Interlaboratory validation of apixaban levels in ex vivo patient samples using a chromogenic anti‐factor Xa assay

Abstract SANORG 34006 is a new sulfated pentasaccharide obtained by chemical synthesis. It is an analog of the “synthetic pentasaccharide” (SR 90107/ ORG 31540) which represents the antithrombin (AT) binding site of heparin. SANORG 34006 showed a higher affinity to human AT than SR 90107/ORG 31540 (kd = 1.4 ± 0.3 v 48 ± 11 nmol/L), and it is a potent and selective catalyst of the inhibitory effect of AT on factor Xa (1,240 ± 15 anti–factor Xa U/mg v850 ± 27 anti-factor Xa U/mg for SR 90107/ORG 31540). In vitro, SANORG 34006 inhibited thrombin generation occurring via both the extrinsic and intrinsic pathway. After intravenous (IV) or subcutaneous (SC) administration to rabbits, SANORG 34006 displayed a long-lasting anti–factor Xa activity and inhibition of thrombin generation (TG) ex vivo. SANORG 34006 was slowly eliminated after IV or SC administration to rats, rabbits, and baboons, showed exceptionally long half-lives (between 9.2 hours in rats and 61.9 hours in baboons), and revealed an SC bioavailability near 100%. SANORG 34006 displayed antithrombotic activity by virtue of its potentiation of the anti–factor Xa activity of AT. It strongly inhibited thrombus formation in experimental models of thromboplastin/stasis-induced venous thrombosis in rats (IV) and rabbits (SC) (ED50values = 40.0 ± 3.4 and 105.0 ± 9.4 nmol/kg, respectively). The duration of its antithrombotic effects closely paralleled the ex vivo anti–factor Xa activity. SANORG 34006 enhanced rt-PA–induced thrombolysis and inhibited accretion of125I-fibrinogen onto a preformed thrombus in the rabbit jugular vein suggesting that concomitant use of SANORG 34006 during rt-PA therapy might be helpful in facilitating thrombolysis and preventing fibrin accretion onto the thrombus under lysis. Contrary to standard heparin, SANORG 34006 did not enhance bleeding in a rabbit ear incision model at a dose that equals 10 times the antithrombotic ED50 in this species and, therefore, exhibited a favorable therapeutic index. We suggest that SANORG 34006 is a promising compound in the treatment and prevention of various thrombotic diseases.

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RPR120844, a Novel, Specific Inhibitor of Coagulation Factor Xa Inhibits Venous Thrombosis in the Rabbit

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614434 ◽

1999 ◽

Vol 81 (01) ◽

pp. 157-160 ◽

Cited By ~ 14

Author(s):

Ross Bentley ◽

Suzanne Morgan ◽

Karen Brown ◽

Valeria Chu ◽

Richard Ewing ◽

...

Keyword(s):

Jugular Vein ◽

Drug Effect ◽

Ex Vivo ◽

Thrombus Formation ◽

Specific Inhibitor ◽

Factor Xa ◽

Coagulation Factor ◽

Antithrombotic Activity ◽

Fxa Inhibitor

SummaryThe in vivo antithrombotic activity of RPR120844, a novel synthetic coagulation factor Xa (fXa) inhibitor (Ki = 7 nM), was assessed by its ability to inhibit thrombus formation in a damaged segment of the rabbit jugular vein. Intravenous dose-response studies were performed and thrombus mass (TM), activated partial thromboplastin time (APTT), prothrombin time (PT), inhibition of ex vivo fXa activity and plasma drug levels (PDL) were determined. TM, measured at the end of a 50 min infusion, was significantly reduced (p <0.05 vs saline-treated animals) by RPR120844 at 30 and 100 μg/kg/min. At doses of 10, 30 and 100 μg/kg/min, APTT was prolonged by 2.1, 4.2 and 6.1-fold, and PT was prolonged by 1.4, 2.2 and 3.5-fold, respectively. PDL were determined by measuring anti-fXa activity using an amidolytic assay. Peak PDL were 0.8 ± 0.3, 1.5 ± 0.9 and 2.4 ± 0.6 μM, respectively. The drug effect was reversible with APTT, PT and PDL returning toward pretreatment values 30 min after termination of treatment. The results suggest that RPR120844, or similar compounds, may provide an efficacious, yet easily reversible, means of inhibiting thrombus formation.

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ANTITHROMBOTIC ACTIONS OF A SULFOMUCOPOLYSACCHARIDE MIXTURE (ATERIOD) IN ANIMAL MODELS

10.1055/s-0038-1644160 ◽

1987 ◽

Author(s):

U Cornelli ◽

J M Welena ◽

J Fareed ◽

X Huan ◽

D Hoppensteadt

Keyword(s):

Time Course ◽

Ex Vivo ◽

Rabbit Model ◽

Factor Xa ◽

Heparin Cofactor Ii ◽

Platelet Factor ◽

Thrombosis Model ◽

Mucosal Lining ◽

Cellular Modifications

Ateriod obtained from beef mucosal lining is a sulfomuco-polysaccharide mixture of various glycosaminoglycans which contains derma tans, heparatans and traces of heparin. It has been used in the treatment ofatherosclerosis and related vaso-oclusive disorders. Ateriod is standardized in terms of its lipoprotein lipase activation actions. Ateriod contains signfi-cant in vitro anticoagulant and antiprotease (anti-factor Xa and anti-factor Ila) activities as measured by clot-based and chromr ogenic substrate methods. However, this in vitro activity is 7-10 times lesser than heparin. In order to study the antithrombotic actions of this agent in subcutaneous, intravenous and oral routes, we utilized a rabbit stasis thrombosis model with a prothrombin complex concentrate/Russell's viper venom thrombogenic challenge and prolonged stasis. The apparent ED50 for the antithrombotic action were found to be: IV (75-100 ug/ kg), SC (0.8-1.3 mg/kg) and oral (20-30 mg/kg). In both the IV- and SC studies, sustained anticoagulant and antiprotease actions were evident. The observed antithrombotic actions did not relate to the anti-factor IIa or anti-factor Xa actions. Pretreatment of Ateriod with equigravimetric amounts of protamine and platelet factor 4 did not neutralize the antithrombotic actions of this agent in the rabbit model. In a primate (Macaca mulatta) model of pharmacokinetics, ex vivo analysis following subcutaneously administered Ateriod showed sustained anticoagulant and antiprotease effects. The time course of the subcutaneously administered Ateriod was markedly different than heparin and a low molecular weight heparin. Treated animals were shown to resist induced hypercoagulability following injection of homologous serum as measured by FPA generation for extended periods. These studies suggest that Ateriod produces a strong antithrombotic action and that it has highly sustained pharmacokinetics. The antithrombotic activity appears to be primarily mediated via non-antithrombin - HI dependent events which may be related to heparin cofactor II and vascular/ cellular modifications.

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Catalytically inactive Gla-domainless factor Xa binds to TFPI and restores ex vivo coagulation in hemophilia plasma

Haematologica ◽

10.3324/haematol.2017.174037 ◽

2017 ◽

Vol 102 (12) ◽

pp. e483-e485 ◽

Cited By ~ 1

Author(s):

Atanur Ersayin ◽

Aline Thomas ◽

Landry Seyve ◽

Nicole Thielens ◽

Mathieu Castellan ◽

...

Keyword(s):

Ex Vivo ◽

Factor Xa

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Dual Inhibition of Blood Coagulation Factors Xa and Iia Synergize To Reduce Thrombus Weight and Thrombin Generation in a Rabbit Arteriovenous Shunt Model of Thrombosis.

Blood ◽

10.1182/blood.v106.11.1866.1866 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1866-1866

Author(s):

Thomas B. McClanahan ◽

Sangita M. Baxi ◽

Liguo Chi ◽

Tawny Dahring ◽

Weston R. Gould ◽

...

Keyword(s):

Blood Coagulation ◽

Single Molecule ◽

Thrombin Generation ◽

Ex Vivo ◽

Factor Xa ◽

Coagulation Cascade ◽

Vehicle Group ◽

Thrombin Inhibitor ◽

Antithrombotic Effect ◽

Dual Inhibitor

Abstract Several compounds currently in development for the treatment of thrombotic disorders demonstrate high levels of specificity for single targets of the blood coagulation cascade such as factor Xa and thrombin. However, development of a single molecule dual inhibitor against factor Xa and thrombin may expand the efficacy to safety ratio of treatment options for arterial and venous thrombosis. The objective of this study was to determine if simultaneous administration of PD 0313052, a selective Xa inhibitor and argatroban, a direct thrombin inhibitor, would lead to a synergistic antithrombotic effect in a rabbit AV shunt model of thrombosis. Intravenous administration of PD 0313052 alone at doses of 0.1, 0.3, and 1.0 mg/kg/min resulted in thrombus weight (TW) reductions of 11±3, 25±10 and 67±7 % compared to the vehicle group. Argatroban at 1, 3 and 10 mg/kg/min reduced TW 16±13, 47±10 and 75±6 %. When PD 0313052 was administered at 0.1 mg/kg/min in combination with argatroban at 1, 3 or 10 mg/kg/min TW was reduced 50±7, 60±7 and 82±9 %. Likewise, argatroban at 1 mg/kg/min combined with 0.1, 0.3 or 1mg/kg/min of PD 0313052 resulted in TW reductions of 56±9, 60±9 and 84±5 %, respectively. At the lowest combined doses of PD 0313052 and argatroban there was no change in bleeding time relative to the additive fold-increases from each drug alone. The EC50 of intravenously administered PD 0313052 and argatroban was 67±23 and 178±58 ng/ml, respectively. When the drugs were combined the EC50 was reduced to 12±6 ng/ml with the PD 0313052/argatroban combination and to 83±29 ng/ml with the argatroban/PD 0313052 combination. A synergistic effect was also observed in an ex vivo assay of thrombin generation (TG). Predicted additive inhibition of TG based on the individual effects of each compound was −9±7, 9±2 and 29±7 % compared to 10±5, 32±5 and 55±3 % with the 313052/argatroban combination. The predicted effects of the argatroban/PD 0313052 combination was −9±7, 1±7 and 16±9 % compared to the actual inhibition of 5±3, 14±5 and 31±7 %. These results demonstrate a significant synergistic antithrombotic effect by combining low doses of a factor Xa and a thrombin inhibitor and support the hypothesis that development of a single molecule inhibitor against different hemostatic targets may offer greater efficacy in the prevention and treatment of venous and arterial thrombosis.

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Animal Models of Thrombosis Help Predict the Human Therapeutic Concentration of PRT54021, a Potent Oral Factor Xa Inhibitor.

Blood ◽

10.1182/blood.v108.11.901.901 ◽

2006 ◽

Vol 108 (11) ◽

pp. 901-901 ◽

Cited By ~ 6

Author(s):

Keith Abe ◽

Gail Siu ◽

Susan Edwards ◽

Pei Hua Lin ◽

Bing Yan Zhu ◽

...

Keyword(s):

Animal Models ◽

Venous Thrombosis ◽

Thrombin Generation ◽

Ex Vivo ◽

Vena Cava ◽

Factor Xa ◽

Fold Change ◽

In Vivo Models ◽

Antithrombotic Activity ◽

Fxa Inhibitor

Abstract Factor Xa (fXa) inhibition has resulted in the emergence of a new class of antithrombotics. Pharmacodynamic monitoring of these agents has proven problematic. The present study was designed to determine the target concentration of an oral fXa inhibitor required for clinical trials using both thrombin generation assays and three in vivo models and determine whether clotting assays such as activated partial thromboplastin time (aPTT) and prothrombin time (PT) would be suitable for monitoring human dosing. PRT54021 (PRT021) is a potent inhibitor of human fXa (Ki=117pM). PRT021 and fondaparinux, an indirect fXa inhibitor, both significantly inhibited TAT and F1.2 generation in human whole blood. Compared to a therapeutic level of fondaparinux (200nM), PRT021 (200nM) was more potent in suppressing both markers. Multiple doses of PRT021 were evaluated in three animal models. The first model, which measured clot accretion on cotton threads placed in rabbit abdominal vena cava, compared inhibition of thrombus mass by PRT021 to that of supratherapeutic doses of enoxaparin (a LMW heparin). The second model compared the ability of PRT021 to maintain vessel patency under arterial flow conditions in FeCl3 induced thrombosis in rat carotid artery to that achieved by enoxaparin or clopidogrel (an antiplatelet agent). The third model investigated inhibition of 111In labeled platelet deposition on dacron grafts and expansion chambers placed in femoral arteriovenous shunts in baboons. PRT021 and enoxaparin were administered as IV infusions and clopidogrel was dosed orally for three days. Ex vivo PT and aPTT were measured in all models. The models encompass stringent criteria of arterial and venous thrombosis and PRT021 produced dose-responsive antithrombotic activity in each of the three models. The efficacy of PRT021 compared favorably to supratherapeutic levels of enoxaparin and clopidogrel. Unlike in the rodent models, efficacy in primates was attained at a much lower dose with minimal prolongation of PT. Species specificity was also demonstrated by in vitro extensions of PT and aPTT in rat, rabbit, baboon and human plasma. A 2X change of PT was attained at concentrations of 8.9, 1.6, 1 and 0.4μM respectively. The data indicate that doses of PRT021 that inhibit thrombin generation in human blood and that provide anticoagulation similar to baboon dosed at 0.49mg/kg may be sufficient to prevent venous thrombosis in humans. Comparative modeling of extents of change in PT to levels of antithrombotic efficacy also leads us to predict that human therapeutic activity for PRT021 may be attained without concurrent changes in ex vivo clotting parameters. The targeted concentration is currently being tested in Phase II trials for its ability to prevent venous thromboembolism in orthopedic surgery patients. Model of Thrombosis Agent, Dose Antithrombotic Activity aPTT fold change PT fold change Rabbit vena cava PRT021,3mg/kg 76% inhibition 2.22 2.34 Rabbit vena cava Enoxaparin, 1.6mg/kg 96% inhibition 2.06 2.01 Rat carotid PRT021,19.1mg/kg 90% patency 1.69 2.20 Rat carotid Enoxaparin, 7.6mg/kg 70% patency 3.49 1.19 Rat carotid Clopidogrel, 3mg/kg/day 80% patency 1.03 1.01 Baboon arteriovenous PRT021,0.49mg/kg 90% inhibition (venous), 32% inhibition (arterial) 1.29 1.17

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A Zymogen-like Factor Xa Improves Hemostasis in a Murine Bleeding Model

Blood ◽

10.1182/blood.v124.21.1476.1476 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1476-1476 ◽

Cited By ~ 3

Author(s):

Jasuja Reema ◽

Sunita Patel-Hett ◽

Rodney M. Camire ◽

Joachim Fruebis ◽

Debra Pittman

Keyword(s):

Blood Loss ◽

Whole Blood ◽

Thrombin Generation ◽

Ex Vivo ◽

Factor Xa ◽

Coagulation Cascade ◽

Effective Control ◽

Normal Male ◽

Severe Bleeding ◽

K Value

Abstract In many clinical indications, effective control of bleeding is needed. Factor Xa (FXa) is a vitamin K-dependent trypsin-like serine protease that interacts with non-enzymatic coagulation factor Va (FVa) on negatively charged membrane surfaces to generate thrombin during hemostasis. Based on its central role in the coagulation cascade at the intersection of both intrinsic and extrinsic pathways, direct administration of FXa is an attractive approach to restoring hemostasis in bleeding disorders by leading to direct thrombin generation and fibrin formation. However, the short plasma half-life of the activated FXa protease renders it inadequate as a therapeutic for acute bleeding. Here, we investigate FXaI16L,a recently described variant of coagulation FXa engineered to overcome these limitations. The FXaI16L variant has an isoleucine (I) to leucine (L) substitution at amino acid 16 (based on chymotrypsin numbering). FXaI16L exhibits zymogen-like properties with both reduced activity and sensitivity toward plasma inhibitors. In the presence of its cofactor, FVa, FXaI16L activity is restored. We assessed the hemostatic activity of FXaI16L in an acute tail bleeding model that results in severe bleeding in normal mice. Ex vivo pharmacodynamic parameters in plasma and whole blood were also measured. FXaI16L was administrated intravenously to normal male C57BL/6J mice at doses of 1, 10, 25, 50, 100, or 200 μg/kg. Control mice received vehicle only. Two minutes post administration, a 3 mm tail transection was made. Tails were immediately immersed in tubes containing pre-warmed phosphate buffered saline for blood collection over a ten minute period. Bleeding times were recorded and volume of blood loss was determined by measurement of the hemoglobin content in the collected blood. Following administration of FXaI16L, a dose dependent reduction in bleeding was observed. Mice dosed with FXaI16Lshowed a decrease in blood loss of 12% (1 μg/kg), 16.6% (10 μg/kg), 26.7% (25 μg/kg), 45.3% (50 μg/kg), 62.9% (100 μg/kg), and 69.6% (200 μg/kg) compared to vehicle-dosed mice. The estimated ED50 was 46 μg/kg. Following infusion of FXaI16L (25 μg/kg) or vehicle into normal male CD-1 mice, we measured the ex vivo activity in plasma using an activated partial thromboplastin time (aPTT) clotting assay and a thrombin generation assay (TGA). Plasma collected from FXaI16L-dosed animals at 2 minutes post-injection displayed a 67% reduction in aPTT compared to vehicle-dosed mice. Dosing of FXaI16L at 25 μg/kg also enhanced thrombin generation, as reflected by a shortened lag phase, increased peak thrombin, increased endogenous thrombin potential and higher velocity index compared to vehicle treated mice. We also measured thromboelastography (TEG) parameters of whole blood collected from mice infused with FXaI16L. At a 10 μg/kg intravenous dose of FXaI16L, the TEG R-value and K-value measures of clotting time decreased, while TEG alpha angle and maximum amplitude increased compared to vehicle treated mice. We conclude that administration of FXaI16L in normal mice enhances hemostasis, decreasing bleeding in an injury model. Together, these studies suggest that FXaI16L may provide a new and unique way to achieve hemostasis in clinical situations of uncontrolled bleeding. Disclosures Reema: Pfizer: Employment. Patel-Hett:Pfizer: Employment. Camire:Pfizer: Consultancy, Patents & Royalties, Research Funding. Fruebis:Pfizer: Employment. Pittman:Pfizer: Employment.

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Preparation, Characterization and Ex vivo Permeability Study of Transdermal Apixaban O/W Nanoemulsion Based Gel

Iraqi Journal of Pharmaceutical Sciences ( P-ISSN 1683 - 3597 E-ISSN 2521 - 3512) ◽

10.31351/vol29iss2pp214-222 ◽

2020 ◽

Vol 29 (2) ◽

pp. 214-222

Author(s):

Mustafa R. Abdulbaqi ◽

Nawal A.Rajab

Keyword(s):

Water Solubility ◽

Ex Vivo ◽

Factor Xa ◽

Coagulation Factor ◽

Good Method ◽

Gelling Agent ◽

Permeation Enhancer ◽

Permeability Study ◽

Anticoagulant Drug ◽

Triton X

This study designed to prepare ultrafine apixaban (APX) o/w nanoemulsion (NE) based gel with droplet size below 50 nm as a good method for transdermal APX delivery without using permeation enhancer, alternatively, the formulation components itself act as permeation enhancer. APX, a potent oral anticoagulant drug that selectively and directly inhibit coagulation factor Xa, was selected as a good candidate for transdermal delivery as it displays poor water solubility (0.028 mg/mL) and low bioavailability (50%). APX-NE gel was prepared using triacetin, triton-x-100 and carbitol as oil phase, surfactant and cosurfactant respectively, while Carbopol 940 used as a gelling agent. Ex vivo permeation of APX-NE gel through human stratum corneum reveal

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Αξιολόγηση των σφαιρικών δοκιμασιών της αιμόστασης στην ex vivo μελέτη της αντιπηκτικής και αντιαιμοπεταλιακής δράσης των νεότερων από του στόματος αντιπηκτικών και της ασενοκουμαρόλης σε ασθενείς με μη βαλβιδική κολπική μαρμαρυγή

10.12681/eadd/47717 ◽

2020 ◽

Author(s):

Κωνσταντίνος Κατωγιάννης

Keyword(s):

Light Transmission ◽

Ex Vivo ◽

Factor Xa ◽

Thrombin Inhibitors ◽

Light Transmission Aggregometry

Σκοπός: Τα δεδομένα που υπάρχουν στην κλινική πράξη για τη δράση των άμεσων από του στόματος αντιπηκτικών (DOACs) είναι περιορισμένα. Στόχος μας ήταν να εκτιμήσουμε την ισχύ της αντιπηκτικής δράσης των DOACs σε ασθενείς με μη βαλβιδικής αιτιολογίας κολπική μαρμαρυγή (NVAF). Μέθοδοι: Μελετήσαμε 80 ασθενείς με NVAF και 20 υγιείς μάρτυρες με παρόμοια χαρακτηριστικά ως προς το φύλο και την ηλικία (20 λάμβαναν dabigatran 110 mg δύο φορές την ημέρα, 20 λάμβαναν rivaroxaban 20 mg μια φορά την ημέρα, 20 λάμβαναν apixaban 5 mg δύο φορές την ημέρα, 20 λάμβαναν ασενοκουμαρόλη). Σε όλους τους 80 ασθενείς και στα 20 άτομα της ομάδας ελέγχου, πραγματοποιήθηκαν οι συμβατικές δοκιμασίες πήξης (PT/INR, APTT, FIB), οι σφαιρικές δοκιμασίες αιμόστασης (θρομβοελαστομετρία, ROTEM και δοκιμασία παραγωγής θρομβίνης, ETP) και επιπλέον η πρότυπη μέθοδος εκτίμησης της ενεργοποίησης των αιμοπεταλίων, η οπτική θολοσιμετρική συσσώρευση (Light Transmission Aggregometry, LTA) με διεγέρτη την επινεφρίνη. Τέλος, με την ειδική δοκιμασία Hemoclot Thrombin Inhibitors (HTI) μετρήθηκαν τα επίπεδα στο πλάσμα του dabigatran και με την ειδική δοκιμασία Factor Xa Direct Inhibitor (DiXaI) μετρήθηκαν τα επίπεδα στο πλάσμα των rivaroxaban και apixaban. Αποτελέσματα: Σε ασθενείς υπό dabigatran 110 mg παρατηρήθηκε οριακά σημαντική μείωση της συσσώρευσης αιμοπεταλίων σε σχέση με ασθενείς που λάμβαναν ασενοκουμαρόλη (p=0,068) και σημαντικά μειωμένη συσσώρευση συγκριτικά με ασθενείς υπό rivaroxaban (p=0,045), όπως προέκυψε από τη μέθοδο LTA. Επίσης, ασθενείς που λάμβαναν dabigatran 110 mg σε σύγκριση με αυτούς που λάμβαναν ασενοκουμαρόλη, παρουσίασαν σημαντικά χαμηλότερες τιμές όσον αφορά το δείκτη Li-60 (p=0,011), ενώ δεν παρατηρήθηκε στατιστικά σημαντική διαφορά στις τιμές του ίδιου δείκτη μεταξύ των ασθενών που λάμβαναν rivaroxaban και apixaban (p=0,499). Η ασενοκουμαρόλη επηρέασε την παραγωγή θρομβίνης περισσότερο από το dabigatran 110 mg (AUC, p<0,001), με βάση το ενδογενές δυναμικό θρομβίνης (ETP). Ανάλογα ευρήματα παρατηρήθηκαν μετά τη σύγκριση του rivaroxaban και του apixaban με την ασενοκουμαρόλη (p<0,001). Επίσης, το ενδογενές δυναμικό θρομβίνης (ETP) μειώθηκε σημαντικά σε ασθενείς υπό rivaroxaban σε σύγκριση με εκείνους που λάμβαναν apixaban (p<0,003). Το Apixaban μειώνει σημαντικά την ETP σε σύγκριση με την ομάδα ελέγχου, αλλά σε μικρότερο βαθμό σε σχέση με το rivaroxaban.Επιπλέον, ανιχνεύθηκαν σημαντικές συσχετίσεις μεταξύ των επιπέδων dabigatran 110 mg, όπως προσδιορίστηκαν με τη δοκιμασία HTI, και σχεδόν όλων των παραμέτρων της δοκιμασίας ETP (AUC, p<0,001). Παρομοίως, παρατηρήθηκαν σημαντικές συσχετίσεις μεταξύ των συγκέντρωσης του rivaroxaban στο πλάσμα, όπως προσδιορίστηκε με τη χρωμογονική μέθοδο DiXaI, και των ακόλουθων παραμέτρων της δοκιμασίας ETP (Tlag, p=0,045, Tmax, p=0,016 και Cmax, p=0,003). Τέλος, σημειώθηκε στατιστικά σημαντική, αντίστροφη συσχέτιση μεταξύ της συγκέντρωσης του apixaban στο πλάσμα, όπως προσδιορίστηκε με τη χρωμογονική μέθοδο DiXaI και του ETP (AUC, p<0,001). Συμπέρασμα: Με βάση τις δοκιμασίες ROTEM, ETP και LTA, προέκυψαν τα ακόλουθα συμπεράσματα, όσον αφορά την αντιπηκτική δράση των DOACs, όταν αυτά χορηγούνται στα συγκεκριμένα δοσολογικά σχήματα σε πραγματικούς ασθενείς με NVAF: i) το dabigatran 110 mg, πέραν της αναστολής της θρομβίνης, φαίνεται να έχει αντιαιμοπεταλιακή δράση και να ενισχύει την ινωδόλυση, γεγονός που ενδεχομένως ερμηνεύει τον αυξημένο αιμορραγικό κίνδυνο, ii) οι μετρήσεις της δοκιμασίας ETP συνιστούν ένα πιο ασφαλές προφίλ για το apixaban, σε σχέση με το υπόλοιπα DOACs, ως προς τον αιμορραγικό κίνδυνο, iii) τα μέγιστα επίπεδα των DOACs συσχετίζονται με τις παραμέτρους ETP (αλλά όχι με τις παραμέτρους ROTEM), γεγονός που υποδηλώνει έναν πιθανό ρόλο των παραμέτρων του ETP στην παρακολούθηση των επιπέδων των DOACs.

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Synthesis and Thrombin, Factor Xa and U46619 Inhibitory Effects of Non-amidino and Amidino N2-Thiophenecarbonyl- and N2-Tosylanthranilamides

10.20944/preprints201702.0009.v1 ◽

2017 ◽

Author(s):

Soo Hyun Lee ◽

Wonhwa Lee ◽

Nguyen Thi Ha ◽

Il Soo Um ◽

Jong-Sup Bae ◽

...

Keyword(s):

Platelet Aggregation ◽

Bleeding Time ◽

Ex Vivo ◽

Factor Xa ◽

Inhibitory Effects ◽

Human Endothelial Cells ◽

Antithrombotic Activity ◽

Pharmacological Targets

Thrombin (factor IIa) and factor Xa (FXa) are key enzymes at the junction of the intrinsic and extrinsic coagulation pathways and are the most attractive pharmacological targets for the development of novel anticoagulants. Twenty non-amidino N2-thiophencarbonyl- and N2-tosyl anthranilamides 1-20 and six amidino N2-thiophencarbonyl- and N2-tosylanthranilamides 21-26 were synthesized and evaluated prothrombin time (PT) and activated partial thromboplastin time (aPTT) using human plasma at concentration 30 μg/mL in vitro. From these results, compounds 5, 9, and 21-23 were selected to study the further antithrombotic activity. The anticoagulant properties of 5, 9, and 21-23 significantly exhibited a concentration-dependent prolongation of in vitro PT and aPTT, in vivo bleeding time, and ex vivo clotting time. These compounds concentration-dependently inhibited the activities of thrombin and FXa and inhibited the generation of thrombin and FXa in human endothelial cells. In addition, data showed that 5, 9, and 21-23 significantly inhibited thrombin catalyzed fibrin polymerization and mouse platelet aggregation and inhibited platelet aggregation induced U46619 in vitro and ex vivo. N-(3'-Amidinophenyl)-2-((thiophen-2''-yl)carbonyl amino)benzamide (21) was most active.

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