Real Time Product Temperature Monitoring in Freeze Drying
During freeze drying process, is the product temperature the most important critical quality attribute. For example, product temperature above the critical formulation temperature during primary drying commonly results in severe damage to the product. The wireless and battery-free Tempris sensors are applicable on all scales of freeze dryers. It thereby provides the most comparable and consistent data for this parameter. In real time. Throughout development, transfer and production of a lyophilized product. Even in combination with automatic loading systems.
In a freeze drying process, product temperature cannot be controlled directly. Thus it is determined by a combination of process and product parameters. The shelf temperature and chamber pressure are controlled directly based on the user-defined recipe. Indeed they constitute the main variables for achieving a suitable product temperature over time profile.
Another important factor with high impact on product temperature in freeze drying is the product resistance over the dried layer, Rp; which again depends on the solute concentration, cake thickness and freezing conditions. High product resistance against the flow of water vapor through the dried layer leads to elevated product temperature.
Further parameters influence the product temperature as well, such as the geometry of the container system, the extent of radiative heat transfer to the vials, and the physicochemical state of the product. Due to this multitude of factors, it is very difficult to keep all product units within the batch at a target product temperature throughout the process. This challenge can be overcome by application of Tempris, a process analytical technology capable of measuring the product temperature in real time.
We specifically designed Tempris temperature sensors for monitoring and optimization of freeze-drying processes. They have proven their reliability in many industrial and academic applications. Tempris sensors has a variety of advantages over other sensors measuring temperature in freeze drying: