Peptide Therapeutics in Focus: How Amino Acid Analysis Ensures Quality — With a Spotlight on GLP-1 Analogs

Introduction: The Peptide Drug Revolution

Peptide therapeutics are transforming modern medicine. These short chains of amino acids, typically comprising 2 to 50 residues, offer exceptional selectivity, safety, and versatility—bridging the gap between small-molecule drugs and complex biologics.

Since the landmark introduction of insulin nearly a century ago, over 80 peptide-based drugs have entered the global market, providing effective treatment options for conditions ranging from diabetes and cancer to osteoporosis, multiple sclerosis, HIV, and chronic pain. The development of these drugs reflects decades of innovation—from early human hormone therapies to today’s advanced strategies leveraging rational design, natural sources, and cutting-edge peptide chemistry.

One of the most compelling success stories in this space is the rise of GLP-1 receptor agonists. Initially developed for type 2 diabetes, drugs such as liraglutide, semaglutide, dulaglutide, and tirzepatide have now become essential tools in managing obesity, cardiovascular conditions, and broader metabolic disorders.

As the therapeutic potential of peptides expands, so does the complexity of their design. Modern peptide drugs frequently incorporate non-natural amino acids, lipid conjugates, and specialized linkers to enhance stability, bioavailability, and target specificity. Emerging strategies—such as integrated venomics and peptide-display libraries—are further accelerating discovery, while more than 150 peptide candidates are currently in clinical development and an additional 400–600 are undergoing preclinical studies.

With this increasing complexity comes the critical need for precise analytical techniques to ensure product quality, batch-to-batch consistency, and regulatory compliance. This is where amino acid analysis takes center stage—as a powerful tool to assess structural integrity, composition, and consistency in both innovator and biosimilar peptide products.

Peptide Drugs: Why Amino Acid Analysis Matters

Regardless of whether a peptide is produced through chemical synthesis or recombinant expression systems, the quantitative and qualitative analysis of its amino acid composition is essential. Such analysis plays a pivotal role in:

• Confirming the primary structure
• Detecting sequence variants or misincorporated residues
• Supporting biosimilarity assessments
• Verifying batch-to-batch consistency
• Performing label claim (% assay) validation
• Meeting regulatory compliance for global filings

To address these stringent analytical needs, ion-exchange chromatography (IEC) combined with post-column derivatization has become the method of choice. Compared to pre-column derivatization techniques, IEC offers superior resolution, reproducibility, and quantitative accuracy, particularly for peptides containing complex or non-standard amino acid residues.

As peptide drugs continue to expand their role in modern therapeutics, robust amino acid analysis using IEC remains foundational—not only for scientific verification but also for ensuring regulatory compliance and successful clinical translation.

Global Regulatory Expectations for Peptide-Based Biosimilars

As the global pipeline of peptide-based therapeutics grows, so too does the scrutiny from regulatory bodies tasked with ensuring safety, efficacy, and product consistency. Today, amino acid analysis stands as a regulatory cornerstone in the approval of both innovator peptides and their biosimilar counterparts.

Regulatory authorities now mandate comprehensive molecular characterization, with a specific focus on accurately confirming the amino acid sequence and identifying any sequence variants or peptide-related impurities that could affect biological activity or safety.

Here’s how leading agencies frame these requirements:

WHO (World Health Organization):
　The WHO Guidelines for Similar Biotherapeutic Products (SBPs) emphasize that the amino acid sequence of the biosimilar must exactly match the reference product. Any sequence variants must be detected and critically evaluated.

Ref: WHO Annex 3 – Evaluation of Biosimilars, 2022

FDA (U.S. Food and Drug Administration):
　In its 2021 guidance, “ANDAs for Certain Highly Purified Synthetic Peptide Drug Products”, the FDA requires manufacturers to demonstrate sameness through comparative amino acid sequencing and impurity profiling, particularly with regard to misincorporated amino acids.

Ref: FDA Peptide Guidance, 2021

EMA (European Medicines Agency):
　The EMA’s biosimilar quality guideline clearly states that the amino acid sequence of a biosimilar must precisely match that of the originator product.

Ref: EMA Biosimilar Quality Guideline

Regulatory authorities—including WHO, FDA, and EMA—require confirmation of the amino acid sequence (primary structure) for peptide-based biosimilars. Manufacturers must demonstrate sequence identity to the reference product and detect any sequence variants or peptide impurities that could impact safety or efficacy.

Hitachi LA8080 AminoSAAYA: A Trusted Solution for Peptide Quality Control

To meet these demanding regulatory standards, analytical platforms must offer high precision, reproducibility, and compliance with globally accepted pharmacopeial methods. The Hitachi LA8080 Amino Acid Analyzer delivers exactly that. Built on ion-exchange chromatography with ninhydrin-based post-column derivatization, the LA8080 provides accurate and reproducible amino acid profiles that are fully aligned with regulatory guidelines, including USP <1052>, Ph. Eur. 2.2.56, and JP 2.47.

Key Advantages of the Hitachi LA8080:

• High-resolution separation of structural isomers such as Leucine/Isoleucine and Alloisoleucine/Isoleucine and Leucine/Norisoleucine.
• Exceptional sensitivity, with low detection limits (~2.5 pmol), reproducibility of peak area is 1% and Peak retention time is 0.3%.
• Suitable for detection and quantification of nonproteinogenic amino acids.
• Minimal matrix interference, ensuring reliable results even in excipient-rich formulations.
• Streamlined automation, including inline degassing, temperature control, and automated reagent delivery.
• Regulatory-compliant performance, offering high reproducibility suitable for batch release, stability studies, and impurity profiling.

With global regulators placing ever-increasing emphasis on primary structure confirmation and sequence fidelity, the Hitachi LA8080 AminoSAAYA stands out as a robust and trusted solution for supporting peptide drug quality control—from development through to regulatory submission.

Case in Focus: GLP-1 Analogs like Semaglutide and Liraglutide

Among the growing class of therapeutic peptides, GLP-1 receptor agonists stand out due to their clinical success in managing type 2 diabetes, obesity, and cardiometabolic disorders. These peptide drugs—typically composed of 31 to 39 amino acids—are structurally more complex than conventional peptides, owing to deliberate chemical modifications designed to improve their pharmacological properties.

To enhance half-life, resistance to enzymatic degradation (particularly DPP-4), and therapeutic efficacy, GLP-1 analogs often include the following structural enhancements:

• Acylated lysine residues for improved albumin binding and prolonged circulation
• PEGylation or linker attachments to increase molecular stability and bioavailability
• Incorporation of non-natural amino acids, such as AIB (aminoisobutyric acid) and AEEA (aminoethoxyethoxyacetic acid), to resist proteolytic cleavage.

While these modifications are pharmacologically beneficial, they might introduce additional complexity in quality control and regulatory evaluation. Standard peptide characterization methods may fall short in detecting these engineered modifications or sequence variants.

This is where robust amino acid analysis—particularly using ion-exchange chromatography (IEC) with post-column derivatization—becomes crucial. Not only does it support primary structure confirmation and quantitative assay validation, but it also plays a key role in impurity profiling, especially in modified residues or non-proteinogenic amino acids.

As highlighted in regulatory guidance from WHO, FDA, and EMA, the integrity of the amino acid sequence and the accurate identification of any modifications are essential for both innovator peptides and biosimilar submissions. For GLP-1 analogs like semaglutide and liraglutide, amino acid analysis is a regulatory necessity and scientific imperative—ensuring safety, efficacy, and global compliance.

LA8080’s Contribution to Peptide Quality Control Workflows

The Hitachi LA8080 Amino Acid Analyzer serves as a critical tool across multiple stages of peptide drug development and quality control. Its ion-exchange chromatography platform—combined with post-column derivatization—enables absolute molar quantitation of amino acids with high precision and regulatory alignment.

These features empower LA8080 to address critical analytical goals in peptide quality control, including:

By providing quantitative, reproducible, and pharmacopeia-aligned results, the LA8080 is a vital orthogonal tool that complements LC–MS/MS, RP-HPLC, and other techniques—ensuring comprehensive peptide characterization and regulatory readiness.

Looking Ahead: The Peptide Frontier

As of mid-2025, several advanced peptide therapeutics—particularly in the obesity and metabolic disease space—are progressing through late-stage clinical trials or have already gained approval, such as mazdutide (a dual GLP-1/glucagon receptor agonist approved in China) and ecnoglutide (a long-acting GLP-1 agonist with completed Phase III trials). These next-generation peptides, typically 30–40 amino acids long, incorporate non-natural residues, lipid conjugates, and engineered linkers to enhance pharmacokinetics and receptor specificity, reflecting increasing structural complexity. Such complexity necessitates multi-dimensional analytical approaches beyond conventional mass spectrometry or chromatography. By delivering pharmacopeial-compliant, high-resolution amino acid profiling, the LA8080 amino acid analyzer plays a critical role in supporting peptide developers across clinical development and regulatory submission—filling a key gap in the orthogonal testing landscape.

Conclusion: Amino Acid Analysis — A Pillar in Peptide Drug Quality

Whether you're working with traditional injectable peptides like liraglutide or pushing innovation with oral delivery systems, amino acid analysis is a foundational step in verifying drug quality, safety, and compliance.

Hitachi LA8080 AminoSAAYA provides the precision, robustness, and regulatory confidence needed to support modern peptide drug development. As an essential part of orthogonal analytical workflows, it helps pharmaceutical innovators and biosimilar manufacturers move from bench to market — with trust in every molecule.

Connect with Center of Excellence, Hitachi High-Tech India & Envirocare Labs to explore application notes, or live demos of the LA8080 Amino Acid Analyzer.

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