The molecular structure of heparin Sodium is an acidic mucosaccharide
anticoagulant with sulfate group. Heparin is the general name of a cluster of
acidic mucopolys mixtures with varying molecular weights, consisting of linear
chains of hexose or ocose repeating units, with molecular weights ranging from
3000 to 30000 and an average molecular weight of 15000 or so.
The preparation of heparin consists of two steps: the extraction of heparin protein complex, dissociation and separation purification of heparin. The heparin molecule contains sulfuric acid group and carboxyl group, which is strongly acidic and polyanion, and can react with cation to form salt. These cations include metallic cations: Ca2+,Na+,K+, long-chain pyridine compounds of organic bases, cation exchangers, and positively charged proteins such as protamine. The n-sulfate group in heparin structure is closely related to the anticoagulant effect, and its anticoagulant activity is decreased if it is damaged. N-sulfuric acid group is sensitive to acid hydrolysis and is fairly stable under alkaline conditions. The free hydroxyl group in heparin molecule is esterified, such as acidification, the anticoagulant activity also decreases, and acetylation does not affect its anticoagulant activity.
Heparin sodium is white or white powder, tasteless, hygroscopic, soluble in water, insoluble in ethanol, acetone and other organic solvents. It has strong negative charge in aqueous solution and can form molecular complex with some cations. Aqueous solution is stable at pH 7.
As an anticoagulant, heparin sodium is a kind of mucosaccharide, which is the sodium salt of glucosamine sulfate extracted from the intestinal mucosa of pigs, cattle and sheep. In human body, it is secreted by mast cells and naturally exists in the blood. Heparin sodium has the effect of avoiding platelet aggregation and destruction, blocking the transformation of fibrinogen into fibrin monomer, blocking the formation of thrombin and the opposite of the existing thrombin, and blocking the transformation of prothrombin into thrombin and opposite of thrombin. Heparin sodium in vivo and in vitro can delay or obstruct blood coagulation. Its mechanism of effect is messy and affects many links in the process of blood coagulation.
Its effect is as follows:
(1) Block the formation and effect of prothrombin, thus preventing prothrombin from becoming prothrombin;
(2) In higher concentrations of fashion has the effect of blocking thrombin and other coagulation factors, preventing fibrinogen from becoming fibrin;
(3) can block platelet aggregation and destruction, etc.
In addition, the anticoagulant effect of heparin sodium is related to the negatively charged sulfate in the molecule, and the positively charged alkaline substances such as protamine or toluidine blue can neutralize its negative charge, thus blocking its anticoagulant effect. Because heparin can activate and release lipoprotein esterase in vivo and hydrolyze triglyceride and lipoprotein of chylomicron, it also has the effect of lowering blood lipid.