What is the required ISO classification for the buffer area in sterile compounding?

The buffer area in sterile compounding must meet the requirements of an ISO Class 7 environment. This classification is crucial because the buffer area acts as a transition space between the controlled, sterile environment of the cleanroom and the outside areas.

ISO Class 7 allows for a certain level of particulate contamination, with a maximum allowable particle count of 352,000 particles per cubic meter for particles 0.5 micron or larger. This level of control is necessary to protect the integrity of compounded sterile preparations during the preparation and storage phases. Within this environment, compounding personnel can safely prepare sterile products while minimizing the risk of contamination.

In contrast, areas classified as ISO Class 5 are reserved for the direct compounding area where sterile product preparation occurs; this area requires much stricter controls to ensure that contamination levels are minimized to an acceptable standard. ISO Classes 8 and 9 have even higher allowable particulate counts and are not adequate for the buffer area, which requires stricter measures to maintain the standards necessary for safe sterile compounding practices.