Prism eurolab 16

Melt granulation was performed using a co-rotating intermeshing twin-screw granulator (Prism Eurolab 16) (Thermo Fisher Scientific, Karlsruhe, Germany) with a barrel length of 25 L/D, where L is the axial screw length of the machine and D is the inner bore diameter. The screw design was identical for all experiments containing one kneading zone located in the fifth segment and consisting of 6 kneading discs positioned at a 60 • stagger angle in reversed direction. The premixed samples (Table 1) were fed into the granulator using a DD Flexwall 18 gravimetric feeder (Brabender Technologie, Germany), which was set in the gravimetric feeding mode. Throughput and screw speed were kept constant at 0.3 kg/h and 150 rpm, respectively. The barrel was divided into 6 barrel zones. Barrel temperature from segment 2 to 5 was kept constant at 60 • C. Segment 6, which is located at the end of the barrel, had a lower temperature of 40 • C during all runs in order to cool down the granules and hence avoiding them to stick together when leaving the granulator. Granule samples were collected after melt granulation of each mixture (Table 1). Afterwards, samples were stored at room temperature.

Pure PVOH, mixtures of PVOH/HCT and mixtures of PVOH/sorbitol were processed using a co-rotating, fully intermeshing twin screw extruder (Prism Eurolab 16, Thermo Fisher, Germany), operating at a screw speed of 100 rpm and processing temperatures of 130-180°C. The extruder was equipped with a gravimetric feeder, two Archimedes screws with 3 mixing zones and a cylindrical die of 3 mm. Afterwards, the extrudates were either manually cut using surgical blades into mini-tablets of 2 mm length or quench-cooled in liquid nitrogen, cryomilled and sieved through a 300 micron sieve.
Mixtures of cryomilled PVOH/sorbitol extrudate (<300µm) and CEL were processed using a co-rotating twin screw extruder (Haake MiniLab II Micro Compounder, Thermo Electron, Karlsruhe, Germany), operating at a screw speed of 60 rpm and a processing temperature of 140°C. The extruder was equipped with a pneumatic feeder, two Archimedes screws and a 2 mm cylindrical die. The extrudates were quench-cooled in liquid nitrogen, cryomilled and sieved through a 300-micron sieve.

HME experiments were performed using a co-rotating, fully intermeshing twin-screw extruder (Prism Eurolab 16, Thermo Fisher, Germany) equipped with a DD Flexwall  gravimetric feeder (Brabender Technology, Germany), two co-rotating twin-screws with 3 mixing zones (length to diameter ratio L/D=25) and a cylindrical die of 3 mm. A data logging system allowed monitoring of the screw torque and barrel well temperature during extrusion.
The extrusion barrel is divided into 6 segments which can be heated/cooled separately. Barrel temperature from segment 1 to 5 were set at the same temperature (the actual temperature depended on the experiment as the extrusion temperature was included as a variable in the study), while the die temperature was 140 °C for all experiments to guarantee a solid end product. For each run, 300 g of extrudates were collected at steady state extrusion conditions.
After cooling, the extrudates were milled using a knife mill (Moulinex AR110510, France) for 60 s and sieved through a 150 m sieve.