Microencapsulation by spray drying

Spray drying technique has been widely used for drying heat-sensitive foods, pharmaceuticals, and other substances, because of the solvent rapid evaporation from the droplets. Although most often considered a dehydration process, spray drying can also be used as an encapsulation method when it entraps 'active' material within a protective matrix, which is essentially inert to the material being encapsulated. Compared to the other conventional microencapsulation techniques, it offers the attractive advantage of producing microcapsules in a relatively simple continuous processing operation. This chapter will present a brief overview of the main considerations involved in the application of spray drying for microencapsulation, with a special emphasis given to microencapsulation of volatile materials. The potential use of spray drying microencapsulation for pharmaceutical applications, particularly the preparation of microparticulate drug delivery systems, will also be discussed.