Peptide therapeutics, a class of drug molecules, have gained popularity among pharmaceutical and biotechnology companies due to their unique attributes such as high specificity and discernment, small sizes, low production costs, and ease of modification. These attributes are helping peptide therapeutics to achieve success in cancer treatment, which is expected to be the fastest growing segment of the peptide therapeutics market.
Peptides are also being used to treat various other conditions such as autoimmune diseases, infectious diseases, and metabolic disorders. The rising incidence of these diseases is the driving factor for demand growth in the peptide therapeutics market.
Although peptides have several beneficial properties when used as drugs, such as low production cost, short circulation half-life, easy penetration through membranes, and high biological activity, they are not without limitations. Currently, most peptides are administered via injection, and there are only a few oral peptide drugs in existence such as cyclosporine (Neoral(tm)) and desmopressin (Minirin(tm)). A number of chemical strategies have been developed to enhance the physicochemical properties of peptides for orally-available delivery. These include the stabilization of a-helixes and salt bridge formations, N-methylation, cyclization, and the establishment of intramolecular hydrogen bonds.
Another important strategy to improve pharmacokinetic properties is lipidation. Lipidation enables peptides to be delivered to target tissues by passive diffusion, and can significantly improve their absorption, distribution, metabolism, and excretion. The method of lipidation, the type of lipid used, and the position of the lipid on the peptide all have significant effects on peptide physicochemical properties such as lipophilicity.