The main goal of a sterile barrier system (SBS) is to ensure a medical device or therapy remains sterile until the point-of-use. To accomplish this, the SBS and sterilization work together, with sterilization being a key component of the overall process. Like most things, there are varying methods of sterilization, each with their pros and cons. Industry has historically favored EO sterilization due to its ability to work with a wide range of materials and its known effects. But, as industry innovates and we look for better ways to get our devices to market, we are seeing different methods of sterilization gain traction. One in particular is Vaporized Hydrogen Peroxide (VHP) sterilization.
What is VHP?
In industrial sterilization terms, VHP is relatively new. It has long been used in hospitals as an alternative to EO and steam for sterilizing reusable devices. In an announcement made in January of 2024, the FDA now considers VHP as an Established Category A sterilization process. VHP is considered a very effective sterilant and has many similarities to EO, which in my opinion, is why we are seeing industry consider this method of sterilization more and more. Like EO, VHP has a wide range of material compatibility, however it does have its limitations.
What is the VHP Process?
VHP is a three-stage process—preconditioning, sterilization, and post conditioning. The process includes vacuum, moderate temperature (80-100°F), and sterilant. The sterile barrier system is sterilized without cartons and shippers and is conducted on a much smaller scale compared to EO sterilization. Typical cycle times are a few hours vs. many hours to even days for EO.
What are the limitations of VHP?
Unlike EO, VHP is not good for highly absorbent materials, such as cellulose based products like paper and corrugate. As with other gas-based modalities, it is important to use porous materials for at least part of the SBS. Some types of film laminations may not be suitable for VHP, for example laminations that don’t use adhesive to bond layers together.
Because corrugate and paper cartons can’t be used, there is an impact to the flow and supply chain of a single use device. VHP must take place earlier in the supply chain process than if sterilizing with EO.
Other limitations with this method are around the current size availability when processing. Right now, a process can only manage 1-4 pallets, which is significantly less than other sterilization methods.
How Does VHP Compare to EO?
VHP has many similarities to EO, in the chart below we compare the two. Highlighted in orange are the benefits each.
What is next?
While VHP is compatible with many packaging materials, there are also materials that are still unproven. This doesn’t mean that the materials can’t be sterilized with VHP, it just means we as an industry, can be working to gather more data to support the use of VHP.