Peptides are prepared by Solid Phase Peptide Synthesis (SPPS). The fundamental premise of solid phase synthesis is that amino acids can be assembled into a peptide of any desired sequence while one end of the chain is anchored to an insoluble support. In practical SPPS the carboxyl terminus of the peptide is linked to a polymer. After the desired sequence of amino acids has been linked together on the support, a reagent can be applied to cleave the peptide chain from the support and liberate the crude peptide into solution.

[Click image for larger view. Image courtesy Wikipedia and Dan Cojocari]

When the C-terminal of a peptide is an amide the derivative is a peptide amide. Peptide-amides are extremely important derivatives since many naturally occurring peptide hormones are present as the amide. To synthesize peptide amides solid phase resins have been developed which yield peptide amides directly upon cleavage.

After the desired sequence of amino acids has been linked together on the support, Trifluoroacetic acid (TFA) containing scavengers can be used to cleave the peptide chain from the support as well as all protecting groups. Purification is performed on the crude peptide, using High Performance Liquid Chromatography (HPLC).

Peptide manufacture involves significant capital expenditure, and R&D companies are increasingly outsourcing the production of their peptides to contract manufacturers.