THE DESIGN OF PEPTIDE ANALOGS FOR IMPROVED ABSORPTION

A series of elementary analyses have been conducted with the aim of defining the basic design features for a potent, specific and absorbable peptide drug. The studies show that the required characteristics can be obtained using a peptide of just 4-6 amino acid residues, provided that it has a total surface area of around 350 Angstrom(2), and a polar surface area of less than or equal to 50 Angstrom A(2). Such a molecule is predicted to have a biological activity in the nanomolar range, and to exhibit a very respectable target specificity. A case is also presented, however, to show that the molecule will have only a very limited peptide character, with the overall conclusion that successful 'peptide' drugs will probably not qualify as peptides at all.