Ex-Vivo and In-Vitro Evidence that Low Molecular Weight Heparins Exhibit Less Binding to Plasma Proteins than Unfractionated Heparin

We have compared the non-specific binding of unfractionated heparin (UFH) with that of low molecular weight heparin (LMWH) to plasma proteins both ex-vivo and in-vitro. Non-specific binding to plasma proteins was assessed by comparing the heparin levels measured as anti-factor Xa activity before and after the addition of low affinity heparin, which is essentially devoid of anti-factor Xa activity, in order to displace heparin bound to plasma …