Aseptic isolator and RABS

An isolator is, in Annex 1’s words, "an enclosure capable of being subject to reproducible interior bio-decontamination, with an internal work zone meeting grade A conditions that provides uncompromised, continuous isolation of its interior from the external environment". Operators work through gloves. A closed isolator transfers material only through aseptic connections and "remain[s] sealed throughout operations"; an open isolator lets material in or out through engineered openings, kept clean by continuous overpressure, and Annex 1 asks for airflow studies at those openings showing no air ingress (4.20 i c).

A RABS (restricted access barrier system) is "enclosed, but not fully sealed": a rigid-wall enclosure with integrated gloves that keeps a grade A interior separate from the surrounding cleanroom, with doors "rarely opened, and only under strictly pre-defined conditions". Annex 1 expects its interior surfaces to be treated by "routine application of a sporicidal agent using a method that has been validated" (4.22 ii); the automated, validated gassing cycle is the isolator’s requirement (4.22 i).

Where it sits: Around the critical zone of aseptic operations: filling, stoppering and capping, aseptic compounding, and sterility testing, wherever sterile product, containers or closures are exposed.

• —Sterile injectables fill-finish
• —Biologics and vaccine filling
• —Cell and gene therapy aseptic steps
• —Hospital and compounding aseptic preparation
• —Sterility testing laboratories (isolators)

In the reference facility: Aseptic filling & isolator line, Microbiology & environmental monitoring laboratory

Not covered on this page: Biosafety cabinets and containment for operator protection only; Negative-pressure containment isolators for potent or radioactive products, except where noted; Full-suit systems.

• 01Rigid enclosure and window panels. The physical barrier between the grade A interior and the room; its seals and gaskets are part of the barrier.
• 02Glove ports, gloves and sleeves (or half-suits). The only way an operator reaches inside, and a common point of barrier failure, which is why Annex 1 sets glove testing frequencies (4.21).
• 03HEPA-filtered air supply and fans. Deliver grade A air and, where the design needs it, unidirectional first-air protection over exposed product.
• 04Pressure control (dampers or fan speed). Holds the enclosure positive to its surroundings (negative only where containment is essential).
• 05Transfer systems: rapid transfer ports (RTPs), airlocks, aseptic connections. Move material in and out without opening the barrier; each is a potential breach.
• 06Bio-decontamination generator and distribution (isolators). Delivers the sporicidal agent, usually vaporised hydrogen peroxide; see the VHP system page.
• 07Control system and data recording. Runs cycles, alarms and interlocks, and keeps the record of each.

Connects to: Background cleanroom and its HVAC; Process equipment inside the enclosure (filling machine); Sterilised components entering through transfer systems; Building management or SCADA for alarms and records.

• 01Differential pressure transmitter. Enclosure pressure relative to the surrounding room, and pressure drop across filters. Watch for: ports connected the wrong way round, reversing the sign.
• 02Airflow velocity probe (anemometer). Air speed in the critical zone at the qualified working plane. Watch for: readings taken at a different height from the one qualified.
• 03Optical particle counter. Non-viable particles in the critical zone during operation. Watch for: sample tubing long or bent enough to lose large particles.
• 04Glove leak tester. Integrity of each glove and port assembly. Watch for: a test that passes a pinhole below its detection capability.
• 05Humidity sensor. Humidity of the enclosure air, which the decontamination cycle depends on. Watch for: condensation or peroxide exposure shifting the sensor.
• 06Temperature sensor (RTD or thermocouple). Enclosure air temperature. Watch for: sensor not at the location that matters (cold spot, load centre).

• 01Pressure differential (setpoint, Pa). Enclosure to background room; positive unless containment is essential (Annex 1, 4.19 i c).
• 02Pressure differential (limit, Pa). The alarm and action limits the site qualified for its own design; not a universal figure.
• 03Airflow velocity (measured, m/s). At the working plane over exposed product, where the design requires unidirectional flow.
• 04Airborne particle concentration (measured, particles/m³ per size channel). In the critical zone, in operation, against grade A limits.
• 05Glove integrity test result (attribute, pass / fail against a defined criterion or Pa over a defined time). Per glove, at the start and end of each batch or campaign as a minimum for isolators (Annex 1, 4.21 i a).

SPEQ publishes no universal alarm or acceptance values: they depend on the process, the product and the site’s own qualification.

• 01Control loop: Pressure control. Adjusts fans or dampers to hold the enclosure differential.
• 02Alarm: Loss of pressure or airflow. Tells the operator the barrier conditions have moved outside their qualified range so the response can be decided.
• 03Interlock: Door and transfer-port interlocks. Prevent opening a door or port in a state that would breach the barrier, such as during gassing.
• 04Procedure: Glove inspection and testing. Visual inspection at each use and after any manipulation that may affect integrity, and leak testing at defined intervals (Annex 1, 4.21).
• 05Procedure: Intervention control. Defines which interventions are allowed through gloves and what happens after a barrier is opened.

An alarm asks for a response; an interlock stops an action; a safety function protects people and has its own risk basis.

• 01Design and risk assessment. User requirements and intended use; Contamination control strategy covering the background grade decision (Annex 1, 4.20); Airflow and transfer design review.
• 02Supplier and factory testing. Factory acceptance tests; Material certificates for gloves and seals; Leak test of the enclosure.
• 03Installation and qualification. Filter integrity (installed leak) tests; Airflow velocity and visualisation (smoke) studies; Pressure differential and alarm tests; Classification of the grade A zone (Annex 1, 4.23–4.25; Annex 15).
• 04Process qualification. Bio-decontamination cycle validation (isolators); Sporicidal disinfection validation (RABS); Aseptic process simulation (media fill) covering interventions.
• 05Routine operation. Glove inspections and leak tests; Environmental monitoring; Cycle and alarm records.
• 06Change and requalification. Change control for load, glove or transfer changes; Periodic integrity and leak testing of the isolator system (Annex 1, 4.21 i b).

• 01EU GMP Annex 1: Manufacture of Sterile Medicinal Products — European Commission (EudraLex Volume 4), 2022 revision, in operation 25 August 2023. EU / EEA; revised jointly with the PIC/S Committee; in force. Supports: Definitions of isolator and RABS (glossary); design (4.19), background grade (4.20), gloves and leak testing (4.21), cleaning and bio-decontamination (4.22), qualification (4.23–4.25).
• 02EU GMP Annex 15: Qualification and Validation — European Commission (EudraLex Volume 4), 2015. EU / EEA; in force. Supports: Qualification approach the grade A zone and the barrier are qualified under (Annex 1, 4.24).
• 03PI 014-3: Isolators Used for Aseptic Processing and Sterility Testing — PIC/S, 25 September 2007. PIC/S participating authorities (recommendation); guidance. Supports: Inspectorate recommendation on isolators for aseptic processing and sterility testing.
• 04ISO 13408-6: Aseptic processing of health care products — Part 6: Isolator systems — ISO (TC 198), 2021 (Edition 2). International; consensus standard. Supports: Specification, qualification, bio-decontamination, validation and control of isolator systems; does not cover RABS or sterility-testing isolators.
• 05ISO 14644-7: Cleanrooms and associated controlled environments — Part 7: Separative devices — ISO (TC 209), 2004 (revision at enquiry as ISO/DIS 14644-7). International; consensus standard. Supports: Design, construction, installation and test of separative devices, including isolators.
• 06Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing — Current Good Manufacturing Practice — US FDA, September 2004. United States; guidance. Supports: FDA’s expectations for aseptic processing in the United States, including its appendix on isolators.