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Control of Bacterial Endotoxin in Hospital Infusion Preparations and Notices for Detection


The 2005 edition of Chinese Pharmacopoeia (Part II) (hereinafter referred to as Pharmacopoeia) stipulates that bacterial endotoxin test can be used to control the pyrogen of commonly used infusion preparations. In order to control bacterial endotoxin in hospital infusion preparations, the author discussed and studied the control measures of bacterial endotoxin, the detection of bacterial endotoxin and the matters needing attention in the production process.

Control of Bacterial Endotoxin in Production Process of Infusion Preparations

1.1 Control of Bacterial Endotoxin in Water for Injection

Our hospital (General Hospital) uses a combination of stainless steel activated carbon filter, precision filter, electrodialyzer, ion exchange resin bed and multi-effect distillation water machine to prepare water for injection. In order to control the bacterial endotoxin in water for injection, the preparation room of our hospital (General Team Hospital) has taken the following measures: 1. Regular maintenance and regeneration of activated carbon filter, precision filter, electrodialyzer, ion exchange resin, etc. (2) Check whether the trap of multi-effect distillation water machine is blocked periodically to ensure the smooth flow of the trap. (3) When making water, the steam pressure, deionized water flow and cooling water flow should be monitored in real time to ensure the relative balance of the three. (4) To strengthen the monitoring of the conductivity of feed water and final water, the conductivity should be controlled below 1.0 ugs/cm, and the temperature of final water should be above 90 C. The quality control room carries out a monthly quality inspection of water for injection, and batches of routine testing. Bacterial endotoxin is a compulsory test item. Once problems are found, the causes and improvements should be found in time.

1.2 Control of Bacterial Endotoxin in Raw Materials and Accessories

In order to ensure the quality of raw materials and accessories, we must adhere to the main channel and point purchase, adhere to the quality sampling system, and ensure storage conditions to prevent raw materials and accessories from being polluted. For the raw material of sodium chloride, because it contains more organic impurities, the bacterial endotoxin can be effectively removed by drying the sodium chloride at 180 ~C for 2.0 h or at 250 ~C for 1.0 h before preparation.

1.3 Control of Bacterial Endotoxin in the Preparation of Infusion Preparations

Before preparation, all utensils, pipes and accessories should be fully cleaned or disinfected after cleaning. When sterilizing, the steam pressure, temperature and time should be fully guaranteed. Insufficient temperature and time can also lead to unqualified bacterial endotoxin test. Bacterial endotoxin of infusion preparation mainly depends on the adsorption of activated carbon to remove. Therefore, operators should pay attention to the use of activated carbon, and adjust it according to the degree of pollution of raw materials and excipients and the decline of adsorption of activated carbon after moisture absorption in storage. If activated carbon absorbs moisture, it can be dried for 2.0 hours at 120 C before use. At the same time, we should strictly control the purchase quality of activated carbon and avoid the excessive bacterial endotoxin limit in transfusion caused by the use of inferior activated carbon. In the process of drainage, reflux and filling, do not stop and loosen the pump at will, so as not to destroy the filter-aid layer of activated carbon and reduce the ability of activated carbon to actively adsorb endotoxin.

Effect of 1.4 Microporous Membrane Treatment on Bacterial Endotoxin Limit of Infusion Preparations

In practice, it was found that improper treatment of microporous membrane could cause bacterial endotoxin pollution and seriously affect the quality of infusion. The results show that the mixed cellulose ester microporous membrane has reversible adsorption on bacterial endotoxin, and it needs a lot of water for injection or liquid medicine to wash out gradually. Therefore, when immersing the microporous membrane, the immersion time should be shortened as far as possible to prevent the bacterial endotoxin produced by the immersion water for injection during the immersion process. Otherwise, the bacterial endotoxin limit of the infusion preparation in the initial filling stage will be unqualified. Therefore, it is suggested that charged microporous membrane be used instead of mixed cellulose ester microporous membrane. This is due to the positive charge of charged microporous membrane and negative charge of bacterial endotoxin. When endotoxin-containing liquid passes through the membrane, endotoxin is adsorbed and removed [1].

2 Notes for Bacterial Endotoxin Detection of Infusion Preparations [2]

At present, the examination of bacterial endotoxins in transfusion preparations is mainly gel method, and the operators should pay attention to the following matters in strict accordance with the provisions of the Pharmacopoeia.

2.1 Tachypleus amebocyte lysate should be purchased to meet the sensitivity prescribed in the Pharmacopoeia, and the standard of bacterial endotoxin for suitable units should be purchased. In order to ensure the stability and reliability of the experimental results, the author believes that it is better to select the same manufacturers of tachypleus amebocyte lysate, bacterial endotoxin working standard and inspection water.

2.2 Before the experiment, the batch number and expiration date of the standard should be carefully checked. Because the test results of different batches of bacterial endotoxin standard are different, the sensitivity should be checked when replacing the bacterial endotoxin standard to ensure the accuracy of the test results. In addition, in all experiments, the control required by each experiment should be carried out at the same time. In order to save costs and reduce experimental links, no experimental control should be made or chosen. All experiments should be conducted under the condition that the control reaction is effective before calculation and result judgment can be made.

2.3 Glass utensils for experiment are washed with detergent and tap water and immersed in the washing solution after controlling the dry water for 4 hours. After cleaning, they are dried for 1 hour at 250 C or 2 hours at 180 C. The baked utensils can be used within two weeks without opening metal containers. Otherwise, exogenous endotoxins may be removed by reheating again. Pay attention to the use of fresh distilled water to wash the final flushing utensils. Purified water and long-standing distilled water are forbidden.

2.4 After limulus reagent resolving and adding to the sample, it should be gently vibrated and blended so as to avoid the occurrence of wall-hanging detention and the adsorptive effect of the wall of the test tube (ampoule) resulting in inadequate dosage and false negative. When the horseshoe crab reagent is redissolved, the bacterial endotoxin test water should be added along the test tube (An Bu) wall to avoid excessive foam. When the reaction has not been completed, the observation should not be taken out, while the table of the thermostat water bath should be kept stable. In the process of heat preservation and taking the test tube (ampoule), vibration should be avoided, otherwise false negative results may occur. During the heat preservation period, the temperature variation will also directly affect the experimental results. Therefore, the temperature fluctuation of the constant temperature water bath should be less than 1 C. In addition, the thermometer of constant temperature water bath should be calibrated regularly to ensure the authenticity of temperature display. During the whole experiment process, we should avoid any possible contamination, so as to avoid the appearance of false positive results.

2.5 The operation time and ambient temperature will affect the experimental results. During the experiment, the operator should move quickly and shorten the operation time as much as possible. At the same time, because the reaction temperature is 37 C + + 1 C, and the summer temperature is sometimes as high as 38~40 C, which exceeds the reaction temperature. In order to avoid the phenomenon of "no gel" in the positive control, we should consider installing air conditioning control room temperature [3] at this time.

2.6 The standard bacterial endotoxin solution dissolved in water for bacterial endotoxin test should be sealed with a sealing film and kept at 4 C for less than 2 weeks. However, it is only suitable for the national standard of bacterial endotoxin, if it is the standard of bacterial endotoxin work, it is best to use it up at one time and no longer store it.

2.7 Studies have shown that the reaction between tachypleus amebocyte lysate and endotoxin is not specific. Some non-endotoxin substances, such as beta-glucan, can activate factor G in the tachypleus amebocyte lysate agglutination system and produce agglutination reaction. The fungal cell wall and some hollow fiber filters and filters contain beta-glucan. Therefore, in the process of infusion production and bacterial endotoxin test, we should prevent contamination by microorganisms and cellulose substances, so as to avoid false positive results [4]. At the same time, in practical work, we should distinguish and avoid misjudgement. Of course, we can use specific limulus reagent to abandon factor G limulus reagent or add factor G inhibitor to eliminate interference.

3 discussion

The control of bacterial endotoxin in hospital infusion preparations runs through the whole process of infusion production and bacterial endotoxin detection. This requires not only to continuously improve the production level of hospital infusion preparations, improve production technology and operation skills, but also to make full use of the supervision means of bacterial endotoxin test to control bacterial endotoxin in every link of hospital infusion preparations production. System. At the same time, the detection methods should be constantly improved and updated to improve the detection level and quality. Strengthen the research and application of photometric method, i. e. quantitative method, to further improve the control standard of bacterial endotoxin limit for infusion preparations, so as to provide safer and more effective infusion preparations for clinical use.