Oligonucleotide API Development
Developing an oligonucleotide candidate into a reproducible, scalable, and well-controlled active pharmaceutical ingredient (API) process requires more than establishing a synthesis route. Sequence length, chemical modifications, coupling efficiency, impurity formation, purification behavior, recovery, and API isolation can all influence process performance and final drug substance quality. Protheragen provides integrated oligonucleotide API development Services to support the transition from laboratory-scale synthesis to a robust drug substance manufacturing process.
Overview of Oligonucleotide API Development
Oligonucleotide API development focuses on establishing a robust, reproducible, and scalable manufacturing process for oligonucleotide active pharmaceutical ingredients (APIs). The development process typically covers synthesis route selection, solid-phase synthesis optimization, cleavage and deprotection, purification, concentration, desalting, isolation, and drying, with analytical evaluation integrated throughout the development process.
Unlike many conventional small-molecule APIs, oligonucleotide APIs can generate a complex profile of product-related impurities, including truncated sequences, deletion sequences, modified oligonucleotides, and degradation products. Their relatively large molecular size, sequence-dependent properties, and diverse chemical modifications can also affect synthesis efficiency, purification behavior, recovery, and product stability. Therefore, oligonucleotide API development requires coordinated optimization of both upstream synthesis and downstream purification processes.
Process development generally evaluates critical parameters such as coupling efficiency, reaction conditions, reagent ratios, deprotection conditions, purification loading, chromatographic separation, concentration, and API isolation. These studies help establish appropriate process ranges and improve product yield, impurity clearance, process consistency, and scalability.
Fig.1 The typical unit operations for the manufacture of oligonucleotide API. (Muslehiddinoglu J, et al., 2020)
Our Services
Oligonucleotide API development encompasses a series of interconnected activities designed to establish an efficient, reproducible, and scalable drug substance manufacturing process.
Synthesis Route and Process Development
Protheragen evaluates and optimizes oligonucleotide synthesis routes according to molecular structure, modification pattern, sequence length, and target production scale. Development activities can address coupling, capping, oxidation or sulfurization, detritylation, and other cycle-specific operations to improve overall synthesis efficiency and reproducibility.
Solid-Phase Synthesis Optimization
Solid-phase synthesis is optimized to achieve consistent coupling performance and minimize the accumulation of failure sequences and truncated products. Process conditions can be systematically evaluated to balance reaction efficiency, product quality, cycle time, reagent consumption, and scalability.
Deprotection and Cleavage Development
Cleavage and deprotection conditions are developed to achieve effective removal of protecting groups while limiting degradation and undesirable side reactions. The process is adjusted according to the oligonucleotide backbone, nucleotide modifications, and chemical protection strategy.
Purification Process Development
Purification methods are developed to achieve the required purity and impurity clearance while maintaining acceptable recovery. Process development can evaluate chromatographic conditions, loading, gradient, flow rate, resin selection, fraction collection, and downstream pooling strategies.
Impurity Control and Clearance
Oligonucleotide API development requires control of both product-related and process-related impurities. Development activities may evaluate truncated sequences, deletion sequences, modified oligonucleotide species, depurinated products, residual reagents, solvents, protecting-group-related impurities, and other degradation products.
Analytical characterization can be used to identify major impurities and guide upstream process optimization and downstream purification development.
Concentration and Desalting Development
Concentration and desalting operations are optimized to reduce processing losses and achieve a suitable API quality profile. Parameters such as membrane selection, concentration factor, buffer composition, conductivity, pH, and processing conditions can be evaluated according to molecule characteristics.
API Isolation and Drying Development
For solid API programs, isolation and drying processes are developed to achieve appropriate recovery, residual solvent or moisture control, physical stability, and handling characteristics.
Where appropriate, lyophilization can be evaluated as part of API isolation and storage strategy.
Process Characterization
Process characterization studies are conducted to understand the relationship between process parameters and product quality. Critical process parameters and critical quality attributes can be evaluated using risk-based development principles to establish appropriate process controls and operating ranges.
Scale-Up and Technology Transfer Support
Process development is designed with future scale-up in mind. Laboratory and pilot-scale observations can be translated into manufacturing parameters, equipment considerations, material requirements, and process controls to facilitate technology transfer into GMP manufacturing.
Oligonucleotide API Development Workflow
The API development workflow is designed to progressively establish a robust and scalable manufacturing process while maintaining control of critical quality attributes.
API Development Across Different Development Stages
Process development parameters are selected according to the characteristics of the specific oligonucleotide drug candidate. Important areas may include:
Preclinical Development
Early-stage API development focuses on establishing synthesis feasibility, identifying major impurities, evaluating purification approaches, and producing material suitable for preclinical studies.
The objective is to generate sufficient process understanding while maintaining flexibility for subsequent optimization.
Clinical Development
As a program advances toward clinical development, API development becomes increasingly focused on process robustness, reproducibility, scale-up, analytical control, and manufacturing consistency.
Process characterization and control strategies can be progressively strengthened to support GMP manufacturing and regulatory documentation.
Late-Stage and Commercial Development
For late-stage programs, development activities can focus on manufacturing efficiency, process validation readiness, scale-up, technology transfer, supply continuity, and long-term process control.
The development strategy can be aligned with the intended commercial manufacturing process to reduce the risk associated with later process changes.
Critical Quality Attributes in Oligonucleotide API Development
An effective API development strategy needs to connect manufacturing parameters with the quality attributes that define the final drug substance.
Depending on the molecule and development stage, relevant quality attributes include:
- Identity
- Sequence confirmation
- Molecular weight
- Assay
- Purity
- Related substances
- Truncated and failure sequences
- Modification-related impurities
- Residual solvents
- Residual reagents
- Water content
- Counter-ion content
- Elemental impurities
- Microbial quality
- Endotoxin
- Stability-related attributes
Analytical methods such as HPLC, ion-exchange chromatography, mass spectrometry, UV analysis, and other orthogonal techniques may be incorporated into the development strategy as appropriate. Industry oligonucleotide workflows commonly integrate LC-based purity analysis, LC-MS molecular-weight and sequence confirmation, residual solvent testing, and elemental/counter-ion analysis.
Why Choose Protheragen
- Integrated Oligonucleotide Development
API development is connected with upstream sequence design, conjugation technology, process development, analytical characterization, manufacturing, and drug product development.
- Process-Focused Development Strategy
Development focuses not only on obtaining the target oligonucleotide but also on establishing a reproducible and scalable manufacturing process with appropriate impurity and quality controls.
- Multiple Oligonucleotide Modalities
Development support can be adapted to ASOs, siRNAs, PMOs, CpG oligonucleotides, and other chemically modified oligonucleotide therapeutics.
- Scale-Up-Oriented Process Development
Process parameters, purification strategies, material requirements, and downstream operations can be considered from an early stage to facilitate subsequent scale-up and manufacturing transfer.
- Integrated Analytical Support
Analytical characterization is incorporated throughout process development to monitor product quality, identify impurities, evaluate process performance, and support CMC decision-making.
- Flexible Development Scope
Development programs can be tailored according to molecule complexity, development stage, target scale, quality requirements, and manufacturing objectives.
A well-designed oligonucleotide API development program provides the bridge between candidate optimization and reliable drug substance manufacturing. By integrating synthesis chemistry, purification, analytical characterization, process understanding, and scale-up considerations, Protheragen supports the development of oligonucleotide APIs with a clear path toward clinical and commercial manufacturing. Whether the program involves an ASO, siRNA, PMO, CpG oligonucleotide, or another chemically modified nucleic acid therapeutic, Protheragen can provide customized development strategies aligned with project objectives and CMC requirements. Contact us to discuss your oligonucleotide API development project and develop a customized path from process development to clinical-stage manufacturing.
Reference
- Muslehiddinoglu J, et al. "Technical Considerations for Use of Oligonucleotide Solution API" Nucleic Acid Ther. 2020; 30(4):189-197.
