The rise of peptide therapeutics within global pharmaceutical pipelines saw a rise in research on efficient strategies of peptide synthesis. Hybrid peptide synthesis offers several advantages over solid-phase synthesis by allowing simultaneous generation of multiple fragments and their subsequent coupling by liquid-phase route. This allows higher reaction yields, reduced solvent usage and offers flexibility of scale of production. The hybrid synthesis necessitates development of efficient processes for isolation of the fragments at each step before they undergo coupling.
Peptide fragments are challenging to isolate owing to their tendency to phase separate and gel at lower temperatures and higher concentrations. Moreover, its bulky molecular structure renders it difficult to crystallize. This results in impurity rejection and processability challenges owing to physical attributes. Hence, navigation of the design space becomes critical to crystallize the required form of the fragment, whilst avoiding gelation and achieving high impurity rejection, yield and purity.
In this work, we discuss rational design of experiments and computational tools to map the design space towards effective navigation of process variables. We develop and present workflows for process design development of the crystallization strategy towards obtaining the peptide fragment in the desired form. We present further optimization of the process developed to achieve high yield and purity. Such a methodology will help inform further developmental studies for peptide isolation.
