Preparation of nanoscale pulmonary drug delivery formulations by spray drying

Advances in preparation technologies for nanomedicines have provided novel formulations for pulmonary drug delivery. Application of drugs via the lungs can be considered as one of the most attractive implementations of nanoparticles for therapeutic use due to the unique anatomy and physiology of the lungs. The colloidal nature of nanoparticles provides important advantages to the formulation of drugs, which are normally difficult to administer due to poor stability or uptake, partly because nanoparticles protect the drug from the physiological milieu, facilitate transport across biological barriers and can offer controlled drug release. There are numerous methods for producing therapeutic nanoparticles, each with their own advantages and suitable application. Liquid atomization techniques such as spray drying can produce nanoparticle formulations in a dry powder form suitable for pulmonary administration in a direct one-step process. This chapter describes the different state-of-the-art techniques used to prepare drug nanoparticles (with special emphasize on spray drying techniques) and the strategies for administering such unique formulations to the pulmonary environment.