Dapheparin sodium belongs to low molecular weight heparin sodium, white or white powder. Almost odorless, tasteless, hygroscopic. Soluble in water and salt water, insoluble in ethanol, acetone, benzene, chloroform and ether. 1% aqueous solution pH 6.0~7.5.

　　Preparation method of daheparin sodium: purification of daheparin sodium with anion exchange resin, the steps are as follows:

　　(1) The anion exchange resin is loaded into the column, and then the resin is regenerated by alkaline mixture;

　　(2) After regeneration, the resin was cleaned with purified water, and then the resin was balanced with sodium chloride solution;

　　(3) The crude product of daheparin sodium was dissolved in purified water, sample was added, and then washed with sodium chloride solution to remove impurities and excess small molecules in the crude product;

　　(4) Use sodium chloride solution to elute intermediate products in step (3);

　　(5) After elution, the chromatography column was rinsed with purified water;

　　(6) The eluent was precipitated with ethanol and dried under pressure to obtain the heparin sodium API that met the quality standards.