Peptide drug delivery: Colonic and rectal absorption

To date, a limited number of peptides and proteins have been used therapeutically. However, this number is growing rapidly. Some have been synthesised chemically or extracted from tissue and have been used in the clinic for decades. Recently, advances in cell and molecular biology have led to a much greater perception of the therapeutic value of many other peptides and proteins. Recombinant DNA technology has enabled high level expression and the biotechnology industry has made available large scale production for clinical use. In order to ensure that maximal use is made of this class of drug, scientists will need to devise patient compliant formulations. Clearly, these formulations will have to be safe and pharmacologically relevant. In addition, the route of administration will have to be acceptable to the patient given any particular indication. Almost all therapeutic peptides and proteins are administered by injection. It has been recognised that specific regions of the gastrointestinal tract may offer potential in terms of macromolecular 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.