Medical Device Packaging Materials & Considerations For Sterilization Processes
Selecting a packaging method to be used in the sterilization qualification
To determine which packaging method to be used in the sterilization qualification of your device consider the following:
- Suitability of the packaging material for the sterilization cycle and type, such as steam permeability, moisture retention, susceptibility to gas degradation, etc.
- Strength of the package
- Type of packaging, such as a reusable woven textile wrapper, single-use nonwoven textile wrapper, paper–plastic pouch, reusable rigid sterilization container system, etc.
- Ability of the packaging to protect device or instrumentation during transport or from contamination
- Ability of the packaging to accommodate multipart construction, such as disassembled or reassembled parts of the device
Package integrity properties required by the device design.
Non-traditional packaging configurations and approaches
A few years ago, sterile barrier systems consisted of primarily pouches and trays. Now many medical device companies are electing to use novel packaging. For instance, tubing that was traditionally packaged in a pouch can alternatively be fitted with caps and validated as its own sterile barrier system. Novel packaging systems often reduce the amount of packaging materials used for the device at the expense of challenges in validation testing of the new packaging system. As validation testing is designed for traditional packaging, development of appropriate test methods to prove adequate barrier strength, package integrity, microbial barrier properties, etc. can be difficult.
Product Packaging Materials
Product packaging must have appropriate preformed sterile barrier systems or materials to protect devices from contamination while in storage.
Materials (such as wrapping materials, plastic film, papers, nonwoven fabrics or reusable fabrics) should meet the 8 general performance requirements detailed below:
- Materials must be non-leaching and odorless, such that neither performance nor safety of the materials are impaired and the medical devices they contain are not adversely affected.
- Materials must be free of holes, cracks, tears, creases or localized thickening and/or thinning that would impair their function.
- Materials must have a consistent basis weight (mass per unit area) according to their specifications.
- Materials must have appropriate levels of cleanliness, particulate matter, and linting.
- Materials must meet established specific or minimum mechanical properties (such as tensile strength, thickness variation, tear resistance, air permeance and burst strength).
- Materials must meet established specific chemical properties (such as pH value, chloride, and sulfate content) to meet the requirements of the medical device, packaging system and sterilization process.
- Materials must NOT contain (or release) substances known to be toxic in sufficient quantity to cause a health hazard either before, during or after sterilization.
Materials must meet acceptance criteria for microbial barrier properties, unless they meet certain criterion of impermeability.
Materials compatibility for EO Sterilization
Regarding compatibility for devices being sterilized with ethylene oxide (EO), metals and glass do not absorb EO and are do not present any problems for sterilization. Additionally, EO is compatible with many plastics.
However, ethylene oxide is not suitable for sterilization of the items listed below:
- Liquid solutions (As EO is highly soluble, it will be dissolved rather than sterilize).
- Protein type material (degradation)
- Products placed in non-breathable packaging
Caution must be taken when using EO with the following items:
- Electronic devices, batteries, and powder (as these items may create an explosion risk)
- Vacuum-sensitive products (as EO cycles require vacuum environment)
- Mated surfaces (stopcocks, three-way valves).
- Coatings applied to solid bleached sulphate, SBS, materials (as these coatings can drastically affect porosity and dwell time required in the EO sterilization cycle).
Overall, EO packaging must be able to intake and outtake gas. Thus, a breathable packaging material must be used. The use of Tyvek® for EO sterilization has become widespread. Tyvek® is a flash-spun HDPE material and has consistently demonstrated reliability and performance for EO applications. Medical papers are a less expensive option, which may also be suitable for certain applications.
Summary
Overall, choosing the appropriate packaging method for your sterilization type, packaging configuration, and packaging materials are key elements in developing an effective sterile packaging system. Note that altering the materials of the device itself may heavily effect the type of packaging and configuration needed to provide appropriate sterilization.
Ethide Labs is a contract testing organization that specializes in Sterilization Validations and EO Residual Testing. Ethide Labs provides in-vitro cytotoxicity tests in-house and outsources in-vivo cytotoxicity work for toxicity testing of medical devices, products, and drugs. Ethide Labs also offers Microbiology Testing, Bioburden Testing, Environmental Monitoring, Bacterial Endotoxin Testing, Package Integrity Testing & Cytotoxicity Testing services for medical device companies and allied industries. Ethide is an ISO 13485 certified facility.
References
International Organization for Standardization. Packaging for terminally sterilized medical devices- Part1: Requirements for materials, sterile barrier systems and packaging systems. Geneva (Switzerland): ISO; 2019. (ISO 11607-1:2019)
EO Sterilization & Packaging. Packaging Compliance Labs. 2021.
