a delayed response and the mechanism was still unclear.

Methods:

To explore the mechanism of the poor response of ticagrelor in post-percutaneous coronary intervention (PCI) patients, we enrolled 65 high platelet reactivity (HPR) patients and 90 controls (normal platelet reactivity [NPR]). Pharmacokinetic assessment result showed that the plasma concentrations of ticagrelor and its metabolism production, AR-C124910XX, were lower in HPR patients than controls. Further single nucloetide polymorphism (SNP) analysis identified that there is no difference in ATP binding cassette subfamily B member 1 (ABCB1) gene expression between the NPR group and the HPR group. Metagenomic and metabolomic analyses of fecal samples showed that HPR patients had higher microbial richness and diversity. Transplantation of the gut microbiota from HPR donors to microbiota-depleted mice obviously decreased plasma concentration of ticagrelor.

Results:

Our findings highlight that gut microbiota dysbiosis may be an important mechanism for the ticagrelor of HPR in patients with STEMI and support that modify gut microbiota is a potential therapeutic option for STEMI.

Conclusions:

Our findings highlight that gut microbiota dysbiosis may be an important mechanism for the ticagrelor of HPR in patients with ST elevation myocardial infarction (STEMI) and support that modify gut microbiota is a potential therapeutic option for STEMI

Funding:

NSFC 82170297 and 82070300 from the National Natural Science Foundation of China.

A Validated LC-MS/MS Method for the Simultaneous Determination of Ticagrelor, Its Two Metabolites and Major Constituents of Tea Polyphenols in Rat Plasma and Its Application in a Pharmacokinetic Study

Ticagrelor is recommended for management of patients with acute coronary syndromes. Green tea is one of the most popular beverages in China and around the world. Their concomitant use is unavoidable. In this study, a selective and sensitive liquid chromatography-tandem mass spectrometry method for the simultaneous determination of plasma concentrations of ticagrelor, its two metabolites and four major constituents of tea polyphenols (TPs) in rats was developed for co-administration study of ticagrelor and TPs. Diazepam was used as internal standard (IS). Plasma samples were extracted employing a liquid-liquid extraction technique. Chromatographic separation was carried out on a Kinetex C18 column (2.1 × 75 mm, 2.6 μm) by gradient elution using 0.1% formic acid in water, acetonitrile and methanol. Seven analytes and IS were detected by a mass spectrometer with both positive and negative ionization by multiple reaction monitoring mode. The method was fully validated to be reliable and reproducible in accordance with food and drug administration (FDA) guidelines on bioanalytical method validation. The method was then successfully applied for pharmacokinetic study of ticagrelor, its two metabolites and four major constituents of TPs in rat plasma after oral administration of ticagrelor and tea polyphenol extracts.

Concise synthesis of the major metabolite M8 from ticagrelor and simultaneous determination of ticagrelor and M8 by a novel LC/MS method

Ticagrelor is an oral antiplatelet agent that has been approved for preventing de novo and recurrent acute coronary syndrome. To date, only a few studies have attempted to clarify population differences in the pharmacokinetics and pharmacodynamics of ticagrelor between Caucasians and Asians. Our aim was to develop a simple quantification method for ticagrelor and its pharmacologically active metabolite M8 (AR-C124910XX) in human plasma and urine. First, we concisely synthesized M8 from ticagrelor via a five-step sequence: the hydroxyethyl group of ticagrelor was removed by bromination and subsequent zinc-mediated chemoselective reduction. Then, we developed a simple liquid chromatography–mass spectrometry method using ticlopidine as an internal standard. Ticagrelor, M8, and internal standard were separated with a reverse-phase C18 column, and ticagrelor and M8 were detected at m/ z [+] of 523.25 and 479.25, respectively, with good sensitivity and precision in the concentration ranges of 10 to 100 µM and 5 to 50 µM, respectively. This novel liquid chromatography–mass spectrometry system may be attractive to investigators in private laboratories because it is less costly than liquid chromatography/mass spectrometry/mass spectrometry systems. Our method is expected to accelerate further clinical studies on the disposition and pharmacodynamics of ticagrelor.

Validation of an HPLC-MS/MS Method for the Determination of Plasma Ticagrelor and Its Active Metabolite Useful for Research and Clinical Practice

Ticagrelor is an antiplatelet agent which is extensively metabolized in an active metabolite: AR-C124910XX. Ticagrelor antagonizes P2Y12 receptors, but recently, this effect on the central nervous system has been linked to the development of dyspnea. Ticagrelor-related dyspnea has been linked to persistently high plasma concentrations of ticagrelor. Therefore, there is a need to develop a simple, rapid, and sensitive method for simultaneous determination of ticagrelor and its active metabolite in human plasma to further investigate the link between concentrations of ticagrelor, its active metabolite, and side effects in routine practice. We present here a new method of quantifying both molecules, suitable for routine practice, validated according to the latest Food and Drug Administration (FDA) guidelines, with a good accuracy and precision (<15% respectively), except for the lower limit of quantification (<20%). We further describe its successful application to plasma samples for a population pharmacokinetics study. The simplicity and rapidity, the wide range of the calibration curve (2–5000 µg/L for ticagrelor and its metabolite), and high throughput make a broad spectrum of applications possible for our method, which can easily be implemented for research, or in daily routine practice such as therapeutic drug monitoring to prevent overdosage and occurrence of adverse events in patients.

Rapid fluorometric determination of ticagrelor in tablets and rat plasma: Application to pharmacokinetics study

The new antiplatelet drug ticagrelor has been determined based on its native fluorescence properties. These properties were studied and optimized to develop fast, simple and sensitive spectrofluorimetric method. The study included two approaches. The first approach is depending on measuring the native fluorescence at 300 nm after excitation at 222 nm. While the second approach combined synchronous and derivative scanning modes to measure ticagrelor at 286 nm using Δ λ = 100 nm. Ticagrelor was measured in aqueous solution starting from the concentration of 200 to 5000 ng/mL in both native and first derivative synchronous approaches. The developed methods were validated in accordance with ICH guidelines to be acceptable for quality control laboratories. Lowest concentrations that could be quantitated using the native and first derivative synchronous methods were 189 and 151 ng/mL while lowest detectable concentrations were 63 and 50 ng/mL, respectively. Moreover, the derivative synchronous fluorimetric approach was utilized to determine ticagrelor at 286 nm in presence of other commonly co- administered drugs and the results demonstrate the enhanced selectivity of the proposed method. The same approach was also used to determine ticagrelor in rat plasma with acceptable recoveries. A preliminary pharmacokinetic study in rats was conducted and could be used to monitor plasma ticagrelor levels in humans.

Ticagrelor Pharmacokinetics and Pharmacodynamics in Chinese Patients with STEMI and NSTEMI Without Opioid Administration

INTRODUCTION

The pharmacodynamics (PD) and pharmacokinetics (PK) study of ticagrelor loading dose (LD) in Chinese patients with acute coronary syndrome (ACS) without opioid administration has never been investigated. Therefore, the aim of this study was to evaluate the antiplatelet effects and the PK parameters of ticagrelor in Chinese patients with ACS without opioid administration.

METHODS

A sample size of 30 eligible patients with ACS were enrolled in this study. Blood samples were obtained predose and 1, 2, 4, 8, and 12 h after 180 mg LD of ticagrelor. P2Y₁₂ reactivity units (PRU) and plasma concentrations of ticagrelor and its two metabolites were measured.

RESULTS

In total, 15 patients were admitted to ST segment elevation myocardial infarction (STEMI) and non-ST segment elevation myocardial infarction (NSTEMI) groups, respectively. For patients with NSTEMI, PRU declined significantly during the first 4 h and maintained a relatively stable antiplatelet effect from 4 to 12 h after LD. A similar trend was found in the STEMI group without significant differences of PRU in each designed time compared with patients with NSTEMI (P > 0.05). T_max of metabolite AR-C124910XX was 4 h after LD for both groups. There were no significant differences for drug concentration, C_max, or AUC of ticagrelor and AR-C124910XX between patients with STEMI and NSTEMI (P > 0.05).

CONCLUSIONS

For Chinese patients with ACS, at least 4 h was needed to achieve an adequate antiplatelet effect for ticagrelor LD. There were no differences in PK or PD between Chinese patients with STEMI and NSTEMI.

CLINICAL TRIAL REGISTRATION

ChiCTR1800014764.

Liquid Chromatography-Tandem Mass Spectrometry Method for Ticagrelor and its Active Metabolite Determination in Human Plasma: Application to a Pharmacokinetic Study

Background:

Ticagrelor is a highly recommended new antiplatelet agent for the treatment of patients with acute coronary syndrome at moderate or high ischemic risk. There is a real need for rapid and accurate analytical methods for ticagrelor determination in biological fluids for pharmacokinetic studies. In this study, a sensitive and specific LC-MS method was developed and validated for quantification of ticagrelor and its Active Metabolite (AM) in human plasma over expected clinical concentrations.

Methods:

Samples were handled by Liquid-Liquid Extraction (LLE). A linear gradient was applied with a mobile phase composed of formic acid 0.1% and acetonitrile with 0.1% of formic acid using a C18 reversed-phase column. MS spectra were obtained by electrospray ionization in negative mode and optimized at 521.4→360.9 m/z, 477.2→361.2 m/z and 528.1→367.9 m/z transitions for ticagrelor, AM and ticagrelor-d7, respectively.

Results:

This method allowed rapid elution, in less than 4 minutes, and quantification of concentrations as low as 2 ng/mL for ticagrelor and 1 ng/mL for AM using only 100 μL of human plasma. LLE using hexane/ethyl acetate (50/50) was an optimal compromise in terms of extraction recovery and endogenous compounds interference. Trueness values of 87.8% and 89.5% and precisions of 84.1% and 93.8% were obtained for ticagrelor and AM, respectively. Finally, the usefulness of the method was assessed in a clinical trial where a single 180 mg ticagrelor was orally administered to healthy male volunteers. Pharmacokinetic parameters of ticagrelor and its active metabolite were successfully determined.

Conclusion:

A sensitive and specific quantification LC-MS-MS method was developed and validated for ticagrelor and its active metabolite determination in human plasma. The method was successfully applied to a clinical trial where a single ticagrelor 180 mg dose was orally administered to healthy male volunteers. The described method allows quantification of concentrations as low as 2 ng/mL of ticagrelor and 1 ng/mL of the metabolite using only 100 μL of plasma.

Evaluation of the inhibition of chlorophenols towards human cytochrome P450 3A4 and differences among various species

Chlorophenols (CPs) are important pollutants detected frequently in the environment. This study intended to detect the inhibitory effects of fourteen CPs (2-CP, 3-CP, 4-CP, 4C2AP, 4C3MP, 2.4-DCP, 2.3.4-TCP, 2.4.5-TCP, 2.4.6-TCP, 3.4.5-TCP, 2.3.4.5-TECP, 2.3.4.6-TECP, 2.3.5.6-TECP and PCP) towards human liver cytochrome P450 3A4 (CYP3A4). Throughout the tests, testosterone was used as the probe substrate and CPs were used as inhibitors. A series of experiments (enzyme activity assays, preliminary screening tests, inhibition kinetics determination) were conducted to determine the inhibition of CPs towards human liver CYP3A4. CPs with the inhibitory effect >80% were selected for the inhibition evaluation in liver microsomes from different animal species (monkey, rat, dog, pig). The results showed that 2.3.4-TCP, 3.4.5-TCP, and 2.3.4.5-TECP inhibited the activities of CYP3A4 by 80.3%, 93.4%, 91.6%, respectively. Inhibition kinetics type were non-competitive and inhibition kinetics constant (K_i) values were 26.4 μM, 13.5 μM, and 8.8 μM for the inhibition of 2.3.4-TCP, 3.4.5-TCP, and 2.3.4.5-TECP towards human CYP3A4, respectively. Inhibition kinetics type was competitive and K_i value was 4.9 μM for the inhibition of 2.3.4-TCP towards CYP3A4 in Monkey liver microsomes (MyLMs). Inhibition kinetic types were non-competitive and K_i values were 8.1 μM and 28.7 μM for the inhibition of 3.4.5-TCP and 2.3.4.5-TECP towards CYP3A4 in MyLMs. Inhibition kinetic types were non-competitive and K_i values were 13.8 μM, 0.6 μM, and 6.1 μM for the inhibition of 2.3.4-TCP, 3.4.5-TCP, and 2.3.4.5-TECP towards CYP3A4 in Dog liver microsomes (DLMs), respectively. By comparing K_i values and inhibition kinetic types, the dog was the most suitable model to assess the inhibition of 2.3.4-TCP and 2.3.4.5-TECP towards CYP3A4, and monkey was the most suitable model to assess the inhibition of 3.4.5-TCP towards CYP3A4. In conclusion, our recent study on the inhibition of CPs towards CYP3A4 and species differences was important for further toxicological studies of CPs in human bodies.

Simultaneous quantification of ticagrelor and its active metabolite, AR-C124910XX, in human plasma by liquid chromatography-tandem mass spectrometry: Applications in steady-state pharmacokinetics in patients

A sensitive and simple liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of ticagrelor and its active metabolite, AR-C124910XX from 50 µL human plasma using tolbutamide as an internal standard as per regulatory guidelines. Analytes in plasma were extracted by simple protein precipitation using acetonitrile, followed by chromatographic separation with an Acclaim™ RSLC 120 C₁₈ column (2.2 µm, 2.1 × 100 mm) and a gradient acetonitrile-water mobile phase containing 0.1% formic acid within 8 min. Mass spectrometric detection and quantitation were conducted by selected reaction-monitoring on a negative electrospray ionization mode with the following transitions: m/z 521.11 → 361.10, 477.03 → 361.10, and 269.00 → 169.60 for ticagrelor, AR-C124910XX, and tolbutamide, respectively. The lower limit of quantifications was 0.2 ng/mL with linear ranges of 0.2–2,500 ng/mL (r² ≥ 0.9949) for both analytes. All validation data, including selectivity, cross-talk, precision, accuracy, matrix effect, recovery, dilution integrity, stability, and incurred sample reanalysis, were well within acceptable limits. This assay method was validated using K₂-EDTA as the specific anticoagulant. Also, the anticoagulant effect was tested by lithium heparin, sodium heparin, and K₃-EDTA. No relevant anticoagulant effect was observed. This validated method was effectively used in the determination of ticagrelor and its active metabolite, AR-C124910XX, in plasma samples from patients with myocardial infarction.

The MOVEMENT Trial

Background

Morphine administration is a strong predictor of delayed onset of action of orally administered ticagrelor in patients with ST‐segment–elevation myocardial infarction, likely because of impaired gastrointestinal motility. The aim of this study was to evaluate whether the peripheral opioid antagonist methylnaltrexone could improve pharmacodynamics and pharmacokinetics of orally administered ticagrelor in patients with ST‐segment–elevation myocardial infarction receiving morphine.

Methods and Results

The MOVEMENT (Methylnaltrexone to Improve Platelet Inhibition of Ticagrelor in Morphine‐Treated Patients With ST‐Segment Elevation Myocardial Infarction) trial was a multicenter, prospective, randomized, controlled trial in patients with ST‐segment–elevation myocardial infarction treated with morphine and ticagrelor. Upon arrival to the catheterization laboratory, patients were randomized to a blinded intravenous injection of either methylnaltrexone (8 or 12 mg according to weight) or 0.9% sodium chloride. The proportion of patients with high on‐treatment platelet reactivity and plasma concentrations of ticagrelor and AR‐C124910XX were assessed at baseline (arrival in the catheterization laboratory) and 1 and 2 hours later. A total of 82 patients received either methylnaltrexone (n=43) or placebo (n=39). Median (interquartile range) time from ticagrelor administration to randomization was 41 (31–50) versus 45.5 (37–60) minutes (P=0.16). Intravenous methylnaltrexone administration did not significantly affect prevalence of high on‐treatment platelet reactivity at 2 hours after inclusion, the primary end point, when compared with placebo (54% versus 51%, P=0.84). Plasma concentrations of ticagrelor and its active metabolite, the prespecified secondary end points, did not differ significantly between the groups over time. There was no significant difference in patient self‐estimated pain between the groups.

Conclusions

Methylnaltrexone did not significantly improve platelet reactivity or plasma concentrations of orally administered ticagrelor in patients with ST‐segment–elevation myocardial infarction receiving morphine.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02942550.

Oral Delivery of the P2Y12 Receptor Antagonist Ticagrelor Prevents Loss of Photoreceptors in an ABCA4-/- Mouse Model of Retinal Degeneration

Purpose

Accumulation of lysosomal waste is linked to neurodegeneration in multiple diseases, and pharmacologic enhancement of lysosomal activity is hypothesized to reduce pathology. An excessive accumulation of lysosomal-associated lipofuscin waste and an elevated lysosomal pH occur in retinal pigment epithelial cells of the ABCA4-/- mouse model of Stargardt's retinal degeneration. As treatment with the P2Y12 receptor antagonist ticagrelor was previously shown to lower lysosomal pH and lipofuscin-like autofluorescence in these cells, we asked whether oral delivery of ticagrelor also prevented photoreceptor loss.

Methods

Moderate light exposure was used to accelerate photoreceptor loss in albino ABCA4-/- mice as compared to BALB/c controls. Ticagrelor (0.1%-0.15%) was added to mouse chow for between 1 and 10 months. Photoreceptor function was determined with electroretinograms, while cell survival was determined using optical coherence tomography and histology.

Results

Protection by ticagrelor was demonstrated functionally by using the electroretinogram, as ticagrelor-treated ABCA4-/- mice had increased a- and b-waves compared to untreated mice. Mice receiving ticagrelor treatment had a thicker outer nuclear layer, as measured with both optical coherence tomography and histologic sections. Ticagrelor decreased expression of LAMP1, implicating enhanced lysosomal function. No signs of retinal bleeding were observed after prolonged treatment with ticagrelor.

Conclusions

Oral treatment with ticagrelor protected photoreceptors in the ABCA4-/- mouse, which is consistent with enhanced lysosomal function. As mouse ticagrelor exposure levels were clinically relevant, the drug may be of benefit in preventing the loss of photoreceptors in Stargardt's disease and other neurodegenerations associated with lysosomal dysfunction.

Development Strategy and Relative Bioavailability of a Pediatric Tablet Formulation of Ticagrelor

BACKGROUND AND OBJECTIVE

Ticagrelor is a P2Y₁₂ receptor inhibitor approved as an antiplatelet drug for patients with acute coronary syndrome or a history of myocardial infarction. Ticagrelor is also being investigated for the reduction of vaso-occlusive crises in pediatric patients with sickle cell disease. A pediatric formulation suitable for this age range was developed; the development strategy is described. Primary objectives were determining the relative bioavailability of ticagrelor pediatric tablets and granules for oral suspension to the adult immediate-release tablet, and the pediatric tablets taken whole and dispersed/suspended in water to the granules for oral suspension. Bioequivalence between the pediatric tablet taken whole or suspended in water was also assessed. Secondary objectives were comparing the formulations' safety and tolerability.

METHODS

We conducted a randomized, four-period, cross-over, single-dose study. Pharmacokinetic parameters were assessed for ticagrelor and its active metabolite AR-C124910XX. Bioequivalence was concluded if the 90% confidence intervals of the maximum plasma concentration and area under the plasma concentration-time curve ratios were contained completely within the 80.00-125.00% limits for ticagrelor/AR-C124910XX.

RESULTS

Forty-four healthy adults (95% white; 57% male) were included. Similar bioavailability of ticagrelor (and AR-C124910XX) was demonstrated for all comparisons tested. Ticagrelor pediatric tablets taken whole were bioequivalent to pediatric tablets suspended in water. The plasma concentration-time profiles for ticagrelor and AR-C124910XX were similar, showing rapid ticagrelor absorption and AR-C124910XX formation. All formulations were well tolerated.

CONCLUSION

Similar bioavailability of a new pediatric dispersible tablet formulation of ticagrelor for use across a wide age range of pediatric patients was demonstrated compared with other oral ticagrelor formulations. CLINICALTRIALS.

GOV IDENTIFIER

NCT03126695.

EUDRACT

2017-000371-93.

Validated liquid chromatography-tandem mass spectrometry method for quantification of ticagrelor and its active metabolite in human plasma

A rapid, simple and sensitive LC-MS/MS method was established and validated for simultaneous quantification of ticagrelor and its active metabolite AR-C124910XX in human plasma. After plasma samples were deproteinized with acetonitrile, the post-treatment samples were chromatographed on a Dikma C₁₈ column interfaced with a triple quadrupole tandem mass spectrometer. Electrospray negative ionization mode and multiple reaction monitoring were adopted to assay ticagrelor and AR-C124910XX. Acetonitrile and 5 mΜ ammonium acetate was used as the mobile phase with a gradient elution at a flow rate of 0.5 mL/min. The method was linear in the range of 0.781-800 ng/mL for both ticagrelor and AR-C124910XX with a correlation coefficient ≥0.994. The intra- and inter-day precisions were within 12.61% in terms of relative standard deviation and the accuracy was within ±7.88% in terms of relative error. The LC-MS/MS method was fully validated for its sensitivity, selectivity, stability, matrix effect and recovery. This convenient and specific LC-MS/MS method was successfully applied to the pharmacokinetic study of ticagrelor and AR-C124910XX in healthy volunteers after an oral dose of 90 mg ticagrelor.

Pharmacokinetic-pharmacodynamic modelling of platelet response to ticagrelor in stable coronary artery disease and prior myocardial infarction patients

Aims

To characterize ticagrelor exposure‐response relationship for platelet inhibition in patients with stable coronary artery disease (CAD) and a history of myocardial infarction (MI), using nonlinear mixed effects modelling and simulation.

Methods

Platelet function data were integrated with plasma concentration data of ticagrelor and its active metabolite AR‐C1249010XX in a population pharmacokinetic (PK) and pharmacodynamic (PD) model, based on two clinical studies. In the ONSET/OFFSET study, PK and platelet function were assessed in 123 CAD patients receiving placebo, ticagrelor (180 mg followed by 90 mg twice daily) or clopidogrel (600 mg followed by 75 mg once daily). In the PEGASUS‐TIMI 54 platelet function substudy, PK and platelet function were assessed during maintenance dosing in 180 prior MI patients receiving placebo, ticagrelor 60 mg or ticagrelor 90 mg twice daily.

Results

Platelet inhibition by ticagrelor was described by a sigmoidal E_max model. On average, half maximal inhibition was reached at ticagrelor concentrations of 116 (RSE: 5.3%) nmol l^–1. Simulations showed that near maximal platelet inhibition is achieved with both ticagrelor 60 and 90 mg twice daily. At simulated lower doses, platelet inhibition is overall reduced, more variable between patients, and show greater peak‐to‐trough variability. Ticagrelor antiplatelet response was similar between the studied patient populations.

Conclusions

In patients with stable CAD or a history of MI, near maximal platelet inhibition is achieved with both ticagrelor 60 and 90 mg twice daily. At modelled doses <60 mg, the response is reduced overall, more variable between patients, and patients will display greater peak‐to‐trough variability.

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.

A dose-ranging study of ticagrelor in children aged 3-17 years with sickle cell disease: A 2-part phase 2 study

Antiplatelet treatment is a potential therapeutic approach for sickle cell disease (SCD). Ticagrelor inhibits platelet aggregation and is approved for adults with acute coronary syndrome and following myocardial infarction. HESTIA1 (NCT02214121) was a 2-part, phase 2 dose-finding study generating ticagrelor exposure, platelet inhibition, and safety data in children with SCD (3-17 years). In part A (n = 45), patients received 2 ticagrelor single doses, 0.125-2.25 mg/kg (washout ≥7 days), then 7 days of twice-daily (bid) dosing with 0.125, 0.563, or 0.75 mg/kg. In the 4-week blinded Part B extension (optional), patients received ticagrelor (0.125, 0.563, or 0.75 mg/kg bid; n = 16) or placebo (n = 7). Platelet reactivity decreased from baseline to 2 hours postdosing, and returned to near baseline after 6 hours postdosing. Dose-dependent platelet inhibition was seen with ticagrelor; mean relative P2Y12 reaction unit inhibition 2 hours after a single dose ranged from 6% (0.125 mg/kg) to 73% (2.25 mg/kg). Ticagrelor plasma exposure increased approximately dose proportionally. No patients experienced a hemorrhagic event during treatment. No differences were seen between groups in pain ratings and analgesic use during Part B. Ticagrelor was well tolerated with no safety concerns, no discontinuations due to adverse events (AEs), and reported AEs were mainly due to SCD. In conclusion, a dose-exposure-response relationship for ticagrelor was demonstrated in children with SCD for the first time. These data are important for future pediatric studies of the efficacy and safety of ticagrelor in SCD.

Ticagrelor does not impact patient-reported pain in young adults with sickle cell disease: a multicentre, randomised phase IIb study

Ticagrelor is an antiplatelet agent for adults with coronary artery disease. The inhibition of platelet activation may decrease the frequency of vaso-occlusion crisis (VOC) in sickle cell disease (SCD). The HESTIA2 study (NCT02482298) randomised 87 adults with SCD (aged 18-30 years) 1:1:1 to twice-daily ticagrelor 10, 45 mg or placebo for 12 weeks. Numerical decreases from baseline in mean proportion of days with patient-reported pain (primary endpoint) were seen in all three groups, as well as in pain intensity and analgesic use, with no significant differences between placebo and ticagrelor treatment groups. Plasma ticagrelor concentrations and platelet inhibition increased with dose. Adverse events were distributed evenly across groups and two non-major bleeding events occurred per group. Ticagrelor was well tolerated with a low bleeding risk, but no effect on diary-reported pain was detected. Potential effects on frequency of VOCs will need to be evaluated in a larger and longer study.

Metabolism of ticagrelor in patients with acute coronary syndromes

Ticagrelor is a state-of-the-art antiplatelet agent used for the treatment of patients with acute coronary syndromes (ACS). Unlike remaining oral P2Y12 receptor inhibitors ticagrelor does not require metabolic activation to exert its antiplatelet action. Still, ticagrelor is extensively metabolized by hepatic CYP3A enzymes, and AR-C124910XX is its only active metabolite. A post hoc analysis of patient-level (n = 117) pharmacokinetic data pooled from two prospective studies was performed to identify clinical characteristics affecting the degree of AR-C124910XX formation during the first six hours after 180 mg ticagrelor loading dose in the setting of ACS. Both linear and multiple regression analyses indicated that ACS patients presenting with ST-elevation myocardial infarction or suffering from diabetes mellitus are more likely to have decreased rate of ticagrelor metabolism during the acute phase of ACS. Administration of morphine during ACS was found to negatively influence transformation of ticagrelor into AR-C124910XX when assessed with linear regression analysis, but not with multiple regression analysis. On the other hand, smoking appears to increase the degree of ticagrelor transformation in ACS patients. Mechanisms underlying our findings and their clinical significance warrant further research.

Quantification of unbound concentration of ticagrelor in plasma as a proof of mechanism biomarker of the reversal agent, MEDI2452

Ticagrelor, a P2Y12 antagonist, is approved for prevention of thromboembolic events. MEDI2452 is a potential reversal agent for ticagrelor and ticagrelor active metabolite (TAM). The total plasma exposure of ticagrelor and TAM in patients are roughly 0.5-1 and 0.2-0.5 μmol/L, respectively. Both have similar high potency vs. P2Y12 (Ki 2 nmol/L) but are plasma protein-bound to 99.8% and only the 0.2% free fraction is able to inhibit the P2Y12 receptor. Thus, for unbound concentration measurements to be a proof of mechanism biomarker for MEDI2452 a very high sensitivity is required. Using established techniques as equilibrium dialysis and LC-MS/MS, made it possible to evaluate the efficacy of the reversal agent by measuring reduction of unbound concentration of ticagrelor in the presence of MEDI2452. With challenges such as ultra-low concentrations, small sample volumes, recovery issues and adsorption to plastic we managed to develop a highly sensitive assay for determining unbound concentration levels of ticagrelor and TAM in plasma with a quantification limit of 30 pmol/L and 45 pmol/L, respectively. With this method we were able to detect close to a 100-fold MEDI2452 mediated reduction in the unbound concentration of both ticagrelor and TAM. The assay provided proof of mechanism as MEDI2452 concentration- and dose-dependently eliminated unbound concentration of ticagrelor and reversed its antiplatelet activity in preclinical models and will support future development of MEDI2452.

Pharmacokinetics and pharmacodynamics of ticagrelor in subjects on hemodialysis and subjects with normal renal function

PURPOSE

This single-dose, randomized, open-label, parallel-group, and crossover study assessed pharmacokinetics (PK), pharmacodynamics (PD), and safety of ticagrelor in subjects on hemodialysis versus healthy subjects.

METHODS

Hemodialysis subjects were randomized, receiving a single ticagrelor 90-mg dose 1 day post-hemodialysis or just before hemodialysis, with an intervening washout of ≥ 7 days. Healthy subjects (creatinine clearance ≥ 90 mL/min) received a single ticagrelor 90-mg dose. PK, PD (P2Y₁₂ reaction units [PRU], inhibition of platelet aggregation [IPA]), and safety were evaluated.

RESULTS

Twenty-seven subjects (14 hemodialysis, 13 healthy) received ticagrelor. The mean maximum plasma concentration (C_max) and area under the plasma concentration curve from time zero to infinity (AUC_0-∞) of ticagrelor were 598.4 ng/mL and 3256.1 ng·h/mL, respectively, in pre-hemodialysis subjects; 560.3 ng/mL and 3015.1 ng·h/mL, respectively, in post-hemodialysis subjects; and 370.8 ng/mL and 2188.8 ng·h/mL, respectively, in healthy subjects. C_max and AUC_0-∞ of AR-C124910XX, the active metabolite, were 152.3 ng/mL and 1144.2 ng·h/mL, respectively, in pre-hemodialysis subjects; 130.8 ng/mL and 1127.8 ng·h/mL, respectively, in post-hemodialysis subjects; and 111.7 ng/mL and 1000.4 ng·h/mL, respectively, in healthy subjects. Mean IPA time curves over 24 h post-dose were almost indistinguishable for all three treatments. The greatest reduction in mean PRU occurred approximately 2 h post-dose for all three treatments. No safety or tolerability issues were identified.

CONCLUSION

Hemodialysis resulted in modestly higher exposure to ticagrelor and AR-C124910XX, with no clinically significant effect on PD or tolerability. Accordingly, no dose adjustment is required for hemodialysis patients. Timing of hemodialysis has little impact on ticagrelor PK, or the effect of ticagrelor on IPA.

Pharmacokinetic Profiles of Ticagrelor Orodispersible Tablets in Healthy Western and Japanese Subjects

Background and Objectives

Ticagrelor is an antiplatelet agent for patients with acute coronary syndrome or a history of myocardial infarction. Two studies compared pharmacokinetic profiles of orodispersible (OD) ticagrelor tablets versus immediate-release (IR) tablets in Western and Japanese subjects.

Methods

Both studies were open-label, randomized, crossover, single-center trials. Thirty-six healthy subjects (94% white, 6% other race; Western study NCT02400333) and 42 Japanese healthy subjects (Japanese study NCT02436577) received a single 90-mg ticagrelor dose as an OD tablet [with/without water, and via a nasogastric tube (Western study only)], and an IR tablet; washout between treatments was ≥7 days. Assessments included ticagrelor and AR-C124910XX (active metabolite) plasma concentrations for pharmacokinetic analyses, and safety evaluations.

Results

In the Western study, the 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) for ticagrelor and AR-C124910XX maximum plasma concentration (C_max) and area under the plasma concentration–time curve (AUC) were within the acceptance interval (80%–125%) for OD tablets (with/without water, via a nasogastric tube) versus the IR tablet; except for an ~15% lowering of ticagrelor C_max (90% CI: 76.77%–93.78%) for the OD tablet taken with water. In the Japanese study, 90% CIs of the GMRs for AUC and C_max of both ticagrelor and AR-C124910XX were all within the acceptance intervals for the OD (with/without water) versus IR tablet. No new safety issues were identified.

Conclusions

Ticagrelor administered as an OD tablet to Western (without water, and via a nasogastric tube) and Japanese (with/without water) subjects was bioequivalent to the IR tablet.

Electronic supplementary material

The online version of this article (doi:10.1007/s40261-017-0554-8) contains supplementary material, which is available to authorized users.

Simultaneous measurement of multiple organic tracers in fine aerosols from biomass burning and fungal spores by HPLC-MS/MS

Three monosaccharide anhydrides (MAs: levoglucosan, mannosan, and galactosan) and sugar alcohols (arabitol and mannitol) are widely used as organic tracers for source identification of aerosols emitted from biomass burning and fungal spores, respectively. In the past, these two types of organic tracer have been measured separately or conjointly using different analytical techniques, with which a number of disadvantages have been experienced during the application to environmental aerosol samples, including organic solvent involved extraction, time-consuming derivatization, or poor separation efficiency due to overlapping peaks, etc. Hence, in this study a more environment-friendly, effective and integrated extraction and analytical method has been developed for simultaneous determination of the above mentioned organic tracers in the same aerosol sample using ultrasonication and high performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). The ultrasonication assisted extraction process using ultrapure water can achieve satisfactory recoveries in the range of 100.3 ± 1.3% to 108.4 ± 1.6% for these tracers. All the parameters related to LC and MS/MS have been optimized to ensure good identification and pronounced intensity for each compound. A series of rigorous validation steps have been conducted. This newly developed analytical method using ultrasonication and HPLC-MS/MS has been successfully applied to environmental aerosol samples of different pollution levels for the simultaneous measurement of the above mentioned five organic tracers from biomass burning and fungal spores.

Five organic tracers in fine aerosols can be simultaneously analysed by coupling ultrasonication and HPLC-MS/MS without a derivatization process.

Pharmacodynamics and pharmacokinetics of ticagrelor vs. clopidogrel in patients with acute coronary syndromes and chronic kidney disease

BACKGROUND

Pivotal clinical trials found that ticagrelor reduced ischaemic complications to a greater extent than clopidogrel, and also that the benefit gradually increased with the reduction in creatinine clearance. However, the underlying mechanisms remains poorly explored.

METHODS

This was a single-centre, prospective, randomized clinical trial involving 60 hospitalized Adenosine Diphosphate (ADP) P2Y12 receptor inhibitor-naïve patients with chronic kidney disease (CKD) (estimated glomerular filtration rate <60 ml min^-1 1.73 m^-2 ) and non-ST-elevation acute coronary syndromes (NSTE-ACS). Eligible patients were randomly assigned in a 1:1 ratio to receive ticagrelor (180 mg loading dose, then followed by 90 mg twice daily) or clopidogrel (600 mg loading dose, then followed by 75 mg once daily). The primary endpoint was the P2Y12 reactive unit (PRU) value assessed by VerifyNow at 30 days. The plasma concentrations of ticagrelor and clopidogrel and their active metabolites were measured in the first 10 patients in each group at baseline, and at 1 h, 2 h, 4 h, 8 h, 12 h and 24 h after the loading dose.

RESULTS

Baseline characteristics were well matched between the two groups. Our results indicated a markedly lower PRU in patients treated with ticagrelor vs. clopidogrel at 30 days (32.6 ± 11.29 vs. 203.7 ± 17.92; P < 0.001) as well as at 2 h, 8 h and 24 h after the loading dose (P < 0.001). Ticagrelor and its active metabolite AR-C124910XX showed a similar time to reach maximum concentration (C_max ) of 8 h, with the maximum concentration (C_max ) of 355 (242.50-522.00) ng ml^-1 and 63.20 (50.80-85.15) ng ml^-1 , respectively. Both clopidogrel and its active metabolite approached the C_max at 2 h, with a similar C_max of 8.67 (6.64-27.75) ng ml^-1 vs. 8.53 (6.94-15.93) ng ml^-1 .

CONCLUSION

Ticagrelor showed much more potent platelet inhibition in comparison with clopidogrel in patients with CKD and NSTE-ACS.

Simultaneous Determination of Twenty-Five Compounds in Rat Plasma Using Ultra-High Performance Liquid Chromatography-Polarity Switching Tandem Mass Spectrometry and Its Application to a Pharmacokinetic Study

An attempt was made to characterize the pharmacokinetic profiles of Qishen Keli (QSKL) that has been widely proved to be effective in clinical practice. A method using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) for the simultaneous determination of 25 analytes in rat plasma was developed and validated. Satisfactory chromatographic separation was achieved on an ACQUITY UPLC HSS T3 column with gradient elution using mobile phase consisting of 0.02% aqueous formic acid (A) and acetonitrile fortified with 0.02% formic acid (B), and analyte detection was carried out using polarity-switching multiple reaction monitoring mode. Method validation assays in terms of selectivity, linearity, inter- and intra-day variations, matrix effect, and recovery demonstrated the newly developed method to be specific, sensitive, accurate, and precise. Following the oral administration of QSKL at a single dose, the qualified method was successfully applied for pharmacokinetic investigations in sham and model rats. Mild differences occurred for the pharmacokinetic patterns of most components between those two groups, whereas significant differences were observed for glycyrrhizic acid and glycyrrhetic acid. The obtained findings could provide meaningful information for the clarification of the effective material basis of QSKL.

Comparison of Ticagrelor Pharmacokinetics and Pharmacodynamics in STEMI and NSTEMI Patients (PINPOINT): protocol for a prospective, observational, single-centre study

INTRODUCTION

The most common classification of acute myocardial infarction (AMI) is based on electrocardiographic findings and distinguishes ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI). Both types of AMI differ concerning their epidemiology, clinical approach and early outcomes. Ticagrelor is a P2Y12 receptor inhibitor, constituting the first-line treatment for STEMI and NSTEMI. According to available data, STEMI may be associated with lower plasma concentration of ticagrelor in the first hours of AMI, but currently there are no studies directly comparing ticagrelor pharmacokinetics or antiplatelet effect in patients with STEMI versus NSTEMI.

METHODS AND ANALYSIS

The PINPOINT study is a phase IV, single-centre, investigator-initiated, prospective, observational study designed to compare the pharmacokinetics and pharmacodynamics of ticagrelor in patients with STEMI and NSTEMI assigned to the invasive strategy of treatment. Based on an internal pilot study, the trial is expected to include at least 23 patients with each AMI type. All subjects will receive a 180 mg loading dose of ticagrelor. The primary end point of the study is the area under the plasma concentration-time curve (AUC_(0-6)) for ticagrelor during the first 6 hours after the loading dose. Secondary end points include various pharmacokinetic features of ticagrelor and its active metabolite (AR-C124910XX), and evaluation of platelet reactivity by the vasodilator-stimulated phosphoprotein assay and multiple electrode aggregometry. Blood samples for the pharmacokinetic and pharmacodynamic assessment will be obtained at pretreatment, 30 min, 1, 2, 3, 4, 6 and 12 hours post-ticagrelor loading dose.

ETHICS AND DISSEMINATION

The study received approval from the Local Ethics Committee (Komisja Bioetyczna Uniwersytetu Mikołaja Kopernika w Toruniu przy Collegium Medicum im. Ludwika Rydygiera w Bydgoszczy; approval reference number KB 617/2015). The study results will be disseminated through conference presentations and peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02602444; Pre-results.

Effect of CYP3A4∗1G and CYP3A5∗3 Polymorphisms on Pharmacokinetics and Pharmacodynamics of Ticagrelor in Healthy Chinese Subjects

Ticagrelor is the first reversible, direct-acting, potent P2Y₁₂ receptor antagonist in management of acute coronary syndromes. It is rapidly absorbed and extensively metabolized. AR-C124910XX, the major active metabolite, antagonizes the P2Y₁₂ receptor at approximately equal potency. The metabolism of ticagrelor to AR-C124910XX involves CYP3A4 and CYP3A5. CYP3A polymorphisms have been well documented, and CYP3A4^∗1G (g.20230G>A, rs2242480) and CYP3A5^∗3 (g.6986A>G, rs776746) are the most important single nucleotide polymorphisms in Chinese. Genetic differences in CYP3A4 and CYP3A5 expression in human volunteers and patients might affect the clearance of ticagrelor or AR-C124910XX in vivo resulting in subsequent variable patient response. Thus, this study is designed to explore the effects of CYP3A4^∗1G and CYP3A5^∗3 polymorphisms on the pharmacokinetics and pharmcodynamics of ticagrelor in healthy Chinese subjects. The results indicated that the CYP3A4^∗1G polymorphism significantly influenced the pharmacokinetics of AR-C124910XX, and it may be more important than CYP3A5^∗3 with respect to influencing ticagrelor pharmacokinetics by increasing CYP3A4 activity. However, the significant effect of CYP3A4^∗1G polymorphism on AR-C124910XX plasma levels did not translate into detectable effect on inhibition of platelet aggregation. Therefore, it seems not necessary to adjust the dosage of ticagrelor according to the CYP3A4 or 3A5 genotype.

Ticagrelor and Rosuvastatin Have Additive Cardioprotective Effects via Adenosine

BACKGROUND

Ticagrelor inhibits the equilibrative-nucleoside-transporter-1 and thereby, adenosine cell re-uptake. Ticagrelor limits infarct size (IS) in non-diabetic rats and the effect is adenosine-dependent. Statins, via ecto-5'-nucleotidase activation, also increase adenosine levels and limit IS.

HYPOTHESIS

Ticagrelor and rosuvastatin have additive effects on myocardial adenosine levels, and therefore, on IS and post-reperfusion activation of the NLRP3-inflammasome.

METHODS

Diabetic ZDF rats received via oral gavage; water (control), ticagrelor (150 mg/kg/d), prasugrel (7.5 mg/kg/d), rosuvastatin (5 mg/kg/d), ticagrelor + rosuvastatin and prasugrel + rosuvastatin for 3d. On day 4, rats underwent 30 min coronary artery occlusion and 24 h of reperfusion. Two additional groups received, ticagrelor + rosuvastatin or water in combination with CGS15943 (CGS, an adenosine receptor antagonist, 10 mg/kg i.p. 1 h before ischemia).

RESULTS

Both ticagrelor and rosuvastatin increased myocardial adenosine levels with an additive effect of the combination whereas prasugrel had no effect. Similarly, both ticagrelor and rosuvastatin significantly reduced IS with an additive effect of the combination whereas prasugrel had no effect. The effect on IS was adenosine dependent as CGS15943 reversed the effect of ticagrelor + rosuvastatin. The ischemia-reperfusion injury increased myocardial mRNA levels of NLRP3, ASC, IL-1β and IL-6. Ticagrelor and rosuvastatin, but not prasugrel, significantly decreased these pro-inflammatory mediators with a trend to an additive effect of the combination. The combination also increased the levels of anti-inflammatory 15-epilipoxin A₄.

CONCLUSIONS

Ticagrelor and rosuvastatin when given in combination have an additive effect on local myocardial adenosine levels in the setting of ischemia reperfusion. This translates into an additive cardioprotective effect mediated by adenosine-induced effects including downregulation of pro- but upregulation of anti-inflammatory mediators.

Ticagrelor, but not clopidogrel, reduces arterial thrombosis via endothelial tissue factor suppression

AIMS

The P2Y₁₂ antagonist ticagrelor reduces mortality in patients with acute coronary syndrome (ACS), compared with clopidogrel, and the mechanisms underlying this effect are not clearly understood. Arterial thrombosis is the key event in ACS; however, direct vascular effects of either ticagrelor or clopidogrel with focus on arterial thrombosis and its key trigger tissue factor have not been previously investigated.

METHODS AND RESULTS

Human aortic endothelial cells were treated with ticagrelor or clopidogrel active metabolite (CAM) and stimulated with tumour necrosis factor-alpha (TNF-α); effects on procoagulant tissue factor (TF) expression and activity, its counter-player TF pathway inhibitor (TFPI) and the underlying mechanisms were determined. Further, arterial thrombosis by photochemical injury of the common carotid artery, and TF expression in the murine endothelium were examined in C57BL/6 mice treated with ticagrelor or clopidogrel. Ticagrelor, but not CAM, reduced TNF-α-induced TF expression via proteasomal degradation and TF activity, independently of the P2Y₁₂ receptor and the equilibrative nucleoside transporter 1 (ENT1), an additional target of ticagrelor. In C57BL/6 mice, ticagrelor prolonged time to arterial occlusion, compared with clopidogrel, despite comparable antiplatelet effects. In line with our in vitro results, ticagrelor, but not clopidogrel, reduced TF expression in the endothelium of murine arteries.

CONCLUSION

Ticagrelor, unlike clopidogrel, exhibits endothelial-specific antithrombotic properties and blunts arterial thrombus formation. The additional antithrombotic properties displayed by ticagrelor may explain its greater efficacy in reducing thrombotic events in clinical trials. These findings may provide the basis for new indications for ticagrelor.

Crushed Versus Integral Tablets of Ticagrelor in ST-Segment Elevation Myocardial Infarction Patients: A Randomized Pharmacokinetic/Pharmacodynamic Study

OBJECTIVE

The objective of this study was to assess the pharmacokinetic and pharmacodynamic behavior of ticagrelor administered either as crushed (in the semi-upright sitting position) or as integral (in the supine position) tablets in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI).

METHODS

We randomized 20 patients to ticagrelor 180 mg either as 2 integral tablets administered in the supine position (standard administration) or as 2 tablets crushed and dispersed, administered in the semi-upright sitting position. Blood samples were drawn for pharmacokinetic and pharmacodynamic assessment at randomization (0 h) and at 0.5, 1, 2, and 4 h.

RESULTS

At 1 h, ticagrelor plasma exposure and area under the plasma concentration-time curve from time zero to 1 h (AUC1) (co-primary endpoints) were higher in the crushed versus integral tablets group (median 586 vs. 70.1 ng/mL and 234 vs. 24.4 ng·h/mL, respectively), with a ratio of adjusted geometric means (95% confidence interval [CI]) of 12.67 (2.34-68.51) [p = 0.005] and 19.28 (3.51-106.06) [p = 0.002], respectively. Time to maximum plasma concentration was shorter in the crushed versus integral tablets group (median 2 vs. 4 h), with a ratio of adjusted geometric means (95% CI) of 0.69 (0.49-0.97) [p = 0.035]. Parallel findings were observed with AR-C124910XX (active metabolite). Platelet reactivity (VerifyNow(®)) at 1 h was lower with crushed versus standard administration with least squares estimates mean difference (95% CI) of 92 (-158.4 to 26.6) P2Y12 reaction units (p = 0.009).

CONCLUSIONS

In patients with STEMI undergoing primary PCI, ticagrelor crushed tablets administered in the semi-upright sitting position seems to lead to a faster-compared with standard administration-absorption, with stronger antiplatelet activity within the first hour.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02046486.

Ticagrelor promotes atherosclerotic plaque stability in a mouse model of advanced atherosclerosis

Objective

There is increasing evidence supporting the role of platelets in atherosclerotic vascular disease. The G-protein-coupled receptor P2Y₁₂ is a central mediator of platelet activation and aggregation but has also been linked to platelet-independent vascular disease. Ticagrelor is an oral P2Y₁₂ antagonist that is used as a standard treatment in patients after acute myocardial infarction. However, the effects of ticagrelor on advanced atherosclerosis have not been investigated.

Materials and methods

Twenty-week-old apolipoprotein-E-deficient mice received standard chow or standard chow supplemented with 0.15% ticagrelor (approximately 270 mg/kg/day) for 25 weeks. The lesion area was evaluated in the aortic sinus by Movat’s pentachrome staining and lesion composition, thickness of the fibrous cap, and size of the necrotic core evaluated by morphometry. RAW 264.7 macrophages were serum starved and treated with ticagrelor in vitro for the detection and quantification of apoptosis. In addition, oxLDL uptake in RAW 264.7 macrophages was evaluated.

Results

A trend toward the reduction of total lesion size was detected. However, data did not reach the levels of significance (control, n=11, 565,881 μm² [interquartile range {IQR} 454,778–603,925 μm²] versus ticagrelor, n=13, 462,595 μm² [IQR 379,740–546,037 μm²]; P=0.1). A significant reduction in the relative area of the necrotic core (control, n=11, 0.46 [IQR 0.4–0.51] versus ticagrelor, n=13, 0.34 [IQR 0.31–0.39]; P=0.008), and a significant increase in fibrous caps thickness (control, n=11, 3.7 μm [IQR 3.4–4.2 μm] versus ticagrelor, n=13, 4.7 [IQR 4.3–5.5 μm], P=0.04) were seen in ticagrelor-treated mice. In vitro studies demonstrated a reduction in apoptotic RAW 264.7 macrophages (control 0.07±0.03 versus ticagrelor 0.03±0.03; P=0.0002) when incubated with ticagrelor. Uptake of oxLDL in RAW 264.7 was significantly reduced when treated with ticagrelor (control 9.2 [IQR 5.3–12.9] versus ticagrelor 6.4 [IQR 2.5–9.5], P=0.02).

Conclusion

The present study demonstrates for the first time a plaque-stabilizing effect of ticagrelor in a model of advanced vascular disease, potentially induced by a reduction of oxLDL uptake or an inhibition of apoptosis as seen in vitro.

Pharmacodynamics, pharmacokinetics, and safety of ticagrelor in Chinese patients with stable coronary artery disease

AIM

The aim of the study was to assess ticagrelor's effects on inhibition of platelet aggregation (IPA), P2Y12 reaction units (PRU, measure of platelet P2Y12 receptor blockade), pharmacokinetic (PK) parameters and safety in Chinese patients with stable coronary artery disease (CAD).

METHODS

This was an open label, single centre, randomized study. Thirty-six patients on low dose aspirin (75-100 mg day(-1) ) received ticagrelor 45, 60 or 90 mg (single dose, days 1 and 7; twice daily, days 3-6). IPA (final extent), PRU and ticagrelor and AR-C124910XX plasma concentrations were determined.

RESULTS

On day 1, peak IPA >80% occurred 2-6 h post-dose (all doses). PRU was markedly reduced at 1 h vs. baseline (all doses). With ticagrelor 45 and 90 mg twice daily, maximum IPA (mean, SD) was 91% (13%), and 99% (3%), and maximum PRU reduction from baseline (mean, SD) was 82% (17%) and 92% (9%), respectively. Approximate dose-proportional increases (mean [%CV]; 45 vs. 90 mg twice daily) in ticagrelor Cmax (616 [37] vs. 1273 [43] ng ml(-1) ) and AUC (3882 [42] vs. 8206 [51] ng ml(-1) h) and AR-C124910XX parameters were seen. Pharmacodynamic and PK differences between 45 and 60 mg were small. No safety issues were identified.

CONCLUSIONS

In Chinese patients with CAD, ticagrelor (45, 60 and 90 mg) markedly reduced platelet aggregation. The IPA and PRU magnitude increased generally with increasing doses. However, the mean pharmacodynamic differences between 45 and 60 mg doses were small. Following single and multiple doses, the mean Cmax and AUC values of ticagrelor and AR-C124910XX increased approximately dose proportionally between 45 and 90 mg doses.

Simultaneous Determination of Ticagrelor and Its Metabolites in Human Plasma and Urine Using Liquid Chromatography-Tandem Mass Spectrometry

We have developed and validated a rapid, selective and sensitive method using high-performance liquid chromatography-tandem mass spectrometry (MS) for the quantification of ticagrelor and all of its as-yet-identified metabolites in human plasma and urine. For the analysis of ticagrelor, its metabolites and the internal standard (IS) plasma samples were processed by liquid-liquid extraction using ethyl acetate and urine was processed by protein precipitation. Separations were performed on an Ultimate XB-C18 column (2.1 mm × 150 mm, 3 μm), using aqueous ammonium acetate (0.025 mM)/acetonitrile (35 : 65, v:v) as the mobile phase. Ticagrelor and all 11 metabolites were eluted within 4.5 min. Quantification was performed using electrospray ionization, operating in negative ion mode. The ticagrelor and metabolite M8 (AR-C124910XX) responses were optimized at the m/z 521.2 → 361.2 and m/z 477.2 → 361.1 transitions, respectively. The assay was validated over the linear range of 0.5-2,000 ng/mL for ticagrelor and M8. The intra- and inter-assay precisions were ≤14.6% for ticagrelor and ≤14.7% for M8, respectively. The matrix effects of plasma and urine were in the range of 98.3-110.7% for ticagrelor and 102.1-112.3% for M8. The relative quantification of other metabolites was performed by assessing the ratio of metabolite to IS peaks. The newly developed method was successfully used in a pharmacokinetic study characterizing ticagrelor metabolism in human volunteers.

Retinal Electrophysiology Is a Viable Preclinical Biomarker for Drug Penetrance into the Central Nervous System

Objective. To examine whether retinal electrophysiology is a useful surrogate marker of drug penetrance into the central nervous system (CNS). Materials and Methods. Brain and retinal electrophysiology were assessed with full-field visually evoked potentials and electroretinograms in conscious and anaesthetised rats following systemic or local administrations of centrally penetrant (muscimol) or nonpenetrant (isoguvacine) compounds. Results. Local injections into the eye/brain bypassed the blood neural barriers and produced changes in retinal/brain responses for both drugs. In conscious animals, systemic administration of muscimol resulted in retinal and brain biopotential changes, whereas systemic delivery of isoguvacine did not. General anaesthesia confounded these outcomes. Conclusions. Retinal electrophysiology, when recorded in conscious animals, shows promise as a viable biomarker of drug penetration into the CNS. In contrast, when conducted under anaesthetised conditions confounds can be induced in both cortical and retinal electrophysiological recordings.

Determination of avibactam and ceftazidime in human plasma samples by LC-MS

AIM

Avibactam, a novel non-β-lactam β-lactamase inhibitor co-administrated with the β-lactam antibiotic ceftazidime, is in clinical development. The need to evaluate its PK and PD requires accurate and reliable bioanalytical methods.

METHODS

We describe LC-MS/MS methods for the determination of avibactam and ceftazidime in human plasma. Avibactam was extracted using weak anionic exchange solid-phase extraction and analyzed on an amide column. Ceftazidime was extracted using protein precipitation and analyzed on a C18 column. Calibration curves were established over 10-10,000 ng/ml (avibactam) and 43.8-87,000 ng/ml (ceftazidime).

RESULTS & CONCLUSION

Method validation, cross-validation between three laboratories and incurred sample re-analysis demonstrated method robustness. The methods were successfully applied to multiple clinical studies.

Four process-related potential new impurities in ticagrelor: Identification, isolation, characterization using HPLC, LC/ESI-MS(n), NMR and their synthesis

Five process-related impurities were detected in the range of 0.08-0.22% in ticagrelor laboratory batches by HPLC and LC-MS methods. These impurities were named as TIC Imp-I, -II, -III, -IV and -V. Four of these impurities, TIC Imp-I to -IV were unknown and have not been reported previously. Based on LC-ESI/MS(n) study, the chemical structures of new impurities were presumed as (1S,2S,3S,5S)-3-(2-hydroxyethoxy)-5-(7-amino-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d] pyrimidin-3-yl)cyclopentane-1,2-diol (TIC Imp-I), (1S,2S,3S,5S)-3-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylsulfinyl)-3H-[1,2,3]triazolo [4,5-d]pyrimidin-3-yl)-5-(2-hydroxyethoxy)cyclopentane-1,2-diol (TIC Imp-II), (1S,2R,3S,4S)-4-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl)cyclopentane-1,2,3-triol (TIC Imp-III) and (3S,5S)-3-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl)-5-(2-hydroxyethoxy)cyclopentane-1,2-diol (TIC Imp-IV). The unknown impurities were isolated from enriched crude sample by column chromatography and preparative HPLC. The complete spectral analysis, MS, 1D NMR ((1)H, (13)C and DEPT), 2D NMR (HSQC and HMBC) and IR confirmed the proposed chemical structures of impurities. Identification, isolation, structural characterization, prospects for the formation of impurities and their synthesis were first reported in this paper.

An open-label, randomized bioavailability study with alternative methods of administration of crushed ticagrelor tablets in healthy volunteers

Objective: To compare the bioavailability and safety profile of crushed ticagrelor tablets suspended in water and administered orally or via nasogastric tube, with that of whole tablets administered orally. Methods: In this single-center, open-label, randomized, three-treatment crossover study, 36 healthy volunteers were randomized to receive a single 90-mg dose of ticagrelor administered orally as a whole tablet or as crushed tablets suspended in water and given orally or via a nasogastric tube into the stomach, with a minimum 7-day wash-out between treatments. Plasma concentrations of ticagrelor and AR-C124910XX were assessed at 0, 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 16, 24, 36, and 48 hours post-ticagrelor dose for pharmacokinetic analyses. Safety and tolerability was assessed throughout the study. Results: At 0.5 hours postdose, plasma concentrations of ticagrelor and AR-C124910XX were higher with crushed tablets administered orally (148.6 ng/mL and 13.0 ng/mL, respectively) or via nasogastric tube (264.6 ng/mL and 28.6 ng/mL, respectively) compared with whole-tablet administration (33.3 ng/mL and 5.2 ng/mL, respectively). A similar trend was observed at 1 hour postdose. Ticagrelor t_max was shorter following crushed vs. whole-tablet administration (1 vs. 2 hours, respectively). Geometric mean ratios between treatments for AUC and C_max were contained within the bioequivalence limits of 80 – 125% for ticagrelor and AR-C124910XX. All treatments were generally well tolerated. Conclusions: Ticagrelor administered as a crushed tablet is bioequivalent to whole-tablet administration, independent of mode of administration (oral or via nasogastric tube), and resulted in increased plasma concentrations of ticagrelor and AR-C124910XX at early timepoints.