Leak Rate Testing For Freeze Dryers: A Scientific Approach

Assurance of the vacuum integrity of freeze-dryers used for the manufacture of sterile pharmaceutical products is essential for GMP operations; however, there is currently no generally accepted scientific rationale for establishing acceptance criteria for such testing.

As it stands, current acceptance criteria are generally based on equipment capability – perhaps proposed by the manufacturer, or from data collected during qualification of a new freeze-dryer. The targeted specification is often one cited by The Parenteral Society, “A frequently specified leak rate for new, clean, dry, and empty freeze-dryers would be 2 x 10-2 mbar-liter/sec (15 μm (mTorr) liters per sec). The leak rate should not change significantly during the life of the freeze-dryer.