Candice Sun

Candice Sun

Specialist, Scientific Affairs, CN

December 07, 2020

Best Practice for Reducing Coring and Fragmentation

For injectable drug products, coring and fragmentation of elastomer stoppers is a critical concern. This is caused by tearing or shearing a fragment of the stopper in a vial during insertion of a needle or a spike. The cores/fragments that enter the drug product may lead to harmful patient outcomes. Testing of stoppers is a must for many pharmacopeias. Coring and fragmentation is complex and influenced by many factors, in particular the stopper and the needle.


The first factor is the stopper; formulation, design, siliconization, and sterilization have an effect. Generally, the softer the stopper and the thinner the diaphragm, the lower the level of cores/fragments. Also, siliconization may lower the level of cores/fragments. Regarding sterilization, steam processed stoppers have lower levels as compared to those gamma processed. Compression force may also have an effect; high compression forces should be avoided. As expected, stoppers intended for multi-dose application will see higher levels.

The second factor is the needle; type, gauge, needle lubricity, and penetration force have an effect. Very importantly, also having an effect on the level of cores/fragments are the angle of puncturing, speed of puncturing, location of puncture, and reuse of needle. These points are the focus of a new Technical Report by West: Impact of Piercing Techniques on Stopper Coring & Fragmentation. Studies showed that different piercing techniques and practices could result in stopper coring and fragmentation issues. Hence, to reduce levels of cores/fragments, it is recommended that healthcare professionals and end users follow best practices such as piercing within the target ring to avoid hitting stopper legs, piercing at appropriate speeds, and limiting reuse of needles.

West’s commitment to patient safety involves developing and supplying components that can meet not only the requirements of pharmacopeias, but comply with even stricter standards. For more on how West can help in stopper selection, contact a Technical Customer Service (TCS) representative or Account Manager.

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