Dabigatran Research Articles

Bleeding Risk of Anticoagulation Reversal Strategies Before Heart Transplantation: A Retrospective Comparative Cohort Study

Heart transplantation (HT) poses high bleeding risks, especially for patients on anticoagulation. This study evaluates the use of idarucizumab for dabigatran (DBG) reversal compared to vitamin K antagonist (VKA) strategies in HT. A retrospective analysis of HT patients from January 2018 to December 2022, excluding those requiring ECMO immediately before or after surgery, was conducted. Outcomes included transfusion needs, re-surgery due to bleeding, ICU stay lengths, and 30-day survival. A cost analysis compared the direct expenses of each strategy. Among 34 patients, 20 were on DBG and 14 on VKAs or not anticoagulated. Idarucizumab significantly reduced the number of patients requiring transfusion (p = 0.034) and ICU stay lengths (p = 0.014), with no significant impact on re-surgery rates (p = 0.259) or survival (p = 0.955). Despite higher initial costs, overall expenses for idarucizumab were comparable to VKA reversal due to reduced transfusion needs and shorter ICU stays. Idarucizumab offers a viable and potentially cost-neutral anticoagulation reversal option for HT patients on DBG, presenting an alternative to VKA strategies. However, due to the retrospective nature of the study and the small sample size, further prospective studies are needed to confirm these findings.

Evaluation of Drug–Drug Interactions Between Clarithromycin and Direct Oral Anticoagulants Using Physiologically Based Pharmacokinetic Models

Objective: This study assessed the pharmacokinetic (PK) interactions between clarithromycin (a P-glycoprotein [P-gp] inhibitor) and four direct oral anticoagulants (DOACs) (P-gp substrates) using physiologically based PK (PBPK) models to elucidate the influence of P-gp in the interaction between them. Methods: PBPK models for clarithromycin, DABE–dabigatran (DAB), rivaroxaban, apixaban, and edoxaban were constructed using GastroPlus™ (version 9.9), based on physicochemical data and PK parameters from the literature. The models were optimized and validated in healthy subjects. We evaluated the predictive performance of the established model and further assessed the impact of P-gp on the PK of the four DOACs. Successfully validated models were then used to evaluate potential drug–drug interactions (DDIs) between clarithromycin and the DOACs. Results: The established PBPK models accurately described the PK of clarithromycin, DABE–DAB, rivaroxaban, apixaban, and edoxaban. The predicted PK parameters (Cmax, Tmax, AUC0-t) were within 0.5–2 times the observed values. A sensitivity analysis of P-gp parameters indicated that an increase in P-gp expression was reduced by in vivo exposure to DOACs. The models demonstrated good predictive ability for DDIs between clarithromycin and the anticoagulants, and the ratio of the predicted values to the observed values of Cmax and the area under the curve (AUC) in the DDI state was within the range of 0.5–2. Conclusions: Comprehensive PBPK models for clarithromycin, DABE–DAB, rivaroxaban, apixaban, and edoxaban were developed, which can effectively predict DDIs mediated by P-gp’s function. These models provide theoretical support for clinical dose adjustments and serve as a foundation for future PBPK model development for DOACs under specific pathological conditions.

Pharmacokinetic interaction between single and multiple doses of darunavir, in combination with cobicistat or ritonavir, and single-dose dabigatran etexilate in healthy adults

ObjectiveDarunavir (DRV) is a P-glycoprotein (P-gp) inhibitor. Dabigatran etexilate, prodrug of the anticoagulant dabigatran, is a P-gp probe substrate. This study evaluated the effect of single and multiple doses of DRV, coadministered with cobicistat (COBI) or ritonavir (rtv), on the pharmacokinetics (PK) of single-dose dabigatran etexilate.MethodsThis was an open-label, fixed-sequence, single-center, 2-panel, phase 1 study in which healthy adult participants were equally divided over 2 panels. In panel 1, participants received single and multiple doses of DRV/COBI 800/150 mg coadministered with single-dose dabigatran etexilate 150 mg. In panel 2, participants received single and multiple doses of DRV 800 mg + rtv 100 mg coadministered with single-dose dabigatran etexilate 150 mg. Key PK parameters evaluated were maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time zero to infinity (AUCinf) for free and total dabigatran.ResultsOverall, 28 participants were enrolled and treated (n = 14 per panel). Dabigatran Cmax and AUCinf increased 2.64-fold after a single dose of DRV/COBI and 1.99- and 1.88-fold, respectively, after multiple doses of DRV/COBI. Dabigatran Cmax and AUCinf increased 1.64- and 1.72-fold, respectively, after a single dose of DRV + rtv and 1.22- and 1.18-fold, respectively, after multiple doses of DRV + rtv. In both panels, the most commonly reported adverse events were diarrhea and headache.ConclusionFindings of increased dabigatran exposure with DRV/COBI or DRV + rtv coadministration indicate an inhibitory effect of single-dose boosted DRV on P-gp, and a mixed inhibitory/inductive effect of multiple doses of boosted DRV on P-gp.Trial registrationClinicalTrials.gov, NCT04208061. Registered December 19, 2019

The pharmacokinetics of dabigatran in a rat model of hyperlipidaemia induced by poloxamer 407

Various pharmacokinetic changes have been reported in experimental hyperlipidemic (HL) animal models. To evaluate whether P-glycoprotein (P-gp) activity was affected in HL rats, we assessed the pharmacokinetics of dabigatran after oral administration of dabigatran etexilate (DABE); this is a dabigatran prodrug and a well-known P-gp substrate. HL and control rats exhibited similar area under the plasma concentration-time curve (AUC), total body clearance (CL), and steady state volume of distribution (Vss) values following intravenous administration of dabigatran (1 mg/kg). This suggested that the distribution and elimination of dabigatran were similar in control and HL rats. The hepatic and intestinal P-gp protein levels did not differ significantly between control and HL rats. The dabigatran AUC and extent of absolute oral bioavailability (F) values were similar in control and HL rats following oral administration of DABE (10 mg/kg as dabigatran). Therefore, there was no apparent change in intestinal P-gp activity in HL rats compared to control rats. This study revealed no significant change in P-gp expression or activity in the intestine or liver of HL rats, and similar pharmacokinetics of dabigatran. Hyperlipidaemia may not directly affect the oral absorption of P-gp substrate drugs.

Handling delayed or missed direct oral anticoagulant doses: model-informed individual remedial dosing

AbstractNonadherence to direct oral anticoagulant (DOAC) pharmacotherapy may increase the risk of thromboembolism or bleeding, and delayed or missed doses are the most common types of nonadherence. Current recommendations from regulatory agencies or guidelines regarding this issue lack evidence and fail to consider individual differences. This study aimed to develop individual remedial dosing strategies when the dose was delayed or missed for DOACs, including rivaroxaban, apixaban, edoxaban, and dabigatran etexilate. Remedial dosing regimens based on population pharmacokinetic (PK)-pharmacodynamic (PD) modeling and simulation strategies were developed to expeditiously restore drug concentration or PD biomarkers within the therapeutic range. Population PK-PD characteristics of DOACs were retrieved from previously published literature. The effects of factors that influence PK and PD parameters were assessed for their impact on remedial dosing regimens. A web-based dashboard was established with R-shiny to recommend remedial dosing regimens based on patient traits, dosing schedules, and delay duration. Addressing delayed or missed doses relies on the delay time and specific DOACs involved. Additionally, age, body weight, renal function, and polypharmacy may marginally affect remedial strategies. The proposed remedial dosing strategies surpass current recommendations, with less deviation time beyond the therapeutic range. The online dashboard offers quick and convenient solutions for addressing missed or delayed DOACs, enabling individualized remedial dosing strategies based on patient characteristics to mitigate the risks of bleeding and thrombosis.

Synthetic Approaches toward Dabigatran Etexilate, an Oral Anticoagulant Drug

Synthetic Approaches toward Dabigatran Etexilate, an Oral Anticoagulant Drug

Cost-Effectiveness of Rivaroxaban Compared with Other Direct Oral Anticoagulants for Stroke Prevention in Atrial Fibrillation in Public Sector of Malaysia

Despite the amount of research performed, the cost-effectiveness of direct oral anticoagulants (DOACs) in subpopulations with different risk factors for stroke has been very little studied. This study aims to explore the cost-effectiveness of the DOACs available in Malaysia in preventing stroke in different subpopulations from a government perspective. An existing Markov model was adapted to assess the cost-effectiveness of the DOACs that are available in Malaysia namely, apixaban (AP), dabigatran (DA) and rivaroxaban (RV). Each was compared with vitamin K antagonists (VKA) in stroke prevention in different patient subpopulations including chronic kidney disease (CKD), high-age, diabetes (DM), and prolonged hospital stay. Cost-effectiveness was assessed by the incremental cost-effectiveness ratio (ICER) benchmarked against the local threshold for cost-effectiveness. The total cost of VKA, AP, DA and RV was Malaysian Ringit (RM) RM9,811 (1USD=RM4.76), RM16,858, RM18,318 and RM20,161 respectively. The quality adjusted life-years (QALYs) gained compared with VKA were 6.11, 6.09 and 6.15 respectively. The ICER when compared with VKA at base case was 57,539, -90,682 and 68,156 respectively. AP had the most favourable ICER at base case. RV had the best ICER compared to AP and DA in patients with CKD and DM at a willingness-to-pay threshold of 1-GDP. Probabilistic sensitivity analysis showed that RV was consistently the most favourable DOAC under a threshold of 2-GDP for all subpopulations. These findings suggested that rivaroxaban has the most favourable ICER in the CKD and DM patient subgroups for stroke prevention among the DOACs available in Malaysia at a threshold of 2-GDP.

Pharmacokinetics and bioequivalence of the generic and original dabigatran etexilate after a single dose in healthy volunteers

Aim. To study the comparative pharmacokinetics and confirmation of bioequivalence of the generic (T) and original (R) dabigatran etexilate in healthy volunteers after a single oral dose under fasted conditions.Material and methods. To confirm bioequivalence, an open-label, randomized, replication, crossover, four-step study was conducted to compare the pharmacokinetics and bioequivalence of generic and original dabigatran with a single oral dose 150 mg dabigatran etexilate under fasted conditions in adult healthy male and female volunteers. Sixty-eight subjects participated in the study. During the study, blood plasma samples were taken from volunteers, in which the concentration of total and free dabigatran was determined. Based on the data obtained, pharmacokinetic and statistical analysis was carried out and 90% confidence intervals were calculated for the ratio of mean pharmacokinetic parameters (Сmax, Tmax, AUC0-t, AUC0-∞, AUCt-∞, T1/2, AUCt-∞/AUC0-∞) for total and free dabigatran.Results. The established 90% confidence intervals for the ratio of AUC0-t, AUC0-∞ and Cmax values for total dabigatran were 82,56-96,36% (mean ratio, 89,19%), 82,39-95,90% (mean ratio, 88,89%) and 85,98-99,17% (mean ratio, 92,34%), respectively. The established 90% confidence intervals for the ratio of AUC0-t, AUC0-∞ and Сmax values for free dabigatran were 83,37-98,29% (mean ratio, 90,53%), 82,98-97,33% (mean ratio, 89,87%) and 85,04-99,28% (mean ratio, 91,88%), respectively. For the estimated pharmacokinetic parameters of dabigatran etexilate, 90% confidence intervals ranged from 80-125% for AUC0-t, AUC0-∞ and Cmax. Additional safety analysis was carried out. Generic and original dabigatran were well tolerated by the volunteers. There were no significant differences in vital signs, paraclinical characteristics throughout the study compared with the initial data, as well as significant differences between the drugs in all studied parameters of adverse events.Conclusion. The study showed that generic and original dabigatran are bio­equivalent. In addition, the data obtained indicate that the agents have similar safety profiles.

A new method of development and validation of Methanesulfonic acid ester (Methyl, Ethyl) impurity content in dabigatran etexilate mesylate by GC MS

We attempted to establish a method for estimating methane sulfonic acid methyl or ethyl ester in the dabigatran etexilate Mesylate in bulk and pharmaceutical dosage form. Dabigatran is an anticoagulant used in deep vein thrombosis and lung thrombosis. Methane sulfonic acid and ethyl sulfonic acid are DNA ethylating agents and genotoxic. These compounds can be estimated using the GC MS method using Helium as a carrier gas, and the compounds are estimated to be at 79 and 400 masses. The 60% methanol is used as diluent and blank. The method is validated as per the procedures of ICH, and all the validation parameters are within the acceptable limit of the impurities guidelines, as stated in the Q4 section. The different batches were analyzed using the same technique, and no impurities were found; hence, the batches were passed.

Study of Use of Dabigatran in Cerebral Venous Sinus Thrombosis.

Cerebral venous sinus thrombosis (CVST) is a challenging condition to diagnose and treat due to its diverse range of clinical presentations. The incidence of CVST is increasing, and although diagnostic techniques have improved, the mainstay of treatment is heparin followed by vitamin K antagonist (VKA), warfarinhas remained largely unchanged for the past three decades. However, new direct oral anticoagulants (NOACs) like dabigatran have been developed to address the limitations of VKA therapy. Magnetic resonance imaging (MRI) with magnetic resonance venography (MRV) is the current preferred diagnostic method for CVST due to its exceptional sensitivity and specificity. This prospective observational study was set out to investigate the efficacy and safety of dabigatran in treating cerebral venous sinus thrombosis. The study included 30 patients who reported regular intake of 150 mg dabigatran etexilate twice a day. Among the participants, headache was the most commonly reported symptom. The study found that patients treated with dabigatran experienced favorable outcomes, with all patients achieving re-canalization and reporting no major complications. These promising results suggest that dabigatran could be an effective treatment option for CVST cases. However, the study emphasizes the need for larger, multi-center studies to further validate these findings and improve the overall understanding of the condition and its treatment options.

Dual benefits of NBD-Cl fluorogenic action and sample pretreatment (SALLE) technology in the assessment of anticoagulant medication: Dabigatran in pharmaceutical capsules and plasma samples.

Dabigatran (DBG), marketed as Pradaxa, is an anticoagulant medication prescribed for the treatment and mitigation of blood clots and to lower the risk of stroke in individuals with the heart condition known as atrial fibrillation. This medication is specifically indicated for preventing blood clots post hip or knee replacement surgeries and in patients with a prior history of clots. Compared to warfarin, dabigatran serves as a viable alternative that does not necessitate routine blood monitoring tests. The complimentary benefits associated with SALL (salting-out assisted liquid-liquid extraction) and the fluorogenic capabilities of benzofurazan. These methods were combined to provide an affordable and sensitive DBG assaying method. The spectral strength of the yellow luminous product was examined at 533.8nm and by adjustment of a wavelength of 474.7nm for excitation. To assess its linearity, the calibration chart was tested across a DBG concentration range of 30-500 ng/ml. Via accurate computation based on ICH, the detection limit (LD) was determined to be 9.5ng/ml, and the strategy can quantify the DBG to a limit of 28 ng/ml. To ensure success, various crucial parameters for method implementation have been extensively studied and adapted. The validation of the strategy adhered to the policies outlined by ICH, affirming its precision in quantifying DBG in capsules. Furthermore, the inclusion of SALLE steps facilitated accurate monitoring of DBG in plasma samples, introducing a unique and advanced methodology for analyzing this compound in biological samples.

Formulation, Optimization and Evaluation of Dabigartan Etexilate Encapsulated Solid Supersaturated Self-Nanoemulsifying Drug Delivery System

Objective: The present study proposed Dabigatran Etexilate loaded solid supersaturat-ed self-nanoemulsifying drug delivery system (solid S-SNEDDS) for enhancement of payload, drug solubility, dissolution rate as well as minimization of drug precipitation. Methods: The study involved formulation optimization using the Box-Behnken design. The op-timal SNEDDS consisting of Caprylic acid (32.9% w/w), Cremophor EL (50.2% w/w) and Transcutol HP (18.8% w/w) as Oil, Surfactant and Co-surfactant, respectively were formulated and evaluated for particle size, PDI, Zeta potential and saturation solubility. The SNEDDS was further incorporated with PPIs for the preparation of supersaturated SNEDDS (S-SNEDDS) to in-crease the drug payload in the formulation. S-SNEDDS was converted to solid S-SNEDDS by ad-sorption onto the porous carrier i.e., Aerosil®200. The in-vitro drug release study was also con-ducted for solid S-SNEDDS. Results: SNEDDS had size, PDI, and Zeta potential of 82 nm, 0.347, -10.50 mV, respectively. SNEDDS enhanced the saturation solubility of the drug by 93.65-fold. Among PPIs, HPMC K4M showed the most effective response for the formulation of S-SNEDDS. The S-SNEDDS had a more substantial drug payload, which further increased the solubility by 150 times of pure drugs and 16 times of SNEDDS. Solid S-SNEDDS exhibited free-flowing properties. Reconstituted sol-id S-SNEDDS had acceptable size, PDI, and Zeta potential of 131.3 nm, 0.457, and -11.3 mV, respectively. In-vitro drug release study revealed higher drug dissolution and minimized drug pre-cipitation by SNEDDS compared to marketed products and pure drugs. Conclusion: Proposed nano-formulation was found to efficiently improve the aqueous solubility of the drug and avoid the drug precipitation, thereby avoiding drug loss and improving drug bioa-vailability.

Pleiotropic Effects of Direct Oral Anticoagulants in Chronic Heart Failure and Atrial Fibrillation: Machine Learning Analysis.

Oral anticoagulant therapy (OAT) for managing atrial fibrillation (AF) encompasses vitamin K antagonists (VKAs, such as warfarin), which was the mainstay of anticoagulation therapy before 2010, and direct-acting oral anticoagulants (DOACs, namely dabigatran etexilate, rivaroxaban, apixaban, edoxaban), approved for the prevention of AF stroke over the last thirteen years. Due to the lower risk of major bleeding associated with DOACs, anticoagulant switching is a common practice in AF patients. Nevertheless, there are issues related to OAT switching that still need to be fully understood, especially for patients in whom AF and heart failure (HF) coexist. Herein, the effective impact of the therapeutic switching from warfarin to DOACs in HF patients with AF, in terms of cardiac remodeling, clinical status, endothelial function and inflammatory biomarkers, was assessed by a machine learning (ML) analysis of a clinical database, which ultimately shed light on the real positive and pleiotropic effects mediated by DOACs in addition to their anticoagulant activity.

Role of CES1 and ABCB1 Genetic Polymorphisms on Functional Response to Dabigatran in Patients with Atrial Fibrillation.

Background: Dabigatran etexilate is a pro-drug hydrolyzed into dabigatran by carboxylesterases (CES) and is a substrate of the P-Glycoprotein encoded by the adenosine-triphosphate-binding cassette sub-family B member (ABCB)1 genes. We evaluated the functional response to dabigatran according to different CES1 and ABCB1 single-nucleotide polymorphisms (SNPs) in patients with atrial fibrillation (AF). Methods: A total of 100 consecutive patients with AF taking dabigatran were enrolled by two Italian centers. A venous blood sample was drawn for genetic determinations, as well as a measurement of the diluted thrombin time (dTT) and drug plasma concentrations, at the trough and peak. The main objective was the relationship between the dTT values and CES1 rs2244613, CES1 rs8192935 and ABCB1 rs4148738 SNP while on two different dabigatran doses (110 and 150 mg BID). Results: A total of 43 patients were on a 110 mg dabigatran dose and 57 on 150 mg. The DTT values at the trough and at peak were not different among patients with different CES1 rs2244613 and CES1 rs8192935 genotypes, regardless of the dabigatran dose. In patients on 150 mg dabigatran, the dTT values at the trough were 77 (44-111) ng/mL in patients with the ABCB1 rs4148738 heterozygous CT genotype vs. 127 (85-147) ng/mL in the wild-type CC genotype vs. 110 (47-159) ng/mL in the mutant trait TT genotype (p = 0.048). In patients with the ABCB1 rs4148738 CT genotype, OR for having dTT values at a trough below the median was 3.21, 95% CI 1.04-9.88 (p = 0.042). Conclusions: ABCB1 rs4148738 CT heterozygous is associated with the reduced anticoagulant activity of dabigatran at the trough in patients receiving the higher dose regimen.

Association of Oral Anticoagulant Therapy with the Prevalence and Severity of Vascular Calcification among Patients with Atrial Fibrillation: A Cohort Study.

Many patients with atrial fibrillation (AF) requiring long-term use of oral anticoagulants (OACs) are at high risk for vascular calcification and anticoagulation therapy with warfarin exacerbate vascular calcification. However, the effect of nonvitamin K agonists on vascular calcification has not been clearly investigated. This study explored the effects of dabigatran etexilate, rivaroxaban, and warfarin on vascular calcification among 1527 patients with AF. Demographics, comorbidities, laboratory test data, medications, and the prevalence and severity of vascular calcification in different vascular beds were compared. After propensity score matching, the incidence of vascular calcification in the rivaroxaban and warfarin group was significantly higher than that in the nonanticoagulant group, while there was no difference between the dabigatran etexilate group and the nonanticoagulant group. Similarly, we found that the rivaroxaban group had more severe calcification in the overall vascular level (P < 0.001), thoracic aorta (P < 0.001), aortic arch (P = 0.001), and left common carotid artery (P = 0.005) than the nonanticoagulant group. In addition, in the left common carotid artery, there was more severe calcification in the rivaroxaban group than that in the dabigatran group (P = 0.005). Our results suggest that rivaroxaban can significantly increase both the incidence and severity of vascular calcification among patients with AF, while dabigatran etexilate has no such effect. Many patients with AF requiring long-term use of OACs are at high risk for vascular calcification. This is the first study to conduct a head-to-head comparison of the effects of dabigatran etexilate and rivaroxaban on vascular calcification. Rivaroxaban, rather than dabigatran etexilate, promotes vascular calcification in patients with AF, providing important implications to aid clinicians in their choice for OAC selection, especially those at high risk for vascular calcification.

Lymphatic Uptake of a Highly Lipophilic Protease Inhibitor Prodrug from a Lipid-Based Formulation is Limited by Instability in the Intestine

Dabigatran etexilate (DABE) is a lipophilic double alkyl ester prodrug of dabigatran (DAB) which is a serine protease inhibitor used clinically as an anticoagulant. Recently, translocation of serine protease enzymes, including trypsin, from the gut into the mesenteric lymph and then blood has been associated with organ failure in acute and critical illnesses (ACIs). Delivery of DABE into mesenteric lymph may thus be an effective strategy to prevent organ failure in ACIs. Most drugs access the mesenteric lymph in low quantities following oral administration, as they are rapidly transported away from the intestine via the blood. Here, we examine the potential to deliver DABE into the mesenteric lymph by promoting association with lymph lipid transport pathways via co-administration with a lipid-based formulation (LBF). A series of self-emulsifying LBFs were designed and tested in vitro for their potential to form stable DABE loaded emulsions and keep DABE solubilised and stable over time in simulated gastrointestinal conditions. The LBFs were found to form fine emulsions with a droplet size of 214 ± 30 nm and DABE was stable in the formulation. The stability of DABE in vitro in simulated intestinal conditions, plasma and lymph samples was also evaluated to ensure stability in collected samples and to evaluate whether the prodrug is likely to release active DAB. Ultimately, a highly uniform and stable self-emulsifying Type III A LBF of DABE was chosen for progression into in vivo studies in male Sprague Dawley rats to confirm the lymphatic uptake and plasma pharmacokinetics. Both in vitro and in vivo in plasma and lymph, DABE was rapidly converted to an intermediate and DAB. The main species present in vivo in both plasma and lymph was DAB and mass transport of DABE and DAB in lymph was minimal (∼0.5 % of dose). Importantly, the concentration of DABE in lymph was substantially (20–176 fold) higher than in plasma, supporting that if the prodrug were stable and did not convert to DAB in the intestine, it would be lymphatically transported. Future studies will therefore focus on optimizing the design of the prodrug and formulation to improve stability during absorption and further promote lymphatic uptake.

Unified Methodology for the Primary Preclinical In Vivo Screening of New Anticoagulant Pharmaceutical Agents from Hematophagous Organisms.

The development of novel anticoagulants requires a comprehensive investigational approach that is capable of characterizing different aspects of antithrombotic activity. The necessary experiments include both in vitro assays and studies on animal models. The required in vivo approaches include the assessment of pharmacokinetic and pharmacodynamic profiles and studies of hemorrhagic and antithrombotic effects. Comparison of anticoagulants with different mechanisms of action and administration types requires unification of the experiment scheme and its adaptation to existing laboratory conditions. The rodent thrombosis models in combination with the assessment of hemostasis parameters and hematological analysis are the classic methods for conducting preclinical studies. We report an approach for the comparative study of the activity of different anticoagulants in vivo, including the investigation of pharmacodynamics and the assessment of hemorrhagic effects (tail-cut bleeding model) and pathological thrombus formation (inferior vena cava stenosis model of venous thrombosis). The reproducibility and uniformity of our set of experiments were illustrated on unfractionated heparin and dabigatran etexilate (the most common pharmaceuticals in antithrombic therapy) as comparator drugs and an experimental drug variegin from the tick Amblyomma variegatum. Variegin is notorious since it is a potential analogue of bivalirudin (Angiomax, Novartis AG, Basel, Switzerland), which is now being actively introduced into antithrombotic therapy.

In Vitro Simulation of the Fasted Gastric Conditions and Their Variability to Elucidate Contrasting Properties of the Marketed Dabigatran Etexilate Pellet-Filled Capsules and Loose Pellets.

Variability of the gastrointestinal tract is rarely reflected in in vitro test protocols but often turns out to be crucial for the oral dosage form performance. In this study, we present a generation method of dissolution profiles accounting for the variability of fasted gastric conditions. The workflow featured 20 biopredictive tests within the physiological variability. The experimental array was constructed with the use of the design of experiments, based on three parameters: gastric pH and timings of the intragastric stress event and gastric emptying. Then, the resulting dissolution profiles served as a training data set for the dissolution process modeling with the machine learning algorithms. This allowed us to generate individual dissolution profiles under a customizable gastric pH and motility patterns. For the first time ever, we used the method to successfully elucidate dissolution properties of two dosage forms: pellet-filled capsules and bare pellets of the marketed dabigatran etexilate product Pradaxa. We showed that the dissolution of capsules was triggered by mechanical stresses and thus was characterized by higher variability and a longer dissolution onset than observed for pellets. Hence, we proved the applicability of the method for the in vitro and in silico characterization of immediate-release dosage forms and, potentially, for the improvement of in vitro-in vivo extrapolation.

The Effect of ABCB1 and CES1 Polymorphisms on Plasma Levels of Dabigatran and Risk of Hemorrhagic Complications in Ischemic Stroke Patients.

Dabigatran directly inhibits thrombin and is used in primary and secondary stroke prevention in individuals with nonvalvular atrial fibrillation. The prodrug dabigatran etexilate is absorbed by enteral P-glycoprotein (ABCB1) and then activated by hepatic and intestinal carboxylesterases (CES1) to produce active metabolites. Variations in dabigatran metabolism because of genetics may affect concentration levels and clinical outcomes. We conducted a study to assess how polymorphisms in the CES1 (rs2244613) and ABCB1 (rs4148738) genes affect the through plasma level (c min ) of dabigatran and its correlation to clinical outcomes. Retrospective multicentric study of consecutive patients on dabigatran therapy. Examination of CES1 rs2244613 and ABCB1 rs4148738 polymorphisms, c min 12 hours after administration, clinical follow-up (ischemic stroke, major or clinically relevant hemorrhage, myocardial infarction, other thromboembolism, and death). A total of 432 patients received treatment for an average of 19.78 months (SD of 20.165). The sex distribution of the patients was 56.5% male, and the average age was 67.56 years (SD of 14.7). The ABCB1 variant genotype was present in 67.8% of patients, whereas 37.5% carried the CES1 polymorphism. Compared with wild-type patients, patients with the CES1 variant had significantly lower dabigatran plasma levels (with a mean difference of 16.986; 95% confidence interval, 5.794-28.178 ng/mL, P = 0.003). We also found a significant risk of major bleeding in patients carrying the ABCB1 rs4148738 allele (hazard ratio = 1.99, confidence interval 95% 1.10 to 3.59, P = 0.024). The CES1 variant genotype rs2244613 is closely linked with reduced c min of dabigatran. Carriers of the ABCB1 rs4148738 polymorphism exhibit a tendency toward higher plasma levels of dabigatran, which leads to a significantly increased risk of bleeding.

Assessing the relative contribution of CYP3A-and P-gp-mediated pathways to the overall disposition and drug-drug interaction of dabigatran etexilate using a comprehensive mechanistic physiological-based pharmacokinetic model.

Dabigatran etexilate (DABE) is a clinical probe substrate for studying drug-drug interaction (DDI) through an intestinal P-glycoprotein (P-gp). A recent in vitro study, however, has suggested a potentially significant involvement of CYP3A-mediated oxidative metabolism of DABE and its intermediate monoester BIBR0951 in DDI following microdose administration of DABE. In this study, the relative significance of CYP3A- and P-gp-mediated pathways to the overall disposition of DABE has been explored using mechanistic physiologically based pharmacokinetic (PBPK) modeling approach. The developed PBPK model linked DABE with its 2 intermediate (BIBR0951 and BIBR1087) and active (dabigatran, DAB) metabolites, and with all relevant drug-specific properties known to date included. The model was successfully qualified against several datasets of DABE single/multiple dose pharmacokinetics and DDIs with CYP3A/P-gp inhibitors. Simulations using the qualified model supported that the intestinal CYP3A-mediated oxidation of BIBR0951, and not the gut P-gp-mediated efflux of DABE, was a key contributing factor to an observed difference in the DDI magnitude following the micro-versus therapeutic doses of DABE with clarithromycin. Both the saturable CYP3A-mediated metabolism of BIBR0951 and the solubility-limited DABE absorption contributed to the relatively modest nonlinearity in DAB exposure observed with increasing doses of DABE. Furthermore, the results suggested a limited role of the gut P-gp, but an appreciable, albeit small, contribution of gut CYP3A in mediating the DDIs following the therapeutic dose of DABE with dual CYP3A/P-gp inhibitors. Thus, a possibility exists for a varying extent of CYP3A involvement when using DABE as a clinical probe in the DDI assessment, across DABE dose levels.