A Novel Hybrid SPPS/LPPS Strategy for the Synthesis of Tirzepatide via Native Chemical Ligation

The development of scalable, efficient manufacturing processes for high-volume, complex synthetic peptide and proteins remains a significant challenge, largely due to the limitations of traditional Solid Phase Peptide Synthesis (SPPS) and Liquid Phase Peptide Synthesis (LPPS).1 To enable the commercial synthesis of Tirzepatide (TZP, 1), we designed an innovative four-fragment hybrid SPPS/LPPS strategy that integrates the strengths of both platforms.2 This approach, coupled with flow chemistry for fragment condensation and nanofiltration for intermediate purification, represents a step-change in process efficiency for large-scale peptide production. Given the broader reliance on inefficient linear SPPS in the field, our work underscores the potential of hybrid synthesis strategies to transform peptide manufacturing. In parallel with commercial process development, we established an alternative two-fragment synthesis route using Native Chemical Ligation (NCL) followed by tandem desulfurization. This method enables the chemoselective coupling of two unprotected peptide fragments in aqueous media without epimerization, offering a powerful, orthogonal route to TZP. Together, these advances represent meaningful innovation in synthetic peptide process chemistry.