Molecular weight, pharmacokinetics assays

Low-molecular-weight heparins ( 4500 Da, or 15 monosaccharide units) are isolated from standard heparin by gel filtration chromatography, precipitation with ethanol, or partial depolymerization with nitrous acid and other chemical or enzymatic reagents. Low-molecular-weight heparins differ from standard heparin and from each other in their pharmacokinetic properties and mechanism of action ("see below). The biological activity of low-molecular-weight heparin is generally measured with a factor Xa inhibition assay, which is mediated by antithrombin. 

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