Leak Testing of Freeze Dryers – PS (PHSS) Technical Monograph No.7

Many parenteral products require freeze-drying during which low pressures are required in the system, which require accurate measurement and control. Leakage into the system during the drying cycle may affect the control parameters of the cycle and also jeopardise the integrity of the system. Excessive leakage may increase the risk of producing a non-sterile product.
This Monograph covers the types of leaks associated with freeze dryers, the "leak-up rate test", the sources of leaks, and routine operation and maintenance.