Helium Leak Detection vs. Dye Leak Testing

THE CHALLENGE

A global pharmaceutical entity approached Leak Detection Associates (LDA, now a PTI company) with early package failures from stability studies for a new drug product. The package was a cold-formed foil blister card that contained a wafer type product.During stability packaging, samples were leak tested using dye ingress methods and no leak failures were noted. However, after a very brief period under accelerated storage conditions, packaged samples were failing at an alarming rate. Since the product was highly sensitive to moisture, it was easy to determine failures by just shaking the blister. Once moisture entered the cavities, the wafer would dissolve into a small hardened “ball” that would rattle within the cavities.

THE SOLUTION

Stability blister card samples sent to LDA were leak tested by utilizing a SIMS helium leak detector. Since there was no helium sealed inside the cavities, each sample card had to have each cavity flushed with helium prior to performing the vacuum leak test. By using small gage syringe needles, helium was purged through the lidding and these puncture sites were sealed using an adhesive backed foil disk. This eliminated the possibility of any leak signal caused by the puncture sites. Helium leak rate data was collected from apparent well sealed blisters (no rattles) and failed blisters (product rattles).