Protection Provided by a Sterile Compounding Glove Box

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.

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.