SPPS (solid-phase peptide synthesis) is a standard method for obtaining peptides.

The peptide, linked by its C-terminal amino acid to a carrier resin, an inert, insoluble but swellable polymer, is assembled in the C→ N direction. It is elongated stepwise by coupling suitably protected derivatives of the amino acids constituting its sequence until coupling the N-terminus. After each coupling step, the “temporary” Nα-blocking group has to be removed without affecting the lateral protective groups and the link to the carrier.

The method can be fully automated. Thus, peptides can be obtained by SPPS far more rapidly than in solution, but the method requires large excesses of expensive amino acid derivatives for driving the coupling steps to completion.