Spray Freeze Drying (SFD) is an innovative lyophilization technology that is now entering industrial applications in lab, pilot and manufacturing scale for aseptic processing in pharmaceutical applications, as well as for the areas of medical devices, diagnostics and fine chemicals. 

SFD applies the bulkware concept from solid dosage form processing to the area of aseptic freeze drying. It yields in highly homogeneous, free flowing bulkware which can be stored and accurately dosed. Filling is done after lyophilization, with a high degree of flexibility regarding dosing, primary packaging device design and unit number. 
Accordingly, the supply chain becomes highly flexible and allows for patient centricity by even providing personalized medication, but also by bringing the required medication to the market or patient very fast. 

In addition, product innovation potential is achieved by e.g. enabling to process high solid concentrations up to 40%, with still fast reconstitution characteristics of the lyophilized product. Furthermore, it allows for combinatory products by filling the various lyophilized compounds as required. 

Many approaches have been taken to freeze material into particles for subsequent drying under cold condition. From dripping liquids directly into liquid nitrogen [1] to spraying in an cold air flow [2, 3]. 

The bulk freeze drying process can be carried out at atmospheric pressure (e.g. in a fluidized bed), in conventional freeze-dryers as a layer in trays, which are positioned on the shelfs or as shown here in a dynamic system with continous mixing to provide effecient mass and heat transfer. Drying at atmospheric pressure is feasible in lab scale but have been failing so far in the scale-up due to, in the frozen state, low glass transition temperature  (Tg'). Vacuum freeze drying seems to be the gold standard. While tray freeze drying requires a lot of manual handling, which is especially difficult in the light of the recently published Annex 1 of the GMP guideline [4], dynamic freeze drying offers a contained processing with nearly no manual interference.required.