Powder and other divided solids mixing. Scale-up and parametric study of a ribbon blender used in pharmaceutical powders mixing.

This work is aimed at evaluating the effect of ribbon blender operational parameters on mixture quality. Mix quality parameters and blend uniformity limits are enforced by regulatory bodies. These limits have served in this present work as targets for blending end-points. In a laboratory-scale model ribbon blender, built by scaling down a real industrial unit, powder mixtures composed of white and blue microcrystalline cellulose (MCC) were blended. Blend uniformity was evaluated using a statistical analysis method under various operating conditions such as loading patterns, blender filling percentage, impeller rotational speeds, and mixing times. It was shown that the filling percentage is the most influential mixing parameter. At high impeller rotational speed, the blending end-point was never reached during experimentation.