Clean air and containment equipment plays a critical role in day-to-day pharmacy operations, especially for the preparation of sterile injectable drugs. A glovebox isolator, or pharmacy glovebox, is essential pharmacy equipment for minimizing potential contamination and exposure during compounding.  According to USP <797>, these types of primary engineering controls must provide ISO Class 5 or better air quality when being used to perform compounding activities.

When product protection of non-hazardous drugs is required, a compounding aseptic isolator (CAI) offers a contained, positive pressure work area.  When working with hazardous pharmaceutical compounds, a compounding aseptic containment isolator (CACI) provides both personnel and product protection within a contained, leak-tight negative pressure work area.

Product Protection in a Compounding Aseptic Isolator

The pressure balance of this type of pharmacy glovebox ensures product protection.  The isolator main chamber pressure (vs. ambient) is positive to the room.  It is best that the main chamber be slightly more positive than the pass-thru interchange to maintain aseptic conditions in the main chamber.

Unidirectional (downflow) airflow purges airborne particulates from the work area.  A full-ceiling, front-loading HEPA supply filter provides better than ISO Class 5 (Class 100) air within the pass-thru and main working chambers.  This filter configuration creates an internal airflow from top to bottom to achieve a piston effect, sweeping aerosols and particulates from the work area to the HEPA filter.  The plenum should apportion and distribute air across, then through the HEPA supply filter, which will improve downflow uniformity, extending useful filter file and reducing noise.  Additionally, use of a front loading filter mount provides a direct seal of the filter to the plenum, which simplifies filter replacement.

A positive pressure compounding isolator only provides product protection, not operator or environmental protection. Cabinet construction is typically not leak tight, and unfiltered air is exhausted to the room.  Therefore, positive pressure isolators should only be used for aseptic compounding of non-hazardous pharmaceuticals.

Containment, Personnel and Product Protection in a Compounding Aseptic Containment Isolator

In a containment pharmacy glovebox, the isolator pass-through interchange and main chamber pressure (vs. ambient) are negative to the room.  The pass-through interchange should be slightly more negative than the main chamber to prioritize cleanliness in the main chamber while ensuring containment of hazardous compounds throughout the isolator.  The interchange door and inter-chamber door should be mechanically interlocked to prevent both doors from being opened simultaneously.

Like the positive pressure glovebox, unidirectional (downflow) airflow purges airborne particulates from the work area.  A full-ceiling, front-loading HEPA supply filter provides better than ISO Class 5 (Class 100) air within the pass-thru and main working chambers.  This filter configuration creates an internal airflow from top to bottom to achieve a piston effect, sweeping aerosols and particulates from the work area to the HEPA filter.

Unlike the positive pressure glovebox, the negative pressure glovebox is hard ducted to a facility’s HVAC system and utilizes HEPA exhaust filters below the work surface.  Air from the work area is filtered before being exhausted to the building’s exhaust system.  It is optimal to be able to remove filters using a bag-out provision to contain hazardous compounds prior to disposal.  Additionally, negative pressure isolators must be gas-tight and meet the American Glovebox Society leak rate requirements (0.5% to total volume) in order to ensure personnel protection.

A negative pressure compounding aseptic containment isolator offers a contained, leak-tight, negative pressure work area suitable for hazardous pharmaceutical compounds, chemotherapy agents or IV admixtures that can be harmful to pharmacy personnel.

Compounding Aseptic Isolators vs. Compounding Aseptic Containment Isolators

Compounding Aseptic
Isolator
Compounding Aseptic
Containment Isolator
For Use with non-hazardous
pharaceutical compounds
hazardous
pharaceutical compounds
Pass-Through Interchange Pressure +
Work Chamber Pressure ++
Protection Profile Product Protection Yes Yes
Operator Protection n/a Yes
Environmental Protection No Protects environment from particulates. Also protects environment from vapors and gases if connected to a treated exhaust system.
Downflow HEPA HEPA
Exhaust Vented to Room HEPA filter to facility exhaust system through a hard connection

For More Information

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