Coring and Fragmentation of a Rubber Stopper

Coring and fragmentation are two typical events that can occur when a needle is pierced through a vial closure to withdraw drugs from the vial or expel drugs into the vial.

Despite being used interchangeably, coring and fragmentation are two different mechanisms.  Coring happens when a needle shears out cores (or slivers) from a rubber closure as it pierces the closure. Cores are, at times, longitudinal in shape. On the other hand, fragmentation is the formation of characteristically small, irregular particles when a needle pierces through a rubber closure and abrades the rubber material.

The two major factors causing coring and fragmentation are, of course, the rubber closure and the needle. Despite seeming simple to control, each comes with a number of variables that need to be addressed and regulated. Regarding the closure, the main concerns are the hardness of the rubber formulation and the thickness of the stopper diaphragm where the needle pierces through.

However, with regard to the needle, there are varying quality parameters (sharpness, consistency, etc.), designs (bevel angle, needle gauge, heel type, etc.) and textures (smoothness, siliconization, etc.). Also, there are different piercing techniques (speed, angle of puncture, number of times needle is reused, etc.) practiced by the many healthcare providers around the world and patients who are self-administering drugs at home.

To effectively prevent coring and fragmentation, it is critical that there is good communication between drug manufacturers and healthcare providers and/or at-home patients/caregivers. A drug manufacturer needs to understand the puncturing technique most commonly used by the intended healthcare providers. Similarly, healthcare providers should reach out to drug manufacturers to communicate their needs.

For more in-depth discussion about coring and fragmentation, please contact your Technical Customer Support representative.