What processes are effective for identifying and closing gaps in the medical device packaging process?

One of the most effective methodologies for identifying gaps is the Failure Mode and Effects Analysis (FMEA). Engineers use this method to identify were there may be failures in the package itself or in the assembly. Another popular method for identifying gaps is the Process Failure Mode and Effects Analysis (PFMEA). This method focuses more on the actual packaging process. Engineers use a PFMEA to confirm the specific actions that operators should take to properly package the medical device.

What is the difference between multi-piece and single-piece flow?

Operators using multi-piece flow process multiple pieces together, at the same time. This is similar to multi-tasking and although it may sound efficient, it usually is not because of the number of potential errors that are introduced. Operators using single-piece flow handle and package one product at a time and are disallowed from starting the next one until the first package is completely finished. Much of the medical device industry is shifting from multi-piece flow to single-piece flow as a way to reduce packaging risk. A PFMEA can determine whether multi-piece flow or single-piece flow is optimal for any given packaging process.

Are there other examples where PFMEA is used?

A PFMEA can also help determine the best way for operators to orient a pouch for the most effective seal. If a pouch is comprised of dissimilar materials, the operator must know which side needs to be placed in the machine facing the operator and which side needs to be placed in the machine facing away from the operator. They also need to orient the pouch correctly so the seal is made in the right place. Historically, operators have been asked to check their work by simply holding the pouch upside down to confirm the seal (if the product drops out, the seal is not good). However, newer machines have sensors that can alert the operators if they did not place the package into the sealer correctly. Orienting the lid correctly on a tray is just as critical.

What are the areas to focus on to mitigate sealing risk and ensure a good hermetic seal?

To mitigate sealing risk and ensure a good hermetic seal, the heat sealer used must be maintained to factory specifications, validatable and have alarm capabilities for all process parameters associated with the validated window. A validatable heat sealer with alarm capability can alert the operator and terminate the seal cycle when there is a detectable variance beyond the validated window.

What is validation and what parameters are reviewed for a validatable window?

For any kind of heat-sealing process, the validated parameters are time (or speed when using a rotary band pouch sealer), temperature, and pressure. To create a hermetic seal for a pouch or tray, the heat sealer needs to be able to deliver a repeatable and even temperature over repeatable time (or speed), and at a repeatable pressure. Validation provides information about how stable the sealer performs at the required times/speeds, temperatures, and pressures. The validatable window allows for a small amount of deviation from these defined parameters. Then, if the sealer performs outside of that window, the machine alerts the operator to the deviation. This is a fundamental part of risk mitigation for the seal process. If the validated window is not protected, the operator could unknowingly process the pouch or tray resulting in a poor seal. That, in turn, would allow the improperly sealed package to go out into the field. By the time that medical device is needed, the seal could be broken or have voids in it that allowed microbes into package, creating an infection risk for the end user.

How is a validatable window established with the three variables of time, temperature, and pressure?

A validatable window is established using a process called a design of experiment (DOE). The engineers input different times, temperatures, and pressures and then test the packaging at these various combinations. They create a 3D mathematical/testing model of the results, which helps them determine the most repeatable recipe for creating the barrier seal for that package. For lightweight medical devices, the goal might be a minimum of a one-pound peel strength. Heavier products require a stronger peel strength. Ultimately, the goal is to achieve a hermetic seal that can: 1) maintain sterility throughout the shelf life of the medical device and 2) be easily opened in a controlled manner by medical professionals in a sterile setting.

Beyond validation, what other areas are important for seal risk mitigation review?

In addition to establishing a validatable processing window, it is also important to ensure that the medical device being packaged does not interfere with the seal area. If there is product in the seal area, it is not possible to create a hermetic seal. Ensuring that the product is away from the seal area might involve reducing the opening height of the guarding, ensuring that the product can’t migrate into the seal area, or using height indicators that produce an alarm to notify the operator that the product is too close to the seal area. Risk mitigation review should also include the labeling process. All labels must be applied correctly so that they do not encroach upon the seal area and interfere with the creation of a hermetic seal.