Biologic drug substances (DSs) are stored and transported as frozen bulk in various containers, each having disadvantages. We evaluated a powder-based bulk storage approach based on spray drying and demonstrate for the first time that monoclonal antibodies (mAbs) can be spray dried with >90% powder collection yield using a laboratory-scale spray dryer, which outperformed three benchtop units in yield and water content reduction. Cyclone design was critical to collection yield, which remained sensitive to sample formulations. High yield was achieved for three mAbs formulated at a 2:1 mAb: trehalose weight ratio. Increasing the amount of trehalose beyond this ratio decreased yield by increasing the amount of powder retained in the drying chamber, apparently due to increased particle tackiness. Despite a high inlet temperature, the physical stability of spray-dried mAbs was comparable to or greater than that of freeze-dried counterparts. Water content of the spray-dried powder was affected more by gas residence time in the dryer than by outlet and inlet temperatures. The laboratory-scale unit, which allowed longer gas residence time, produced drier powders even at high liquid feed rate. Characterization of spray-dried mAb reconstitution time and reconstituted solution turbidity demonstrated that the process was suitable for powder-based biologic DS bulk storage applications.

This study evaluates a pilot-scale spray dryer against a laboratory-scale dryer to spray-dry multiple monoclonal antibodies (mAbs) from the perspective of scale-up, impact on mAb stability, and feasibility of a high-concentration preparation. The data demonstrated that there is no process limitation in solution viscosity when high-concentration mAb formulations are prepared from spray-dried powder reconstitution compared with concentration via the conventional ultrafiltration process. This study offers a commercially viable spray-drying process for biological bulk storage and a high-concentration mAb manufacturing option for subcutaneous administration. The outcomes of this study will benefit scientists and engineers who develop high-concentration mAb products by providing a viable manufacturing alternative.