Introduction
A formal nitrosamine risk assessment should begin during the preclinical stage of development, specifically during candidate selection and the early design of the active pharmaceutical ingredient’s (API) route of synthesis. Conducting this evaluation at the earliest point in the drug development lifecycle enables sponsors to identify potential vulnerabilities proactively, optimize manufacturing processes, and meet increasingly stringent global regulatory expectations before clinical exposure occurs.
In contemporary pharmaceutical development, understanding exactly When to Start Nitrosamine Risk Assessment Drug Development is no longer considered a secondary concern or merely a post-marketing regulatory obligation. Since the 2018 discovery of N-nitrosodimethylamine (NDMA) contamination in the cardiovascular drug valsartan, regulatory authorities worldwide have fundamentally changed their approach, requiring sponsors to establish a thorough mechanistic understanding of impurity formation from the earliest stages of development. These genotoxic impurities are categorized as “cohort of concern” compounds under the International Council for Harmonisation (ICH) M7 guideline because of their strong mutagenic potential and their capacity to cause DNA damage even at extremely low concentrations.
Need expert guidance for your submission? View our Nitrosamine Risk Assessment for ANDA Submission services.
To safeguard patient health and ensure uninterrupted product development, pharmaceutical companies must shift away from reactive, post-marketing corrective actions and adopt predictive, early-stage quality risk management strategies. This proactive methodology ensures that all potential risk pathways—whether arising from the drug substance structure, excipient interactions, raw material synthesis, manufacturing operations, or packaging degradation—are systematically identified, evaluated, quantified, and controlled.
Article Summary:
- Nitrosamine risk assessment should begin during the preclinical phase, ideally during candidate selection and route-of-synthesis design, to identify potential risks before clinical development and regulatory submissions.
- Nitrosamines can form when vulnerable amines interact with nitrosating agents under favorable conditions such as acidic pH, heat, or moisture. Common sources include APIs, raw materials, solvents, excipients, manufacturing environments, and packaging materials.
- A lifecycle-based risk management strategy is essential, with assessments conducted throughout preclinical development, clinical trials, registration batch production, commercial launch, and post-approval changes.
- Early-stage evaluations help optimize synthesis routes and formulation design, reducing the likelihood of nitrosamine formation and minimizing costly remediation efforts later in development.
- Regulatory agencies require documented risk assessments and confirmatory testing before IND, CTA, NDA, or ANDA submissions, supported by appropriate control strategies and stability data.
- Nitrosamine impurities are controlled using toxicological thresholds and acceptable intake (AI) limits, with potency categories assigned through scientific risk assessment approaches such as the Carcinogenic Potency Categorization Approach (CPCA).
- Delaying nitrosamine assessments can lead to serious consequences, including clinical holds, regulatory rejections, product recalls, increased development costs, and commercialization delays. Advanced analytical methods such as LC-MS/MS and GC-MS/MS are critical for detecting and controlling trace-level impurities throughout a product’s lifecycle.
Chemical and Process Factors Driving Nitrosamine Formation
Nitrosamine formation is predominantly caused by a chemical reaction between a susceptible amine precursor and a nitrosating agent. This reaction is further accelerated by acidic conditions, elevated temperatures, and moisture during manufacturing and storage. Identifying the sources of these precursors and the environmental conditions that facilitate the reaction is the cornerstone of a scientifically sound nitrosamine risk assessment.
A comprehensive risk evaluation requires process chemists and formulation scientists to investigate the precise thermodynamic and kinetic pathways that enable the generation of genotoxic impurities. The well-established “nitrosamine triangle” illustrates that three essential components must be present simultaneously for nitrosamine formation to occur:
[ Vulnerable Amine ]
(API, Degradants, or
Raw Materials)
/ \
/ \
/ \
[ Nitrosating Agent ] ----------- [ Conducive Environment ]
(Nitrites, Nitrates, (Acidic pH, Moisture,
or Nitrogen Oxides) Heat, or Solvent)Struggling with manufacturing impurities? Learn about our Nitrosamine Solvent Catalyst Mitigation strategies.
The chemistry underlying nitrosamine formation differs depending on whether the impurity is a volatile, small-molecule nitrosamine that is structurally unrelated to the API or a Nitrosamine Drug Substance-Related Impurity (NDSRI) that shares structural elements with the active pharmaceutical ingredient.
Concerned about material compatibility? Explore our Packaging Leachables Nitrosamine EL testing.
Small-molecule nitrosamines such as NDMA and N-nitrosodiethylamine (NDEA) are frequently associated with process-related factors, including the thermal degradation of solvents such as dimethylformamide (DMF) into dimethylamine or contamination resulting from recovered solvents processed through third-party recycling systems. Conversely, NDSRIs present a more complex and challenging risk because they can form when an API contains a susceptible secondary amine, a tertiary amine capable of dealkylation, or a quaternary amine salt that reacts with trace nitrites present in formulation excipients.
To help development teams identify and manage these risks, the following table outlines the primary chemical and process-related hazards that should be evaluated during the early stages of development:
| Source Category | Specific Risk Factors | Chemical Mechanism / Pathway | Risk Mitigation Strategy |
|---|---|---|---|
| API Synthesis & Intermediates | Secondary & Tertiary Amines | Direct nitrosation by nitrous acid (HNO₂) generated under acidic conditions | Optimize the route of synthesis to eliminate vulnerable amine reagents and modify reaction sequences |
| Raw Materials & Solvents | Recovered Solvents, Catalysts, and Reagents | Amine impurities in solvents or contamination from shared solvent recycling systems | Use dedicated recycling streams, rigorously qualify suppliers, and establish stringent raw material specifications |
| Formulation Excipients | Excipient Nitrite Impurities | Trace inorganic nitrites react with amine-containing APIs during long-term storage | Select low-nitrite excipient grades and incorporate nitrite scavengers such as ascorbic acid |
| Process Environment | Mechanical Stress & Drying Air | Nitrogen oxides (NOx) present in drying gas streams react with amines during processing | Conduct critical milling and drying operations under inert nitrogen atmospheres |
| Packaging Systems | Nitrocellulose-Based Lidding Foils | Migration of nitrosamines or nitrating species from packaging materials | Evaluate container-closure systems and transition to non-nitrocellulose packaging when appropriate |
When to Start Nitrosamine Risk Assessment Drug Development: The Phased Lifecycle Timeline
Initiating a nitrosamine risk assessment during preclinical candidate selection is essential for incorporating structural de-risking measures and formulation optimization before manufacturing registration batches or submitting clinical applications. Establishing a phased, lifecycle-based strategy allows organizations to achieve compliance progressively while avoiding delays in critical development milestones.
The timeline for implementing a nitrosamine control program should align with the standard stages of pharmaceutical research and development. Strategic lifecycle planning helps ensure that sponsors are not forced to choose between extending development timelines and facing potential regulatory rejection.
Need to adjust your formulation? Read our Nitrosamine Reformulation Strategy guide.
Preclinical Candidate Selection and Route of Synthesis Design
A paper-based risk assessment should be initiated during the design of the route of synthesis (ROS) for the drug substance and during early pre-formulation planning for the drug product. Beginning the assessment at this stage enables process chemists to leverage in silico predictive tools, including Quantitative Structure–Activity Relationship (QSAR) models, to evaluate the lead candidate’s molecular structure and synthetic reagents for nitrosatable functionalities.
When a candidate contains a secondary or tertiary amine, the synthetic process can be designed to minimize acidic reaction conditions near nitrite-containing materials. Furthermore, the early adoption of fresh, dedicated solvent systems can reduce the risk of contamination associated with third-party solvent recovery operations. Addressing these chemistry-related vulnerabilities during the preclinical phase is widely regarded as the most efficient and cost-effective strategy for controlling nitrosamine risk.
Investigational New Drug Applications and Clinical Development
Before submitting an Investigational New Drug (IND) application or a Clinical Trial Application (CTA), sponsors should prepare and document a formal paper-based risk assessment within the Investigational Medicinal Product Dossier (IMPD). This assessment should summarize all potential risk factors associated with API synthesis, raw materials, excipient compatibility, and manufacturing operations.
During Phase I and Phase II clinical development, as formulation development progresses toward finalization, sponsors should perform forced degradation studies under nitrosating conditions to determine whether the API’s molecular structure is susceptible to solid-state nitrosation. If a credible risk is identified, immediate confirmatory testing of early clinical batches should be conducted to protect patient safety and establish preliminary control parameters.
IND / CTA DOSSIER ENTRY PROTOCOL
Is the API or raw materials chemically vulnerable?
|
+------------+------------+
| |
Yes No
| |
Conduct Step 2 Testing; Document Step 1 Report;
Establish Control Strategy Maintain Dossier on Site
and Submit Summary in IMPD and Submit Summary in IMPDRegistration Batches and Commercial Launch
Before submitting a New Drug Application (NDA) or an Abbreviated New Drug Application (ANDA), sponsors must complete a comprehensive nitrosamine risk assessment supported by confirmatory analytical testing from at least three representative registration or commercial-scale batches. These studies should include both long-term and accelerated stability evaluations to demonstrate that nitrosamine levels remain controlled throughout the proposed shelf life.
The resulting control strategy—including validated release specifications, raw material controls, supplier qualification programs, and manufacturing controls—should be fully integrated into the Chemistry, Manufacturing, and Controls (CMC) section of the regulatory submission. Following commercial approval, the risk assessment should remain a living document that is updated whenever manufacturing changes, scale-up activities, site transfers, process modifications, or new suppliers are introduced.
Ensuring long-term safety? See our Nitrosamine Testing in Stability Studies capabilities.
Understanding Nitrosamine Thresholds and Potency Categorization
Toxicological thresholds for nitrosamines are established using the Carcinogenic Potency Categorization Approach (CPCA), which assigns structure-based acceptable intake limits. These limits determine the testing requirements and control strategies necessary for both clinical and commercial products. Aligning analytical sensitivity with toxicological thresholds is essential for maintaining regulatory compliance and preventing product rejection.
When a nitrosamine impurity is identified, toxicologists must establish a compound-specific Acceptable Intake (AI) value. For well-characterized nitrosamines such as NDMA and NDEA, these limits are derived from extensive rodent carcinogenicity studies, resulting in daily exposure limits of 96 ng/day and 26.5 ng/day, respectively.
Acceptable Intake Formula:
AI = (TD₅₀ × 50 kg body weight) ÷ 50,000
For NDSRIs and other nitrosamines lacking comprehensive carcinogenicity data, regulatory agencies apply the CPCA framework. This methodology evaluates structure–activity relationships, including α-hydrogen feature scores, steric hindrance, and electronic deactivating substituents, to classify impurities into one of five potency categories:
- Category 1 (High Potency): 26.5 ng/day
- Category 2: 100 ng/day
- Category 3: 400 ng/day
- Category 4: 1500 ng/day
- Category 5 (Low Potency): 1500 ng/day
When multiple nitrosamines are detected in a single drug product, the combined daily exposure should not exceed the AI limit of the most potent impurity unless an alternative toxicological justification is accepted by regulatory authorities.
For products intended for short-term treatment, Less-Than-Lifetime (LTL) exposure adjustments may be applied. Under the ICH M7 framework, acceptable daily exposures can be increased according to treatment duration, thereby reducing analytical sensitivity requirements during early clinical development.
| Treatment Duration | LTL Adjustment Factor | Example AI Limit for NDMA | Mandatory Analytical Action Thresholds |
| ≤ 1 Month | 10x | 960 ng/day | If impurity <10% AI: Document and monitor |
| >1 to ≤12 Months | 5x | 480 ng/day | If impurity 10%–30% AI: Evaluate process variability |
| >1 to ≤10 Years | 2x | 192 ng/day | If impurity 30%–100% AI: Implement routine release specifications |
| >10 Years (Lifetime) | 1x | 96 ng/day | If impurity ≥100% AI: Halt release and optimize formulation or ROS |
Regulatory Deadlines and Post-Marketing Compliance Milestones
Global health authorities have established strict timelines for both retrospective evaluations of marketed products and prospective submissions for clinical and commercial development programs. Failure to provide validated risk assessment data within these timelines can result in market suspensions, regulatory delays, or outright application rejection.
Since nitrosamine contamination first emerged as a major regulatory concern, health authorities worldwide have introduced progressive compliance milestones to support systematic remediation across the pharmaceutical industry. These requirements distinguish between volatile small-molecule nitrosamines and more complex NDSRIs, reflecting advancements in scientific understanding.
Confused by regulatory limits? Understand the difference in our Nitrosamine Alert Limit vs Action Limit analysis.
For marketed products, original deadlines for Step 1 risk assessments and Step 2 confirmatory testing have largely passed. However, manufacturers remain responsible for continually reassessing products whenever new toxicological information, revised regulatory guidance, process changes, or emerging scientific evidence become available.
Notably, on June 23, 2025, the FDA issued updated guidance regarding products with potential NDSRI-related vulnerabilities. Recognizing the complexity associated with reformulation efforts, custom impurity synthesis, and long-term stability studies, the agency provided additional time for companies to submit required variations, provided structured progress reports were included as an “NDSRI Update” within Annual Reports submitted by August 1, 2025. Manufacturers of non-application products, including OTC monograph drugs, were also required to prepare and maintain similar documentation for GMP inspection readiness.
Sponsors preparing NDA or ANDA submissions must ensure that all Step 1 and Step 2 evaluations are completed before submission and supported by validated analytical control strategies.
Need help with compliance? Review our Nitrosamine Batch Release Testing Requirements.
Consequences of Delaying Nitrosamine Risk Assessment in Drug Development
Delaying nitrosamine risk assessments can lead to severe regulatory consequences, including clinical holds, Refuse to File (RTF) actions, and Complete Response Letters (CRLs). Such outcomes can halt development programs, increase operational costs, and significantly delay product commercialization.
CONSEQUENCES OF DELAYED COMPLIANCE
|
+-----------+-----------+
| |
[ Regulatory Impact ] [ Operational Cost ]
- Clinical Holds - Investor Concerns
- CRLs - Product Recalls
- RTF Actions - Supplier Requalification
- Market Delays - Manufacturing DowntimeComplete Response Letters (CRLs)
Publicly available regulatory records from 2023–2024 identified multiple instances in which the FDA issued CRLs due to insufficient nitrosamine control information within submitted NDAs and ANDAs. Common deficiencies included incomplete Step 1 assessments, analytical methods lacking adequate sensitivity, and stability data demonstrating nitrosamine concentrations above acceptable intake limits. These deficiencies resulted in delayed approvals and required sponsors to conduct additional toxicology studies and long-term stability programs.
Refuse to File (RTF) Actions
RTF decisions occur when a submission is considered too incomplete for formal scientific review. Although nitrosamine-related deficiencies are not always the sole reason for an RTF, regulatory agencies increasingly consider inadequate nitrosamine risk assessments as part of broader CMC deficiencies that justify immediate filing rejection.
Clinical Holds
For clinical-stage products, delayed compliance can have especially serious consequences. Several high-profile clinical programs have been placed on hold due to nitrosamine-related concerns. Such actions are typically triggered when nitrosamines are detected in clinical trial materials or when sponsors fail to provide adequate evidence demonstrating product safety prior to patient exposure.
Warning Letters and Commercial Recalls
For approved products, late-stage identification of nitrosamine issues often results in regulatory enforcement actions. Between 2020 and 2025, multiple inspections generated Form 483 observations and Warning Letters related to inadequate nitrosamine controls, weak supplier qualification programs, and failures to report out-of-specification impurity findings. These deficiencies led to numerous product recalls worldwide, generating substantial financial losses and reputational harm.
Advanced Analytical Testing and Method Validation Best Practices
To meet global regulatory expectations, confirmatory nitrosamine testing must utilize highly sensitive and validated mass spectrometry methodologies capable of detecting trace-level impurities below established action limits while avoiding analytical artifacts. Robust sample preparation and method validation procedures are essential for eliminating false-positive results and ensuring regulatory acceptance.
Because nitrosamines are classified as highly potent genotoxic carcinogens, analytical methods often require limits of quantitation (LOQs) in the low parts-per-billion (ppb) or even parts-per-trillion (ppt) range. Conventional chromatographic techniques, such as HPLC with UV detection, generally lack the sensitivity and selectivity necessary for accurate trace-level quantification in complex pharmaceutical matrices.
Choosing the right partner? See our Nitrosamine Testing CRO Selection guide.
Preferred Analytical Platforms
LC-MS/MS (Liquid Chromatography–Tandem Mass Spectrometry):
Widely regarded as the preferred platform for detecting complex and non-volatile NDSRIs. Operation in Multiple Reaction Monitoring (MRM) mode provides highly selective ion fragmentation and minimizes matrix interference.
GC-MS/MS (Gas Chromatography–Tandem Mass Spectrometry):
Particularly effective for volatile, low-molecular-weight nitrosamines such as NDMA and NDEA. Headspace injection techniques enhance analyte isolation while protecting instrumentation from contamination.
Critical Sample Preparation and Clean-Up Strategies
Pharmaceutical formulations present highly complex matrices that may suppress mass spectrometric signals or increase background noise. To address these challenges, specialized sample preparation approaches are often employed:
- Solid-Phase Extraction (SPE): Concentrates target nitrosamines while removing large quantities of API and excipients.
- Liquid-Liquid Extraction (LLE): Separates impurities based on differential solubility characteristics.
- Hydrophilic Interaction Chromatography (HILIC): Provides effective separation of highly polar nitrosating species while preserving column performance.
Mitigating Artefactual Nitrosamine Formation
One of the most significant analytical challenges in ultra-trace nitrosamine testing is the potential for artefactual formation during sample preparation. When a secondary amine-containing API is exposed to trace nitrites under acidic or elevated-temperature conditions, nitrosamines may form directly within the sample vial, resulting in false-positive findings.
To minimize this risk, advanced testing laboratories implement stringent preventive measures, including the exclusive use of certified nitrite-free solvents, maintenance of neutral or slightly basic extraction conditions, and incorporation of nitrite scavengers such as sulfamic acid or ammonium sulfamate into extraction diluents. These controls rapidly eliminate active nitrosating species before they can react with susceptible APIs.
Facing a contamination issue? Review our NDMA Root Cause Investigation Case Study.
Conclusion
Implementing a nitrosamine risk assessment at the earliest stages of drug development is a critical operational requirement for protecting patient safety, maintaining regulatory compliance, and preventing costly late-stage development setbacks. Addressing chemical vulnerabilities early enables pharmaceutical developers to establish inherently safer manufacturing processes and preserve a clear path toward commercialization.
Understanding exactly When to Start Nitrosamine Risk Assessment Drug Development is a strategic consideration that can determine whether a therapeutic candidate progresses successfully through global regulatory review or becomes delayed by clinical holds, Refuse to File actions, or Complete Response Letters. Conducting a formal paper-based Step 1 hazard assessment during candidate selection and route-of-synthesis design allows sponsors to eliminate toxicological risks before investing in costly pivotal clinical studies. As development progresses, implementation of highly sensitive analytical methodologies ensures that identified risks are accurately quantified and controlled in accordance with international regulatory expectations.
For organizations seeking support in navigating these complex requirements, collaboration with a specialized testing laboratory can provide substantial value. ResolveMass Laboratories Inc. offers comprehensive expertise in nitrosamine risk assessment, custom impurity synthesis, and validated ultra-trace confirmatory testing using advanced LC-MS/MS and GC-MS/MS technologies. Integrating these capabilities into early development programs helps protect clinical timelines, satisfy regulatory requirements, and ensure that safe and effective therapies reach patients without unnecessary delays.
To learn more about implementing compliant nitrosamine risk management strategies or to schedule confirmatory batch release testing, please contact the expert scientific team directly:
Frequently Asked Questions
A nitrosamine risk assessment should be initiated during the earliest phases of drug development, ideally during candidate selection and route of synthesis planning. Conducting a comprehensive Step 1 paper-based evaluation at this stage allows developers to identify potential nitrosamine formation pathways before clinical manufacturing begins. Early assessment helps eliminate structural and process-related risks, reducing the likelihood of costly development delays and regulatory concerns later in the product lifecycle.
Yes. Current regulatory expectations from agencies such as the FDA and EMA require nitrosamine risk assessments for both small-molecule and biological medicinal products. Although proteins and other macromolecules are generally less prone to direct nitrosation, nitrosamine risks may still originate from manufacturing materials, cell culture components, cleaning agents, processing aids, or packaging systems. Therefore, biological products must also undergo appropriate risk evaluations.
Many commonly used pharmaceutical excipients, including lactose, starch, and microcrystalline cellulose, may contain trace amounts of nitrites as residual environmental contaminants. Over time, these nitrites can interact with susceptible amine-containing drug substances or degradation products within tablets and capsules. This reaction can gradually generate Nitrosamine Drug Substance-Related Impurities (NDSRIs) during storage, making excipient selection and characterization important elements of risk management.
The Carcinogenic Potency Categorization Approach (CPCA) is a scientific framework used to estimate the carcinogenic potential of nitrosamines when long-term animal data are unavailable. The approach evaluates key structural characteristics such as α-hydrogen content, steric effects, and electronic influences that affect mutagenic activity. Based on these characteristics, an impurity is assigned to a potency category, which determines the corresponding Acceptable Intake (AI) limit used for regulatory control.
Step 2 laboratory testing becomes necessary whenever a Step 1 risk assessment identifies a realistic possibility of nitrosamine formation, contamination, or carryover during the product lifecycle. Confirmatory analytical studies are performed to determine whether nitrosamines are actually present and, if so, at what concentration. If a scientifically justified Step 1 assessment demonstrates no credible risk, laboratory testing may not be required, and the documented evaluation can be retained as supporting evidence.
When a CPCA-derived limit appears overly conservative, developers may generate additional scientific evidence to support an alternative toxicological assessment. One commonly accepted approach is performing a Good Laboratory Practice (GLP)-compliant Enhanced Ames Test (EAT) on the specific NDSRI. If the study demonstrates a lack of mutagenic activity, regulators may permit a higher acceptable intake threshold, reducing unnecessary manufacturing and analytical constraints.
Highly sensitive mass spectrometry techniques are considered the industry standard for nitrosamine testing. LC-MS/MS is typically preferred for complex and non-volatile NDSRIs, while GC-MS/MS is widely used for volatile, low-molecular-weight nitrosamines such as NDMA and NDEA. These advanced analytical platforms provide the selectivity, sensitivity, and accuracy needed to detect trace-level impurities in complex pharmaceutical matrices.
LTL exposure principles allow regulatory authorities to adjust acceptable nitrosamine intake limits based on the expected duration of patient treatment. For short-term therapies and early clinical studies, higher daily exposure limits may be permitted because overall lifetime risk remains low. This approach helps reduce analytical challenges during early development while still maintaining patient safety and compliance with ICH M7 principles.
Artefactual nitrosamine formation occurs when nitrosamines are unintentionally generated during sample preparation rather than being present in the original drug product. This can happen when susceptible amines encounter trace nitrites under favorable reaction conditions during testing. Laboratories minimize this risk by using nitrite-free reagents, controlling sample pH, maintaining appropriate extraction conditions, and incorporating nitrite scavengers to prevent unwanted reactions.
If testing confirms that an NDSRI exceeds its established Acceptable Intake limit, the developer must implement corrective actions and communicate the findings to regulatory authorities. This typically involves submitting a formal regulatory update outlining the root cause investigation, risk mitigation strategy, and planned manufacturing or formulation changes. Depending on the situation, additional regulatory submissions, process modifications, stability studies, and routine monitoring programs may also be required to ensure continued product safety and compliance.
Reference:
- International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). (2025, May 7). Final concept paper: Addendum to ICH M7 on risk assessment and control of N-nitrosamine impurities. https://database.ich.org/sites/default/files/ICH_M7SubGroup_Final_Concept_Paper_2024_0424.pdf
- Vikram, H. P. R., Kumar, T. P., Kumar, G., & Ramesh, M. (2024). Nitrosamines crisis in pharmaceuticals—Insights on toxicological implications, root causes and risk assessment: A systematic review. Journal of Pharmaceutical Analysis, 14(5), 100919. https://doi.org/10.1016/j.jpha.2023.12.009
- Boetzel, R., Schlingemann, J., Hickert, S., Korn, C., Kocks, G., Luck, B., Begrow, F., Koglin, J., & Harrison, M. (2023). A nitrite excipient database: A useful tool to support N-nitrosamine risk assessments for drug products. Journal of Pharmaceutical Sciences, 112(6), 1615–1624. https://doi.org/10.1016/j.xphs.2022.04.016
- Akkaraju, H., Tatia, R., Mane, S. S., Khade, A. B., & Dengale, S. J. (2023). A comprehensive review of sources of nitrosamine contamination of pharmaceutical substances and products. Regulatory Toxicology and Pharmacology, 143, 105355. https://doi.org/10.1016/j.yrtph.2023.105355
- Medicines and Healthcare products Regulatory Agency. (2026, April 28). Common issues: Pharmaceutical. GOV.UK. https://www.gov.uk/government/publications/common-issues-identified-during-clinical-trial-applications/common-issues-pharmaceutical
- Naiffer_Host. (2023, August 4). FDA – Recommended acceptable intake limits for nitrosamine drug substance-related impurities (NDSRIs) guidance for industry [Online forum post]. USP Nitrosamines Exchange. https://nitrosamines.usp.org/t/fda-recommended-acceptable-intake-limits-for-ndsris-guidance-for-industry/7145
- U.S. Food and Drug Administration. (2023, August). Recommended acceptable intake limits for nitrosamine drug substance-related impurities (NDSRIs): Guidance for industry. Center for Drug Evaluation and Research. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/recommended-acceptable-intake-limits-nitrosamine-drug-substance-related-impurities
Get In Touch With Us
About The Author
