Medical Device Sterilization and Categories

Sterilization is a critical process in the medical device industry as it provides a reliable way to ensure that devices are free from harmful microorganisms when they are used on patients. This blog talks about the categories of sterilization currently used on medical devices in manufacturing settings. It also addresses concerns surrounding the use of ethylene oxide (EtO), an indispensable method for sterilizing heat and moisture sensitive devices.

As per FDA, there are mainly two categories of sterilization methods currently used in manufacturing settings: established and novel.

Established Sterilization Methods

1. Established Category A:
   • This category consists of methods that have a long history of safe and effective use in the medical device market demonstrated through literature, 510(k) clearances or premarket approvals (PMAs), and satisfactory quality system inspections.
   • There are voluntary consensus standards recognized by FDA that address the development, validation, and routine control of these established methods.
   • Some examples of methods of sterilization that are considered Established Category A are:
     • Ethylene Oxide with devices in a fixed, rigid chamber
     • Moist Heat or Steam
     • Dry Heat
     • Radiation (e.g., electron beam, gamma)
     • Vaporised Hydrogen Peroxide
2. Established Category B:
   • This category consists of methods that do not have FDA-recognized dedicated consensus standards, but do have published information on development, validation and routine control of medical devices.
   • Some examples of methods that are considered Established Category B sterilization are:
     • Flexible bag systems (e.g., ethylene oxide in a flexible bag system, diffusion, injection)
     • Ozone

Novel Sterilization Methods

• A sterilization method is considered to be novel when the specific process does not appear to have been evaluated by FDA, either because the parameters of an FDA cleared sterilizer have been altered or because process validation data has not been evaluated and found to be adequate in previous cleared or approved submissions.
• These methods are considered newly developed for which there exists little or no published information.
• In such methods, there are no history of comprehensive FDA evaluation of sterilization development and validation data through an FDA -cleared 510(k) or approved PMA for devices, and no FDA recognised dedicated consensus standards on development, validation and routine control.
• Involvement of Chemical Component in Sterilization:
  • Any sterilization method that uses chemical(s) that have not been previously cleared or approved by FDA as a chemical sterilant or have not been identified in the scientific literature as a chemical sterilant, would be considered novel.
  • Moreover, if a sterilization method uses a chemical combination that has not been previously cleared or approved by FDA as a sterilant, it would be considered novel (even if the individual chemicals in the combination have been previously cleared or approved separately as chemical sterilants).
• Some example methods of sterilization that are considered novel:
  • Ultraviolet light
  • Sound waves
  • High intensity light or pulse light
  • Vaporised peracetic acid
  • Microwave radiation

Recent Concerns Surrounding Ethylene Oxide Sterilization (EtO)

Overview of Ethylene Oxide Sterilization (EtO) and Usage

Concerns Surrounding Ethylene Oxide Sterilization

Ethylene oxide has come under scrutiny due to environmental and health concerns, despite its efficacy.

The major concerns can be summarised as follows:

Standards and Regulatory Bodies:

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