Abstract: Objective To study the anticoagulant activity of hirulog. Methods Rabbits blood samples were collected before and after injecting hirulog. Thrombin clot time (TT), prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured to investigate the dose-effect and time-effect relationship of hirulog and compared the efficacy with heparin. Results TT, PT and APTT of rabbits blood samples were prolonged remarkably by hirulog, and the action duration was about 60 min, that was similar to heparin. Conclusion Hirulog showed obvious anticoagulant effects with clear dose-effect relationship.

Key words: hirulog, anticoagulant, rabbits