One thing is clear: new air quality requirements for compounding. The traditional critical air environment of ISO Class 5, must now be surrounded by a positive pressure buffer room of ISO Class 7.(2, 3) The buffer room is required if the critical area is in a Laminar Airflow Workbench (LAFW); it is recommended if the critical area is within a Barrier Isolator.(2)
Pharmacists also are being asked to implement and improve the air environment surrounding the production of hazardous drugs.
Hazardous drug compounding should be done in a biological safety cabinet, vented 100 percent to the outside, according to The National Institute for Occupational Safety and Health (NIOSH), in September 2004.(4)
The cabinet should be in a negative pressure cleanroom, as recommended in a December symposium sponsored by the American Society of Health System Pharmacists (ASHP).(5) A USP subcommittee on 797 is "working on statements" concerning the air flow and the pressure of the cabinets' location. Those proposals may also be published in the April revisions.
A cleanroom is the best way to create the buffer room. It consists of smooth, impervious floor, walls and ceiling with proper vents and doors, to support the heart of a cleanroom, the HVAC with HEPA filters, which controls the air pressure, creating the ISO Class 7 during operation. It also maintains the desired temperature and humidity. The HVAC basically operates itself, making the room a clean, simple, and thus employee friendly way to be compliant and produce safe product.
Consider possible layouts of the "Cleanroom Complex" as one ASHP panel expert describes it.(5) The ante-room, or gowning room, can open to two positive pressure rooms, with one for low to medium risk compounding and the other for high-risk; or a positive pressure room for all three levels; or a positive pressure and a negative pressure room; or just one positive pressure room. Rooms connect only through hands-free doors or strip curtains, and if needed, pass through cabinets for product.
This set-up insures that air flow and pressure is ALWAYS maintained in the buffer room to provide as clean an environment as possible. As one Texas pharmacist put aptly, "an atmosphere with the least amount of chance of a problem."(6)
Not only is the atmosphere as safe as possible, it can be argued that the cleanroom complex promotes good aseptic procedure.
Simply having to enter a special area, don special garb, and pass through another door into an environment containing only the needed equipment, promotes the mindset that special and proper procedures are routine in the space. Documented and non-documented are observed and self-caught lapses in good technique or practice; the cleanroom complex fosters attention to standard practices. A technician's work quality and productivity is enhanced, not hurt, by putting the traditional Laminar Airflow Workbench (LAFW) into a cleanroom.
With its temperature and humidity controls, its professionally designed HEPA filtering and HVAC specific to the critical area location, and its modular construction, the cleanroom provides the safest, most durable and viable compounding atmosphere, particularly as one looks years ahead. Future compliance requirements, increase in space needs due to growth in amount of compounding, or to change to physical space is all easily accommodated through the modular construction. Cleanrooms provide a clean environment for using any equipment, benches, or cabinets.
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