What is the Bacterial Endotoxin Detection Method?

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Bacterial endotoxin detection is used to determine whether the bacterial endotoxin in the sample meets the requirements. Endotoxins are lipopolysaccharides of the cell wall of Gram-negative bacteria, the toxic component of which is lipid A. Cells are released after death and disintegration. Bacterial endotoxin detection includes gel method and photometric method, the latter includes turbidimetric method and chromogenic matrix method. Any of these methods can be used to test the test article. In case of any dispute regarding the assay results, unless otherwise specified, the results of the gel method shall prevail. The types and proportions of bacteria in the body are normal, and the human body is in a state of dynamic balance.

The pyrogens are mainly endotoxins released by bacteria. Pyrogen entering the body's blood circulation system can cause a series of adverse reactions such as fever. Therefore, the detection of pyrogens or bacterial endotoxins for injection is an important quality index to ensure injection safety. Abnormal results: In clinical practice, when a large amount of intravenous infusion is performed, due to the presence of pyrogens in the drug solution, the patient will experience symptoms such as chills, high fever, sweating, dizziness, and vomiting within 0.5-1h . 40 ℃, severe cases even shock. When establishing a bacterial endotoxin detection method, when calculating the endotoxin limit L , MVD , and MVC , it is necessary to pay attention to important parameters such as the dosage for human use, product specifications, and the sensitivity of the LAL reagent, because errors in the calculation will lead to all subsequent work. s failure. Common problems include: ( 1 ) Incorrect determination of clinical dose. Only conventional doses are used, regardless of clinically significant doses and routes of administration. In the limit value calculation formula L=K/M , the definition of K and M values ​​is not clear, so the assignment of K and M is inaccurate, which eventually leads to the calculation error of the limit value. For example, 40 to 80 mg intravenously for adults and 10 to 20 mg intravenously for infants (over three months old) . The limit calculated based on the adult ( 60kg ) dose is3.75EU/mg , and the baby's weight is only about 5kg , the calculated limit is about 1.25EU/mg . Bacterial endotoxin limits will vary significantly if high doses per kilogram of clinical body weight are not considered. ( 2 ) The bacterial endotoxin limit of some declared varieties is not calculated according to the clinical dose, but calculated according to the pyrogen test dose of the same variety, resulting in limit errors. ( 3 ) The limit values ​​of bacterial endotoxins for some varieties are formulated from foreign pharmacopoeias, without considering the clinical dosage of the varieties in the domestic market and the difference between the average body weight in China and abroad, which also leads to wrong determination of the limit values. ( 4 ) Miscalculation of the daily dose (multiple doses in one day). ( 5 ) When the variety specification (concentration) changes, the MVD calculation is not adjusted. ( 6 ) The large dose used to establish the method has exceeded the clinical dose.