Purpose It was investigated if continuous wet granulation and drying could be combined in a twin-screw granulator with the aimto provide (pre-) dried granules in a single-step process, i.e. in-barrel-drying. Methods To have a consistent and robust material propulsionmechanism, a twin-screw granulator was divided into two compartments. One compartment was operated at lower temperature to granulate and to pre-heat the material, while another compartment was operated at very high temperature to evaporate the granulation liquid as rapidly as possible. Design of experiments was used to investigate the in-barrel-drying process in detail. The process was further investigated for twin-screw wet granulation with API suspension feed, and compared against traditional fluidised-bed drying. Granule and compact properties were evaluated to study the process impact on the product quality. Results In-barrel-drying was demonstrated as feasible and yielded completely dried and granulated material at specific settings. The evaporation zone temperature and the processed mass of water were identified as key parameters to balance the evaporation capacity of the process and the material throughput. Granules and compacts showed an acceptable product quality. Conclusions In-barrel-drying can be used to condense the wet granulation and drying process steps into one piece of equipment, thereby limiting or even omitting downstream drying process steps.

• Novartis AG

• Oral solid dose

1. API suspension feed
2. Design of experiments
3. fluidised-bed drying
4. oral solid dose
5. Research Article
6. telescoped process
7. Twin screw wet granulation