The current USP requirements for particle monitoring can be summarized as ‘to prove that a cleanroom, or clean device, meets the defined ISO 14644-1 classifications.’ Therefore, laminar flow hoods used in the manipulation of sterile product should meet ISO 5 limits. Background areas and ante rooms should meet either ISO 7 or ISO 8, depending on the activities performed in those areas.
To ensure that the designated zone is maintained in a clean state, a particle monitoring program should be designed based upon contamination risk to finished product quality. The ISO 14644-2 standard is referenced and is the recertification schedule for proving continued compliance. However, this is not a monitoring program. The Parenteral Drug Association (PDA) offers guidance pertaining to monitoring frequency which is based upon risk in manufacturing environments and is in accord with FDA requirements.