Mixture of sulfated polysaccharides, useful as antithrombotic agent having selective factor Xa inhibiting activity, obtained by depolymerization of heparin benzyl ester quaternary ammonium salt

摘要

A mixture (A) of sulfated polysaccharides (I) is new. A novel mixture (A) of sulfated polysaccharides (I) is claimed, where: (1) (I) have the general structure of the constituent polysaccharides of heparin; (2) (A) have average molecular weight 1500-3000 Daltons, anti-Xa activity 100-150 IU/mg, anti-IIa activity 0-10 IU/mg and a ratio of anti-Xa activity to anti-IIa activity of more than 10; (3) (I) contain 2-26 saccharide units and have a 4,5-unsaturated glucuronic acid 2-O-sulfate unit at at least one terminal; and (4) (A) are in alkali metal or alkaline earth metal salt form. An Independent claim is also included for the preparation of (A) by: (a) depolymerizing a quaternary ammonium salt (II) of heparin benzyl ester in an organic medium, using a strong organic base of pKa more than 20 or sodium imidazolate; (b) converting the obtained depolymerized quaternary ammonium salt of heparin benzyl ester into the sodium salt; (c) saponifying the ester; and (d) optionally purifying the product.