Factory acceptance tests (FAT)
are normally performed by manufacturer on “empty and dry” lyophilizers.
Sometimes, manufacturers also perform “sublimation tests” to ensure that the
condenser is capable of capturing the sufficient amount of water, specified by
the user. These tests, however, might not generate enough meaningful data to
enable a successful lyophilization process scale up. Drug product manufacturers
often need information on heat transfer coefficients for the containers of use
as well as information on capability of the dryer to maintain pressure set
points at different loads.
In this presentation, the methodology of measurement
of vial heat transfer coefficient (Kv) and minimum controllable pressure as a
function of sublimation rate (Pmin) will be described. Kv and Pmin are key
inputs in primary drying models, application of which to process design and
scale up will be discussed and demonstrated.