Manufacture of disulfide bonded peptides

A method for the manufacture of a peptide having at least one intramolecular disulfide bond, the method comprising:

• a) providing a liquid reaction medium inside a reaction vessel, which vessel allows for mixing of its contents;
• b) providing a solution of a peptide, which peptide comprises at least two sulfhydryl groups;
• c) providing a solution of an oxidizing agent;
• d) simultaneously adding, via spatially separated inlets, the solution of the oxidizing agent and the solution of the peptide into the reaction medium inside the reaction vessel while mixing the vessel's contents, wherein the addition is performed such that:
• i) the concentration C1, which is the average concentration of the peptide in its reduced state inside the reaction vessel, is below the concentration C0, which is the final concentration of the peptide inside the reaction vessel at the end of peptide addition, independent of its oxidation state;
• and
• ii) the average concentration of oxidizing agent inside the reaction vessel is kept at essentially zero during the time of simultaneous addition of oxidizing agent and peptide;
• and
• e) continuing addition of the oxidizing agent beyond the end of peptide addition, while keeping the concentration of the oxidizing agent at essentially zero;
• wherein steps d) and e) are repeated at least once in alternation.