(T1530-03-16) A Comparative Study of Product Recovery in Laboratory-Scale Spray Dryers: Standard Cyclone vs. the Discovery Module

Purpose: The objective of this study is to evaluate and compare the product recovery performance of the Discovery Module versus a standard cyclone separator in benchtop and laboratory-scale spray drying systems. The study assesses how the collection mechanism influences yield across different formulation types and equipment scales, with a focus on applications where material efficiency is critical in research and development settings.

Methods: Spray drying trials were conducted using both solvent-based, Shin-Etsu AQOAT^® hydroxypropyl methylcellulose acetate succinate (HPMC-AS) in acetone and a 1:4 ratio of Indomethacin to Evonik Eudragit^® E100 (IND:EPO 1:4) in acetone, and an aqueous formulation, GPC M-100 Maltodextrin in deionized (DI) Water. The performance of the Discovery Module was compared with standard cyclone-based collection systems. Parameters such as inlet temperature, product temperature, feed rate, and yield varied between formulations and were measured across multiple trials on both the GENESIS^™ GSD-LAB Micro and GENESIS^™ GSD-200 spray dryers. To ensure consistency across all formulations, 10 pounds per square inch (PSI) of atomization air and 10 cubic feet per minute (CFM) of airflow were maintained on the GSD-LAB Micro, while 15 PSI of atomization air and 17 CFM of airflow were used on the GSD-200. The Discovery Module's filtration efficiency, particle collection, and yield were evaluated. For the GSD-LAB Micro, HPMC-AS was processed at an inlet temperature of 80°C with an average product temperature of 44°C; Maltodextrin at 190°C and 101°C, respectively; and IND:EPO 1:4 at 110°C with an average product temperature of 55°C. On the GSD-200, Maltodextrin was spray dried at 180°C inlet temperature and 75°C product temperature, while IND:EPO 1:4 was processed at an inlet temperature of 60°C and product temperature of 44°C. To ensure accurate comparison of collection efficiency, inlet and product temperatures were held constant across both the Discovery Module and standard cyclone configurations for each formulation. Maintaining identical product temperatures was especially critical to eliminate any confounding effects from residual moisture, which could artificially increase the weight of recovered solids and skew yield data. Spray-dried powders were collected directly from the respective collection systems, either from the Discovery Module beneath the drying chamber or from the collection vessel below the cyclone. All recovered material was collected into pre-weighed plastic bags using a brass brush and stainless-steel spatulas, then weighed on small laboratory scales. Because the HPMS-AS was only 1% of the solution and theoretically only 100mg of solids were sprayed, this material was carefully transferred to pre-weighed glass vials and weighed on a calibrated analytical balance (±0.0001 g). Theoretical solids sprayed were calculated based on feed rate, solids concentration, and spray time, and percent yield was determined by comparing the collected mass to the theoretical mass of solids sprayed.

Results: Use of the Discovery Module resulted in increased product recovery compared to the standard cyclone configuration across all tested formulations and both spray drying systems. In the GSD-LAB Micro, the average yield increased by 19.4%. For HPMC-AS formulations in acetone, the Discovery Module achieved a yield of 74.6%, compared to 15.8% with the standard cyclone. Maltodextrin in DI water yielded 47.8% with the Discovery Module and 44.4% with the standard system. IND:EPO (1:4) formulations in acetone reached a yield of 35.6% with the Discovery Module, while the standard system yielded 5.2%. In the GSD-200 configuration, similar trends were observed. For maltodextrin in DI water, the Discovery Module yielded 53.5%, compared to 30.2% with the standard cyclone. For IND:EPO (1:4) in acetone, the Discovery Module achieved a yield of 38.3%, while the standard configuration produced 18.9%. The average increase in yield using the Discovery Module on the GSD-200 was 21.3%.

Conclusion: This study demonstrates that the Discovery Module substantially improves product recovery in spray drying processes at both benchtop (GSD-LAB Micro) and laboratory/pilot scale (GSD-200). Across all evaluated formulations, the Discovery Module consistently achieved higher yields than standard cyclone-based collection systems. For solvent-based formulations on the GSD-LAB Micro, yield increases of up to sixfold were observed, while the GSD-200 exhibited more than a twofold improvement. In the case of aqueous formulations, such as maltodextrin, yield improvements reached up to 23%. These findings indicate that the Discovery Module enhances recovery efficiency across diverse formulation types and scales, supporting its utility in pharmaceutical development.


Table 1. Comparison of yield and recovery for HPMC-AS, maltodextrin, and IND:EPO processed using the Discovery Module and standard cyclone configuration on the GSD-Micro.


Table 2. Comparison of yield and recovery for maltodextrin and IND:EPO processed using the Discovery Module and standard cyclone configuration on the GSD-200.


Figure 1. Bar graph comparing percent yield for three formulations—HPMC-AS in acetone, maltodextrin in deionized water, and IND:EPO (1:4) in acetone—processed using both the Discovery Module and the standard cyclone configuration. Data for all three formulations were obtained on the GSD-LAB Micro, while yield comparisons for maltodextrin and IND:EPO (1:4) were also conducted on the GSD-200.