Pharmacokinetics and Safety of Dabigatran Etexilate after Single and Multiple Oral Doses in Healthy Chinese Subjects

Gastric stress events impact the bioavailability of a poorly soluble weak base dabigatran from pellet-filled capsules: An outcome from pharmacokinetic simulations based on biorelevant dissolution testing, machine learning, and a novel timewise first-order dissolution model

Current physiologically-based biopharmaceutics modeling (PBBM) neglects the effect of gastrointestinal stress events on the disintegration and dissolution of oral solid dosage forms. Biorelevant dissolution testing can simulate the behavior of drug products under physiological agitation but a workload limits variability examination. In this study, we overcame these deficiencies by inputting dissolution profiles generated by machine-learning (ML) into PBBM-based simulations. Our specific aim was to examine how the varied timing of intragastric stress and housekeeping wave (GET) and fasted stomach pH affect dabigatran exposure from the Pradaxa capsule. Twenty experimental dissolution profiles of dabigatran etexilate from the flow-through apparatus PhysioCell and 1,036 ML-derived profiles representing various gastric motility patterns were a basis for single-dose simulations. A novel timewise dissolution model, which estimates the first-order rate constants at consecutive two-point time intervals, provided an excellent fit to the highly irregular and variable dissolution curves (coefficient of determination ≥ 0.9835, median 0.9992). The time between the onset of dissolution (Tlag), either intragastric stress-related or spontaneous, and the housekeeping wave (GET) systematically impacted the bioavailability of dabigatran. Regardless of gastric emptying rate constant and pH, the dabigatran bioavailability was an increasing sigmoid function of the GET - Tlag difference, with the midpoint around 7 min and plateau of 7-8% after 20 min. The plasma concentrations and bioavailability of dabigatran simulated under varied gastric motility well matched clinical data reported for healthy subjects. We expect that the proposed approach will improve the prediction of the in vivo variability of oral formulations.

Extraction methods and compositions of polyphenols in Shanxi aged vinegar

The extraction, purification, qualification, and quantification of polyphenols (PPs) in vinegar are challenging owing to the complex matrix of vinegar and the specific physicochemical and structural properties of PPs. This study aimed to develop a simple, efficient, low-cost method for enriching and purifying vinegar PPs. The enrichment and purification effects of five solid phase extraction (SPE) columns and five macroporous adsorption resins (MARs) for PPs were compared. The results show that SPE columns were more effective in purifying vinegar PPs than MARs. Among them, the Strata-XA column showed a higher recovery (78.469 ± 0.949%), yield (80.808 ± 2.146%), and purity (86.629 ± 0.978%) than other columns. In total, 48 PPs were identified and quantified using SPE and gas chromatography-mass spectrometry from the SPE column extracts; phenolic acids, such as 4-hydroxyphenyllactic acid, vanillic acid, 4-hydroxycinnamic acid, 4-hydroxybenzoic acid, protocatechuic acid, and 3-(4-Hydroxy-3-methoxyphenyl) propionic acid, occupy a major position in SAV. Furthermore, considering the potential applications of PPs, the concentrates were characterized based on their bioactive properties. They exhibited high total PP, flavonoid, and melanoidin contents and excellent anti-glycosylation and antioxidant activities. These results indicate that the established methodology is a high-efficiency, rapid-extraction, and environment-friendly method for separating and purifying PPs, with broad application prospects in the food, chemical, and cosmetic industries.

Development and validation of LC-MS/MS method for simultaneous determination of dabigatran etexilate and its active metabolites in human plasma, and its application in a pharmacokinetic study

Dabigatran is a direct thrombin inhibitor widely used for preventing various thrombotic events. Although there are several established LC-MS/MS based methods for quantification of plasma dabigatran etexilate and its active metabolites (dabigatran and dabigatran acylglucuronide), so far, there are no studies for simultaneous quantification of dabigatran etexilate, dabigatran, and dabigatran acylglucuronide in human plasma samples. In the present study, a novel and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for assessment of dabigatran pharmacokinetics in human plasma samples according to FDA guidelines. We used the new method to simultaneously quantify dabigatran etexilate, dabigatran, and dabigatran acylglucuronide in human plasma samples. After deproteinization using acetonitrile, the supernatants were evaporated, dissolved in a mobile phase, and finally injected onto an HPLC system with a silica-based C₁₈ reverse-phase column. Mass spectrometer system was operated in multiple reaction monitoring mode (MRM) (dabigatran etexilate: m/z 629.464→290.100; dabigatran: m/z 472.300→289.100, and dabigatran acylglucuronide: m/z 648.382→289.100) and all the components were confirmed using positive electrospray ionization (ESI). Correlation coefficients > 0.999 were achieved for all the calibration curves with linear regression. The intra-day and inter-day accuracies of dabigatran etexilate, dabigatran, and dabigatran acylglucuronide were 95.84-109.44 %, 99.4-103.42 %, and 98.37-104.42 %, respectively, while their corresponding precisions were 3.84-9.79, 1.07-8.76 %, and 2.56-4.51 %, respectively. We successfully applied the new method to determine the pharmacokinetic profiles of dabigatran etexilate, dabigatran, and dabigatran acylglucuronide in humans. Our findings demonstrated the method as robust, reliable, and sensitive.

Safety of Dabigatran as an Anticoagulant: A Systematic Review and Meta-Analysis

Background: Dabigatran is a univalent low-molecular-weight direct thrombin inhibitor which was developed as an alternative to vitamin K antagonists (VKAs). However, the safety of dabigatran remains controversial so far. In this study, we aimed to compare the risk of bleeding, fatal adverse events, and the all-cause mortality of dabigatran with those of the control group by a systematic review and meta-analysis of randomized controlled trials. Methods: We systematically searched PubMed, Web of Science, Cochrane Library, Medline, Embase, Wanfang database, Clinical trial, China National Knowledge Infrastructure Chinese Scientific Journal database (VIP), and Chinese Biological Medicine database (CBM), for clinical trials on conventional treatments compared with dabigatran, published between January 2014 and July 2020. The reported outcomes, including the endpoints of primary safety, were systematically investigated. Results: Seven RCTs (n = 10,743) were included in the present systematic review. Compared to the control groups, dabigatran was not associated with an increased risk of major bleeding (relative risk [RR] 0.86, 95% confidence interval [CI]: 0.61 to 1.21, p = 0.06), intracranial hemorrhage (RR 0.89, 95% CI: 0.58 to 1.36, p = 0.41), fatal adverse reactions (RR 0.87, 95% CI: 0.65 to 1.17, p = 0.66), all-cause mortality (RR 0.88, 95% CI: 0.70 to 1.11, p = 0.45, I2 = 0%), and significantly reduced risk of clinically relevant non-major bleeding (RR 0.96, 95% CI: 0.65 to 1.42, p = 0.0007). However, dabigatran is associated with an increased risk of gastrointestinal (GI) bleeding (RR 1.78, 95% CI: 1.02 to 3.13, p = 0.05). Conclusion: Dabigatran has a favorable safety profile in terms of major bleeding, intracranial hemorrhage, and life-threatening events, among other safety outcomes. The present study suggested that dabigatran may be a suitable alternative to VKAs as an oral anticoagulant. However, more data are necessary to clarify the incidence of other adverse events and serious adverse reactions.