Freeze drying, also termed lyophilization or sublimation drying, is a gentle drying technique. It has been used in the pharmaceutical industry for many years to improve the stability of medications.
Biopharmaceuticals in particular require an especially gentle manufacturing process due to their complex andthermosensitive molecular structure. In this regard, freeze drying represents the method of choice for improving storage stability of biopharmaceuticals, which is insufficient in the liquid formulation. While presently already approx. 60% of these products are freeze dried, a further increase in this percentage is to be expected in the coming years..
A freeze drying process is divided into three stages: freezing process, primary drying and secondary drying. The freeze dryers necessary for this are complex, computer-controlled systems. The main components are a vacuum chamber with vacuum pump and ports for attaching the product as well as the cooled condenser, where deposit of the subliming steam from the product occurs on its surfaces. Automated cleaning and sterilization units complete the range of functions. Production freeze dryers are integrated into process lines and equipped with automatic loading and unloading systems to satisfy both aseptic requirements and higher product throughput while at the same time decreasing error rates.