Arixtra

Fondaparinux (Arixtra) is an anticoagulant medication. As shown in the box to the right, Fondaparinux contains a synthetic pentasaccharide. Apart from the O-methyl group at the reducing end of the molecule, the identity and sequence of the five monomeric sugar units contained in Fondaparinux is identical to a sequence of five monomeric sugar units that can be isolated after either chemical or enzymatic cleavage of the polymeric glycosaminoglycans heparin and heparan sulfate (HS). Within heparin and heparan sulfate this monomeric sequence is thought to form the high affinity binding site for the anti-coagulant factor antithrombin III (ATIII). Binding of heparin/HS to ATIII has been shown to increase the anti-coagulant activity of antithrombin III 1000 fold. See the heparin article for a detailed rationale behind the development of Fondaparinux as an anticoagulant.
See more at Wikipedia.org...