Welch Chromatographic Solutions for Peptide Drugs

Peptide therapeutics have become one of the fastest-growing segments of the pharmaceutical industry, driven by their high target specificity, strong biological activity, and expanding applications in metabolic diseases, oncology, among other therapeutic areas. As peptide drugs become more structurally complex, comprehensive analytical strategies are increasingly important for ensuring product quality, safety, and regulatory compliance throughout development and manufacturing.

Chromatography plays a central role in peptide characterization, impurity profiling, and quality control.

Welch Materials provides a complete portfolio of chromatographic solutions tailored for peptide drug analysis. These solutions cover the chiral analysis of protected amino acids, the determination of peptide related substances, the analysis of peptide aggregates by size exclusion chromatography, and the evaluation of amino acid ratios using the Welch Ultisil Amino Acid Method Kit. Together, these solutions form an integrated analytical platform for peptide research, development, and manufacturing.

Note: This article only presents some of the applications from the document. Download the full solution document at the end of the article for more application examples.

In the process development of chemically synthesized peptide APIs, protected amino acids serve as starting materials, and their quality directly impacts the quality of the peptide drug. Chiral isomers are common impurities in Fmoc-protected amino acids. For the analysis of these chiral isomers, Welch Materials offers a variety of coated polysaccharide chiral stationary phases to address such separation challenges.

The production of chemically synthesized peptides involves multiple steps, including deprotection, activation, coupling, and cleavage of the final sequence from the solid-phase support. Peptide-related impurities can affect product safety and efficacy; RP-HPLC is commonly used for analysis, and selecting the appropriate stationary phase is critical for achieving optimal separation of the various components. To this end, Welch Materials offers a wide range of reverse-phase stationary phases to choose from.

Recommendations for column selection:

• Small peptides and peptides with low hydrophobicity: C18 columns.
• Highly hydrophobic peptides (which often exhibit excessive retention on C18 columns): C8 or C4 columns. Example: long-chain peptides with fatty acid side chains like liraglutide and semaglutide.
• Peptides requiring specific selectivity: Phenyl or PFP columns may be tried.

During storage or formulation, peptide drugs can form dimers and polymers. These aggregates pose a risk of triggering immunogenic reactions and reducing the drug’s biological activity. Therefore, during the development of peptide drugs, special attention must be paid to the analysis of aggregate impurities to ensure the drug’s safety, efficacy, and stability. SEC is the most widely used method for the analysis of peptide aggregates.

The stationary phase of the Welch Xtimate Bio SEC column is prepared using a unique surface modification technique, involving the bonding of hydrophilic polymers to an ultrapure silica matrix. Controlled chemical modification ensures reliable reproducibility across different batches of the column. The hydrophilic polymers are fully and uniformly polymerized on the silica surface, providing extensive coverage and resulting in minimal non-specific adsorption of biological samples such as peptides. This makes them widely used for the separation and detection of biological samples.

The types and sequences of amino acids in peptide drugs determine their biological activity and function; therefore, accurate determination of their amino acid composition is crucial for drug quality control. For the amino acid analysis of proteins and peptides, the sample must first be hydrolyzed into free amino acids, which typically require derivatization before determination (Chinese Pharmacopoeia, 2025 Edition). Pre-column derivatization reversed-phase chromatography is a common technique for determining amino acids in pharmaceuticals.

Welch Ultisil Amino Acid Method Kit uses Ultisil Amino Acid columns which are developed dedicatedly for amino acid analysis by Welch Materials. It uses Phenyl isothiocyanate (PITC) as the derivatization reagent to derivatize amino acids prior to chromatography. It features a fast reaction rate, high stability of the derivatives, a single product, and excellent peak shape, offering an excellent option for analyzing the amino acid composition and ratios of peptide drugs.