Ultrasensitive LC-MS/MS quantitation of the N-nitroso-dabigatran etexilate impurity in dabigatran etexilate mesylate using an electrospray ionization technique

Nitrosamine impurities, particularly nitrosamine drug substance-related impurities (NDSRIs), pose significant health risks due to their potential mutagenicity and carcinogenicity. Consequently, stringent regulatory guidelines have been established for their detection and quantification in pharmaceutical products. This study presents a simple, robust, and ultrasensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify the N-nitroso-dabigatran etexilate (NDE) impurity in the drugs and capsules of dabigatran etexilate (DEM) using an electrospray ionization technique. Using a gradient elution program, with mobile phase A consisting of 5 mM ammonium formate buffer (pH 7.0 ± 0.1) and mobile phase B 100% acetonitrile, chromatographic separation was achieved on a Sapphirus C18 HP-classic column (250 mm × 4.6 mm × 5 μm). The system utilized an Agilent 1290 infinity series LC with a 6470B LC/TQ tandem mass spectrometer, operating at a 0.6 mL min-1 column flow rate. Detection and quantitation of the N-nitroso dabigatran etexilate (NDE) impurity were performed in positive ESI mode using multi-reaction monitoring (MRM). The validation of the method adhered to the ICH Q2 (R2) guidelines, showing excellent signal-to-noise ratios for the detection and quantification limits, with linearity observed (correlation coefficient > 0.99) over a range of 18-120 ppb. Accuracy was confirmed through recovery studies, yielding satisfactory results between 80 and 120% of spiked concentrations. This validated LC-MS/MS method is suitable for routine and stability analysis of N-nitroso-dabigatran etexilate (NDE) impurities in both drug substance and finished capsules.

Clinically Significant Drug Interactions for Direct Oral Anticoagulants: State of the Art

The article is devoted to modern ideas about the role of drug interactions as a factor affecting the efficacy and safety of the use of direct oral anticoagulants (DOACs) in clinical practice. Data on drug interactions of apixaban, rivaroxaban and dabigatran with the drugs most frequently used in patients with cardiovascular diseases are given. Drug interactions for DOACs, depending on concomitant use of drugs that are inhibitors or inducers of the CYP3A4 enzyme or P-glycoprotein enzymes, are determined by most of the drug interactions of DOACs are considered. The results of studies in which drug interactions of DOACs were assessed by changes in indicators such as the area under the concentration-time curve and the maximum or minimum concentration of drugs in the blood are discussed. The data presented in the article may be useful for accounting for drug interactions in the treatment of patients with DOACs in clinical practice, despite the current lack of reasonable dose adjustment rules depending on the majority of such interactions. The data presented in the article suggest that apixaban has the fewest number of clinically significant interactions among the DOACs available in Russia.

Direct Oral Anticoagulants and Coronary Artery Disease

Coronary artery disease is a leading cause of morbidity and mortality worldwide. Acute coronary syndrome as a first presentation is common and patients with established disease have a high rate of recurrent ischemic events, despite antiplatelet therapy. Over the past several years, direct oral anticoagulants have become available and have been studied in patients with coronary artery disease. These medications directly inhibit either thrombin or factor Xa which contribute to atherothrombosis. This review will summarize the clinical data regarding the use of direct oral anticoagulants in different patient populations with coronary disease and the balance between protection against ischemia and bleeding. Additionally, the review will summarize the available data on the use of direct oral anticoagulants periprocedurally in patients undergoing percutaneous coronary intervention. The future direction of coronary artery disease and the role of direct oral anticoagulants will rely on further studies determining the optimal combination of antiplatelet and oral anticoagulant regimens that derive ischemic benefit without increased rates of bleeding. Additional upstream blockade of the coagulation cascade with factor XIIa and factor XIa inhibitors may also improve treatment in the future.

Real-World Comparisons of Low-Dose NOACs versus Standard-Dose NOACs or Warfarin on Efficacy and Safety in Patients with AF: A Meta-Analysis

Objective

We aimed to further investigate the efficacy and safety of low-dose NOACs by performing a meta-analysis of cohort studies.

Background

Meta-analyses of randomized controlled trials (RCTs) have demonstrated that low-dose non-vitamin K antagonist oral anticoagulants (NOACs) showed inferior efficacy compared with standard-dose NOACs, although they are still frequently prescribed for patients with atrial fibrillation (AF) in the clinical practice.

Methods

Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and MEDLINE were systematically searched from the inception to September 9, 2021, for cohort studies that compared the efficacy and/or safety of low-dose NOACs in patients with AF. The primary outcomes were ischemic stroke and major bleeding, and the secondary outcomes were mortality, intracranial hemorrhage (ICH), and gastrointestinal hemorrhage (GH). Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with the random-effect model.

Results

Twenty-five publications involving 487856 patients with AF were included. Compared with standard-dose NOACs, low-dose NOACs had comparable risks of ischemic stroke (HR = 1.03, 95% CI 0.96 to 1.11), major bleeding (HR = 1.12, 95% CI 0.97 to 1.28), ICH (HR = 1.09, 95% CI 0.88 to 1.36), and GH (HR = 1.11, 95% CI 0.92 to 1.33), except for a higher risk of mortality (HR = 1.41, 95% CI 1.21 to 1.65). Compared with warfarin, low-dose NOACs were associated with lower risks of ischemic stroke (HR = 0.72, 95% CI .67 to 0.78), mortality (HR = 0.67, 95% CI 0.59 to 0.77), major bleeding (HR = 0.64, 95% CI 0.53 to 0.79), ICH (HR = 0.57, 95% CI 0.42 to 0.77), and GH (HR = 0.78, 95% CI 0.64 to 0.95).

Conclusions

Low-dose NOACs were comparable to standard-dose NOACs considering risks of ischemic stroke, major bleeding, ICH, and GH, and they were superior to warfarin. Low-dose NOACs might be prescribed effectively and safely for patients with AF. Considering limitations, further well-designed prospective studies are foreseen.

Apolipoprotein B and Cardiovascular Disease: Biomarker and Potential Therapeutic Target

Apolipoprotein (apo) B, the critical structural protein of the atherogenic lipoproteins, has two major isoforms: apoB48 and apoB100. ApoB48 is found in chylomicrons and chylomicron remnants with one apoB48 molecule per chylomicron particle. Similarly, a single apoB100 molecule is contained per particle of very-low-density lipoprotein (VLDL), intermediate density lipoprotein, LDL and lipoprotein(a). This unique one apoB per particle ratio makes plasma apoB concentration a direct measure of the number of circulating atherogenic lipoproteins. ApoB levels indicate the atherogenic particle concentration independent of the particle cholesterol content, which is variable. While LDL, the major cholesterol-carrying serum lipoprotein, is the primary therapeutic target for management and prevention of atherosclerotic cardiovascular disease, there is strong evidence that apoB is a more accurate indicator of cardiovascular risk than either total cholesterol or LDL cholesterol. This review examines multiple aspects of apoB structure and function, with a focus on the controversy over use of apoB as a therapeutic target in clinical practice. Ongoing coronary artery disease residual risk, despite lipid-lowering treatment, has left patients and clinicians with unsatisfactory options for monitoring cardiovascular health. At the present time, the substitution of apoB for LDL-C in cardiovascular disease prevention guidelines has been deemed unjustified, but discussions continue.

Dabigatran Etexilate Induces Cytotoxicity in Rat Gastric Epithelial Cell Line via Mitochondrial Reactive Oxygen Species Production

Dabigatran is a novel oral anticoagulant that directly inhibits free and fibrin-bound thrombins and exerts rapid and predictable anticoagulant effects. While the use of this reagent has been associated with an increased risk of gastrointestinal bleeding, the reason why dabigatran use increases gastrointestinal bleeding risk remains unknown. We investigated the cytotoxicity of dabigatran etexilate and tartaric acid, the two primary components of dabigatran. The cytotoxicity of dabigatran etexilate and tartaric acid was measured in a cell viability assay. Intracellular mitochondrial reactive oxygen species (mitROS) production and lipid peroxidation were measured using fluorescence dyes. Cell membrane viscosity was measured using atomic force microscopy. The potential of ascorbic acid as an inhibitor of dabigatran cytotoxicity was also evaluated. The cytotoxicity of dabigatran etexilate was higher than that of tartaric acid. Dabigatran etexilate induced mitROS production and lipid peroxidation and altered the cell membrane viscosity. Ascorbic acid inhibited the cytotoxicity and mitROS production induced by dabigatran etexilate. Therefore, we attributed the cytotoxicity of dabigatran to dabigatran etexilate, and proposed that the cytotoxic effects of dabigatran etexilate are mediated via mitROS production. Additionally, we demonstrated that dabigatran cytotoxicity can be prevented via antioxidant treatment.

Review of Direct Oral Anticoagulants and Guide for Effective Drug Utilization

Direct oral anticoagulants (DOACs) have been developed as a viable and in some cases superior alternative to warfarin. These agents have overcome some of the limitations of warfarin, which has a narrow therapeutic window and many food and drug interactions. DOACs have been demonstrated to have a more predictable and reliable pharmacology and, unlike warfarin, do not require frequent monitoring of anticoagulant effect. For these reasons, the use of DOACs is increasing. Despite the many positive attributes of these agents, limitations and contraindications do exist. An understanding of the pharmacology, indications, and contraindications is therefore crucial for effective patient management. We review the available agents to aid in effective drug utilization.

Periprocedural Anticoagulation Management For Nonoperating Room Anesthesia Procedures: A Clinical Guide

Non-operating room anesthesia presents unique challenges for anesthesiologists. Limited preprocedural optimization and unfamiliarity with the location and procedure itself add to the difficulties in delivering safe care for these patients. Management of chronic oral anticoagulation can prove especially problematic since risks of bleeding for non-operating room procedures vary widely and differ from traditional surgeries. In addition, many physicians may not be familiar with the growing number of newly approved oral anticoagulants and their periprocedural management. This review will examine common non-operating procedures, their risks of bleeding, as well as pharmacokinetics of oral anticoagulants available on the market and periprocedural management options.

Approaches to prevent bleeding associated with anticoagulants: current status and recent developments

Anticoagulants are widely used for the prophylaxis and treatment of cardiovascular disorders and to prevent blood clotting during surgeries. However, the major limitation associated with anticoagulant therapy is bleeding; all the current anticoagulants do have a bleeding risk. The propensity to bleed is much higher among the elderly population and patients with renal insufficiency. Therefore, there is an utmost and urgent clinical need for a highly efficient, nontoxic antidote with excellent anticoagulant reversal activity. This will significantly improve the safety of anticoagulation therapy. This review summarizes the current options and approaches to reverse anticoagulation activity of clinically used anticoagulants. We start with an introduction to thrombosis and then summarize the details of current clinically available anticoagulants and their mechanisms of action and limitations. This is followed by current practices in anticoagulant neutralization including the details of the only clinically approved unfractionated heparin antidote, protamine; recent advances in the development of antidotes against heparin-based drugs; and direct oral anticoagulants (DOACs).

Acute kidney injury and undiagnosed immunoglobulin A nephropathy after dabigatran therapy

Dabigatran, a new oral anticoagulant, is a direct thrombin inhibitor used as an alternative to warfarin to reduce the risk of stroke and systemic embolism with nonvalvular atrial fibrillation. We report a case of a man who resumed dabigatran after 6 weeks of prior therapy and began experiencing hematuria with worsening kidney function. Renal biopsy with immunofluorescence and electron microscopy showed mesangial deposits consistent with immunoglobulin A nephropathy. With discontinuation of dabigatran and addition of methylprednisolone, the gross hematuria cleared and urine output improved.

Efficacy of prothrombin complex concentrates for the emergency reversal of dabigatran-induced anticoagulation

Dabigatran is effective in decreasing the risk of ischaemic stroke in patients with atrial fibrillation. However, like all anticoagulants, it is associated with a risk of bleeding. In cases of trauma or emergency surgery, emergency reversal of dabigatran-induced anticoagulation may be required. A specific reversal agent for dabigatran, idarucizumab, has been approved by the US Food and Drug Administration. Alternative reversal agents are available, such as prothrombin complex concentrates (PCCs) and activated PCCs (aPCCs). In this review we evaluate the role of PCCs and aPCCs in the reversal of dabigatran anticoagulation and consider which tests are appropriate for monitoring coagulation in this setting. Pre-clinical studies, small clinical studies and case reports indicate that PCCs and aPCCs may be able to reverse dabigatran-induced anticoagulation in a dose-dependent manner. However, dosing based on coagulation parameters can be difficult because available assays may not provide adequate sensitivity and specificity for measuring anticoagulation induced by dabigatran or the countering effects of PCCs/aPCCs. In addition, PCCs or aPCCs can potentially provoke thromboembolic complications. Despite these limitations and the fact that PCCs and aPCCs are not yet licensed for dabigatran reversal, their use appears to be warranted in patients with life-threatening haemorrhage if idarucizumab is not available.

Discovery of a Potent Parenterally Administered Factor XIa Inhibitor with Hydroxyquinolin-2(1H)-one as the P2' Moiety

Structure-activity relationship optimization of phenylalanine P1' and P2' regions with a phenylimidazole core resulted in a series of potent FXIa inhibitors. Introducing 4-hydroxyquinolin-2-one as the P2' group enhanced FXIa affinity and metabolic stability. Incorporation of an N-methyl piperazine amide group to replace the phenylalanine improved both FXIa potency and aqueous solubility. Combination of the optimization led to the discovery of FXIa inhibitor 13 with a FXIa K i of 0.04 nM and an aPTT EC2x of 1.0 μM. Dose-dependent efficacy (EC50 of 0.53 μM) was achieved in the rabbit ECAT model with minimal bleeding time prolongation.

Warfarin-related nephropathy is the tip of the iceberg: direct thrombin inhibitor dabigatran induces glomerular hemorrhage with acute kidney injury in rats

BACKGROUND

Excessive anticoagulation with warfarin can result in acute kidney injury (AKI) by causing glomerular hemorrhage and renal tubular obstruction by red blood cell (RBC) casts in some patients, especially in those with chronic kidney disease (CKD). This condition was described as warfarin-related nephropathy (WRN). Recent evidence suggests that WRN-like syndromes are not confined to anticoagulation with warfarin, but may be seen with other anticoagulants, such as dabigatran. The aim of this study was to investigate dabigatran effects on kidney function in an animal model of CKD and possible pathogenic mechanisms of AKI.

METHODS

Control and 5/6 nephrectomy rats were treated with different doses of dabigatran and protease-activated receptor 1 (PAR-1) inhibitor SCH79797.

RESULTS

Dabigatran resulted in changes in coagulation in rats similar to those in humans at 50 mg/kg/day. Dabigatran resulted in a dose-dependent increase in serum creatinine (Scr) and hematuria in both control and 5/6 nephrectomy rats. SCH79797 also increased Scr and hematuria, more prominent in animals with CKD. Morphologically, numerous RBC tubular casts were seen in 5/6 nephrectomy rats treated with either dabigatran or SCH79797 and only occasional RBC casts in control rats.

CONCLUSIONS

Our data indicate that WRN represents part of a broader syndrome, anticoagulant-related nephropathy (ARN). ARN, at least partially, is mediated via PAR-1. Our findings suggest that not only CKD patients, but other patients as well, are at high risk of developing AKI if the therapeutic range of anticoagulation with dabigatran is exceeded. Close monitoring of kidney function in patients on dabigatran therapy is warranted.