May 18, 2015
Andrew Jaeger

The terminology used in USP <797> is a bit ambiguous and often inconsistently used throughout the document, which results in a lot of confusion. This is an attempt to clarify some of the most frequently asked questions, and avoid some of the most common mistakes in the design and construction of pharmacies.

When and Where do the USP<797> Standards apply?

The standards outlined in USP<797> are intended to apply to all persons who prepare CSPs (Compounded Sterile Preparations) and all places where CSPs are prepared (e.g., hospitals and other healthcare institutions, patient treatment clinics, pharmacies, physicians' practice facilities, and other locations and facilities in which CSPs are prepared, stored and transported).

Important Equipment terminology you should be familiar with:

Primary Engineering Control (PEC): A device that provides an ISO Class 5 environment for compounding CSPs. Such devices include, but may not be limited to, laminar airflow workstations (LAFWs), biological safety cabinets (BSCs), compounding aseptic isolators (CAIs) and compounding aseptic containment isolators (CACIs).

Direct Compounding Area (DCA): The area within the ISO Class 5 primary engineering control (PEC) where CSPs are being manipulated.

Laminar Airflow Workstation (LAFW): The purpose of LAFWs is to protect the CSPs being compounded from contamination by the operator or environment. The use of these devices is only for non-hazardous CSPs. These devices are usually the 100% re-circulatory type and come in two styles, Horizontal and Vertical Laminar flow.

Horizontal Laminar Flow BSC

Biological Safety Cabinets (BSC): These are vented cabinets meant for the protection of personnel, products and environment, having an open front with inward airflow for personnel protection, downward high-efficiency particulate air (HEPA)-filtered laminar airflow for product protection and HEPA-filtered exhausted air for environmental protection. These cabinets are recommended for hazardous CSPs.  Air drawn by the BSC must be exhausted outdoors.

Compounding Aseptic Isolator (CAI): This form of isolator often referred to as a “glove box” is designed to maintain an aseptic environment within itself.  A compounding aseptic isolator (CAI) provides the worker protection from exposure to undesirable levels of airborne drug throughout the compounding processes and provides an aseptic environment for compounding sterile preparations. Air exchange with the surrounding environment does not occur without the air first passing through a microbial retentive filter (HEPA minimum). Where volatile hazardous drugs are prepared, the exhaust air from the isolator should be exhausted to the outside by properly designed building ventilation. Although they are available in both positive and negative air flow models, they are typically used for hazardous CSPs.

Existing Pharm - CAI

Compounding Aseptic Containment Isolator (CACI): This is a form of CAI, and is specifically designed for compounding pharmaceutical ingredients or preparations and to provide worker protection from exposure to unacceptable levels to drug exposure. 100% exhaust of the air is required while dealing with hazardous substances. Air exchange into and out of the isolator occurs through HEPA filters.

Existing Pharm CACI

Closed-System vial Transfer Device (CSTD): A Closed System Vial Transfer Device is a generic term used to describe a device that does not allow any substance to escape outside the vial or bag during the transfer process. This includes vapors, liquids, powders, etc.  A CSTD system is normally used during hazardous compounding.

Hazardous Drug (also referred to as Cyto-Toxic Drugs): Drugs are classified as hazardous if studies in animals or humans indicate that exposures to them have a potential for causing cancer, development or reproductive toxicity, or harm to organs. These drugs are normally associated with chemotherapy compounding. (Refer to current NIOSH  (National Institute of Occupational Safety and Health) publications for a list of drugs considered to be toxic.) All hazardous drugs must be prepared and stored in a negative pressure room.

Important Architectural terminology you should be familiar with:

Buffer Area (Commonly referred to as the Clean Room or Buffer Room): The area where the primary engineering control (PEC) is physically located. Activities that occur in this area include the preparation and staging of components and supplies used when compounding CSPs. The concentration of the airborne particles is required to meet the level of cleanliness of ISO (International Organization for Standards) Class 7.

Ante-Area (Commonly referred to as an Anteroom): An ISO Class 8 or better space leading into and out of the clean room/buffer area, where personnel hand hygiene, garbing procedures and other high-particulate-generating activities are performed. Anterooms are transition spaces, which provide assurance that pressure relationships are constantly maintained so that air always flows from clean to dirty areas, and reduces the need for the heating, ventilating and air-conditioning (HVAC) control system to respond to large disturbances. (If the architectural design incorporates a common anteroom shared between both hazardous and non-hazardous clean rooms the anteroom must be ISO Class 7) 

Non-hazardous clean rooms should be maintained at 0.02-inch to 0.03-inch positive pressure with respect to their anterooms, which, in turn, should be maintained at 0.02-inch positive air pressure with respect to the adjoining circulation spaces. Hazardous clean rooms should be maintained at 0.02-inch negative pressure with respect to their anterooms, which, in turn, should be maintained at 0.02-inch positive air pressure with respect to the adjoining circulation spaces.

Each anteroom shall be equipped an automatic hand washing basin. Anterooms serving hazardous clean rooms should also be equipped with an eyewash station.

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