LMWHs are a diverse group of chemically distinct compounds. Most are prepared by various chemical or physical depolymerisation techniques; others, such as tinzaparin, are produced by enzymatic depolymerisation .
Clexane® is obtained by chemical β elimination of the benzyl ester of heparin derived from porcine intestinal mucosa. Each LMWH is manufactured using a slightly different method, conferring unique properties on each product. As a result of these differences in manufacturing techniques, the available products differ markedly in terms of their mean molecular weights, mix of polysaccharide chain lengths, and pharmacological properties .
Figure: different methods of LMWH preparation result in distinct chemical structures 
|Manufacturing process||Benzylation followed by alkaline hydrolysis||Heparinase digestion|
|Mean molecular weight (daltons)||4500||6500|
|Elimination half-life (hours)||4.5||3.4|
|Anti-Xa activity (IU/mg)||100||100|