To date, a limited number of peptides and proteins have been used ther
apeutically. However, this number is growing rapidly. Some have been s
ynthesised chemically or extracted from tissue and have been used in t
he clinic for decades. Recently, advances in cell and molecular biolog
y have led to a much greater perception of the therapeutic value of ma
ny other peptides and proteins. Recombinant DNA technology has enabled
high level expression and the biotechnology industry has made availab
le large scale production for clinical use. In order to ensure that ma
ximal use is made of this class of drug, scientists will need to devis
e patient compliant formulations. Clearly, these formulations will hav
e to be safe and pharmacologically relevant. In addition, the route of
administration will have to be acceptable to the patient given any pa
rticular indication. Almost all therapeutic peptides and proteins are
administered by injection. It has been recognised that specific region
s of the gastrointestinal tract may offer potential in terms of macrom
olecular absorption. This paper will address the attractiveness of the
colon and rectum as routes of administration for peptide and protein
drugs. (C) 1997 Elsevier Science B.V.