Lipoamino Acid and Liposaccharide Conjugated Peptides: Enhancement of Bioavailability

The most convenient way to administer drugs is by oral administration. However, intestinal absorption of peptides/proteins is relatively poor, mainly due to extensive enzymatic degradation in the gastrointestinal tract. The aim of the present study was to improve the intestinal absorption and stability of a model peptide IT-100 by chemically conjugating it with a lipid and sugar based carrier system. Lipoamino acids enhance the membrane permeability and metabolic stability of peptides, and have been investigated extensively in drug delivery [1]. However, lipoamino acid conjugation can considerably reduce water solubility. Further sugar conjugation not only improves the physico-chemical properties of the lipophilic compounds (water solubility), but also may allow utilisation of active transport uptake systems such as the Na+ dependent D-glucose transporter [2].