Correlation of molecular weight of low molecular weight heparin from low anticoagulant activity heparin with antithrombotic activity

From low anticoagulant activity heparin, a sideproduct accompanying commercial heparin, three re-fined products of low molecular weight heparin(IMWH) were prepared and their effects on an-tithrombotic activity were evaluated in experimentalrat thrombus model by measuring the time (known asocclusion time) from the beginning of electric stimu-lation to the formation of thrombus in the commoncarotid artery. The results showed that the values ofocclusion time for saline, commercial heparin andthree products with molecular weight 7100, 5300 and4000 d were 17.76±2.51, 24.21±1.89, 37.97±2.84, 63.03±3.42 and 28.72±1.75 min re-spectively. The antithrombotic activity of the LMWHwith molecular weight 5300 d was the strongest.