Sterile medical device packaging design is critical because the package will need to be shipped to its destination with the sterile barrier intact to ensure the safety of the patient. When designing a medical device package, there are a series of steps that need to be taken. Step one is designing a medical device package, step two is distribution testing, step three is package seal integrity testing, and step four is packaging design passing and failing. The International Organization for Standardization 11607 states that “Packaging for terminally sterilized medical devices, should be referenced and followed for designing and testing.”

Step 1: Design a Medical Device Package

When designing a sterile barrier medical package, the person needs to determine the size, weight, and geometry of the products in scope. The products in scope will determine which sterilization method to use, and the packaging material must be compatible with the sterilization method chosen.

One of the most important steps in developing a medical device is choosing a sterilization method. Poor sterilization of the product could lead to infectious diseases, illnesses, and even death to the patient. While the device must have the correct sterilization method, the packaging the device is in must be able to handle the sterilization method the product is going through. There are four types of sterilization methods - steam sterilization, dry heat sterilization, ethylene oxide sterilization, and radiation sterilization. Steam sterilization is characterized by high temperatures and pressures. Therefore, steam sterilization is most appropriate for stable devices and heat-resistant materials such as steel. Dry heat sterilization has very low moisture content and high temperatures. Dry heat sterilization should be used for devices that are heat resistant, but susceptible to water damage. Ethylene oxide sterilization is highly reactive to low temperatures. This type of sterilization can be used for plastic products. The last type of sterilization is radiation sterilization, which has a fluctuation in temperature making it appropriate for use on devices made from heat-sensitive plastics and other materials. Radiation sterilization is used for implants, catheters, and syringes. The most common packaging used for sterile barrier packaging is trays and pouches. Usually, trays are used for heavier products because trays can carry more weight as opposed to pouches, which are used for lighter-weight products. PETG tray, nylon/nylon pouch, Tyvek/mylar pouch, or polyurethane pouch, which can be seen in Figures 1,2,3, and 4, are often used.

An engineer would conduct a feasibility study to assure that the right technology and test method are applied to each packaging system to provide accurate, sensitive, and reliable data for definitive package integrity verification. The engineer would do this by choosing a tray or pouch based on the product and sterilization method used. The engineer would then work with a supplier that produces sterile packaging material and ask for enough prototypes from the supplier to complete the feasibility study. Once the design has been proven to work, stakeholders in the project will have to approve the design. Once the stakeholders have agreed on the packaging design, the engineer can move forward in packaging the products. The design may change along the way due to unforeseen complications.

Step 2: Distribution Testing

Once the sterile barrier packaging systems are packaged with products in scope, the packaging systems will go through simulated distribution testing following ISTA guidelines. The purpose of simulated distribution testing is to validate the packaging system by systematically and repetitiously testing shipping containers by using an environmental conditioning chamber, a drop tester, and a vibration table such as those shown in Figures 5, 6, and 7. Other equipment may be used depending on the package and the test requirements for that package. The environmental conditioning chamber is used to simulate various environmental conditions that the package may go through. This could affect how the packaging system performs during the remaining simulated distribution tests. The drop tester simulates the freefall of a package on its corners, edges, and surfaces at various heights. This enables realistic conditions that can be encountered during shipment such as someone dropping the package while handling it. The vibration table simulates the various types of vibrations that may occur during handling, transportation, and shipping. For example, a truck transporting the product. Simulated distribution testing exposes the packaging system to genuine, real-life hazards that may occur in the distribution environment. If the packaging system passes distribution testing, then the next step would be to test the seal integrity. If the packaging system fails the simulated distribution testing, the package design will need to be reevaluated to ensure it will not fail the retesting.

Step 3: Package Seal Integrity Testing

Once the package has gone through the appropriate simulated distribution testing, the package will go through package integrity testing. This includes bubble emission testing, dye penetration testing, and seal strength testing, which is shown in Figures 8, 9, and 10. Bubble emission testing is when gas is applied to one side of a flexible package and is fully submerged in a fluid, which should not degrade the package. It should have low surface tension and be conducted within a vacuum chamber. The bubbles are evaluated to determine whether the seal integrity passes or fails. Another type of seal integrity testing is dye penetration testing. This process is done by injecting, edge dipping, or using an eyedropper to put a dye in the sterile barrier packaging system to check for seal leaks, which determine if the package a passes or fails. The final example of seal integrity testing is seal strength testing. Seal strength testing is a tensile test performed by a machine that grips a section of the package seal and is pulls it at a controlled rate.

Step 4: Packaging Design Passing or Failing

Once all testing is complete, a report will be filled out to determine whether the testing for the packaging system that was designed passed or failed. If the testing passed, then the design phase of the project will be complete, and the testing will need to be documented. If the testing failed, the sterile barrier packaging will need to be redesigned and the process will need to be repeated until it passes. Once the designing phase is complete, the remaining steps required for the project can proceed.

References:

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