What are the GMP Requirements for Airlocks?

Without airlocks between cleanroom areas of different cleanroom classes, no flow of material or personnel would be possible. But what are the GMP or purity requirements for airlocks?

The production of medicinal products must take place in clean areas. For sterile medicines, for example, the EU GMP Annex 1 and the FDA Aseptic Guide regulate which cleanroom zones are required. And even if, as in the production of solids, there is no designation of a required cleanroom class, an internally defined zoning into clean and unclean areas is required. Clean and unclean areas are never directly connected. Exchange of material or access of personnel takes place via airlocks. In these airlocks, the cleanliness is actively increased before the 'cleaner' area may be entered. In the case of material, this is done, for example, by removing outer packaging and/or disinfecting surfaces. For personnel, this is done by changing their clothing to cleanroom clothing appropriate for the zone and disinfecting their hands. The disinfectant dispenser should be located just before the entrance to the cleaner side of the airlock.

But what requirements apply to the airlocks themselves, which connect clean and less clean areas? For example, for an airlock from cleanroom class D to C, which is divided into the D and the C area by means of a swing-over bench.

Structurally, the airlock corresponds to the cleaner area, i.e. zone C. The ventilation also corresponds to the cleaner area C, i.e. for particle monitoring, the requirements of the cleaner side C must be met. This applies to both 'at rest' and 'in operation' measurements, i.e. with and without personnel. Here, the supply air should enter on the cleaner side of the airlock.

When testing the microbiology by means of a swab test, a distinction is made between qualification (at rest) and in operation. While the entire airlock must meet the requirements for C during qualification, a distinction is made during operation. During operation, the D side of the airlock is tested for compliance with the microbiological requirements for D, the C side for the requirements of C. In contrast to the air, which is distributed in the room together with the particle load, the swab tests of the test for germs are carried out in a defined location on surfaces of the C and D sides.

When it comes to airlocks, people often ask whether zones can be skipped. The answer is: No. Today, GMP inspectors expect an airlock between each cleanroom zone, where cleaning is expected from the less clean side to the cleaner side. An exception can be actively ventilated material pass-throughs.