The design and synthesis of new synthetic low-molecular-weight heparins

Low-molecular-weight heparin (LMWH) has remained the most favorable form of heparin in clinics since the 1990s owing to its predictable pharmacokinetic properties. However, LMWH is mainly eliminated through the kidney, which limits its use in renal-impaired patients. In addition, the anticoagulant activity of LMWH is only partially neutralized by protamine. LMWH is obtained from a full-length, highly sulfated polysaccharide harvested from porcine mucosal tissue. The depolymerization involved in LMWH production generates a broad distribution of LMWH fragments (6-22 sugar residues). This, combined with the various methods used to produce commercial LMWHs, results in variable pharmacological and pharmacokinetic properties. An alternative chemoenzymatic approach offers a method for the synthesis of LMWH that has the potential to overcome the limitations of current LMWHs. This review summarizes the application of a chemoenzymatic approach to generate LMWH and the rationale for development of a synthetic LMWH.