The Restricted Access Barrier System (RABS) is a separative enclosure with a purpose of mitigating microbial contamination risk in aseptic manufacturing facilities. Isolation technologies achieve this by separating personal from the aseptic environment and limiting personnel interaction with sterile materials. RABS involve clear barriers with glove ports (leak tested gloves – minor interventions) and doors that may be opened for maintenance (major interventions).
RABS is a recent innovation in isolation technologies and while there are limitations, it holds key advantages. The main advantages of RABS over other isolator technologies is, the technology is relatively low cost, few validation requirements and it allows flexibility of access.
Evolution of RABS
In the early days of aseptic processing, gloveboxes were used to provide separation between the operator and “sterile field”, providing greater control over microorganisms. In the 1950s, use of HEPA filters allowed development of clean rooms, where gowned personnel could operate equipment resulting in much greater throughput. However, isolation technology was reintroduced in 1980s as it was recognised as providing superior contamination control.
Isolators were perceived as inflexible and had added requirements of leak testing and decontamination. Partial barriers were also used to provide a degree of separation in cleanrooms. This evolved into the restricted access barrier system.
Advantages of Restricted Access Barrier Systems vs. Isolator Technologies
RABS provides contamination control with added advantages over isolation technologies.
- The main advantage of RABS is that it allows flexible access for equipment maintenance where necessary.
- Lower initial capital investment. Operational costs may be higher due to some additional gowning requirements.
- Lower validation requirements – this may change as validation requirements for RABS are not yet defined.
Limitations of Restricted Access Barrier System
- RABS are not as effective as isolators in contamination control. This is because isolators provide a measurable pressure differential while RABS rely on air overspill. Further isolators are frequently decontaminated.
- While RABS do allow access via glove ports (minor interventions) and doors (major interventions), some areas may be difficult to access (depending on design).
- Limited human interventions are a risk to advanced aseptic processing security.
- RABS cannot be used for cytotoxic products as containment is minimal.
The Future of RABS?
In the near future the Restricted Access Barrier System will become more common in cleanrooms since it offers cost effective contamination improvements while still allowing human interventions. However, any form of intervention reduces control over microorganisms. While RABS interventions are controlled (with validated recovery times etc), they still pose some degree of risk. Advancements in flexible robotics, in-process control, equipment self diagnostics and self-correction, information technology etc may lead the way to next level of contamination control without human interaction. This will lead to obsolescence of barrier systems such as RABS. Too soon to plan for this yet though!