What is the proper insertion angle when piercing a rubber stopper of a vial?

The proper insertion angle when piercing a rubber stopper of a vial is generally recommended to be between 45 to 90 degrees. This angle allows for an optimal entry point into the rubber stopper, minimizing the risk of damaging the stopper while ensuring that the needle can adequately penetrate the seal to access the contents of the vial.

Inserting at this angle balances the need for a secure entry while also preventing excessive force, which could lead to the formation of a larger than necessary hole, compromising the sterility of the vial and potentially allowing contaminants to enter. Additionally, this angle helps to ensure that the needle does not break or bend during the process.

A steeper angle, such as those outside the 45 to 90-degree range, may complicate the insertion process, increasing the likelihood of damaging the needle or the vial's seal. Therefore, following the recommended angle is crucial for maintaining the integrity of both the preparation process and the sterile environment.