Spray-drying for the formulation of oral drug delivery systems

Spray-drying is a very well established technology, used for converting emulsions, suspensions, dispersions, or liquids into fine, dispersible particles by the use of an atomizer into a hot drying gas medium. It is a reliable and reproducible technique for particle design and tailored production, suited for a variety of applications, including drug delivery. The oral route is by far the preferred route of administration and, among other advantages, has easy-to-follow therapeutic regimens, and therefore, the highest patient compliance. Considering the myriad of advantages of advanced fabrication methods like spray-drying over conventional particle fabrication methods, the spray-drying technique holds potential in the formulation of oral drug delivery systems with improved solubility and, thereby, oral bioavailability. In this chapter, we review the principles of spray-drying, the equipment configurations used, the parameters and variables affecting particle formulation, and the main considerations for a successful industrial scale-up. We also discuss the formulation of drugs/drug delivery systems for oral administration using spray-drying, providing examples of micro/nano-particles and pure drug particles that have demonstrated the potential of this technology to overcome the limited bioavailability of drug formulations produced by other fabrication methods.