Summary
The use of heparin as the most potent anticoagulant for the prevention of deep vein
thrombosis and pulmonary embolism is nevertheless limited, because it is available
to patients only by parenteral administration. Toward overcoming this limitation in
the use of heparin, we have previously developed an orally active heparin-deoxycholic
acid conjugate (LMWH-DOCA) in 10% DMSO formulation. The present study evaluates the
anti-thrombogenic effect of this orally active LMWH-DOCA using a venous thrombosis
animal model with Sprague-Dawley rats. When 5 mg/kg of LMWH-DOCA was orally administered
in rats, the maximum anti-FXa activity in plasma was 0. 35 ± 0. 02, and anti-FXa activity
in plasma was maintained above 0. 1 IU/ml [the minimum effective anti-FXa activity
for the prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE)] for
five hours. LMWH-DOCA (5 mg/kg, 430 IU/kg) that was orally administered reduced the
thrombus formation by 56. 3 ± 19. 8%;on the other hand, subcutaneously administered
enoxaparin (100 IU/kg) reduced the thrombus formation by 36. 4 ± 14. 5%. Also, LMWH-DOCA
was effectively neutralized by protamine that was used as an antidote. Therefore,
orally active LMWH-DOCA could be proposed as a new drug that is effective for the
longterm prevention of DVT and PE.
Keywords
Low-molecular-weight heparin - deoxycholic acid - chemical conjugate - oral delivery
- deep vein thrombosis