What can be the reason why hard gelatin capsules filled with aspirin burst, when these are enteric encased?

(in collaboration with Dr. J. Vertommen, Capsugel) In the meantime, I have been sent this question by a few other colleagues for capsules filled with another powder. Although the contents of the capsule can also have a certain influence, I think that everything revolves around the moisture content of the capsules. After all, the consumption of capsules in the Officinas has been significantly reduced in recent times. This has its consequences on the turnover and consequently the capsules remain stored on the different levels for a long time. And this storage will not always be done in optimal conditions. The water content for gelatine capsules is between 13 and 16% (loss on drying) and between 5 and 7% for capsules made from Hypromellose. The following graph shows the moisture content according to the humidity.

Consequently, I would advise you to acclamize the capsules for use in a damp room. You can use a large cooking pot with a lid that covers the soil with water. In this large pot you place a smaller one with the bottom facing upwards and on this soil you place a container in which you transfer the capsules to be used. After closing the large cooking pot with the lid, leave this setup for 24 hours. I suspect that after this period the capsules will have reached their equilibrium moisture content. It also pays to test HPMC capsules, which have a lower water content. These are available under the name Vcaps.