Solid-phase peptide synthesis: recent advances through adoption of continuous flow


Vapourtec Ltd, United Kingdom


Two of the major challenges on solid-phase peptide synthesis are the difficulties in monitoring reactions in real time and the need to accommodate volume changes of the resin beads as the peptide elongates. The lack of accurate inline data to monitor reactions and the physical limitation of reactor vessels often slow down the discovery of new peptides. Vapourtec has developed a new “intelligent” packed bed reactor that accommodates volume changes whilst providing valuable insight into the reaction kinetics. By monitoring and controlling the packed density of the resin beads, channelling of reagents is minimised; reducing the need for excessive reagent and wash volumes. 

This accurate control of the reactor volume also allows evaluation in real-time when aggregation events occur.


Peptides cover a niche section in medicinal therapy. By definition, a peptide consists of between 2 and 50 amino acids, it is smaller than a protein. As a drug, it falls between small molecules and proteins. The application of peptides in the pharmaceutical industry has been growing in recent years. Peptides possesses high selectivity and activity against biological targets and low toxicity (1, 2), making them an attractive type of drug.


By 2018, more than 60 peptide drugs had been approved in the US, Europe and Japan; 28 of which are non-insulin peptide drugs released post 2000. In addition to approved peptides, 260 have been tested in clinical trials and over 150 are currently in active clinical development (1).


Since 1963, when R. B. Merrifield published the first synthesis of a peptide supported in solid phase (3) the use of this technology spread fast thanks to the “simplicity” and speed of this technique (4), compared to homogeneous phase peptide synthesis. Figure 1 shows a cycle overview of Solid-phase peptide synthesis (SPPS).


Due to the repetitive sequence of reactions, ...