Why is it important to swab the rubber closure of vials with alcohol?

Swabbing the rubber closure of vials with alcohol is essential to prevent contamination. When a rubber stopper is punctured with a needle or other device, it can introduce potential contaminants into the vial. These contaminants might come from various sources, including environmental pathogens, particles, or residues from previous uses. By swabbing the closure with alcohol, you effectively reduce the microbial load on the surface, significantly decreasing the risk of introducing these contaminants when accessing the vial. This practice is crucial in sterile compounding and ensuring patient safety, as any contamination could lead to severe infections or compromised drug efficacy.

The other options, while related to vial handling, do not fully capture the primary objective of alcohol swabbing. For instance, although sterilizing before insertion might be a part of the broader goal of preventing contamination, the focus of swabbing is on minimizing risk upon accessing the vial. Checking for leaks and improving sealing are not relevant to the purpose of swabbing the closure, which specifically targets surface contamination risks.