High and low anticoagulant activity heparins. Preparation in large scale and degree of complexation with antithrombin III.

Heparin was separated into fractions with high and low anticoagulant activities by selective barium precipitation, gel filtration and ion exchange chromatography methods. Enrichment in the anticoagulant activities were observed in fractions with high molecular weight or high degree of sulfation. The combination of selective barium precipitation and ion exchange chromatography led to the preparation of heparins with very high anticoagulant activities (300 IU/mg). These heparins have a high affinity for antithrombin III (greater than 80%) and were undistinguishable from those prepared by antithrombin III affinity chromatography regarding molecular weight, sulfate/hexosamine ratio, degree of binding to antithrombin III, electrofocusing pattern and anticoagulant activity. These methods allow now the preparation in industrial scale of heparins with high anticoagulant activities for in vivo studies.