Radiopharmaceutical Production QC Testing Bacterial Endotoxins STOP

Bacterial Endotoxins All the pharmacopeia require that radiopharmaceuticals intended for intravenous administration must be tested to ensure that the pyrogen concentration is within acceptable limits. 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). Contents Acceptance Criteria Discussion Example Procedure STOP

Acceptance Criteria Acceptance Criteria: Not More Than 175 EU in the total administered dose. The total administered dose is the maximum administered volume at expiration stated in milliliters. This is often written as 175EU/V. This test should be completed on every batch. The batch may be released prior to completion of the test but should the dose should not be injected into a patient 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.

Discussion 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 18F isotope. Consequently, product may be released for patient use prior to completion of this 60 minute test. However, it is possible to perform an ‘in-process’ LAL test with incubation period of only 20 minute or less, and should be performed. In addition to the gel-clot method, two other methods: turbidimetric and kinetic 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.

Bacterial Endotoxins Procedure The 20 minute Endosafe PTS method Methodology: The Endosafe PTS method involves a prepared, pre-calibrated cartridge which is loaded with all necessary reagents. The cartridge is inserted into the PTS system, loaded with the radiotracer, and the test is performed in less than 20 minutes. The tracer may need to be diluted with buffer or LAL water. In general, for each tracer, a 1:20 dilution is required. Performing a Routine Test: Press the MENU key on the PTS 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

Return to Main Menu