The API is, one might say, the most important element in a pharmaceutical product. Poor-quality APIs that do not meet potency levels and/or those that harbor impurities can create safety risks for the patient. Drug formulations may be destabilized by poor-quality APIs, which could shorten the drug’s shelf life. Poor-quality APIs may result in regulatory actions or recalls that can create production delays for the manufacturer that can impact the supply chain, therefore, keeping drugs from the patients that need them. Poor API quality may also leave the door open for counterfeit drugs to reach the market.
“From a supply chain perspective, poor-quality APIs increase the likelihood of production interruptions, which disrupt the supply to the market,” says Qixuan Lu, vice-president of Process Chemistry at BioDuro. “Because of the poor-quality API, additional quality control measures become necessary, driving up costs and diminishing profit margins. If such issues arise repeatedly, they can harm a company’s reputation and undermine market confidence in its products. Beyond these commercial setbacks, manufacturers also face considerable legal and regulatory risks if they fail to meet the standards required for pharmaceutical quality and patient safety.”
Impurities may result from a lack of a robust process and inadequate quality control, which often evolves from a lack of understanding of critical quality attributes (CQAs). This can manifest in poorly defined design spaces and analytical methods that fail to detect impurities, according to Dirk-Jan van Zoelen, Drug Substance Business Unit director, Ardena. “Moreover, when new impurities are identified, out-of-specification (OOS) results can lead to production delays, affecting the stability and reliability of the supply chain,” van Zoelen explains.
“Poor quality API presents several risks to the drug product, supply chain, and ultimately patients. These risks range from a lack of efficacy to the possibility of toxicity. Poor efficacy may result from low potency API, whereas toxicity may be related to the presence of uncontrolled impurities,” Richard Castledine, head of Drug Substance Operations at Quotient Sciences, says. “Additionally, simple batch-to-batch variability of quality attributes such as particle size and residual solvent concentration may result in differences in downstream manufacturing processes.”
Having strict quality checks, supplier audits, and strong compliance measures are important to maintain a safe and smoothly run system, according to M. Damodharan, chief quality officer, Sai Life Sciences.
Ensuring API quality
A comprehensive control strategy is key for ensuring API quality, according to van Zoelen. This strategy should address an in-depth understanding of the processes involved (e.g., chemical, physical, and cleaning) with defined critical process parameters (CPPs) and acceptable ranges. These processes should then be validated. The critical material attributes of raw materials and starting chemicals should be evaluated using comprehensive fit-for-use assessments to determine impurity clearance. A rigorous supplier qualification process should be put in place to ensure material quality and regulatory compliance. Analytical methods should be developed and validated in accordance with International Council for Harmonisation (ICH) guidelines, and a quality assurance department should be created that has an established quality management system to monitor regulatory compliance, van Zoelen says.
“A strong quality management system, aligned with good manufacturing practice (GMP) requirements, should define detailed production processes and quality control procedures to ensure that every stage of manufacturing is consistently supervised,” Lu agrees. “By actively monitoring the manufacturing workflow, manufacturers can guarantee that each critical step meets the required specifications and prevents potential quality deviations.”
Once parameters are set, they must be understood within the manufacturing process, says Castledine. “By understanding the edge of failure of any given process checks and controls can be implemented to ensure the process remains within the target ranges to produce high quality drug products,” he says. “Establishing a high-quality supply chain for all materials used in the manufacturing operation reduces the risk of introducing substandard materials to the process. Finally, the manufacturing process should be supported by internal analytical capabilities to assess critical quality attributes.”
“When designing a synthetic route for an API, process route design involves finding and selecting a pathway with favorable characteristics to maintain high quality CGMP (current good manufacturing practice) production when the API is manufactured at larger scale,” Castledine continues. “Modification or redesign of the process is often required to prepare for larger batch sizes and ensure that API can be produced in a compliant, efficient manner. Early on, drug developers should be mindful of identifying and developing control strategies for process and degradation impurities which may otherwise remain in the API. Additionally, avoiding niche or expensive starting materials and reagents for API synthesis is recommended; these can result in supply chain difficulties later and possibly lead to poorer quality substitutions being made.”
Material sourcing best practices
Sourcing from GMP-certified suppliers can help ensure API quality, according to Subbareddy Inta, vice-president and head of Quality, Dr. Reddy’s Laboratories North America. “Regular audits and inspections of supplier facilities ensure compliance with safety and quality standards,” Inta says.
“To secure high-quality APIs, manufacturers should implement a rigorous supplier evaluation system that carefully selects qualified raw material providers and conducts periodic audits. Incoming raw materials must undergo thorough inspections to confirm compliance with specified standards,” Lu stresses.
“Suppliers should be seen as an extension of internal manufacturing controls and standards, aligning with the drug manufacturer’s quality and compliance goals/objectives,” Timothy Buckley, vice-president of Global Quality, SK pharmteco, says. “Supplier qualification is critical, not only from a quality perspective, but also to ensure reliable supplies to eliminate potential drug shortages and supply interruptions.”
Materials used that are obtained from a third-party vendor must be rigorously qualified to ensure quality. This can be done through spike/fate and purge studies conducted on multiple lots, according to van Zoelen.
The physical and chemical characteristics of these materials, including crystal form, particle size, solubility, purity, residual solvents, and heavy metals, must be tested for CQAs to determine that they meet requirements. “Moreover, understanding the synthetic route used by the vendor is crucial, since the reagents, reaction conditions, and by-product removal methods should be compatible with the downstream manufacturing process,” Lu states. “This alignment ensures efficient conversion of starting materials or intermediates and minimizes impurities that might otherwise compromise the finished product’s quality.”
Tests performed on third-party-sourced materials, according to Ragavendran Vasudevan, director and head of Operations C2 Pharma India Ltd., include identity testing, purity and impurity profiling, assay testing, physical and chemical characterization, microbial and endotoxin testing, and stability and storage condition studies.
“Identity testing using FTIR (Fourier transform infrared spectroscopy), NMR (nuclear magnetic resonance), HPLC (high-performance liquid chromatography), or GC–MS (gas chromatography–mass spectrometry) confirms chemical structure. Purity and impurity profiling detect unwanted byproducts, while potency is measured through titration, UV-Vis (ultraviolet-visible), or HPLC. Residual solvent analysis via GC-HS (headspace-gas chromatography) ensures no toxic solvents remain,” Damodharan explains. “Water content is checked using Karl Fischer titration, and microbial testing screens for bacteria and endotoxins. Particle size and polymorphism studies assess bioavailability impact. Stability testing evaluates degradation risks, and elemental analysis using ICP-MS (inductively coupled plasma mass spectrometry) checks for toxic metals. These steps ensure the API meets safety and regulatory standards.”
Regulatory compliance and validation
Validation is a crucial step in ensuring the quality of APIs and applies to the regulatory compliance requirements of facilities, equipment, and infrastructure, according to Lu. “Stability testing should also be carried out to track changes in the physical and chemical properties of the API, as well as the formation of any degraded products or impurities over time,” Lu says. “These tests help determine appropriate shelf life and storage conditions, ensuring that the API retains its intended quality and efficacy until it is used.”
Other validation exercises, according to Vasudevan, include supplier qualification, raw material testing, process validation, analytical method validation, and regulatory documentation.
“Validating test methods, such as chromatography and spectrometry, ensures accurate purity and potency analysis,” Inta says. “Conducting stability studies under various storage conditions ensures the API remains stable over time. Ensuring compliance with pharmacopeial standards and regulatory requirements maintains high-quality standards.”
“Confirmation of the manufacturing process used is also essential to ensure that methods used for testing are suitable,” Castledine says. “For example, some manufacturing processes have the potential to generate potentially mutagenic impurities (PMI) which need to be controlled to PPM (parts per million) levels, often requiring the development of specialized HRMS (high-resolution mass spectrometry) methods.”
Quality validation of APIs should be a phase-appropriate approach, according to van Zoelen, with analytical methods getting partial validation in early phase development that focuses on process-related impurities and safety data. “As development progresses to later clinical phases, a more comprehensive validation is required, including full validation of the analytical methods for the API, starting materials, and intermediates,” van Zoelen says. “Impurity profiles are set during early-stage development, with tox-batch validation and process validation as essential milestones. Throughout this process, supplier qualifications should also be conducted to ensure consistency and reliability of materials.”
A transparent supply chain is achieved by good distribution practices, according to Damodharan, and helps prevent counterfeit drugs. “Regulatory compliance is a must, including accurate documentation and real-time monitoring. Staying updated on compliance changes and maintaining data integrity (can) ensure long-term quality,” Damodharan says.
Recording CGMP data for APIs
Maintaining accurate CGMP records for APIs is necessary to assure regulators of compliance, traceability, and product quality. However, according to Vasudevan, many companies lack complete and accurate documentation and have poor record keeping practices. They also have data integrity violations and insufficient training on compliance with CGMPs.
Poor documentation, including incomplete records or backdating, violate CGMPs and data integrity requirements. “Illegible batch records, unverified calculations, and outdated SOPs (standard operating procedures) lead to errors,” Damodharan says. “Failing to record deviations, corrective actions, or equipment calibrations weakens oversight. These slip-ups can trigger compliance issues, recalls, or even regulatory shutdowns.”
It is important to avoid gaps in impurity data in CGMP records. A mistake some manufacturers make, according to van Zoelen, is not aligning analytical methods with an API’s impurity profile in clinical phases. “As development progresses, particularly through the clinical phases, new impurities may emerge, such as genotoxic or mutagenic impurities,” van Zoelen says. “Multiple analytical methods may be employed at different stages, and these may change as the development advances. It is critical to ensure continuous alignment of these methods with impurity data to avoid gaps or discrepancies in CGMP records, especially as the product progresses through clinical phases.”
“Failing to capture batch-specific information or variations in production conditions can compromise data integrity,” Inta says. “Inadequate documentation of deviations or corrective actions can leave issues unresolved. Lastly, not adhering to proper data integrity protocols, such as avoiding falsification or improper handling of electronic records, can severely compromise data quality.”
“While GMP expectations such as data integrity, GDP (good documentation practices), and facility/personnel controls are the same for APIs and drug products, a key issue for API manufacturers is ensuring appropriate documentation and evaluation of supplier changes,” Buckley explains. “Changes in the route of synthesis for critical raw materials, such as regulatory starting materials, can lead to a new or altered impurity profile of existing impurities. This may introduce concerns related to nitrosamines, heavy metals, and/or PEG (polyethylene glycol) residues. Therefore, while there are many GMP considerations, change control and supplier qualification are especially critical in API manufacturing.”
Considerations for highly potent APIs
Highly potent APIs (HPAPIs) have increased pharmacological activity and safety risks according to Vasudevan. Safe production and handling of HPAPIs can be done by implementing stringent quality measures. These include dedicated production areas or isolators and closed-system processing. Using segregated facilities that have independent heating, ventilation, and air conditioning (HVAC) systems can prevent contamination. Maintaining negative pressure environments may contain potent compounds, and using automated handling systems reduces manual intervention, insists Vasudevan.
“More drugs in development than ever are classed as highly potent,” Helen Baker, director of Formulation Design, Quotient Sciences, explains. “HPAPIs present additional CMC (chemistry, manufacturing, and controls) challenges due to the containment requirements to protect both the operators and manufacturing facilities. The production processes may also require greater precision and control due to the very small quantities of drug present in the final dosage form.”
Preventing cross-contamination in the manufacture of HPAPIs is the main concern with ensuring quality for pharmaceutical products that contain these types of ingredients, especially when manufactured in multipurpose facilities, according to van Zoelen, who stresses that stringent cleaning protocols must be adhered to. “The maximum allowed carryover (MACO) should be defined based on health-based occupational exposure limits (HBOEL) to ensure safe transitions between high-potency and low-potency APIs,” van Zoelen says. “Additionally, a comprehensive cross-contamination strategy is essential, including facility design considerations, dedicated equipment, and validated cleaning procedures to mitigate the risk of HPAPI contamination in subsequent batches.”
“If potent compounds are produced in the same facility as less potent products, dedicated production lines or segregated manufacturing areas are essential to eliminate the risk of contamination and to uphold stringent safety standards,” Lu agrees.
“EH&S (environmental, health, and safety) audits are critical to ensure that HPAPIs continually meet CGMP compliance standards and regulatory requirements,” Baker says. “The HPAPI manufacturer should also have a robust risk management program that includes ongoing environmental health monitoring and surrogate monitoring to ensure consistent control over our processes, facilities, cleaning procedures, and SOPs is also critical to ensure that HPAPIs are being manufactured consistently.”
Conclusion
Drug shortages can impede access to life-saving medications, and quality issues are one reason drug shortages may occur (1). Regulatory agencies have guidelines that should be followed to mitigate the risk of poor-quality ingredients, such as APIs. By following these guidelines, having a robust quality system, and qualifying API suppliers, drug manufacturers can help keep the supply chain healthy.
Reference
1. FDA. Drug Shortages. FDA.gov. March13, 2025 (accessed April 11, 2025). https://www.fda.gov/drugs/drug-safety-and-availability/drug-shortages
About the author
Susan Haigney is lead editor of Pharmaceutical Technology®.
Article details
Pharmaceutical Technology®
Vol. 49, No. 4
May 2025
Pages: 10-15
Citation
When referring to this article, please cite it Haigney, S. Poor API Quality Threatens a Healthy Supply. Pharmaceutical Technology 2025 49 (4).
