Wet granulation process via foams and drops

Wet granulation using foaming binder solution is a new approach of liquid delivery to create granules. This study compares wet granulation via foamed binder addition method and sprayed binder addition method by studying the kinetics of foam and drop penetrations into loosely packed powder beds. Foam and drop nucleation kinetics were compared by examining specific penetration time (penetration time per unit mass of liquid drop or foam) and nucleation ratio (ratio of mass of nuclei granules to mass of liquid binder). The mechanisms of foam decay such as liquid drainage and bubble coalescence are critical to the process of foam penetration into the powder pores. Foam penetration rate cannot be completely revealed until the foam characteristics are clearly determined. Nucleation ratio results suggest that foam nucleation method allows more efficient liquid usage and liquid distribution to induce nucleation of powder compared to drop nucleation method.