Sulfated colistin
Sulfuric colistin, also known as sulfuric colistin, colistin, polymyxin E, antibiotics, etc., is a white or nearly white powder, odorless, bitter and hygroscopic, easily soluble in water, slightly soluble in methanol and ethanol, almost insoluble in acetone, ether, etc., and slightly soluble in free alkali in water. Stable within the range of PH3-7.5. Sulfuric colistin is produced by polymyxin and has a strong antibacterial effect on Gram negative bacteria. It is used to treat intestinal diseases caused by Gram negative bacteria, as a feed additive, and has a significant growth promoting effect. It works well when combined with sulfadiazine.
Pharmacodynamics
Sulfuric colistin is a narrow-spectrum fungicide. It has a strong antibacterial effect on Gram negative bacteria such as Escherichia coli, Salmonella, Pasteurella, Shigella, Brucella, Vibrio, Pseudomonas aeruginosa, etc. Among them, it has a strong bactericidal effect on Pseudomonas aeruginosa and Vibrio. The bactericidal mechanism is to damage the bacterial cell membrane, increase its permeability, and cause the leakage of amino acids, purines, pyrimidines, K+, etc. in the bacterial body. It can also affect the function of nucleoplasm and ribosome, leading to bacterial death. Bacteria are not easily resistant to this product and have complete cross resistance to polymyxin B, but there is no cross resistance to other antibiotics. All Gram positive bacteria and Proteus, Brucella, and Serratia are resistant to this product.
Sulfuric colistin is mainly used for the treatment of intestinal infections caused by Gram negative bacteria, and for external use in the treatment of Pseudomonas aeruginosa infections caused by burns and trauma. As a feed drug additive, it has a growth promoting effect.
Pharmacokinetics
This product is rarely absorbed orally, and after absorption, the drug is poorly distributed in the body and lasts for a short period of time. After 8 hours of oral administration, except for bile, there were only trace amounts in other tissues, and after 16 hours, there was no residue in all tissues. After injection, it is widely distributed in the body and reaches its peak in the main tissues within 0.5-1 hours. However, it is not easy to penetrate into the chest cavity, joint cavity, and infection site, and it is also difficult to produce cerebrospinal fluid. After 6 hours, it cannot be detected except for blood, trachea, salivary glands, kidneys, and urine, and after 24 hours, it cannot be detected except for trachea, kidneys, and urine. The protein binding rate of the drug is relatively low. Mainly excreted through the kidneys, it can accumulate in the body when renal function is incomplete.
Anti endotoxin
Endotoxin is a toxin synthesized, produced, and released by bacteria, composed of O-specific side chains, core polysaccharides, and lipid A. All antibiotics have the problem of causing bacterial endotoxin release, while colistin sulfate causes the lowest bacterial endotoxin release. More importantly, sulfated colistin can neutralize endotoxins by binding positively charged - NH2 to negatively charged phosphate groups on endotoxin lipid A produced by bacteria; Therefore, sulfated colistin can eliminate bacterial endotoxins, inhibit the release and activity of bacterial endotoxins, and is a good anti endotoxin drug. According to research reports by Lv Genfa et al. (2004), once endotoxin binds to receptors on the cell surface and mediates cell activation, sulfated colistin will lose its anti endotoxin effect. Therefore, supporting the direct neutralization effect of sulfated colistin on endotoxin is the main way to antagonize endotoxin.