Sep 4, 2007

Validating the packaging process

Medical Device Technology has put "How to Validate a Packaging Process" online which contains pretty thorough information. I've discussed packaging a bit before here. Medium sized companies generally have a packaging engineer while small companies get whoever they can to design packaging and hope.

All sorts of design issues can show up unexpectedly in packaging, a small wrinkle in a bag or pouch seal can mean a complete redesign or worse. My boss's blood pressure skyrockets whenever someone mentions the dye penetration test (ASTM F1929) mentioned in the article. We received a bunch of failed test samples back from a testing lab that were solid coated with dye which supposedly showed how we failed the test, except after the test is over dye coats everything so you can't tell. Ever since then he's hated the test with a passion and if you want to avoid a 15 minute rant its better to stay off the subject.

I was part of a PMA that the FDA specifically required the dye penetration test for to move forward, so you'll likely have to get through it (although you can avoid packaging validation in the early stages of a PMA if you hand carry). The dye penetration test basically consists of pouring a dye solution into the packaging and then observing its progression through the package seal in a certain amount of time. The problem is that the test requires judgment calls regarding wrinkles and has a wide time range. A small wrinkle in the seal can allow the dye to penetrate quickly through the seal.

Dye Penetration Test Results

How do you avoid this problem? There are a couple ways to avoid it completely. If you gamma sterilize you don't need Tyvek breathers and the bags won't leak if you seal them properly in the first place. It is slightly harder to seal completely plastic bags, you can end up with ridiculously large amounts of air in the bag if you're not careful. There is also a company that makes Tyvek windows and you seal the plastic bag, since the Tyvek is not on the edge, you're much less likely to have a problem (I forget the name of the company offhand, but I'll update later). The sterilization degassing time may be longer however. The other packaging option is to use a more expensive tray type instead of a bag.

How do you minimize the problem? Don't handle the packaging bags. It makes me cringe when manufacturing or QA handles the bags roughly. The other thing you can do is properly design the box to limit the movement inside- this is difficult with the larger your product is however.

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