ABSTRACT
This chapter covers the sizing of granulation after drying in a wet granulation process. Granule properties, granule size, and distribution play a pivotal role in the final blend properties and tablet characteristics. Hence, the sizing of granulation is a critical unit operation in the manufacture of oral dosage forms. The chapter begins with a theory of comminution and properties of feed materials affecting the sizing process. Details of various types of equipment and the list of major manufacturers used in the size-reduction process, their merits and demerits, and variables affecting the size-reduction process for dry milling are covered in great detail. Furthermore, the process of wet milling for obtaining uniformly sized granules for uniform drying is also addressed. Scale-up factors with relevant case studies for hammer and conical type mills are explained. Finally, with the ongoing initiative of the US FDA to encourage quality-by-design (QbD), some references focused on process analytical tools to characterize particle-size distribution as well as process modeling tools to simulate particle-size reduction are covered. All of these experimental and modeling tools can be useful during the development and optimization of a successful new drug or generic tablet and capsule products.
