Visualization and understanding of the granulation liquid mixing and distribution during continuous twin screw granulation using NIR chemical imaging

Examining drug hydrophobicity in continuous wet granulation within a twin screw extruder

“…The authors reported increasing liquid heterogeneity with more hydrophobic formulations, and the composition of their particles was found to be increasingly hydrophilic (i.e., greater lactose content) as granule size increased. This finding of the binder being poorly distributed matched the results of others who noted a higher binder content present in larger granules when the dropwise/injection method of binder delivery is employed Fonteyne et al, 2014;Vercruysse et al, 2014). Conversely, it has been noted in studies with a high shear batch mixer that unlike droplet wetting, aspects of nucleation related to liquid penetration show very little dependency on the hydrophobicity of a powder mixture when employing foam granulation.…”

“…Common processing variables such as extruder screw speed, feed rate, liquid-to-solid ratio, binder concentration, and binder viscosity have been well studied and summarized in a recent review of the technology (Thompson, 2015). However, binder spreading and ingredient mixing has only recently been considered for twin screw granulators (El Hagrasy and Litster, 2013a,b;Fonteyne et al, 2014;Kumar et al, 2014;Vercruysse et al, 2014;Yu et al, 2014). The studies that have examined mixing within the machine to date have been based on wetting by liquid injection and noted significant heterogeneity.…”

Conceptual framework for model-based analysis of residence time distribution in twin-screw granulation

“…Kumar et al (2014b) applied near infrared chemical imaging (NIR-CI) to measure the RTD to conclude that the extent of axial mixing is significantly influenced by the screw configuration and barrel filling degree. The adequateness of the NIR-CI as an analytical tool for the visualization of the process in a TSG requiring fast measurements was established in an earlier study by Vercruysse et al (2013). In this study on granulation liquid mixing and distribution along with the residence time analysis in TSG it was concluded that the liquid distribution improved only by increasing the granulation liquid content at the granulator inlet.…”

Continuous twin screw granulation of controlled release formulations with various HPMC grades

“…These multimodal distributions can potentially result in segregation during downstream processing and have a negative effect on the drying uniformity. Efforts have been made to obtain monomodal GSD after continuous granulation through optimization of the feeder performance, screw design, binder addition, liquid pump, nozzle design and operation at low filling degree [22,28,30,35,36]. However, for granulation of HPMC bimodal distributions were also reported on high shear granulation which was attributed to the specific vs. F9 in Figure 3).…”