When Should Transit Testing Be Applied to Medical Device Testing?
ISO 11607 requires both transit simulation testing and shelf life validation of packaging for terminally sterilised medical devices. Both regimes require conditioning of the medical devices in their packages prior to sterile barrier strength and integrity testing.
Normally transit testing and ageing are treated as separate issues. This is mainly because using accelerated ageing to simulate shelf life typical requires over 30 weeks in an environmental chamber -- nobody wants to wait 30 weeks to find out if their transit carton is robust enough to protect the product. But clearly the product could be shipped near the end of its shelf life. So, is it legitimate to only test the transit carton at the beginning of the shelf life?
In most instances the answer is yes. "Time zero" reference testing at the start of the ageing cycle gives a result for pack strength at the outset. Assuming the pack passes the transit testing at time zero and it does not become weaker during ageing then the transit results should still be valid following ageing.
Are there exceptions to this? Yes, if there is some change to the product or seal during the shelf life which affects its robustness in transit, but is not identified in strength testing. This could be a change of gas pressure in the pack, a change in hydration of non-hydrophobic packaging materials or due to pressure on the pack from the product.
Mark Turner, Director, Medical Engineering Technologies