Crude heparin sodium is the sodium salt of aminoglucosan sulfate extracted from the mucosa of pig small intestine. After dissociation, separation and purification of heparin and other steps, it can be prepared into a new type of low molecular weight heparin sodium anticoagulant, which has anticoagulant and antithrombotic effects. Crude heparin sodium is the general name of a cluster of acid mucopolysaccharide mixtures with different molecular weight sizes. It is a linear chain molecule composed of six or eight sugar repeating units. The molecular weight is between 3000 and 30000, and the average molecular weight is about 15000.

　　The preparation of crude heparin is as follows: fresh pig intestines (or frozen pig intestines after natural thawing) are carefully cleaned with water and then enzymolized; The raw materials were finely adjusted to a PH value of 8-9 with a small amount of dilute lye under full agitation, and the liquid temperature was kept at 37-40 degrees for enzymolysis for 3-4 hours. Refined salt (containing NaCL≥95% and calcium magnesium calcium salt <0.5%) of the total weight of the material liquid was added to make the mixture evenly miscible, then the temperature was raised 90 degrees, the heat was kept for 30 minutes, and the filtrate was adjusted to PH=9.0-9.5 for ion exchange adsorption treatment.

　　Elution, filtration, combination of clear liquid and filtrate, fine adjustment of PH=6.0-6.5, add 1.5 times the amount of 95% ethanol precipitation overnight, the next day, carefully drying out the supernatant, collect the lower precipitate, drain to dry (mother liquid can be used in the eluent before PH adjustment). It is dried in a vacuum, and the result is a crude heparin.

　　Crude heparin sodium is yellow, brown, gray or similar color solid particles or powder. Insoluble in ethanol, acetone and other organic solvents, easily soluble in water. The molecule is acidic and is polyanion, which can react with cations to form salts.