Bacterial Endotoxins
      •  All the pharmacopeia require that                    Contents
         radiopharmaceuticals intended for intravenous        •  Acceptance Criteria
         administration must be tested to ensure that the     •  Discussion
         pyrogen concentration is within acceptable limits.   •  Example Procedure
      •  Pyrogens most often originate from gram-
         negative bacterial cell walls – referred to as 
         bacterial endotoxin and that are readily detected 
         by a gel-clot or other techniques based on 
         Limulus amebocyte lysate (LAL). 
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                                             Acceptance Criteria
  Radiopharmaceutical 
       Production
 QC Testing                    Acceptance Criteria:  Not More Than 175 EU in the total 
                               administered dose. The total administered dose is the maximum 
 Baterial Endotoxin            administered volume at expiration stated in milliliters.  This is 
                               often written as 175EU/V. This test should be completed on 
 Contents
 Acceptance Criteria           every batch.  The batch may be released prior to completion of 
 Discussion                    the test but should the dose should not be injected into a patient 
 Example Procedure
                               until the batch has passed this test.
                               Procedure: There are widely used and acceptable tests for 
                               assessing presence of bacterial endotoxin in a 
                               radiopharmaceutical preparation. One is the gel-clot technique 
                               using Limulus Amebocyte Lysate (LAL). The bacterial endotoxin 
                               test can also be performed with devices that utilize the turbidity 
                               and kinetic measurement of gel formation. It is essential that the 
                               test is validated for potential inhibition (and hence false negative 
                               result) and positive controls.   
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                                                      Discussion
  Radiopharmaceutical 
       Production
                             Discussion: The gel-clot test entails typical incubation period of 
                             60 minutes, which is much too long to wait for a 110 min half life 
 QC Testing
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                               F isotope. Consequently, product may be released for patient 
 Baterial Endotoxin          use prior to completion of this 60 minute test. However, it is 
                             possible to perform an ‘in-process’ LAL test with incubation period 
 Contents                    of only 20 minute or less, and should be performed.  In addition to 
 Acceptance Criteria
 Discussion                  the gel-clot method, two other methods: turbidimetric and kinetic 
 Example Procedure           are possible alternate that can be considered. A full 60 minute test 
                             may be performed at a specified time post-release if required. It is 
                             recommended that the shorter version LAL test is validated for its 
                             applicability. USP specifies that the product can be distributed 
                             under control after the bacterial endotoxin test is initiated. 
                             However, endotoxin test results should meet the acceptance 
                             criteria before administrating the product to humans. 
                             The Chromogenic test is demonstrated here.  This test is 
                             complete in 20 minutes and gives a quantitative value for the 
                             concentration of the endotoxins in the sample.  This is very useful 
                             for trending endotoxin levels.
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                              Bacterial Endotoxins Procedure
  Radiopharmaceutical 
       Production                             The 20 minute Endosafe PTS method
                                 Methodology:  The Endosafe PTS method involves a prepared, 
 QC Testing                      pre-calibrated cartridge which is loaded with all necessary 
                                 reagents.  The cartridge is inserted into the PTS system, loaded 
 Baterial Endotoxin              with the radiotracer, and the test is performed in less than 20 
                                 minutes.  The tracer may need to be diluted with buffer or LAL 
 Contents                        water. In general, for each tracer, a 1:20 dilution is required.
 Acceptance Criteria
 Discussion                      Performing a Routine Test: Press the MENU key on the PTS 
 Example Procedure
                                 keypad to turn the unit on. The unit will perform a self test and 
                                 heat itself to 37 ºC.  This will take approximately 5 minutes. The 
                                 unit will display "SELF TEST OK" then "INSERT CARTRIDGE.“ 
                                 Remove a cartridge from its packaging and insert it into the unit.  
                                 The unit will heat the cartridge to 37 ºC. Dispense the sample:  
                                 With (4) separate pipette tips, place 25 µL of sample into each of 
                                 the four wells. Press ENTER on the keypad to start the test.
                                 Test Results: When the test is complete, the PTS reader gives an 
                                 audible signal and displays the results. 
                         Link to Demonstration
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