New Insights in Thrombin Inhibition Structure-Activity Relationships by Characterization of Octadecasaccharides from Low Molecular Weight Heparin.

Low Molecular Weight Heparins (LMWH) are complex anticoagulant drugs that mainly inhibit the blood coagulation cascade through indirect interaction with antithrombin. While inhibition of the factor Xa is well described, little is known about the polysaccharide structure inhibiting thrombin. In fact, a minimal chain length of 18 saccharides units, including an antithrombin (AT) binding pentasaccharide, is mandatory to form the active ternary complex for LMWH obtained by alkaline β-elimination (e.

Isolation of a pure octadecasaccharide with antithrombin activity from an ultra-low-molecular-weight heparin.

Heparin and low-molecular-weight heparins (LMWHs) are anticoagulant drugs that mainly inhibit the coagulation cascade by indirectly interacting with factor Xa and factor IIa (thrombin). Inhibition of factor Xa by antithrombin (AT) requires the activation of AT by specific pentasaccharide sequences containing 3-O-sulfated glucosamine. Activated AT also inhibits thrombin by forming a stable ternary complex of AT, thrombin, and a polysaccharide (requires at least an 18-mer/octadeca-mer polysaccharide).

Heparin sodium compliance to USP monograph: structural elucidation of an atypical 2.18 ppm NMR signal.

The ¹H nuclear magnetic resonance (NMR) acceptance criteria in the new heparin US Pharmacopeia (USP) monograph do not take into account potential structural modifications responsible for any extra signals observed in ¹H NMR spectra, some purified heparins may be non-compliant under the proposed new USP guidelines and incorrectly classified as unsuitable for pharmaceutical use. Heparins from the "ES" source, containing an extra signal at 2.18 ppm, were depolymerized under controlled conditions using heparinases I, II, and III.

Heparin sodium compliance to the new proposed USP monograph: elucidation of a minor structural modification responsible for a process dependent 2.10 ppm NMR signal.

Heparin is a highly sulfated hetero polysaccharide mixture found and extracted from mammalian tissues. It has been widely used as an anticoagulant drug during the past decades. In the new proposed USP heparin monograph, the ¹H NMR acceptance criteria to prevent contamination by over sulfated chondroitin sulfate (OSCS), or other persulfated glycosaminoglycans, specifies that no unidentified signals greater than 4% of the mean of signal height of 1 and 2 should be present in the following ranges: 0.