Experimental and Numerical Analyses of Fill Level and Binder Additive Ratio Effects in a Continuous Twin-screw Granulation

Continuous wet granulation using a twin-screw granulator has attracted much interest in the pharmaceutical industry. The physical properties of granules prepared through the twin-screw granulation process depend on the several factors, such as screw and barrel geometries, operating conditions, and formulations of raw materials. In particular, it is known that the fill level in a twin-screw granulator and the binder additive ratio have an impact on the twin-screw granulation process. In this study, mutual effects of the two major factors on the granulation process was investigated experimentally and numerically. By combining the experimental and numerical analyses, a prediction model of the granule growth rate was proposed. The proposed model demonstrated that the granule growth rate was determined by the total energies (compressive and shear directions) and the index of granulation.