Stay in the Right Lane: Smarter Packaging Validation Starts with Better Questions

The first validation you are going to run when developing a packaging system is your sealing validation. Seal strength is something that should be unique to your packaging system and should be developed statistically. For a long time, there was an industry standard of a 1 lb. minimum seal strength requirement. This number has floated around the industry for years, but it’s not grounded in science or standards. Today, I’m seeing more and more teams moving away from it and instead establishing their own, which is good thing. So, when, where, and how do you determine a minimum seal strength?

Seal strength should be:

• Specific to your packaging system
• Developed statistically
• Defined before validation begins

A strong approach is to run a Design of Experiments (DOE):

• Start with low sealing parameters (where seals fail or are inconsistent)
• Increase until seals become overly strong or destructive
• Identify the optimal window in between

From there, you can:

• Calculate a mean seal strength
• Apply statistical methods
• Establish a meaningful lower specification limit

It’s important to have a seal strength value that makes sense as it is commonly used in manufacturing for startup or in-process testing.

Another common issue is that customers are unsure of what test to run or ask for ones that are not necessary. Not all tests serve the same purpose, and the scope of testing should shift based on the device and packaging needs.

During Sealing Validation (OQ/PQ), you’re focused on the seal itself, so tests like dye penetration (ASTM F1929) and seal strength are important. But post transit and aging testing you’re now evaluating the entire sterile barrier system under real-world conditions, which is better evaluated via a whole package integrity test such as bubble leak testing. At this stage, you’re no longer just asking, “Is the seal good?”. You’re asking, “Does the entire system hold up?”. This shift in perspective is critical, and selecting the wrong method can lead to issues with a submission and possible retesting.

On paper, combining transit and aging makes sense. Real products are shipped and stored, so why not test them together? First, with these tests we’re looking for different types of failures. Transit failures are event-based (drops, vibration, compression) where aging failures are time-based (material degradation, brittleness). If a failure occurs, and you have combined these tests, you lose clarity on where that failure took place. Did it happen during transit? Or overtime? If you can’t answer this, you can’t course correct. Separating these studies gives you:

• Clear root cause identification
• Faster troubleshooting
• Stronger justification in regulatory review

ISO 11607 supports this distinction by treating performance and stability as separate evaluations.

It’s very rare that when we are running packaging validations there are enough devices to test. So, we often use simulated products to test packaging. But when creating your worst-case configurations, it’s important to not just default to the biggest & heaviest device. In some cases, larger products are more stable in the packaging, and the risk is with the smaller items that can move, shift, and cause abrasion. I’ve seen smaller components create more damage during transit. Therefore, I tell customers, instead of assuming heaviest/biggest, ask yourself:

• What will move the most?
• What creates the most stress?
• Do you need to take configuration into account?
• What challenges the packaging system the most?

Usually, you can clearly choose the best path forward. But if it’s not clear, I recommend a bookend approach. Test both the smallest and the largest to be able to help bracket your risk.

ASTM F1980 is the standard that we follow to run accelerated aging. It looks at heightened temperatures as simulating a faster passage of time. Accelerating aging is an extremely powerful tool, but it is easy to misuse. A common temptation is to crank up the temperature to save time, but the problem with this approach is there is a point where instead of simulating time, you’re just damaging the materials. While I wouldn’t recommend it, if you are set on running a test at a higher temperature, consider running parallel studies, one at a higher temp (faster, riskier) and one at a moderate temp (slower, safer). In recent years, guidance has also encouraged considering humidity, not just temperature. Most commonly I see a 50% humidity approach. With this gaining prevalence in industry, even if you don’t include it, you should document your rationale.

If there’s one takeaway I’d emphasize, it’s don’t over test. Engineers are naturally curious, me included. We want more data, more insight, and more validation. But every additional test introduces more complexity, more acceptance criteria, and more opportunities to fail. Every failed test, even if just for informational purposes, requires justification. My recommended approach is test what’s required and label any exploratory data as non-acceptance criteria. When it comes to over testing, more data can create risk. Validation isn’t about doing everything, it’s about doing the right things. If you do that, you’ll keep moving with the flow of industry and will easily stay in the “right lane”.