(252e) Improving Spray Drying Processing through Modeling and Characterization

Advances in engineering spray dried dispersion (SDD) for enhancing the oral bioavailability of drugs enable us to develop robust solid dispersion drug products. To this end, research in pharmaceutical spray drying has focused on coupling characterization of particles, solution and the spray with predictive modeling such as using computational fluid dynamics. Here, I will highlight two approaches we have used to gain fundamental understanding of spray drying process and the SDD particles.

To understand the microscopic characteristics of SDDs, we analysed the morphology and chemical distribution of the drug within SDD particles. Our work revealed the existence of local amorphous amorphous phase separation of drug from the polymer within particles. Using theoretical analysis, we elucidated the role of the complex drying kinetics and the thermodynamics of the process resulting in the observed SDD spatial and chemical microstructure. We also highlight the importance of probing the microscopic origins in such a system.

To understand the transport phenomena during spray drying, we turned to computational modelling of spray drying using solvents. We studied the variation in drying kinetics as a function of various processing conditions and the most influential processing parameters. We highlight the similarities and differences in drying when moving from a pilot to a commercial scale dryer. I will also briefly discuss the computational model of polymeric droplets to describe the specific drying trajectories, accounting for the formation of a polymeric skin on the droplet surface, the variation of the solvent diffusivity throughout drying.