Delivery aspects of small peptides and substrates for peptide transporters.

The present summary highlight chemical strategies applied to improve plasma half-lives and oral bioavailability of peptidic drugs as well as view on intestinal and pancreatic peptidase mediated degradation of peptidic drugs. In general chemical strategies used to increase the oral bioavailability of peptidic drugs consisting of more than three amino acids is disappointing. On the other hand chemical approaches to stabilize peptidic drugs against metabolism seem promising for increasing plasma half-lives of parental peptidic drugs as well as for increasing oral bioavailability of di/tripeptidomimetics and dipeptidyl pro-moieties targeting peptide transporters.