Continuous Oral Solid Dose Manufacture
This chapter focuses on continuous wet granulation, salient aspects of other critical unit operations involved in the manufacture of oral solid dosage forms such as drying and tableting. The many ingredients involved in solid oral dosage forms of drugs have differences in their particle size, shape, hydrophilicity, and water sorption characteristics, all of which impact the manufacturing process. As a result, granulation becomes a necessary step in the preparation of drugs to ensure compositional, handling, and dissolution properties meet stated specifications. Powders and liquids are introduced into the extruder at multiple entry points by feeders and pumps surrounding a twin-screw granulator (TSG). Single- or twin-screw gravimetric feeders are commonly used for highly accurate continuous metering of individual ingredients or blends of ingredients into the TSG. The current regulatory environment supports advancing innovation including a more flexible, efficient, and cleaner continuous process.