Production Process of Automated Closed Solid-Phase Peptide Synthesis

Based on industrial-scale production practices, the standard production process of automated closed solid-phase peptide synthesis can be divided into six steps, with fully closed and automated operation throughout the whole process. The details are as follows:

1.Raw material preparation and pretreatment: Raw materials including resin, amino acids, coupling reagents, deprotection reagents and washing reagents are transferred to corresponding storage tanks through a closed conveying system for pretreatment: resin activation (removing impurities and activating active groups) and amino acid pretreatment (removing moisture and confirming purity). After pretreatment, they are sent to the solid-phase synthesis reactor through an automated conveying system, avoiding manual contact and external pollution during the whole process. Chutian Technology adopts AGV + robotic automatic feeding to replace manual raw material handling, further improving the automation level and safety of raw material conveying, and keeping workers away from irritating and highly sensitizing chemical raw materials.

2.Resin loading and activation: The pretreated resin is loaded into the closed synthesis reactor through an automated device. Inert gas (nitrogen) is introduced to expel air in the reactor. Activation reagents are added, and stirring activation is carried out at a set temperature (25–30℃). The activation time is precisely controlled by the PLC system (usually 30–60 minutes). After activation, unreacted activation reagents are removed by washing reagents through an automated washing system to ensure resin activity.

3.Amino acid coupling and deprotection cycle: This is the core step of peptide synthesis, and the cycle operation is automatically completed by the system. First, the first amino acid is sent into the reactor through a closed conveying system to conduct a coupling reaction with the activated resin. The PLC system controls the reaction temperature (25–40℃), stirring speed (adjusted according to resin type) and reaction time (1–2 hours). After coupling, the resin is washed with washing reagents to remove unreacted amino acids. Then, deprotection reagent (piperidine solution) is added to remove the Fmoc protecting group at the N-terminus of the amino acid. After deprotection, the resin is washed again to enter the next round of amino acid coupling until the synthesis of the target peptide chain length is completed. The cycle process can be pre-programmed through the upper computer software to realize fully automatic operation without manual intervention. The American CEM Liberty 2.0 automatic peptide synthesizer can automatically complete the full synthesis of 12 peptides at one time, greatly improving production efficiency.

4.Peptide chain cleavage: After the completion of peptide chain synthesis, cleavage reagent (TFA solution) is added into the reactor through an automated system. Stirring cleavage is carried out at low temperature (0–5℃) to separate the peptide chain from the resin and remove the protecting groups on the amino acid side chains. The cleavage time is controlled at 2–4 hours, and the whole process is closed to avoid leakage of cleavage reagents and oxidation of peptide chains. Some equipment can realize in-situ and program-controlled peptide cleavage, further improving cleavage efficiency and product purity.

5.Purification and refinement: After cleavage, the resin and peptide chain solution are separated through a closed filtration system. The peptide chain solution is sent to an automated purification system (high-performance liquid chromatography, HPLC). Impurities (unreacted amino acids, by-products) are removed through gradient elution, and high-purity peptide chain components are collected. Then, the peptide chain solution is concentrated and lyophilized through an automated concentration and lyophilization system to obtain the final peptide powder product. The whole process is closed to avoid product contamination and moisture introduction. Asymchem has also creatively developed and optimized a continuous high-efficiency concentration system, which is adapted to the characteristics of large concentration volume and high specification requirements of the preparation system, further improving the efficiency of purification and refinement.

6.Testing and packaging: The finished peptide is sampled through an automated sampling system and sent to the testing module to detect purity, content, impurities, moisture and other indicators. After passing the test, it is subpackaged and sealed through a closed packaging system. After packaging, it is stored in the warehouse. The whole process is automated and closed to ensure stable product quality. The one-piece all-paper packaging production line launched by Chutian Technology can save 30% of packaging materials, with an operating efficiency of 220 boxes per minute, which is in line with the environmental protection concept of European and American markets and helps peptide products go international.