ABSTRACT
Although most peptide and protein drugs are dosed by parenteral administration, considerable effort is invested in testing alternative routes of administration, for example, oral, buccal, nasal, pulmonary, rectal, and transdermal. Patient compliance, improved treatment options, and life-cycle extension of patented drugs are the main driving factors. This chapter will describe the difculties presented by the nonparenteral routes of administration and how they can be overcome. First, the key requirements and considerations of nonparenteral route delivery systems will be presented and, subsequently, the many physical and chemical barriers that need to be overcome will be described. Finally, examples of the delivery strategies utilized today will be presented to give an overview of the current state of the eld.
