Cleanroom Decontamination: Vaporized Hydrogen Peroxide (H₂O₂) Pass-Through Chambers

WHAT:

Vaporized Hydrogen Peroxide (VHP) Pass-through chambers are designed to safely bio-decontaminate and transfer small objects between differing classified areas of a cleanroom to save time and resources. These chambers serve as mini-isolators, facilitating the transfer of components into an isolator/filler after VHP has already been performed on the fill line or a transfer of components from a lower classification to a higher classification room has taken place. Heat-sensitive products and materials like wrapped components, syringes, petri-dishes, rubber stopper bags, API aluminum containers and sterile materials for validation that cannot be processed by moist or dry steam sterilization methods.

There are various technologies that achieve the same goal and are known by several different names: VHP Transfer Hatch, Rapid Decontamination System, Bio-decontamination System, VHP to name a few.

The VHP equipment is generally divided into two different categories: integrated and portable systems. Integrated VHP systems can be installed and integrated with common air handling components and building automation controls to provide decontamination through entire areas. These systems are best suited for frequent use as they minimize set up time and have the fastest cycle times. Portable VHP systems are often commonly used for rapid bio-decontamination of materials being passed through material airlocks and require no permanent installation.

HOW:

VHP is used to decontaminate. The H₂O₂ is heated, converted from liquid to gas, and is blown into the chamber, then creating a lethal environment capable of killing bacteria, viruses, and fungi. A factor that makes this process so appealing is the only heating that’s performed is the heating of the liquid H₂O₂ to vaporize it and then distribute into the chamber.

The sterilization process involves 3 phases:

1. Liquid H₂O₂ gets converted into vapor.
2. VHP fills the sterilization chamber (or room/equipment).
3. The vapor is vacuumed out of the chamber where it is circled back through a generator and broken down into water and oxygen.

The breakdown of H₂O₂ to water and oxygen reduces the aeration time and greatly lowers the toxicity risk.

REQUIREMENTS:

These pass-through chambers must meet the ISO Standard 22441:2022 for the development, validation, and routine monitoring and control of a low temperature sterilization process for medical devices using VHP as the sterilizing agent.

Specifically, hourly leak rates are important for operator safety to ensure H₂O₂ isn’t leaking during the cycle and inhaled. This also helps stabilize the concentration during the cycle.  If leaking, the concentration drops, therefore the cycle won’t be as effective. These chambers may be customized with glass, racks, trolleys, etc. depending on needs.

Cycle development must be performed similar to isolators depending on the product impact of the equipment being decontaminated.  If it’s going into a filler/isolator, the needs are the same requirement as Isolator cycle development.  If it’s cleaning supplies from Grade C to Grade B, this will be less vital.

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