ABSTRACT
Formulating protein powders for aerosol delivery is a dual challenge as it requires not only flowability and dispersibility of the powders but also biochemical stability of the protein molecules. To satisfy the latter requirement, proteins are usually formulated in amorphous glasses, which, however, are physically unstable and tend to crystallize with interparticulate bond formation and loss of powder dispersibility. In addition, the biochemical stability requirement limits the manufacturing processes that can be used for protein powder production. These challenges, and possible ways to tackle them, will be addressed in this chapter. The issues of microbial risks of proteins and local effects of inhaled powders in the respiratory tract, although important, will not be discussed here.
