All sterile medical devices require validation of their packaging. The sterile barrier must be shown to be effective throughout the product's claimed shelf-life. Examination of materials, processes and stability all contribute to demonstrating that the sterilisation process is effective and that sterility is maintained.

The key standard for this process is ISO 11607-1:2006 - Packaging for terminally sterilized medical devices - Part 1: Requirements for materials, sterile barrier systems and packaging systems. It is concerned with design, materials, equipment and the effectiveness of seals or welds. The complete packaging system, including boxing, is covered. The requirements apply equally to terminally sterilised medical devices and to those produced aseptically.

Methods and standards we follow to assess seal integrity and strength:

• ASTM F1886-98: External visual inspection, a relatively simple test we routinely use to supplement information gleaned from other seal tests.
• ASTM D3078: Bubble emission, a vacuum test for non-permeable packs.
• ASTM F1929: Dye penetration test where dye is injected into sealed packs and ingress into seals is then inspected visually. Suitable for packs with at least one transparent web.
• Hospital environment microbial aerosol test. This test has been validated internally and shown to find channels as small as 0.3mm (no attempt has been made to validate below this). It simulates 1 year of storage unprotected on a hospital trolley.
• Liquid immersion test - requires sterile packs.
• ASTM 1140-00: Burst test, a good strength test that assesses the entire seal area, locating the weakest point. Suitable for both porous and non-porous packs.
• ASTM F88: Seal tensile peel test.

Sterile Barrier Seal Testing

Seal strength and integrity testing is usually complemented by Accelerated Ageing as well as Transit Simulation Testing which tests the protection provided by shipping cartons from single units to complete pallets.

Peel testing

Package burst strength test