In pharmaceutical production, freeze-drying is a widely used process for preserving medicines of the highest quality for many years without refrigeration. The cooling technology required for this is complex, as there are different, very specific requirements depending on the manufacturer, medication and process step.
The medication usually leaves the sterile filling process as an aqueous solution in a vial with an open stopper. Several thousand such vials can be fed into the freeze-drying system at the same time. They stand on adjustable plates through which a low-temperature special oil flows. This freezes the medication at temperatures of -40 °C to -55 °C.
In the next step, a vacuum is generated, causing sublimation of the frozen water in the medication. The resulting water vapor enters the cold trap at the ice condenser and is captured there at -80 °C as ice. Once the liquid has been removed, the vial is sealed. The granules inside can now be stored for long periods without refrigeration.
For the quality of the medication, it is important that each batch undergoes the same defined processes for cooling and drying. The required homogeneity places high demands on the design of the freeze dryer.
Innovative freeze dryers that operate without direct emissions and use air as a refrigerant were installed in Marburg a year ago. Optimizations in the operating control system, the central provision of refrigeration and the optimized use of waste heat ensure particularly low energy requirements and increased efficiency. In this way, the site contributes to the company's sustainability objectives.
A video, which was produced together with our partners HOF, Mirai Intex and Refolution, provides an insight into how the freeze-drying systems work.
Watch the video
