Fluidized bed drying is a complex process because of the simultaneous heat transfer and mass transfer and requires optimization of the process parameters through experimental analysis. When the scale of the fluid bed is changed from a laboratory scale to a pilot or production scale, the process parameters change. These process parameters, such as the inlet air velocity, do not change in accordance with the bed diameter. This can make it very challenging when different scales of fluid beds are used in the pharmaceutical process development stage.

The primary considerations during the scale-up approach of the fluid bed are that the hydrodynamics and the drying kinetics of the system should be maintained. This helps in maintaining the reproducibility of the drying runs even in different scales of the fluid beds. The approach which is commonly used for fluidized bed drying is based on Glicksman scaling laws. It has a group of dimensionless parameters that should be maintained across different scales of fluid beds. Since this method focuses only on the fluidization and not on the heat and mass transfer, another approach developed by Kemp and Oakley and then used by Chen et al. can be used which focuses on the drying kinetics in the fluid bed scale-up. This research focuses on the scale-up approach for the fluid bed drying process using these two approaches to maintain the hydrodynamic similarity and the drying kinetics. The experiments were conducted on a smaller scale of a 3L fluid bed dryer, and the scale-up approach was used to predict the process conditions for a larger scale of 6L.