Behind the Headlines Episode 27

Ask the Expert

Small Molecules, APIs, and Excipients—Trends, Challenges, and Opportunities

Drug Digest September 2025

Artificial intelligence, machine learning, and novel instruments are helping drug developers.

Enhancing Bioanalysis and Drug Development with Advanced Tools and Technologies

J.P. Morgan Report Lists Biologics, Obesity, China

Top Trends Reshaping Pharma R&D

A laboratory technician performing a quality control test on a batch of pharmaceutical tablets, highlighting the importance of ensuring drug safety. | Image Credit: ©MAY -stock.adobe.com

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.

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.”

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.”

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.

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.”

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.”

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.

 March13, 2025 (accessed April 11, 2025). 

https://www.fda.gov/drugs/drug-safety-and-availability/drug-shortages

When referring to this article, please cite it Haigney, S. Poor API Quality Threatens a Healthy Supply. 

Articles

Poor API quality may often lead to delays in production and a shortage of supply.

Poor API Quality Threatens a Healthy Supply

Patrick Lavery is an Editor for the MJH Life Sciences brands 

. Previously at MJH, he filled the same role for 

Mississauga, On, Canada - October 24, 2020: Astrazeneca Canada company sign is seen in Mississauga, Ontario, Canada. AstraZeneca plc is a British pharmaceutical and biopharmaceutical company. | Image Credit: © JHVEPhoto - stock.adobe.com

AstraZeneca announced on May 6, 2025 that its Calquence (acalabrutinib), a second-generation, selective inhibitor of Bruton’s tyrosine kinase (BTK), was approved in the European Union in combination with bendamustine and rituximab for treatment of adults with mantle cell lymphoma (MCL) that has been previously untreated, and who are not eligible for an autologous stem cell transplant (1). Acalabrutinib had been previously approved in the EU as monotherapy for treatment of adults with relapsed or refractory MCL.

In a press release, AstraZeneca said the combination of acalabrutinib with bendamustine and rituximab was previously approved in the United States and other countries based on the results of a Phase III trial (ECHO), the findings of which were also used by the European Commission’s Committee for Medicinal Products for Human Use (CHMP) in its positive opinion issued March 31, 2025 (2).

“Treatment with the Calquence combination in first-line mantle cell lymphoma demonstrated a significant improvement in progression free survival and a consistent safety profile for patients in the pivotal ECHO trial,” Dave Fredrickson, executive vice president of the Oncology Haematology Business Unit for AstraZeneca, said in the release (1). “As the first and only BTK inhibitor approved in this indication in the EU, we are proud to provide a much-needed new option to patients living with this difficult disease."

Martin Dreyling, MD, Department of Medicine, University Hospital LMU Munich, and investigator in the trial, added, saying “This approval provides a new first-line treatment option for patients in the EU with mantle cell lymphoma, an aggressive lymphoma with a dismal long-term outcome still today. With a progression-free survival improvement of more than 16 months for these patients, the acalabrutinib combination is a much-needed advance in this challenging disease.”

In February 2025, another MCL treatment, Eli Lilly and Company’s Jaypirca (pirtobrutinib)—a non-covalent or reversible BTK inhibitor—was given a positive opinion by CHMP (3,4). That treatment, according to Lilly, had been approved by FDA in 2023 under an accelerated approval pathway for treatment of adult patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma who have received at least two prior lines of therapy, including a BTK inhibitor and BCL-2 inhibitor, or for treatment of adults with relapsed or refractory MCL after at least two lines of systemic therapy.

Acalabrutinib treatment plus bendamustine and rituximab is currently under review in Japan and several other countries (1).

1. AstraZeneca. Calquence Plus Chemoimmunotherapy Approved in the EU as First and Only BTK Inhibitor for 1st-Line Mantle Cell Lymphoma. Press Release. May 6, 2025.
2. AstraZeneca. Calquence Plus Chemoimmunotherapy Recommended for Approval in the EU by CHMP as First and Only BTK Inhibitor for 1st-Line Mantle Cell Lymphoma. Press Release. March 31, 2025.
3. Eli Lilly and Company. Lilly's Jaypirca (pirtobrutinib) Recommended by CHMP for Approval in the European Union for Adults with Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL) Previously Treated with a BTK Inhibitor. Press Release. Feb. 28, 2025.
4. EMA. Meeting Highlights from the Committee for Medicinal Products for Human Use (CHMP) 24–27 February 2025. Press Release. Feb. 28, 2025.

Calquence (acalabrutinib) plus bendamustine and rituximab reduced risk for disease progression or death by 27% compared with the current standard of care, according to a phase III trial.

EU Approves AstraZeneca Mantle Cell Lymphoma Treatment

Building relationships with customers who are as focused you are on innovation for a better world is a perfect starting point and premise for a successful project. 

, a global health care company working to deliver innovative health solutions for today and the future, chose 

 to solve an urgent need at their facilities in Rahway, New Jersey.

We spoke to a Global Engineering Services representative at Merck and Stefano Specchia, IMA Life Product Manager

 to explore the details of the project and gain insight into the mutual benefits.

According to the customer, the primary objective was to source a flexible, multi-format RTU 

 that could manage a range of products, from serum-based to freeze-dried formulations, without compromising safety or process integrity. The equipment needed to ensure 

compliance with stringent containment requirements

, given the risk level of the substances.

Given the equipment's role as a replacement in an urgent situation, Merck narrowed its choice to those suppliers that were not only able to provide adequate support to 

address the specific needs of handling both potent compounds and live virus formulations

A solution demanding rapid deployment was needed in order to avoid production delays and uphold commitments to stakeholders. Moreover, there were a number of critical requirements that only IMA Life was able to address satisfactorily.

Stefano Specchia underlines the key reasons why Merck opted for the fill-finish line constructed around INJECTA.

 in handling complex, high-potency products and live virus formulations reassured the customer regarding the 

our ability to ensure safe processing without sacrificing operational efficiency

our solution met the technical specifications

we aligned well with the challenging timeline

we provided high-level digital training for Merck's operators

In particular, training aimed at enhancing operational efficiency and ensuring consistent management of the line using standard working parameters. Seen as a crucial requirement, IMA Life was successful in fulfilling this need. According to the customer, there were “no doubts about their commitment to support and optimize our processes.”

Advanced robotics, which is a core principle in terms of INJECTA and its design concept, facilitated 

effective cleaning and containment when dealing with potent compounds

. This feature is critical for compliance and safety in handling high OEB-level products. The design also supports 

 and improving overall production reliability.

The line is also easy to use. Recipe programming is intuitive and enhanced monitoring capabilities also contribute to potentially fewer rejects.

Faced with a tight timeframe, a building that was not designed to accept the line initially, and a challenging path taking us from the first design phase of the processing line right up to commissioning, training and on-site support, IMA demonstrated “

the true value of working with a trusted and committed partner in the field

At all times throughout the project - from the design phase all the way through to qualification and support – one of the key factors ensuring success had to be the partnership between the companies and especially the people working in each team.

Moving ahead, it is clear that IMA’s commitment will not diminish thereby enabling the equipment to function as an integral part of the production environment across its entire life cycle.

IMA Life has supplied a fully integrated, isolated line that spans the entire process

, from RTU container handling through freeze-drying and downstream operations, including external washing and tray loading. This comprehensive approach ensures seamless compatibility and operational efficiency across all stages of production, meeting the highest standards for containment, precision, and reliability.

INJECTA is the first of a new generation of material handling technologies

, setting new standards in the industry. The dedication of the IMA team, their depth of knowledge, and the support resources they provide are instrumental in ensuring timely and effective project outcomes. While certain areas of task execution and design may benefit from minor adjustments, this partnership has underscored IMA’s adaptability and readiness to push technological boundaries to meet evolving industry needs.

For more information on INJECTA and our aseptic processing capabilities:

FLEXIBLE READY-TO-USE COMPONENT PROCESSING LINE • Pharma • IMA Group

HIGH-SPEED PRE-FILLED SYRINGE PROCESSING LINE • Pharma • IMA Group

Supporting Merck toward a new age of aseptic fill-finish processing of highly potent drugs.

Cynthia A. Challener is a contributing editor to Pharmaceutical Technology.

Insulin Vial Trapped in Ice for Diabetic Challenges | Image Credit: ©Nisit – stock.adobe.com

While many parenteral products can be stored and shipped in the liquid state at room temperature, some, including most based on biologic drug substances, must be maintained at low temperatures. When refrigeration is not sufficient, two options remain: keeping the products in a frozen state or freeze-drying (lyophilizing) them into a powdered form. There are advantages and disadvantages to both, with many factors to consider when choosing between the two solutions.

The biggest driver for freezing or freeze-drying parenteral products is instability of the drug substance when in solution. This issue does not often arise for small-molecule APIs, but is common for recombinant proteins and antibody-based molecules. “Developing freeze-dried or frozen parenteral formulations is primarily driven by the inherent instability of biological molecules in solution at or below room temperature, limited shelf life in liquid form, high sensitivity to temperature fluctuations and air-liquid interfaces, and excipient-related limitations,” says Maria Fernanda Zuluaga Estrada, principal scientist and formulation development group leader at Lonza.

Protein molecules, explains Jeremy Guo, senior vice president and head of drug-product development and clinical drug-product manufacturing at WuXi Biologics, are physically and/or chemically unstable during long-term storage, suffering from aggregation and visible particle formation, deamidation, oxidation, and other degradation pathways, even in optimized aqueous formulations after formulation screening.

“Freezing or lyophilizing these formulations is the optimal choice, because physical and/or chemical reactions will be inhibited in the frozen glassy state or freeze-dried state with minimal water content,” Guo says. At Lonza, advanced analytical tools are used for diagnosing vulnerabilities potentially leading to instabilities, including mass spectrometry to detect and foresee post-translational modifications, holistic (i.e., stability-indicating) surfactant analytics, subvisible particle characterization to differentiate potential protein-versus-surfactant instability, in-depth root cause analysis in case of surfactant degradation, in-depth host-cell protein, especially lipase, characterization and quantification, and container-closure integrity testing and qualification.

Beyond instability, time can also be a driver for choosing to freeze or lyophilize a drug candidate. “When the development timeline is very limited for early filing of an investigation new drug (IND) application, the final formulation needs to be locked down without completion of comprehensive formulation screening or generation of sufficient stability data. Freezing or freeze-drying can help ensure long-term stability while still meeting these shorter timelines. Comprehensive screening can then be performed during late-stage development to determine the final, commercial formulation,” Guo observes.

There is one other significant reason for moving forward frozen or freeze-dried formulations during the development of biologics, according to Zuluaga Estrada. Many liquid biologic formulations have limited expected shelf-lives when stored at or below room temperature due to surfactant degradation, which is why Lonza conducts so many surfactant-related analyses. “For cases where extensive lipolytic activity is demonstrated, Lonza’s proprietary lipase assay can support the removal of lipolytic activity during downstream processing,” she notes. The company also has a proprietary approach to lipase inhibition that involves addition of low concentrations of citrate to mitigate surfactant degradation, which can potentially prevent the need for frozen or lyophilized storage, Zuluaga Estrada adds.

Advantages and disadvantages of frozen formulations

The primary advantage of frozen formulations is their ability to preserve unstable formulations due to the immobilization of molecular components, thereby extending the shelf life, observes Zuluaga Estrada. Development of frozen formulations also generally takes less time and is less expensive than the development of lyophilized products, according to Guo. The lack of the need for a reconstitution step, which is required for freeze-dried formulations, is another benefit noted by Guo.

There are several disadvantages to frozen formulations, however. “The complexity of developing frozen formulations is often not considered in full, and the related challenges present a substantial risk in the development of biologics,” Zuluaga Estrada contends. She highlights lack of molecule or excipient stability in certain frozen formulations (e.g., cold denaturation and aggregation of proteins, crystallization of excipients, phase separation) and compromised integrity of the container-closure system at ultralow temperatures as two examples.

Beyond stability issues, the key challenge with frozen products is the need for extensive infrastructure and shipping capabilities to support the cold chain, says Zuluaga Estrada. “Robust freezing parameters, appropriate storage conditions, and adequate supply chain management need to be considered,” she notes.

Temperature excursions during storage and shipment of frozen products, adds Guo, can lead to ice crystal formation, protein denaturation, and a potential decrease in drug efficacy. In addition, the need for temperature control during storage and shipment at manufacturing sites, depots, and clinical centers adds significant cost and inconvenience, he comments.

Other concerns pointed out by Guo include the higher risk of vial breakage and the need for lower filling volumes compared to liquid drug products in the same container to reduce this risk.

To avoid these issues, often redevelopment to a liquid or lyophilized formulation is pursued once a candidate reaches later development stages and looks to be commercialized. However, switching to a liquid or freeze-dried product during late-phase development requires significant additional effort and adds cost and time for programs, according to Zuluaga Estrada.

Lyophilized formulations present opportunities and challenges

Freeze drying also has both positive and negative attributes. In addition to overcoming formulation instability issues, one of the biggest benefits is the ability to store and ship products at refrigerated (2–8 °C) or even room temperatures, Guo says.

Appropriate storage of lyophilized cakes within these temperature conditions (i.e., below their glass-transition temperatures), significantly reduces the logistical and storage constraints compared to frozen products, agrees Zuluaga Estrada. “That translates to greater storage and transport efficiency, particularly for global products and patient-centric delivery,” Guo concludes.

As with frozen formulations, however, it is necessary to use lower filling volumes than those of liquid products in the same container to ensure efficiency of the lyophilization process. In addition, Guo observes that the development of freeze-drying processes requires specialized expertise and capabilities and often adds time. The lyophilization process is also energy-intensive and extends the overall manufacturing time.

The need for reconstitution before administration also poses some concerns. Not only does Guo note the potential risk of product contamination by stopper debris after multiple punctures for reconstitution and sampling, high-concentration formulations can be challenging with respect to the time required and the potential for dosing errors and introduction of contaminants.

Despite the complexity, expense, and extended timelines typically associated with the development of lyophilized products, with the right expertise and robust platform cycles, it is possible to develop freeze-dried formulations in similar timeframes compared to liquid formats, according to Zuluaga Estrada. “We employ specialized characterization techniques including modulated differential scanning calorimetry (mDSC) and freeze-drying microscopy (FDM) to identify key thermal changes and, as required, optimize and develop robust lyophilization cycles in cost-effective timelines and with low material requirements,” she explains.

Given the different advantages and disadvantages of freezing and freeze-drying of parenteral formulations, there are some general factors that often influence the choice of one method over another. First is the ability of the drug substance to withstand the lyophilization process and/or freeze-thaw cycles, according to Zuluaga Estrada. The clinical application and route of administration are also important considerations. For instance, she notes that the acceptance of lyophilized formats is lower for emergency medications that must be administered immediately and medicines given via intravitreal administration. Other aspects that should be taken into account include the development phase, supply chain, timelines, and costs.

In general, says Guo, frozen products are often preferred if the development timeline is severely limited (e.g., six months to IND); the product is unstable and sensitive to the freeze-drying process; and the medicine will only require distribution locally or to clinical centers with sufficient cold-chain infrastructure. In addition, he notes that long-term storage at -20 °C is preferred over storage at ultra-low temperatures due to the greater availability of this capability at clinical centers.

Lyophilization is typically preferred, Guo continues, for unstable products that can withstand the freeze-drying process, there is sufficient time for development of an optimal lyophilization process, a long shelf-life is needed, and/or the product will be distributed to globally, including areas where cold-chain management would pose challenges.

“Overall,” Guo concludes, “when selecting between frozen and freeze-dried formulations, scientific, economic, and practical factors should be considered. Stability of the molecule for long-term storage is the primary concern. Other factors such as timeline, costs, storage availability, and distribution logistics should be evaluated as well.”

The evaluation of lyophilized formats can be a backup option for proteins that are unstable in solution at room temperature or under refrigeration or for cases where considerable surfactant degradation (potentially leading to particle formation) is observed, Zuluaga Estrada says.

When lyophilization does not improve protein stability or a lyophilized format is not suitable, such as when large fill volumes or long reconstitution times are involved, frozen storage of the liquid at sub-zero temperatures should be assessed.

Cynthia A. Challener, PhD, is a contributing editor to 

When referring to this article, please cite it as Challener, C.A. Parenteral Formulation: Deciding When to Go Frozen or Freeze-Dried.

Scientific, economic, and practical factors should be considered when choosing between the frozen state and lyophilization.

Parenteral Formulation: Deciding When to Go Frozen or Freeze-Dried

Felicity Thomas is the former Associate Editorial Director of Pharmaceutical Technology, Pharmaceutical Technology Europe, BioPharm International.

Industry Outlook 2025: European Political Impacts on the Supply Chain

The instability in the European geopolitical climate, as well as other areas of the world, has created some nerves in many industries, but the increased focus on the need to have a healthy and safe supply chain for pharmaceuticals is one positive outcome of a tumultuous time, according to Edwin Stone, CEO of Cellular Origins.

“I think for a long time, people took [supply chains] for granted. There was a narrative that has been born over the last 20-plus years that just in time, was the right model,” says Edwin Stone, CEO of Cellular Origins. “And of course, that's very true in a situation where you're putting a box of corn flakes on a shelf, and every extra week that corn flakes packets on the shelf is probably knocking a quarter off of your margin on it. So, by week four, effectively you're giving away for free. That's not so true in medicines. In medicines, we need to take a bigger picture view. We need to look at the accounts differently. I know companies that took very pragmatic views 10 years ago, to set up facilities where they would hold stock of 18-month supply of certain consumables. And it took a lot of warehousing to do it. This was equipment, supply people. But what it meant was, through the construct supply constraints, we saw, for example, through COVID, that they were able to actually continue to supply where others couldn't. The rationale, actually, the shelf space of these high-value consumables was a fraction compared with the value when they sold them to the customer. So, I think what's been really good is [the instability] has caused that focus on supply chain. I think it's managed to remove some of the assumptions of certainty and some of the lack of risk consideration that we'd got into.”

Click the video above to watch the full interview.

Videos

The PharmTech Group interviewed Edwin Stone, CEO of Cellular Origins, about how geopolitical instability in Europe, and beyond, has impacted the bio/pharmaceutical supply chain.

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FDA Director Martin Makary announced on May 6, 2025 that he has appointed Dr. Vinay Prasad, MD, MPH as the director of FDA’s Center for Biologics Evaluation and Research. Prasad is a hematologist-oncologist and was previously a professor in the department of Epidemiology and Biostatistics at the University of California San Francisco (UCSF).

In a post on X, FDA Director Martin Makary stated (1), “I’m proud to welcome Dr. Vinay Prasad, MD, MPH, as the new head of FDA’s Center for Biologics Evaluation & Research. With 500+ peer-reviewed publications and two books, Dr. Prasad brings the kind of scientific rigor, independence, and transparency we need at CBER—a significant step forward. Welcome aboard, Dr. Prasad.”

According to an online biography, Prasad has run the VKPrasad lab at UCSF, “which studies cancer drugs, health policy, clinical trials and better decision making”, hosted an oncology podcast, and has authored more than 500 academic articles. He graduated from the University of Chicago Pritzker School of Medicine, Johns Hopkins Bloomberg School of Public Health, and Michigan State University (2).

According to media reports, Prasad has criticized the response to the COVID-19 epidemic and certain FDA proposals (3, 4). In March 2025, former CBER Director Peter Marks resigned, citing an “assault on scientific truth” and the current administration’s views on vaccines (4).

“Over the past 13 years I have done my best to ensure that we efficiently and effectively applied the best available science to benefit public health,” Marks said in his resignation letter (5). “As you are aware, I was willing to work to address the Secretary's concerns regarding vaccine safety and transparency by hearing from the public and implementing a variety of different public meetings and engagements with the National Academy of Sciences, Engineering, and Medicine. However, it has become clear that truth and transparency are not desired by the Secretary, but rather he wishes subservient confirmation of his misinformation and lies.”

https://x.com/DrMakaryFDA/status/1919802781466079264

Sagonowsky, E. FDA Commissioner Marty Makary Taps Vinay Prasad to Head Up CBER. 

https://www.fiercepharma.com/pharma/fda-commissioner-marty-makary-taps-vinay-prasad-head-cber

Lawrence, L.; Mast, J.; and Herper, M. Vinay Prasad Tapped to Run FDA Center that Regulates Vaccines, Gene Therapies. STAT. May 6, 2025.

Marks, P. Letter to Sara Brenner, MD, MPH Acting Commissioner of Food and Drugs U.S. Food and Drug Administration. March 28, 2025. Posted by 

FDA chooses Dr. Vinay Prasad, MD, MPH, a hematologist-oncologist, to lead the Center for Biologics Evaluation and Research at FDA.

New CBER Director Appointed

, is senior manager, Manufacturing Science and Technology (MSAT), at AGC Biologics.

Variability in bioburden testing presents a significant challenge in ensuring accurate microbial enumeration during biopharmaceutical manufacturing. This study provides a quantitative framework for understanding and minimizing errors in colony-forming unit (CFU) counts, integrating regulatory guidance with statistical modeling. Through detailed analysis, the author demonstrates how factors such as microbial distribution, dilution steps, and test volume selection contribute to variability, particularly at low CFU levels where Poisson-distributed behavior dominates. Using models grounded in relative error and confidence-based metrics, the author calculates the percentage error associated with replicate counts and test conditions. A root sum of squares approach is further proposed to estimate total combined error from independent sources that include CFU/plate variability, number of replicates, serial dilution, and sample volume. This work offers a statistically rigorous method to enhance microbial detection reliability, thereby supporting consistent quality control and regulatory compliance in biopharmaceutical environments.

Bioburden testing plays a crucial role in ensuring the microbiological quality of biopharmaceutical products by quantifying microbial contamination at various stages of production. Accurate microbial enumeration is essential for compliance with regulatory standards, product safety, and process control. However, numerous factors introduce variability in colony-forming unit (CFU) counts, including microbial distribution, test volume selection, dilution errors, and plating techniques. Understanding the statistical principles that govern these factors is critical to minimizing error and improving the reliability of bioburden testing.

One of the key challenges in microbial enumeration is establishing an acceptable range for CFU counts per plate to ensure accurate results while avoiding errors caused by overcrowding or underrepresentation. Regulatory guidelines such as 

Validation of Microbial Recovery from Pharmaceutical Articles

, and American Society for Testing and Materials (ASTM) standards provide specific CFU ranges to maintain consistency in bioburden assessments. Additionally, sources of variability such as pipetting errors and microbial recovery rates can significantly impact CFU enumeration. Addressing these challenges requires the application of statistical models to quantify errors and establish robust bioburden testing methodologies that enhance data integrity.

1. Breed, R. S.; Dotterrer, W. D. The Number of Colonies Allowable on Satisfactory Agar Plates. 

, 1 (3), 321–331. DOI: 10.1128/jb.1.3.321-331.1916
2. Tomasiewicz, D. M.; Hotchkiss, D. K.; Reinbold, G. W.; Read, R. B., Jr.; Hartman, P. A. The Most Suitable Number of Colonies on Plates for Counting 1. 

, 43 (4), 282–286. DOI: 10.4315/0362-028X-43.4.282
3. USP. General Chapter <1227>. Validation of Microbial Recovery from Pharmaceutical Articles. 

, pg. 3053 (Rockville, Md., 2011).
4. ASTM International. Standard Practice for Determining Microbial Colony Counts from Water Analyzed by Plating Methods. 

 (1998).
5. Maturin, L.: Peeler, J. T. BAM Chapter 3: Aerobic Plate Count. In 

Pharmaceutical Microbiology Manual (ORA.007)

; Revision 2; FDA, 2020.
7. US Forum on Environmental Measurements (FEM) Microbiology Action Team. 

Method Validation of US Environmental Protection Agency Microbiological Methods of Analysis (FEM Document No. 2009-01)

; US Environmental Protection Agency, 2009.
8. Sutton, S. The Environmental Monitoring Program in a GMP Environment. 

, 14 (3), 22–29.
9. Stites, R. Sampling Error and Poisson Processes. 

Naveenganesh Muralidharan, nmural@agcbio.com, is senior manager, Manufacturing Science and Technology (MSAT), at AGC Biologics.

When referring to this article, please cite it as Muralidharan, N. Understanding the Variability in Bioburden Test Results in Biomanufacturing. 

This article explores the impact of test volume, microbial distribution, and dilution errors on bioburden testing variability. It presents statistical approaches to estimate percentage error and discusses strategies to optimize microbial enumeration techniques in biopharmaceutical quality control.

Understanding the Variability in Bioburden Test Results in Biomanufacturing

n-nitrosodimethylamine molecular structure, 3d model molecule, n-nitrosamines, structural chemical formula view from a microscope | Image Credit: © Сергей Шиманович - stock.adobe.com

In January 2025, FDA posted “Determining Recommended Acceptable Intake Limits for N-nitrosamine Impurities in Pharmaceuticals: Development and Application of the Carcinogenic Potency Categorization Approach” in the Spotlight on CDER Science section of the FDA.gov website (1). The presence of nitrosamines, which are cancer causing chemicals, in pharmaceuticals has been an ongoing concern since 2018 (2).

® asked Amit Chivate, senior market manager, Greater Asia and China, Roquette, to give us his perspective on FDA’s recommendations on how manufacturers should approach nitrosamines.

What can you tell us about the recommendations FDA published in January 2025 for the development and application of the Carcinogenic Potency Categorization Approach (CPCA) to nitrosamines?

The CPCA provides a comprehensive framework for assessing the carcinogenic potential of and acceptable intake limits for N-nitrosamine drug substance-related impurities (NDSRIs) (1). The need for such specific advice stems from the fact that, in contrast to simpler, small-molecule nitrosamines, NDSRIs present complex and unique chemical structures, which make the establishment of accurate acceptable limits (AI) particularly challenging. The CPCA proposes a new protocol that predicts the carcinogenic potency of an NDSRI by analyzing its chemical make-up—whether known or merely theoretical. The first step is a review of available science from animal studies and human epidemiological data to determine the relative risk associated with each nitrosamine compound. Next, scores are awarded according to the structure of α-hydrogen atoms, and the presence of activating or deactivating features are combined to assign the NDSRI to a potency category, which then dictates its acceptable daily intake limit. This approach represents a notable breakthrough because it allows for a precise, risk-based assessment—even in the absence of specific long-term carcinogenicity data for a particular NDSRI–—making it an ideal case study for how regulatory updates can simplify the drug development process.

The CPCA also brings a dose of much needed clarity and transparent scientific process to the field of nitrosamine mitigation, making it a win for consistency, quality and— above all—patient safety.

What makes determining acceptable intake so challenging?

Determining an acceptable daily exposure limit for any given drug impurity is an incredibly complex task—especially in the case of NDSRIs, which are usually unique to each individual drug. Extreme specificity, in this instance, means increased uncertainty, as there is unlikely to be enough tailored safety information on each NDSRI for manufacturers to determine safe exposure levels. As a result, formulators often turn to information gathered on structurally similar compounds or apply a conservative default acceptable intake limit, neither of which yield perfectly accurate results and can force drug companies to make unnecessary changes to their production practices to meet disproportionately strict standards.

Inconsistent regulatory guidelines across different countries, limited long-term epidemiological data, and the difficulty of quantifying cumulative risk from multiple sources all add another layer of complexity. FDA, for instance, sets its AI limits based on safety assessments that evaluate the mutagenic and carcinogenic potential of nitrosamines. Here, it uses rodent carcinogenic potency data or structure-activity relationships (SAR) to identify comparable compounds in the absence of robust data. In contrast, the European Medicines Agency (EMA) predicts carcinogenic potency categories and corresponding AI limits based on the presence of activating or deactivating structural features in the molecule, which influence carcinogenic potency. The recently published CPCA was developed to harmonize and simplify these approaches, with the aim of giving drug manufacturers a simpler, faster and more precise strategy for remaining compliant and protecting patients, without always having to resort to the most extreme safety measures.

NDSRIs are a subset of nitrosamine genotoxic impurities with complex chemical structures that typically mirror that of an API. They form when secondary or tertiary amines in the drug substance or formulation interact with nitrosating agents during manufacturing and storage. NDSRIs are particularly concerning because they are probable human carcinogens, as classified by the International Agency for Research on Cancer. In contrast to simpler, small-molecule nitrosamines, which are more general contaminants that can affect any drug formulation, NDSRIs are formed through the nitrosation of the API in response to specific production or storage conditions. In short, NDSRIs are complex, unique, and, therefore, more difficult to manage.

 What can pharma manufacturers do to manage the nitrosamine risk?

At this point, manufacturers are well versed in nitrosamine risk mitigation, but there are some underreported strategies that we think should be brought into the spotlight. First is the benefit of weaving the compliance process throughout the entire production line, start to finish. Though testing to determine whether drugs meet AI limits is typically carried out on finished products, we advise that all raw materials should first be evaluated for their potential to introduce nitrosamine impurities—either during production or on their way to patients’ medicine cabinets. This initial step can help save time and potential expense through the early identification of contaminated raw materials, as well as speed up the verification process of the final product.

Excipients are another essential, yet often overlooked, element to the nitrosamine compliance conversation. Fillers, binders, disintegrants, and diluents make up as much as 90% of a drug’s overall volume, so it stands to reason they receive at least some of the scrutiny when it comes to product safety (3,4).One of the simplest and most effective safeguarding options for pharma producers is to select excipients with a demonstrated low nitrate content. The drawback with this strategy, however, is that since regulators do not yet mandate their assessment for nitrosamine risk, comprehensive or consistent data on the nitrite content of many excipients can be hard to pin down. This is where the support of an experienced formulation partner can be invaluable, not only for providing drug manufacturers with high-quality information and products, but also with tailored advice on how to optimize production conditions, for safety and productivity.

FDA. Determining Recommended Acceptable Intake Limits for N-nitrosamine Impurities in Pharmaceuticals: Development and Application of the Carcinogenic Potency Categorization Approach. Spotlight on CDER Science. 

https://www.fda.gov/drugs/spotlight-cder-science/determining-recommended-acceptable-intake-limits-n-nitrosamine-impurities-pharmaceuticals

FDA. FDA Statement on the FDA’s Ongoing Investigation into Valsartan and ARB Class Impurities and the Agency’s Steps to Address the Root Causes of the Safety Issues. Press Release. Jan. 25, 2019.

Abrantes, C.G.; Duarte, D.; Reis, C.P. An Overview of Pharmaceutical Excipients: Safe or Not Safe. 

. 2016;105:2019–2026. DOI: 10.1016/j.xphs.2016.03.019

Haywood, A.; Glass, B.D. Pharmaceutical Excipients—Where Do We Begin? 

2011;34:112–114. DOI: 10.18773/austprescr.2011.060

Amit Chivate is senior market manager, Greater Asia and China, at Roquette.

Amit holds an MBA and a PhD in pharmaceutical drug delivery, and has more than 20 years of experience working across R&D, strategy, sales, marketing, and product management in both India and the United States. At Roquette, Amit serves as the senior marketing manager for the APAC region, leveraging his technical and business expertise to drive marketing initiatives and strategic growth.

Amit Chivate, senior market manager, Greater Asia and China, Roquette, provides his perspective on FDA’s recommendations regarding nitrosamines. 

Strategies for Mitigating Nitrosamine Risk

United States President Donald Trump has signed an executive order containing several directives to FDA and the Environmental Protection Agency (EPA), aiming to reduce regulatory barriers and restore a robust domestic manufacturing base for prescription drugs (1).

According to a Fact Sheet issued by the White House on May 5, 2025, the order directs FDA to take several steps to reduce the time needed to approve pharmaceutical manufacturing plants located in the US, including eliminating “duplicative and unnecessary” requirements—although, the fact sheet did not clarify what those requirements are—streamlining the review process, and working with domestic manufacturers to offer early support before a facility comes online (1).

Additionally, FDA is being instructed to increase fees for, and inspections of, foreign manufacturing plants, and to improve enforcement of API source reporting by foreign drug producers (1). The administration suggests displaying a public list of those facilities that do not comply.

FDA on May 6 announced an intention to expand unannounced inspections at foreign manufacturing facilities that produce foods, essential medicines, and certain other products (2).

“For too long, foreign companies have enjoyed a double standard—given advanced notice before facility inspections, while American manufacturers are held to rigorous standards with no such warning. That ends today,” FDA Commissioner Martin A. Makary, MD, said (2). “This is a key step for FDA as part of a broader strategy to get foreign inspections back on track.”

Regarding the EPA, the Trump Administration is calling for the acceleration of construction of facilities designed to manufacture prescription drugs, APIs, and any other raw materials necessary. The White House said critical gaps exist in the creation of an affordable and resilient domestic pharmaceutical supply chain, and that current estimates of five to 10 years for building new manufacturing capacity are “unacceptable” in terms of national security (1).

Bio/pharmaceutical companies either headquartered in the US or with major operations within the country have been weighing the potential impacts of the Trump Administration’s tariff policies since the 47th president re-took office in January 2025, with an expectation that 

 sooner or later, one way or another (3). Many companies and executives are 

The White House is instructing FDA to increase fees for and inspections of foreign drug manufacturing plants and reduce the time required to approve such sites that will be newly constructed in the US.

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