Isolators and RABS in Aseptic Process

Isolators and RABS are two technologies used for mitigating contamination risks in the manufacture of sterile medicines through aseptic process.

As per EU GMP Annex 1,

RABS, short for restricted-access barrier systems, isn’t just a combination of physical barriers (gloves, glass surfaces, etc.) with a unidirectional airflow pattern or laminar flow, but a setup focused on reducing the risk of product contamination. These measures include monitoring systems for both viable and non-viable particles, validated manual or automatic decontamination systems, the opening of barriers only in exceptional cases and the recording of each event through a risk assessment, plus other SOPs for the entry and exit of materials.

RABS have distinct design characteristics, which according to the ISPE are:

-Rigid wall enclosure

-ISO 5 unidirectional airflow in the critical area (ISO 7 in the room in operation)

-Sterilisation-in-place (SIP) for parts in contact with a liquid product, if possible

-Sterilisation in autoclave and aseptic assembly.

-Autoclave sterilisation for parts in contact with the product.

-Materials entry through transfer systems that prevent the exposure of sterile surfaces to less clean area.

-Use of glove ports

-Disinfection of all parts without direct contact before each batch.

RABS can be classified as passive systems when using the existing HVAC in the room, or active when equipped with built-in fans. They can also be classified as open RABS with airflow overspill to an ISO 7 or ISO 5 background, or closed RABS including closed ducted systems. They are also classified according to a leak rate.

An important point to consider in the design of an aseptic product line is how the transfer of materials takes place: the objective is to minimise the time of transfer and/or exposure to areas of lower classification thus mitigate the risk of contamination.

There are three types of transfer:

-Mobile laminar flow or closed containers

-Bags or containers previously sterilized.

-Isolators for aseptic zones


Isolators are defined as sealed enclosures that may contain a qualified controlled environment and are at variance with the surrounding conditions designed and tested to a level of leak tightness to international standards, typically ISO 14644-7 and ISO 10648-2. Isolators are used for handling products of high potency or toxic hazard.

The main causes of injectable drugs product recall are the presence of particles, lack of sterility and bacteria contamination.

Differences between RABS and Isolators

The main differences between isolators and RABS are the level of tightness and a different validation system. Validation of an isolator is performed by bioindicators, the validation of a RABS is similar to a traditional cleanroom.

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