(s) acenocoumarol

Acenocoumarol is a short-lived oral anti-coagulant, which, like warfarin, functions by inhibiting vitamin K epoxide reductase. It has higher intrinsic anticoagulant potency than warfarin and phenprocoumon, when evaluated in vitro. Acenocoumarol has a single chiral center that gives rise to two different enantiomeric forms. (S)-Acenocoumarol has a shorter plasma elimination half-life (1.8 hours) and faster plasma clearance (28.5 L/hour), compared to the (R)-enantiomer (6.6 hours, 1.9 L/hour). The S-enantiomer undergoes extensive first-pass metabolism during absorption from the gastrointestinal tract, whereas (R)-acenocoumarol is rapidly absorbed and provides essentially complete oral bioavailability. Perhaps related to these pharmacokinetic characteristics, (S)-acenocoumarol is less potent in vivo as an anti-coagulant than the (R)-enantiomer. As the clearance of acenocoumarol is ~20-fold faster than that for warfarin, the plasma concentrations of acenocoumarol are substantially lower than those for warfarin in patients receiving long-term treatment.

(R)-Acenocoumarol ((R)-Acenocoumarin; (R)-Nicoumalone) 是一种短效且口服有效的抗凝剂，通过抑制维生素 K 环氧还原酶（vitamin K1 recycling）起作用，与Warfarin类似。然而，它在体内的抗凝效力优于Warfarin。该化合物具有单个手性中心，存在两种对映体形式。其中，(R)-Acenocoumarol 相对于 (S)-对映体，具有较长的血浆消除半衰期（6.6 h），较慢的血浆清除率（1.9 L/h），而且体内抗凝效果更为显著。