Many pharmaceuticals today are manufactured in blister packs. They do a very good job of preventing moisture from penetrating sensitive medications today. However, because some newer medications on the market (like hormone drugs) can easily break down, blister packing is under more scrutiny, and the need for a better leak test for blisters is important. In fact, blue dye testing, which is still common, may not be sufficient anymore. Let’s check out the current problems with this method and explore some solutions.
What is the Blue Dye Method?
The concept behind blue dye testing is simple. The tested places a blister pack inside a chamber with liquid dye and a vacuum is applied. The vacuum is then released as the materials return to normal atmospheric pressure. The tester carefully inspects the packs to see if any of the blue dye made its way inside the packaging.
Problems with Blue Dye Leak Test for Blisters
One of the biggest concerns with the blue dye test is possible tampering with the results. For example, after removing the vacuum, the materials have so much time to absorb the dye, and the system works on a timer. However, as soon as the vacuum is gone, the tester could manually remove the pack, so no dye enters. This could give false results.
There’s another problem with the dye test. It’s not accurate enough. In other words, even if the dye can’t enter the packaging, smaller things like contaminating gasses still could.
The Solution
Many companies today are turning to a mass flow leak test for blisters. Mass flow testing doesn’t rely on dyes and can measure exactly how much air is escaping a package. This method is more accurate and reliable, and the testing procedure is quick. It can also measure both flow and leaks.
