On the Use of a Dual-Scale Model to Improve Understanding of a Pharmaceutical Freeze-Drying Process

Advanced approach to build the design space for the primary drying of a pharmaceutical freeze‐drying process

“…Actually, a batch of vials can be highly nonuniform because of various causes, for example, radiation from the walls of the chamber that can significantly heat those vials placed at the borders of the shelves or in corner position. [46][47] Moreover, a pressure difference between the central part and the edges of the shelf can exist, but this value is generally negligible, apart from the case of a very low shelf-toshelf distance and high sublimation flux. 46 Finally, an important source of batch nonuniformity is the nucleation temperature, which affects ice-crystal size distribution (and thus, the parameter R p ) and is randomly distributed among the vials loaded in the freeze dryer.…”

Quality by Design for Biopharmaceutical Drug Product Development

“…In the past, the role played by water vapor fluid dynamics was assumed to be negligible, also because of the difficulty to identify and isolate its effects from the experimental results. Rasetto et al (2008Rasetto et al ( , 2010 and studied the effect of some geometrical parameters of a drying chamber (clearances between the shelves and position of the duct leading the vapor to the condenser) on the fluid dynamics of the water vapor as a function of the sublimation rate, both in a small-scale and in an industrial-scale apparatus. Their results evidenced the presence of significant pressure gradients along the shelves, in particular in the large-scale units (Barresi et al 2010a).…”

Quadrature-based moment closures for non-equilibrium flows: Hard-sphere collisions and approach to equilibrium

“…Furthermore, molecular effects have to be taken into account also in high-speed hydrodynamics (when shock waves appear) [1] or interface processes (evaporation and condensation) [2]. These situations are very common in many applications like aerodynamics, vacuum technology, micro-fluidics and freeze-drying [3,4], just to cite a few.…”