Proteins, pulmonary delivery spray drying

Protein-based drugs have been formulated mainly as stable liquids or in cases where liquid stability is limiting as lyophilized dosage forms to be reconstituted with a suitable diluent prior to injection. This is because their delivery has been limited primarily to the parenteral routes of intravenous (IV), subcutaneous (SC), or intramuscular (IM) administration. There are a few drugs that have been developed for pulmonary delivery, such as rhDNase (Pulmozyme ) and an inhalable formulation of insulin (e.g., Exubra ). However, even such drugs have been formulated as either liquid or lyophilized or spray-dried powders. This chapter will focus only on excipients that are applicable to liquid and lyophilized protein formulations. 

Custom-made SFD towers and apparatuses have been designed, built and improved to produce nearly monodisperse, low-density lyophilisate powders suitable for pulmonary dmg delivery. Spray-freeze-dried particles were characterized regarding their mean geometric particle size, aerodynamic behaviour, surface morphology and interior structure, API (protein) stabihty, powder flowability and reconstitution characteristics. 

---