Annex 1 and material transfer: an interview with Tim Sandle

Our meetings with Tim Sandle continue: in this issue of our CCNews we talk about material transfer.

Comparison with previous version of the Annex 1

The changes required by Annex 1are important and significant.

New Annex 1 elaborates on airlocks and states that they must be designed and used to ensure physical separation and to minimise microbial and particle contamination of different areas. The last step of the airlock must be the same grade as the area to which it gives access.

4.10 The transfer of equipment and materials into and out of the cleanrooms and critical zones is one of the greatest potential sources of contamination. Any activities with the potential to compromise the cleanliness of cleanrooms or the critical zone should be assessed and if they cannot be eliminated, appropriate controls should be implemented. Annex 1

The transfer of materials as well as the associated contamination risks are given great attention in the new Annex 1. The CCS leaves nothing to chance.

What is new compared to past revisions of the document?

In the new Annex, microbiological contamination from materials entering the cleanroom is provided with a far greater emphasis. This has been identified as one of the major routes of contamination for items coming into the facility. The optimal means of transfer is via a double-ended autoclave and using moist heat. Where this is not possible, of where single-use sterile items are required, then a disinfection process is required. This can be automated (as with a decontamination chamber using a vapour like hydrogen peroxide or chlorine dioxide) or a manual process using a transfer hatch equipped with a localised HEPA filter air supply.

The Annex places emphasis upon both cleaning and disinfection. Most disinfectants are very poor at penetrating ‘soil’ and therefore items need to be cleaned prior to the application of a disinfectant.

The Annex also indicates that the disinfectant should be ideally sporicidal and that a sporicide is required for the transfer of materials from Grade C to Grade B. It is also important that items being transferred in are multi-wrapped and that a layer of wrapping can be removed at each stage of the transfer process as the item moves from the external area and through the cleanroom cascade.

Critical steps in the material transfer process

What are the most critical steps in the materials transfer process?

Bacterial spores in the Grade A environment present a significant risk of contamination in aseptically prepared products and potential patient harm. Ensuring that any spores (plus vegetative organisms are not transferred in from Grade C to Grade B is critical. This is to ultimately protect Grade A environments.

In assessing this, an understanding of how goods arrive into a warehouse and end up in the aseptic processing area.

To carry out this task correctly, a quality risk assessment is required. The risk assessment will need to address:

      • The packaging: Are there sufficient layers? Is the packing resistant to the disinfectant?
      • Detergent: Is the detergent suitable for cleaning? Is the detergent compatible with the disinfectant?
      • Disinfectants: Is the disinfectant sporicidal? Has the disinfectant been validated? Is there a risk of residuals?
      • Environmental monitoring: Has the transfer disinfection process been qualified? (it is normal to carry out at least three simulations of wort-case load transfers and to conduct surface environmental monitoring). In addition, at what frequency will this be verified? Here any manual process is subject to variations in technique and there needs to be regular assessment in place. Furthermore, ongoing monitoring of the bioburden associated with incoming items should be undertaken and understood in terms of microbial numbers and species variation.
      • Non-routine items: How will atypical or non-routine items be handled? What is this risk assessment process in place for these?
      • Procedure: It is important that the entire process is documented and that the procedures are used to facilitate personnel training.

With the disinfection step, because there is a high risk of contamination therefore the disinfection process must be carefully controlled. Maintaining a wet contact time is critical for effective disinfection. If the validated time is not being achieved, contamination may persist on the surface of the items.

Material transfer with biodecontamination system

4.11 The transfer of materials, equipment, and components into an aseptic processing area should be carried out via a unidirectional process. Where possible, items should be sterilized and passed into the area through double-ended sterilizers (e.g. through a double-door autoclave or depyrogenation oven/tunnel) sealed into the wall. Where sterilization on transfer of the items is not possible, a procedure which achieves the same objective of not introducing contaminant should be validated and implemented, (e.g. using an effective transfer disinfection, rapid transfer systems for isolators or, for gaseous or liquid materials, a bacteria-retentive filter). Annex 1

The pass-box should have an integrated bio-decontamination system. What are the specific requirements of this integration?

The optimal approach is to automate the decontamination process. This can be put in place using a biodecontamination chamber, for multi-wrapped items. These items must have been sterilised using a proven technology (all items entering Grade A must be sterile). Typically items are sterilised by radiation (such as gamma, X-rays or electron beam) or sometimes by a penetrative gas (such as ethylene oxide).

The most common technology for this is hydrogen peroxide vapour, although there are alternatives. The advantage is that, through development, the process can be qualified and demonstrated to be consistent. In addition, the level of microbial inactivation is far greater than can be achieved with a manual process. To demonstrate this, biological indicators can be used. It is important that the biological indicators selected have proven resistance to the decontamination agent (such as Geobacillus stearothermophilus for hydrogen peroxide vapour) and are of a suitable population to demonstrate a six-log reduction.

With cycle development, controlling key parameters like temperature, humidity, concentration of the biocide, and the contact time are each essential. Attention should be paid to load configuration and for this all items should be hung so that the decontamination agent can circulate around each item.

Items should also be multi-wrapped, enabling a layer of wrapping to be removed for the eventual transfer into Grade A. This is required because the vapours used for decontamination are only effective on the outer surfaces of the items placed within the chambers, they have no penetrative ability.

Activities to reduce contamination

And, if they do not have a bio-decontamination system, what are the main activities that can reduce the risk of contamination?

The most important steps for the manual process are to have a well-built transfer hatch (fashioned from good quality stainless steel) and or the hatch to have a local HEPA supply capable of delivering Grade A air.

Prior to use all surfaces of the hatch must be wiped with a sporicide, and then each item going in must also be treated with sporicide. Items should then be placed inside for the duration of the contact time under the localised HEPA airflow. The wiping of items with sporicide is essential, simply spraying is not effective.

Upon removal, the outer layer of each item must be removed.

Transfer methods

The science-based philosophy behind the new Annex 1 also affects material transfer activities, for which it is explicitly required:

4.13 Where materials, equipment, components and ancillary items are sterilized in sealed packaging and then transferred into the Grade A zone, this should be done using appropriate, validated methods (for example, airlocks or pass-through hatches) with accompanying disinfection of the exterior of the sealed packaging. The use of rapid transfer port technology should also be considered. These methods should be demonstrated to effectively control the potential risk of contamination of the Grade A zone and Grade B area and, likewise, the disinfection procedure should be demonstrated to be effective in reducing any contamination on the packaging to acceptable levels for entry of the item into the Grade B and Grade A areas.

How might this be achieved?

In summary to what we have covered, there is a hierarchy of transfer methods:

      • Autoclaving / depyrogenaton tunnels
      • Automated cycle decontamination chambers
      • ‘Dynamic’ pass-through hatches with HEPA filtered air supply

The important message is that all items that are intended for Grade A need to take this route, including culture media to be used for environmental monitoring. Drawing up a list of approved items is essential to avoid anything for being missed. This includes everything from tools to cables. For each item the route to be taken must be understood.

With the Annex 1 updated, ‘static’ pass through chambers with no air supply are no longer permitted. Organisations have until August 2023 to phase these out. Using risk assessment to mitigate this would not be acceptable.

Other, old-fashioned means of getting items in, such as personnel transferring items (e.g., via changing rooms) must be prohibited.


Don’t miss next Contamination Control News.

Coming next on CCN: Tim Sandle: Cleaning & disinfection e Hands disinfection

Dr. Tim Sandle is a pharmaceutical microbiologist, science writer and journalist. He is a chartered biologist and holds a first class honours degree in Applied Biology; a Masters degree in education; and has a doctorate from Keele University.

Interview by Cristina Masciola, AM Instruments – Marketing & Communication Manager