Performing a side-by-side test method validation will give you the answers you are looking for.  Use a predetermined sample population, having both positive and negative controls within it (0.002 in per the standard for the positive controls), and testing all of the samples using both solutions per the standard.  If the results are the same, then you can use the food coloring solution.

Positive migration would be the forcing out of atmosphere inside of a package by internally pressurizing the package (blowing it up like a balloon). The negative migration would also be the forcing out of atmosphere from the package, but it is done by changing the atmosphere outside of the package (vacuum test simulating an airplane environment when pressurization is lost). This could potentially draw in the outside atmosphere at equilibrium.

A more simple explanation might be that positive migration pushes out atmosphere while negative migration draws in atmosphere.

There is no industry standard, as it pertains to the number of samples required for a test.  This is based on the statistical confidence that you would like for your sealing process. My belief is that many of our customers use the sample size of ten samples for a lot-to-lot comparison.

I would suggest sticking with the 0.002-in. wire since that is the sensitivity of the standard. Perhaps there is a gage block of this size out there, which might make it easier to extract the standard from the package. We typically use a wire, however that has been used on mostly pouch samples and not a tray, and we have not seemed to have this same problem. An alternative contact on this might be to speak with the technical contact of the ASTM F1929 standard. This information is readily available on the ASTM Web site and is accessible to the general public. This individual could probably give you some insight as to how they did this during the Precision and Bias for the standard.

Yes, you should be performing an internal study to show that your internal process that you have set up for seal-strength testing remains consistent.

This would hold true especially if multiple technicians are performing seal-strength testing. It would be very important to verify that the process is being performed identically, data generated by the multiple technicians remain consistent, and variability is kept to a minimum.

Unfortunately, there are no specifications as to how your process needs to be validated. As you stated, it is required that you do it and but it is up to medical device manufacturers to show how they prove it.

I would suggest that you do seal-strength testing at the beginning and the end of your production runs. This would include each lot of product as you inquired about. I would also suggest that you continue to do integrity testing at a minimum at the end of the run.

Should you have additional questions regarding process validations, please contact Scott Levy at scott.levy@testedandproven.com

Unfortunately, there is no guidance on a minimum specification required for the strength of a package. The underlining criterion is whether the sterility has been breached or not. Your most economical package design will probably be the lowest achievable peel strength value that does contribute to the breaching of the package’s sterility.

It is left up to the medical device manufacturer to determine the acceptable minimum value. Some things to consider when determining this minimum value are the weight and shape of product itself and the material substrate of the package.

The most frequent thing we encounter during the performance of our tests that cause sterility breaches or failures is when the primary package is folded and placed into another secondary or tertiary package. This can cause undo stress at the points the package is folded over making it more susceptible to failures. The other cause results in not taking into account any obtrusive or sharp edges or points on the product itself and than not properly placing or packing it inside of the primary package.

There are several good machine manufacturers in the industry that will meet the requirements of the ASTM standards. I would also suggest that you take the time to determine your critical criteria for your testing because you want to make sure you are not paying for additional equipment capabilities that you may or may not need.

Some of the more reputable manufacturers in industry for seal strength equipment are Instron, Test Resources, and Chatillon. Some of the more reputable manufacturers for bubble leak test equipment are TM Electronics and Carleton Technologies. There are also possibilities of designing your own source for air in performing this test.

Some things to consider in determining the packaging material are that gamma sterilization can product elevated temperatures and you want to make sure that your materials can withstand these temperatures. They will also be nonporous in nature to maintain the moisture barrier you are requiring.  I would recommend the following article that was published in MD&DI in the February 2000 issue to assist in this decision entitled “Polymer Materials Selection for Radiation-Sterilized Products,” by Karl Hemmerich.