title: New synthetic thrombin inhibitors: molecular design and experimental verification.
abstract: BACKGROUND
  The development of new anticoagulants is an important goal for the improvement of thromboses treatments.
  
  
  OBJECTIVE
  The design, synthesis and experimental testing of new safe and effective small molecule direct thrombin inhibitors for intravenous administration.
  
  
  METHODS
  Computer-aided molecular design of new thrombin inhibitors was performed using our original docking program SOL, which is based on the genetic algorithm of global energy minimization in the framework of a Merck Molecular Force Field. This program takes into account the effects of solvent. The designed molecules with the best scoring functions (calculated binding energies) were synthesized and their thrombin inhibitory activity evaluated experimentally in vitro using a chromogenic substrate in a buffer system and using a thrombin generation test in isolated plasma and in vivo using the newly developed model of hemodilution-induced hypercoagulation in rats. The acute toxicities of the most promising new thrombin inhibitors were evaluated in mice, and their stabilities in aqueous solutions were measured.
  
  
  RESULTS
  New compounds that are both effective direct thrombin inhibitors (the best K(I) was <1 nM) and strong anticoagulants in plasma (an IC(50) in the thrombin generation assay of approximately 100 nM) were discovered. These compounds contain one of the following new residues as the basic fragment: isothiuronium, 4-aminopyridinium, or 2-aminothiazolinium. LD(50) values for the best new inhibitors ranged from 166.7 to >1111.1 mg/kg. A plasma-substituting solution supplemented with one of the new inhibitors prevented hypercoagulation in the rat model of hemodilution-induced hypercoagulation. Activities of the best new inhibitors in physiological saline (1 µM solutions) were stable after sterilization by autoclaving, and the inhibitors remained stable at long-term storage over more than 1.5 years at room temperature and at 4°C.
  
  
  CONCLUSIONS
  The high efficacy, stability and low acute toxicity reveal that the inhibitors that were developed may be promising for potential medical applications.
authors: Laboratory of Physical Biochemistry, National Research Center for Hematology, Russian Academy of Medical Sciences, Moscow, Russia. sinaurid@list.ru
authors: Elena I
authors: EI
authors: Sinauridze
authors: Alexey N
authors: AN
authors: Romanov
authors: Irina V
authors: IV
authors: Gribkova
authors: Olga A
authors: OA
authors: Kondakova
authors: Stepan S
authors: SS
authors: Surov
authors: Aleksander S
authors: AS
authors: Gorbatenko
authors: Andrey A
authors: AA
authors: Butylin
authors: Mikhail Yu
authors: MY
authors: Monakov
authors: Alexey A
authors: AA
authors: Bogolyubov
authors: Yuryi V
authors: YV
authors: Kuznetsov
authors: Vladimir B
authors: VB
authors: Sulimov
authors: Fazoyl I
authors: FI
authors: Ataullakhanov
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