Granulation techniques and technologies: recent progresses

Granulation, the process of particle enlargement by agglomeration technique, is one of the most significant unit operations in the production of pharmaceutical dosage forms, mostly tablets and capsules. Granulation process transforms fine powders into free-flowing, dustfree granules that are easy to compress. Nevertheless, granulation poses numerous challenges due to high quality requirement of the formed granules in terms of content uniformity and physicochemical properties such as granule size, bulk density, porosity, hardness, moisture, compressibility, etc. together with physical and chemical stability of the drug. Granulation process can be divided into two types: wet granulation that utilize a liquid in the process and dry granulation that requires no liquid. The type of process selection requires thorough knowledge of physicochemical properties of the drug, excipients, required flow and release properties, to name a few. Among currently available technologies, spray drying, roller compaction, high shear mixing, and fluid bed granulation are worth of note. Like any other scientific field, pharmaceutical granulation technology also continues to change, and arrival of novel and innovative technologies are inevitable. This review focuses on the recent progress in the granulation techniques and technologies such as pneumatic dry granulation, reverse wet granulation, steam granulation, moisture-activated dry granulation, thermal adhesion granulation, freeze granulation, and foamed binder or foam granulation. This review gives an overview of these with a short description about each development along with its significance and limitations.