Bacterial endotoxin is a unique structure in the outer layer of the cell wall of Gram-negative bacilli. heat.

Bacterial endotoxin detection is the structure of the outer wall layer of the cell wall of Gram-negative bacilli. As an exogenous heat source, neutrophils, etc. release endogenous heat source substances, which act on the thermoregulatory center to generate heat. The main chemical component of bacterial endotoxin is lipopolysaccharide (LPS). Lipopolysaccharide contains three components: fat A, core polysaccharide and O antigen. Among them, fat A is a kind of saccharin, which is the toxic part of endotoxin and is closely related to dental disease. relevant.

Widely present in nature, mainly released when Gram-negative bacilli die or attach to other cells. For example, the amount of endotoxin contained in tap water is generally 1 ~ 100 EU/ml. Endotoxins can enter the body through the digestive tract without causing harm. Entering human or animal blood by injection etc. can cause other diseases or death. Therefore, it is particularly important to detect bacterial endotoxins such as medical devices, pharmaceuticals, dialysis fluids, and injection water.

At present, the detection method of bacterial endotoxin is mainly based on the reagent test method. According to the particularity of some drugs, the interference cannot be eliminated by the dilution method, and the reagent test method cannot completely replace the rabbit pyrogen test. The current 2020 edition of the Chinese Pharmacopoeia includes two bacterial endotoxin detection methods: gel and photometric methods. The former uses the principle of aggregation reaction caused by reagents and bacterial endotoxins to conduct qualitative or semi-quantitative inspections. The latter includes turbidimetric and colorimetric matrix (colorimetric) methods, which use the turbidity changes during the reaction of reagents and endotoxins and the corresponding thrombin to release specific matrix color blocks, respectively, to detect bacterial endotoxins. The turbidity method and the chromogenic matrix method can be subdivided into dynamic method and endpoint method. When examining test articles, the test can be performed using one of these bacterial endotoxin detection methods. When results are in dispute, the gel limit test results take precedence unless otherwise specified.

The advantage of the gel method is that it is easy to operate, and the instruments used have low requirements for reagents, so it can be used as a qualitative inspection method. The disadvantage is that even if a semi-quantitative test is performed, it is difficult to measure the specific endotoxin value of the test product, and the semi-quantitative test requires too many reagents for the interference test, which is very troublesome to operate.

The advantage of photometry is that it can be used for quantitative detection and has high sensitivity. Some supplies with uncertain endotoxin or unknown endotoxin content can be determined by photometry to determine the specific endotoxin content. The disadvantage is that the operation requirements are high, the reagents used for the test equipment are high, the heat source is not handled well, and false positives are prone to occur.