BIBR 953 (Dabigatran, Pradaxa)

Chromogenic assay

Human thrombin (0.042 U/mL) was pre-incubated for 10 mins at 37 °C with 10 different dilutions (concentration range of 0.003 ~ 100 μM) of BIBR 953 dissolved in DMSO or with DMSO as control. Upon addition of the pre-incubation mixture to the chromogenic substrate, tosyl-glycyl-prolyl-arginine-4-nitranilide acetate, nitraniline was cleaved by thrombin and the increase in absorbance at 405 nm, related to the free nitraniline, was measured in a spectrophotometer. By plotting the absorbance at 405 nm vs the concentration of the test compound, IC50 was calculated.

Samples

Adult and neonatal platelet-poor plasma

Preparation method

The solubility of this compound in DMSO is limited. General tips for obtaining a higher concentration: Please warm the tube at 37 °C for 10 minutes and/or shake it in the ultrasonic bath for a while. Stock solution can be stored below - 20 °C for several months.

Reacting condition

0, 40, 110, 180, 250 or 320 ng/mL

Applications

Without the presence of BIBR 953, neonatal and adult samples showed similar results on the time to clot initiation. In neonatal samples, BIBR 953 significantly delay clotting in a dose-dependent manner, with the difference increasing from 3 times for 40 ng/mL BIBR 953 to 9 times for 320 ng/mL BIBR 953.

Animal models

Rats

Dosage form

i.v.

Applications

Compared with all of the inhibitors tested, BIBR 953 exhibited the strongest activity and the longest duration of action. Besides, it was well-tolerated in rats up to the highest dose of 10 mg/kg. However, BIBR 953 was not orally active because it was a very polar, a permanently charged molecule with a logP of -2.4 (n-octanol/buffer, pH 7.4).

Other notes

Please test the solubility of all compounds indoor, and the actual solubility may slightly differ with the theoretical value. This is caused by an experimental system error and it is normal.

References:

[1]. Hauel NH, Nar H, Priepke H, Ries U, Stassen JM, Wienen W. Structure-based design of novel potent nonpeptide thrombin inhibitors. J Med Chem. 2002 Apr 25;45(9):1757-66.

[2]. Nossair FF, Chan HHW, Gantioqui J, Atkinson HM, Berry LR, Chan AKC. In-vitro assessment of the effect of dabigatran on thrombosis of adult and neonatal plasma: comparisons using thromboelastography and microscopic visualization of fibrin clot structure. Blood Coagul Fibrinolysis. 2017 May 12.