What determines the exposure duration for critical sites to worse than ISO 5 air?

The exposure duration for critical sites to air that is worse than ISO 5 conditions is primarily determined by the nature of the critical site. Critical sites refer to areas where sterile product contact can lead to contamination, such as the access ports, syringe tips, or where sterile components come together. The microbiological risk associated with these sites is influenced by factors such as their physical characteristics, the likelihood of contamination occurring, and how they are handled during the compounding process.

For instance, sites that are more susceptible to contamination due to their structure or exposure patterns will require more stringent control measures and limited exposure times to maintain sterility. This necessitates awareness of how long these critical sites may be exposed to compromised air quality, which can impact the overall sterility of the compounded sterile preparation (CSP). In contrast, while the volume of the CSP, method of administration, and concentration of active ingredients may influence the overall safety and efficacy of a product, they do not fundamentally determine the risk of contamination at the critical site in the same manner as the characteristics of the site itself.