The leak tightness of a closed RABS depends on the industrial safety requirements and the occupational exposure limit value
of the product being handled (10). A RABS must be sealed tighter for products with lower personnel exposure limits and for
which personnel protection is reduced or limited. As sealing requirements increase, the cost of a RABS approaches the cost
of an isolator. In addition, flexibility is reduced because simple transfer systems are no longer sufficient to achieve good
tightness. Postproduction system cleaning also has cost implications. The higher the expectations of an automated cleaning
system (e.g., a washing-in-place system), the higher the expenditure for the process systems. The cost of the RABS system therefore can
approach that of an isolator.
Restricted-access barrier systems are more than just a physical barrier. The systems also require careful handling of interfaces,
interventions, and material transfers. Processes surrounding the isolator and sanitation must be adapted and consistently
observed to take full advantage of RABS. Special aseptic-transfer techniques and solutions can be used with RABS, and they
provide much operational flexibility. Sanitation processes are more complex in a RABS system than in a traditional sterile
area. In addition, just as in isolation systems, glove handling and assembly at the gloveports in RABS are more complicated
because of sterility requirements.
RABS also have a critical disadvantage compared with an isolator installation. Cost savings cannot be achieved by reclassifying
working spaces because the minimum requirement for the RABS operation area must still be classified ISO class 7. For this
reason, a RABS is always a compromise. If operators accept numerous restrictions, they can enjoy increased flexibility and
reduced validation and revalidation expenditure compared with the isolator, resulting in improved production quality in existing
Johannes Rauschnabel is a director of process engineering and a coordinator for barrier systems and the PharmaLab at Bosch Packaging Technology,
Pharma Liquid, Crailsheim, Germany, tel. 149 7951 402 452, email@example.com
Submitted: June 29, 2006. Accepted: Aug. 23, 2006.
Keywords: aseptic processing, barrier systems, cleanrooms, isolators
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2. International Organization for Standardization (ISO), EN/ISO 14644, Clean Rooms and Associated Controlled Environments— Part 1: Classification of Air Cleanliness (ISO, Geneva, Switzerland, 1999).
3. US Food and Drug Administration, Guidance for Industry, Sterile Drug Products Produced by Aseptic Processing—Current Good Manufacturing Practice (FDA, Rockville, MD, 2004).
4. European Commission (EC), EC Guide to Good Manufacturing Practice—Revision to Annex 1: Manufacture of Sterile Medicinal Products (EC, Brussels, Belgium, 2003).
5. ISO, EN/ISO 14644, Clean Rooms and Associated Controlled Environments—Part 7: SD-Module (ISO, Geneva, Switzerland, 2005).
6. J. Lysfjord and M. Porter, "RABS Survey Data," paper presented at the ISPE 14th Annual Barrier Isolation Technology Forum,
Arlington, VA, 2005.
7. International Society for Pharmaceutical Engineering, "Restricted Access Barrier Systems (RABS) for Aseptic Processing:
ISPE Definition," http://
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9. ISO, EN/ISO 14644, Clean Rooms and Associated Controlled Environments—Part 7, Appendix C7: Sleeves and Gloves (ISO, Geneva, Switzerland, January 2005).
10. Berufsgenossenschaft der chemischen Industrie [Professional Association of the Chemical Industry], Merkblatt M 057, "Sicherer
Umgang mit Gefahrstoffen in der pharmazeutischen Industrie" [instruction sheet M 057, "Safe Handling of Hazardous Materials
in the Pharmaceutical Industry"], Dr. Otto Pfeffer, Ed. (Jedermann Verlag, Heidelberg, Germany, 1999).