Drying of Pharmaceutical Products

Pharmaceutical products comprise several types of materials including chemical and biological substances, such as enzymes and proteins, hormones, antibiotics, vaccines, proteins, vegetable extracts, as well as pharmaceutical granules and compression mixtures. On the other hand, some products are produced in small amounts, have high value and are tricky to dry, such as the biopharmaceuticals, including proteins, enzymes, hormones and monoclonal antibodies. The final product should achieve strict quality specifications, essential to ensure the quality, safety and efficacy of the finished product on the market. Several drying systems are used in the pharmaceutical sector, such as the spray drying, freeze-drying, fluidized and spouted bed dryer, and microwave drying. According to several pharmaceutical guidelines, these systems should follow very harsh specifications, as made of stainless steel with sanitary finishing. The selection of the drying system more adequate for a particular application is a challenging task, and should consider factors related to the cost of the product to be processed, physical and chemical properties, thermal sensitivity and the final use of the product, among others. In this chapter is presented an overview of the recent applications and concepts involved in field of pharmaceutical product drying. Some topics of a general nature will be approached, including fundamental aspects of drying, principal types of dryers, methods used for their selection, and regarding to the physicochemical properties of the materials. The drying of some pharmaceutical products will be presented, emphasizing extracts of medicinal plants, enzymes and proteins, microencapsulation and particle coating.

Keywords: Fluid bed drying, spray drying, spouted bed, sorption isotherms, medicinal plants.