This was interesting to me because quite a while back when I first used spiriva and went to throw out the used capsule, I saw it had fractured. I examined the screen that should contain the broken pieces, but noticed that it was not at all capable of retaining small particles of plastic. So I went on to research and it brought me to a copd forum (not this one) where the same question was brought up. The person who asked was answered by educated people that the capsule was gelatin and it would be absorbed. So I did more research right down to the patent for the capsule.
Then performed my own test by dropping a used capsule into water, where it turned into a rubber and did not dissolve at all.
I then continued to open up each capsule and upon close inspection, could see that where the little punctures are, the piece of plastic is still attached and bent to the inside, and one has not inhaled it.
So then I felt much better about it, Still don't like the fact that when it does rupture that tiny particles might escape through the screen.
So just for those who tend to become obsessive in quality research lol.