Twin screw wet granulation is a key process in the continuous manufacture of oral solid dosage forms. Previous Research Article has qualitatively suggested that the channel fill level influences the granules produced. In this paper a quantitative measure of the total volumetric fraction of the conveying element channels of the screw filled with powder (phi) was used. Experimental results are shown which demonstrate that very similar particle size distributions can be obtained at the same phi with the same material and screw configuration but radically different solids feed rates and screw speeds. Morphology of the granules also correlates with phi. This is consistent with previous observations in the literature correlating granule attributes with powder feed rate and screw speed but also considers the two parameters in combination. A process design space approach based on phi is proposed. This can be determined empirically, and potentially has value in setting process control strategies, assuring process robustness and allowing process flexibility during the product lifecycle.

• GlaxoSmithKline

• Oral solid dose

1. Channel fill
2. continuous manufacturing
3. Design space
4. oral solid dose
5. Research Article
6. Residence time
7. Twin-screw granulation