Endotoxin Essentials

Andrew Taylor, ARL Bio Pharma Microbiology Lab Supervisor

Pyrogens are a group of fever causing substances which can be found in compounded sterile preparations (CSPs) if appropriate actions are not taken to reduce or remove them. One of the most widely known groups of pyrogens are bacterial endotoxins. 

Bacterial endotoxins are:

  • Remnants of bacterial cells that can cause fever, diarrhea, or septic shock in patients  
  • Not removed during filter sterilization
  • Not removed during steam sterilization
  • Not detected by a sterility test

USP <797> requires a Bacterial Endotoxin Test (BET) for each preparation of:

  • Category 2 and Category 3 CSPs compounded from one or more nonsterile component(s)
  • Multiple-dose CSPs

USP <797> also requires a description of the depyrogenation process employed, including the temperature, pressure (if applicable), duration, permissible load conditions for each cycle; and the use of endotoxin challenge vials (ECVs) must be included in the facility’s SOPs. The chapter also states that if a CSP is dispensed or administered before Endotoxin testing results are known, a facility must have procedures in place to Immediately notify the prescriber of a test failure with the potential to cause patient harm.

The Food and Drug Administration (FDA) requires a BET for all 503B outsourcing facility drug products reported to be non-pyrogenic.

Even if it is not mentioned specifically in the regulatory documents, it is important to check for the presence of endotoxins in raw materials, at various points in the compounding process, and in finished products before administering a drug to a patient.  

The limit for the maximum amount of endotoxin allowed to be present in a CSP can be found in the applicable USP monograph, or calculated using the route of administration, patient weight, and maximum bolus dose. Once the limit has been established, the primary test method used to determine the amount of bacterial endotoxins in a CSP is described in USP <85> Bacterial Endotoxins Test.   

ARL Bio Pharma’s Bacterial Endotoxin Testing Process

ARL Bio Pharma follows the procedures described in USP <85>. The test is performed using depyrogenated glassware and supplies and the product to be tested is prepared using reagents specifically designed for BET. Each sample is tested in duplicate, using a standard curve, negative control, and positive control. At the conclusion of the test, the amount of endotoxin is calculated for each sample analyzed. If the endotoxin concentration is found to be below the limit, and all quality control parameters of the test are met controls were acceptable, the sample complies with USP <85> requirements.