Leech-derive anticoagulant

Hirudin is a leech-derived anticoagulant that functions by directly inhibiting thrombin. A range of blood-sucking animals contain substances in their saliva that specifically inhibit some element of the blood coagulation system (Table 12.4). 

A. General description Bivalirudin, a 20 amino-acid synthetic peptide, is a direct thrombin inhibitor. It is an analogue of recombinant hirudin (Refludan), a 65 amino-acid anticoagulant derived from the leech. The molecular weight of bivalirudin is about 2.2kDa (anhydrous free base peptide). 

Another natural anticoagulant is hirudin, derived from the saliva of the leech (.hirudo is the Latin word for leech). Leeches, in fact, are still occasionally used themselves therapeutically for certain topical applications. Another possible drug to be used for the dissolution of blood clots is derived from bat saliva and acts as a... 

Classification and Prototypes Anticoagulants reduce the formation of fibrin clots. Two major types of anticoagulants are available heparin and its derivatives, which must be used parenterally and the orally active coumarin derivatives (eg, warfarin). The two groups differ in their chemistry, pharmacokinetics, and pharmacodynamics (Table 34-2). Two other anticoagulant proteins are available lepirudin, a recombinant form of hirudin, a protein found in leech saliva and human antithrombin III, a commercial preparation of an endogenous human anticoagulant. 

---