Before a medical device is allowed on the market, manufacturers must perform numerous tests to determine its exact parameters, requirements, and performance capabilities. For reusable medical devices, one of the biggest testing components revolves around the device’s post processing shelf life.
After use, cleaning, and sterilization, the medical device stays packaged and goes into storage until reuse. If healthcare professionals don’t have proper guidelines for packaging, storing, and shelf life, then the device may not remain sterile between uses. This could render the reprocessing procedure ineffective and creates serious risks for healthcare facilities and their patients.
Using packaging to determine a medical device’s shelf life gives healthcare facilities dependable guidelines for reprocessing and storage. Discover how packaging systems influence shelf life and what kind of tests help establish packaging efficacy with this overview.
Understanding Shelf-Life
Shelf life refers to the length of time after reprocessing, when a reusable medical device in storage remains safe, sterile, and effective for reuse. This period of time is tied to stability, or the intended physical, chemical, and functional properties of the device. Medical devices have different levels of stability depending on their ability to maintain these properties under different conditions. These conditions include factors such as environmental changes—like temperature or humidity fluctuations—or processes such as cleaning and sterilization.
If a change in the device’s conditions compromises stability, then it also compromises performance. The point where a device can no longer meet its performance requirements or samples being validated meet their predetermined period of time in storage, is the products shelf-life expiration. This is the point where the device is no longer suitable for use. The FDA requires a minimum of 30 days of validated post processing shelf life during 510K submissions but a product could also be validated for 6 months, 1 year or even more.
Factors That Influence Shelf-Life Expiration
Manufacturers must determine a reusable medical device’s shelf-life expiration to give users the information they need to use the device safely and reliably. Furthermore, it is important to determine the factors that influence shelf-life expiration. This information allows end users to create a storage environment that preserves sterility, prolongs shelf-life, reduces waste, and promotes greater health and safety for patients.
The factors that can affect a reusable medical device’s shelf life include storage conditions, device preparation before reprocessing and device handling post processing. Storage conditions include factors such as temperature, humidity levels, lighting, and chemical exposure.Device preparation before reprocessing might refer to the type and quality of material used in the device as well as any physical or chemical properties of the medical device. These could include sharp edges or tips in the device that must have tip protectors applied before packaging for sterilization. Device handling post processing is also a critical variable in package failures. If the device is removed from a shelf by dragging it, creating contact with the shelf, instead of picking the device up, it could cause rips or tears in the device packaging and create a non-sterile package.
Packaging conditions also play a significant role in a medical device’s shelf life. A packaging system must provide stable and secure packaging while still allowing for effective sterilization. It must also be able to maintain that sterile barrier and prevent contamination until it is time to use the device again.
Creating and Maintaining a Sterile Barrier
The sterile barrier system is a huge part of how packaging determines a medical device’s shelf life. The goal of a packaging system is to establish the sterile barrier around the device and maintain it until an end user opens the package to use the device again. The longer the sterile barrier remains reliably intact, the longer the device’s shelf life is.
As such, healthcare professionals need sterile packaging systems—such as terminal sterilization wrap, sterilization pouches, or rigid containers—that contain the device throughout the sterilization process and remain in place during the entire storage period. The packaging system must allow for the sterilization method to be effective. It must also provide a protective barrier against impact, tears, puncture, and other damage during movement and storage.
Packaging Shelf-Life Studies
There are many types of packaging tests manufacturers perform to determine the efficacy of a packaging system. Real-time and accelerated aging shelf-life tests can help validate the packaging system and determine how long it is able to maintain the sterile barrier after reprocessing, thus identifying the shelf life of the packaging and the device within. With this information, manufacturers can create reliable instructions for use, make informed suggestions and guidelines for storage conditions, and empower safe use of their reusable medical devices in real-world settings.
Below are some examples of packaging validation studies that help determine shelf-life.
SL-ACCEL
SL-ACCEL is an accelerated aging shelf-life test. To perform the test, researchers place the packaging system in an accelerated aging chamber. The chamber uses increased temperature, humidity, and pressure levels to simulate prolonged storage in a condensed amount of time. Accelerated aging offers an efficient way to study the effects of possible real-life storage conditions and help determine the shelf-life of a device.
SL-STEAM
SL-STEAM is a real-time validation test, which means researchers store and observe the packaging system for a specific period of time under real-world conditions. This form of real-time shelf-life validation focuses on observing the sterile barrier after exposure to a steam sterilization process.
SL-STERRAD
SL-STERRAD, another real-time validation test, focuses on the STERRAD sterilization method. After putting the device and its packaging system through the STERRAD sterilization process, researchers store the packaging system for a minimum of 30 days and monitor the performance of the sterile barrier system. Though 30 days is the minimum period of time set by regulatory agencies, most manufacturers test for longer periods of up to a year or more.
SL-VPRO
The real-time validation test SL-VPRO determines the real-time shelf-life of a packaging system after exposure to V-Pro sterilization.
SL-ETO
SL-ETO is a real-time shelf-life validation test that determines a packaging system’s shelf-life after an exposure to a ethylene oxide sterilization cycle.
Package Integrity Tests
Package integrity also influences shelf life. Packaging systems that result in seal leaks, punctures, or other flaws jeopardize the device. This type of damage allows for the introduction of microbes. It risks device contamination and puts patients and healthcare providers at risk.
Package integrity tests help validate the performance of the sterile barrier system, making them an important part of determining the shelf life of a reusable medical device packaging system. These tests include Bubble Emission tests and dye migration tests.
Bubble Emission (BE-ISO)
A Bubble Emission test is a whole package integrity test that helps identify any leaks in the seal of the packaging system. To perform the test, researchers fill the packaging system with air, then submerge it in water. By monitoring the water for bubbles, researchers are able to determine whether air is leaking out of the package’s seal. The presence of bubbles indicates that there is a failure in the packaging system’s seal, rendering its sterile barrier system useless.
Aerosol Challenge (AC-STEAM)
An aerosol challenge test is a whole package integrity test on a packaging system (wrap, rigid container or sterilization pouch) used as a microbial barrier. A packaging system is processed in a steam cycle and is then exposed to a high concentration of bacterial spores in an aerosol chamber. If the system maintains its package integrity after exposure, there will be no microbial growth of any items within the packaging system, indicating a successful test. Packaging systems can also be exposed to an aerosol challenge after processing in a hydrogen peroxide or ethylene oxide sterilization process.
Dye Migration (DM-ISO)
A dye migration test also validates the package seal to determine the efficacy of its sterile barrier. Researchers apply colored dye to the package interior so that it rests directly against the seal for a set period of time. They then monitor the packaging to see if the dye seeps through the seal. If the packaging system contains the dye without allowing it to seep through, the sterile barrier remains intact, indicating a successful test.
Packaging Validation With Highpower Labs
At Highpower, we know how important packaging is to the reprocessing procedure. Validate your designs and ensure safe use when you take advantage of our medical device package testing. See our wide range of tests and service offerings and get started on your device’s market approval today.