Search Results for: nitrosamine

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Nitrosamines – An Update

NDMA

The linkage between nitrosamines and cancer was first postulated by William Lijinsky in 1970. Then, in 2018, N-nitroso-dimethylamine (NDMA)) was detected in an active pharmaceutical ingredient, Valsartan (an Angiotensin-II-receptor antagonist).  Finally, the FDA issued a guidance for the industry, “Control of Nitrosamine Impurities in Human Drugs”, in the fall of 2020. However, the guidelines continue to evolve. There has been an update in March of 2021, with ongoing risk assessments.  Other regulatory agencies have instituted their own, along with updates. For example, since our blog series on nitrosamines, there have been some regulatory updates from the European Medicines Agency (EMA). Their new guidelines are outlined in a document entitled, “Questions and Answers for Marketing Authorization Holders/Applicants on the CHMP Opinion for the Article 5(3) of Regulation (EC) No 726/2004 Referral on Nitrosamine Impurities in Human Medicinal Products.”1 The updated section answers the crucial question, “Which limits apply for nitrosamines in medicinal products?” 

 The answers are provided with a definition of nitrosamines and acceptable exposures: 

 “The ICH M7(R1) guideline defines N-nitrosamines as substances of the “cohort of concern” for which limits in medicinal products refer to the so-called substance-specific acceptable intake (AI) (the Threshold of Toxicological Concern, TTC, value of 1.5 ug/day cannot be routinely applied) which is associated with a negligible risk (theoretical excess cancer risk of <1 in 100,000 over a lifetime of exposure). The calculation of AI assumes a lifelong daily administration of the maximum daily dose of the medicinal product and is based on the approach outlined in the ICH M7(R1) guideline as well as the principles described in relation to the toxicological evaluation in the assessment report of the CHMP’s Article 5(3) opinion on nitrosamine impurities in human medicinal products.”1,2 (A previous blog examined TTC, here.)  

A Useful List of Nitrosamine Limits  

In Appendix 1 found on the EMA site, there is a list of more than eighty nitrosamines listed, along with CAS numbers, known medicinal sources, CPCA (Carcinogenic Potency Categorization Approach) categories, and their guidance publication dates.3,4  

Some Caveats 

There are some exceptions that should be considered. For example, the EMA states, “The ‘less than lifetime’ (LTL) approach should not be applied in calculating the limits as described above but can only be considered after consultation with competent authorities as a temporary measure until further measures can be implemented to reduce the contaminant at or below the limits defined above.”1  

Additionally, those medications intended for advanced cancers also have some exceptions. For example, “If the active substance itself is mutagenic or clastogenic at therapeutic concentrations, N-nitrosamine impurities should be controlled at limits for non-mutagenic impurities according to ICH M7(R1).”  

There is also guidance when one or more than one nitrosamines may be present. For the latter, the guidance advises one of two approaches: 

  1. The total daily intake of all identified N-nitrosamines is not to exceed the AI of the most potent N-nitrosamine identified. 
  1. The total risk level calculated for all identified N-nitrosamines is not to exceed 1 in 100,000. The approach chosen needs to be duly justified by the MAH (Marketing Authorization Holder)/Applicant.1 

Final Thoughts on Nitrosamines 

Nitrosamine guidance worldwide is ever-evolving, yet the impetus to quantify and regulate them is clear. There will doubtlessly be further updates to regulations. AMPAC Analytical Laboratories – an SK pharmteco company (AAL) is an industry leader in the detection of nitrosamines and other genotoxic impurities (GTI), We have the specialized expertise, equipment, and methodologies to detect these impurities by gas chromatography or high-performance liquid chromatography coupled with mass spectrometry to support your API project.  Also, importantly, AAL can assist in navigating those projects within today’s regulatory landscape. Please contact us with any specific questions or to receive a quote for nitrosamines or other GTIs.  

References  

  1. https://www.ema.europa.eu/en/documents/referral/nitrosamines-emea-h-a53-1490-questions-answers-marketing-authorisation-holders/applicants-chmp-opinion-article-53-regulation-ec-no-726/2004-referral-nitrosamine-impurities-human-medicinal-products_en.pdf 
  2. ICH M7 Principles – Impurity Identification and Control (europa.eu) 
  3. https://www.ema.europa.eu/en/human-regulatory/post-authorisation/referral-procedures/nitrosamine-impurities 
  4. Appendix 1 Nitrosamine AIs (europa.eu) 

Resources 

AMPAC  Analytical

General Information on Nitrosamines  

Nitrosamine and Pharmaceuticals  

Regulatory Experiences with Root Causes and Risk Factors for Nitrosamine Impurities in Pharmaceuticals
https://doi.org/10.1016/j.xphs.2022.12.022 

Blog

Nitrosamines in Food and Beverages

This is the third in a series of entries examining nitrosamines in a range of products. Our first of two previous articles presented an overview of nitrosamines, including a historical look at their implication as a probable carcinogen. In the second entry, we reviewed their presence in active pharmaceutical ingredients (APIs), and how to remove them. 

Nitrosamines are organic compounds found in the human diet and other environmental sources. These highly potent carcinogens can cause tumors in nearly all organs and have been classified as genotoxic impurities (GTI).  

Background on Nitrosamines in Food and Beverages
The possible linkage between cancer and the large class of chemical compounds known as nitrosamines was first postulated by William Lijinsky in 1970.1 Since then, they have been detected above recommended intake limits in numerous foods and beverages, both naturally occurring and through additives in processed foods.  Nitrosamines have been found in a wide variety of different foods ranging from cheeses, soybean oil, canned fruit, meat products, cured or smoked meats, fish and fish products, spices used for meat curing, beer, and other alcoholic beverages.2,3 Beer, meat products, and fish are considered the main sources of exposure. “Drying, kilning, salting, smoking, or curing promotes the formation of nitrosamines.2,4 

 Nitrites and nitrates may occur naturally in water or foods such as leafy vegetables due to the use of fertilizer or may be added to foods to prevent (the) growth of Clostridium botulinum, or to add color or flavor.”2,5 

The nitrosamines most frequently found in food are N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosopiperidine (NPIP), and N-nitrosothiazolidine (NTHZ).2,3 NDMA, NPYR, and NPIP are reasonably anticipated to be human carcinogens based on evidence of carcinogenicity in animal experiments.2,6,7 Evidence from case-control studies supports an association between nitrosamine intake with gastric cancer, but not esophageal cancer in humans.2,8 

Determining Acceptable Levels of Nitrosamine
Levels of nitrosamines have been declining during the past three decades, concurrent with a lowering of the nitrite use in food, use of inhibitors such as ascorbic acid, and application of lower operating temperatures and indirect heating during food processing.2,4 

A triple quadrupole MS

The FDA provides “action levels” for poisonous or deleterious substances found in human food and animal feed. These action levels and tolerances represent limits at or above which FDA will take legal action to remove products from the market.9 Current FDA regulations do not limit nitrosamine levels in foods, but they have established an action level of 10 ppb for individual nitrosamines in both consumer and hospital rubber baby bottle nipples. They have also limited the approval of nitrites in curing mixes to the FDA-regulated food additive process (21 CFR 170.60), and the approval of sodium nitrite as a food additive (food preservative) (21 CFR 172.175). The USDA monitors finished meat products to ensure that nitrite is not present in amounts exceeding 200 ppm (9 CFR 424.21).2 

As investigators summarized in a study published in the World Journal of Gastroenterology, “there is a positive association between nitrite and nitrosamine intake” and gastric cancer, “between meat and processed meat intake and” gastric cancer and esophageal cancer, “and between preserved fish, vegetable, and smoked food intake and” gastric cancer, “but is not conclusive.”8 While there is not an irrefutable link between nitrite and nitrosamine intake to cancer when combined with action-level requirements and guidance from the FDA, the directive for food and beverage producers is certainly clear. 

Final Thoughts 

Nitrosamines are an inevitable chemical outcome in the manufacturing and processing of many foods, beverages, medicines, and numerous other products. Due to their low concentrations, they are also challenging to detect. Fortunately, rigorous testing services are available to screen and remove them from exposure by the end user. AMPAC Analytical has the specialized expertise, equipment, and methodologies to detect these impurities by gas chromatography or high-performance liquid chromatography coupled with mass spectrometry. Please contact us with any specific questions or to receive a quote for nitrosamines. 

References
 Items marked with an asterisk are open access.  

  1. https://doi.org/10.1038/225021a0 
  2. * https://doi.org/10.3390/toxins2092289 
  3. https://ntp.niehs.nih.gov/whatwestudy/assessments/cancer/roc/index.html 
  4. https://onlinelibrary.wiley.com/doi/book/10.1002/9780470430101#page=369 
  5. https://onlinelibrary.wiley.com/doi/book/10.1002/9780470430101#page=566 
  6. * http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s137nsop.pdf
  7.  http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s136nsop.pdf
  8. * https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4087738/ 
  9. * https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-action-levels-poisonous-or-deleterious-substances-human-food-and-animal-feed 

Resources & Further Reading 

AMPAC 

General Information on Nitrosamines 

Nitrosamine and the Diet 

Blog

Nitrosamines in Active Pharmaceutical Ingredients 

This is the second in a series of entries examining nitrosamines in a range of products. Our first article presented an overview of nitrosamines, including a historical look at their implication as probable carcinogens. This entry will review their presence in active pharmaceutical ingredients (APIs) and process mitigation strategies.  

Nitrosamines are organic compounds found in medications, the human diet, and the environment These carcinogens can cause tumors in nearly all organs and have been classified as possible genotoxic impurities (GTI).   

Background on Nitrosamines in Active Pharmaceutical Ingredients 
The linkage between cancer and a large class of chemical compounds known as nitrosamines was postulated by William Lijinsky in 1970.1 Then, in June 2018, their presence (specifically, N-nitroso-dimethylamine (NDMA)) was detected in the API Valsartan, an Angiotensin-II-receptor antagonist.  

NDMA

It later became “obvious that the issue may not only occur with sartans but, in principle, with any API containing a vulnerable amine and a nitrosation source. Hence not only NDMA but a plethora of potential nitrosamines could be created.”2 They have been subsequently detected in other medicines resulting in 250 product recalls, affecting more than 1400 lots.3,4 The cost of recalls could be high.5 APIs or their impurities can become nitrosated “during the later stages of the synthetic process of the drug product manufacturing or even while in the completed, packaged product.”6 As discussed in our previous entry, primary amines are not a concern, as they have limited stability.6 However, secondary and tertiary amines, along with quaternary ammonium compounds, are considered potential nitrosamine precursors, according to the current guidelines of the FDA and EMA.6,7  As a useful reference for amine components, there is a central system for the ingredients in medicinal products known as the Global Substance Registration System (GSRS https://gsrs.ncats.nih.gov/.)8   Some of the possible causes for the presence of nitrosamines are:  

  • The use of sodium nitrite (NaNO2), or other nitrosating agents. 
  • The use of raw materials and intermediates contaminated by nitrosamines 
  • Degradation processes of starting materials, intermediates, and drug substances during formulation or storage 
  • The use of certain contaminated packaging materials 

Detection Tools 

Fortunately, there are many tools to detect nitrosamines. NDMA, NDEA, and other nitrosamine impurities can be detected at ppb level using gas chromatography, such as with a QTOF (Quadrupole Time of Flight Mass Spectrometer) or triple quadrupole.  

 Ways to Mitigate Nitrosamine Formation 

There are numerous ways that nitrosamines can be mitigated through API process design. For example, the FDA’s Control of Nitrosamine Impurities in Human Drugs Guidance for Industry, issued by the Center for Drug Evaluation and Research, states that:  “The following factors should be considered during process development:  

  • Avoiding reaction conditions that may produce nitrosamines whenever possible; when not possible, demonstrating that the process is adequately controlled and is capable of consistently reducing nitrosamine impurities through appropriate and robust fate and purge studies.  
  •  Using bases other than secondary, tertiary, or quaternary amines (when possible) if ROS (Route of Synthesis) conditions may form nitrosamines 
  • Using caution when the ROS involves the use of amide solvents (e.g., N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone) 
  • Replacing nitrites with other quenching agents for azide decomposition processes.  
  • Optimizing and consistently controlling the sequences of reactions, processes, and reaction conditions (such as pH, temperature, and reaction time) 
  • Designing a manufacturing process that facilitates the purge of nitrosamine impurities in the subsequent processing steps. 
  • Auditing API supply chains accompanied by continuous monitoring for any at-risk raw materials, starting materials and intermediates, and avoiding cross-contamination when using recovered materials such as solvents, reagents, and catalysts in the manufacturing process.  
  • Recovered material should be used only in the same step or in an earlier step. API manufacturers should be aware that potable water used in API manufacture may contain low levels of nitrite and even nitrosamines from environmental contamination”.9,10 

 Solutions 

Nitrosamines are an inevitable chemical outcome in the manufacturing and processing of many items, including APIs. Due to their low concentrations, they are also challenging to detect. AMPAC Analytical has rigorous testing services available to screen to trace levels in challenging sample matrices, including process intermediates, drug substances, and drug products. We have the specialized expertise, equipment, and methodologies to detect these impurities by gas chromatography or high-performance liquid chromatography coupled with mass spectrometry. Please contact us with any specific questions or to receive a quote for nitrosamines screening.  

References  

  1. https://doi.org/10.1038/225021a0   
  2. https://jpharmsci.org/article/S0022-3549(23)00018-7/fulltext  
  3. https://doi.org/10.1021/acs.jmedchem.0c02120  
  4. https://doi.org/10.1016/j.xphs.2022.11.013 
  5. https://www.bloomberg.com/news/articles/2022-09-01/drug-recalls-for-nitrosamines-could-cost-big-pharma-millions  
  6. https://www.fda.gov/media/141720/download 
  7. https://www.ema.europa.eu/en/documents/referral/nitrosamines-emea-h-a53-1490-assessment-report_en.pdf https://doi.org/10.1093/nar/gkaa962  
  8. https://doi.org/10.1093/nar/gkaa962   
  9. https://ampacanalytical.com/wp-content/uploads/2023/01/Control-of-Nitrosamine-Impurities-in-Human-Drugs-Guidance-for-Industry.pdf  
  10. https://www.who.int/water_sanitation_health/water-quality/guidelines/en/ 

Resources & Further Reading  

AMPAC  

General Information on Nitrosamines  

Nitrosamine and Pharmaceuticals  

Blog

Nitrosamines: An Overview

This is the first in a series of entries examining nitrosamines in a range of products.  

 Nitrosamines are organic compounds found in the human diet and other environmental outlets. Being potent carcinogens that can cause tumors in nearly all organs, they have been classified as genotoxic impurities (GTIs). There are guidelines and rulings by various regulatory organizations, including the FDA, EPA, EMA, and the IARC (International Agency for Research on Cancer). Their presence and attendant concerns have been noted for many years. A.J. Gushgari and R.U. Halden wrote in Chemosphere,  Nitrosamines were first proposed as “environmental carcinogens by William Lijinsky in 1970, which fostered research on N-nitrosamine occurrences in environmental media.”1 These included “ambient water, aquatic sediments, and municipal sewage sludge (Schreiber and Mitch, 2006; Venkatesan et al., 2014; Zeng and Mitch, 2015; Gushgari et al., 2017).”1 Concern about their presence has significantly expanded to include food and active pharmaceutical ingredients (APIs). Our next two blog entries will explore the effects and mitigation of nitrosamines in these two areas. 

Background on Nitrosamines
Basically, “Nitrosamines are formed from the reaction of nitrite with primary, secondary, or tertiary amines in an acidic medium.”2 Primary and tertiary amines are typically not concerns for nitrosamines, but should be part of the chemical evaluation as there are cases where they can be impacted to form these impurities. 

 Since nitrates and the conditions are common in a wide range of products, vigilance is warranted. The reaction between nitrous acid and primary aromatic amines was first observed and reported in 1864 by Peter Griess. The work of Baeyer and Caro, and Otto Witt in the 1870s further researched the reaction. As Gushgari and Halden state, it was Witt in his 1878 publication that the term “nitrosamine” was first introduced to describe ““any substituted ammonia which contains, instead of at least one atom of hydrogen, the univalent nitrosyl group, NO, in immediate connection with the ammoniacal nitrogen”.”1 Almost one hundred years later, the aforementioned William Lijinsky, studying the environmental causes of cancer and specifically chemical carcinogens, began his decades-long examination of nitrosamines, eventually leading him to appear before multiple congressional committees and to work with the FDA. As a result, the FDA issued numerous guidelines in the following decades, with many released in the last few years. The FDA’s guideline of a current acceptable intake limit is 26.5 ng/day for APIs. For drinking water, it is 7 ng/L. Along with many other resources, they published Control of Nitrosamine Impurities in Human Drugs (PDF) for “immediate implementation” on September 1, 2020.  The European Medicines Agency (EMA) has also been active in this area, with many resources found here.  

 Many Types and an Increasing Concern 
Of course, there is more than one type of nitrosamine to contend with since there are countless combinations of the structural elements available. Sebastian Schmidtsdorff et al. listed a table (Figure 1) of sixteen investigated nitrosamines with their attendant CAS numbers, abbreviations, and interim limits (IL).4 These were discovered during their research using 249 different, randomly selected samples of APIs from 66 manufacturers.   

Figure 1
(N/A = not applicable/interim limits not published yet). 

Name  Abbreviation  CAS-No.  IL Interim Limits (ng/day) 
N-Nitrosodimethylamine  NDMA  62-75-9  96 
N-Nitrosomethylethylamine  NMEA  10595-95-6  NA 
N-Nitrosodiethylamine  NDEA  55-18-5  26.5 
N-Nitrosodiethanolamine  NDELA  1116-54-7  NA 
N-Nitrosoethylisopropylamine  NEiPA  16339-04-1  26.5 
N-Nitrosodiisopropylamine  NDiPA  601-77-4  26.5 
N-Nitrosodi-n-propylamine  NDPA  621-64-7  26.5 
N-Nitrosodi-n-butylamine  NDBA  924-16-3  26.5 
N-Methyl-N-nitrosoaniline (N-nitrosomethylphenylamine)  NMPhA  614-00-6  34.3 
N-Nitrosomethyl(2-phenylethyl)amine  NMEPhA  13256-11-6  8 
N-Nitrosodiphenylamine  NDPhA  86-30-6  NA 
N-Nitrosopyrrolidine  NPyr  930-55-2  NA 
N-Nitrosopiperidine  NPip  100-75-4  1300 
N-Nitrosomorpholine  NMor  59-89-2  127 
1-Methyl-4-nitrosopiperazine  MNPaz  16339-07-4  26.5 
N-Nitroso-N-methyl-4-aminobutyric acid  NMBA  61445-55-4  96 

 The most commonly occurring nitrosamines in APIs are NDMA, NDEA, NMBA, NDPA, NEIPA, NDBA, and NMPA. In addition to the number of nitrosamines, the products where they have been detected have increased dramatically. For example, since the discovery of their presence in an API, Valsartan (an Angiotensin-II-receptor antagonist) in 2018, they have been detected in other medicines resulting in 250 product recalls, affecting more than 1400 lots.5,6 In addition to the financial impact of these recalls costly litigation has risen too. 

 A Positive Note
Interestingly, although nitrosamine impurities in products are an ever-present concern, at least one medication, Carmustine [154-93-8] (Figure 2), is an antineoplastic nitrosourea [13010-20-3] and is used in treating several forms of cancer.7,8 

Figure 2 

carmustine structure

Final Thoughts
Nitrosamines can form during the manufacturing and processing of foods, beverages, medicines, and numerous other products.  In addition, they can form upon storage.5 Despite detection challenges, rigorous testing and mitigation services are available to screen and avoid their formation, thereby protecting consumers. In fact, AMPAC Analytical (AAL) has the specialized expertise, equipment, and implemented stringent methodologies to detect these impurities, utilizing gas chromatography or high-performance liquid chromatography coupled with tandem or high-resolution mass spectrometry. AAL currently maintains three validated procedures for general nitrosamines screening. Please feel free to contact us with any specific questions or to receive a quote for nitrosamine screening in your product. 

 Items marked with an asterisk are open access or available without registering. 

References  

  1. * https://doi.org/10.1016/j.chemosphere.2018.07.098 
  2. https://pubmed.ncbi.nlm.nih.gov/2184959/ 
  3. * https://doi.org/10.1016/j.xphs.2022.11.013 
  4. * https://doi.org/10.1002/ardp.202200484 
  5. https://doi.org/10.1021/acs.jmedchem.0c02120 
  6. https://www.bloomberg.com/news/articles/2022-09-01/drug-recalls-for-nitrosamines-could-cost-big-pharma-millions 
  7. * https://pubchem.ncbi.nlm.nih.gov/compound/Carmustine 
  8. * https://medlineplus.gov/druginfo/meds/a682060.html 

Resources & Further Reading 

AMPAC 

General Information on Nitrosamines 

Nitrosamine Exposure and Environmental Concerns 

Nitrosamine and Pharmaceuticals 

Nitrosamine and the Diet 

 

Nitrosamine Impurities Testing

AMPAC Analytical has implemented test methods using LC-HRMS and GC-MS to identify trace Nitrosamines in drug substances and drug products.

Stay compliant with the FDA, and get your active pharmaceutical ingredient (API) and drug product tested for NDMA.

Test for NDMA today

NDMA and Nitrosamines are difficult molecules to detect

NDMA

General analytical tests previously used by the industry to release API/DP may not have been able to detect the presence of Nitrosamines. AMPAC Analytical Labs has implemented methodologies to detect this class of impurities using LC-HRMS as well as GC-MS.

Why Test For NDMA Impurities

NDMA and Nitrosamines in general, are genotoxic impurities and have been classified by the U.S. Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) as probable human carcinogens. Nitrosamines, such as N-Nitrosodimethylamine (NDMA), can be found at low levels in numerous items of human consumption, including cured meat, fish, beer, tobacco smoke, and most recently, as an impurity in various pharmaceuticals.

In recent reports, there have been several Angiotensin-II-receptor antagonists, AKA “Sartans”, which have been contaminated with NDMA. The EPA has determined that the maximal admissible concentration of NDMA in drinking water is 7 ng/L.

Test Your Products in Compliance For FDA Guidelines

Pharmaceutical products have been on the news as these products are taken for chronic diseases, medications taken multiple times a day, and in varying dosages. Regulatory agencies are actively involved in addressing the issue by detecting, testing, and quantifying these impurities. New applications, renewal, synthetic route modifications, and sourcing of material modifications can be subject to evaluation for the presence of Nitrosamines.

To view the FDA’s “Control of Nitrosamine Impurities in Human Drugs – Guidance for Industry” PDF document, please click the link below.

Read

Learn More About Genotoxic Impurities

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What is NDMA?

N-Nitrosodimethylamine (NDMA) is a yellow, oily liquid with a faint, characteristic odor. It is an industrial by-product or waste product of several industrial processes, such as the manufacturing of unsymmetrical dimethylhydrazine, which is a component of rocket fuel that requires NDMA for its synthesis. NDMA is found at low levels in numerous items of human consumption, including cured meat, fish, beer, tobacco smoke, and, most recently, as an impurity in various pharmaceuticals. In recent reports, there have been several “sartans” that have been contaminated with NDMA, which is highly toxic, especially to the liver, and is a known carcinogen in lab animals. The EPA classifies NDMA as a probable human carcinogen. The US Environmental Protection Agency has determined that the maximal admissible concentration of NDMA in drinking water is 7 ng/L.

How do you analyze nitrosamine impurities?

Nitrosamine impurities such as NDMA and NDEA can be analyzed and quantified using gas chromatography or high-performance liquid chromatography coupled with a high-resolution mass spectrometer.

How do you quantify nitrosamine impurities?

Nitrosamine impurities such as NDMA and NDEA can be quantified using gas chromatography or high-performance liquid chromatography coupled with a high-resolution mass spectrometer.

How do you detect nitrosamine impurities?

Nitrosamine impurities such as NDMA and NDEA can be detected at ppb level using gas chromatography coupled with a high-resolution mass spectrometer.

How do you test for NDMA?

Nitrosamine impurities such as NDMA and NDEA can be analyzed and quantified using gas chromatography or high-performance liquid chromatography coupled with a high-resolution mass spectrometer.

What are nitrosamines?

Nitrosamines are a family of carcinogens impurities which are formed by the reaction of secondary amines, amides, carbamates, derivatives of urea with nitrite or other nitrogenous agents. Nitrosamines are classified by the ICH M7 Guideline as Class 1 impurities, also known as mutagenic carcinogens.

What are the potential root causes for presence of nitrosamines?

  • Use of sodium nitrite (NaNO2), or other nitrosating agents.
  • Use of contaminated raw materials and intermediates by nitrosamine.
  • Degradation processes of starting materials, intermediates, and drug substances. This could potentially occur also during finished product formulation or storage.
  • Use of certain contaminated packaging materials
Blog

Elemental Impurities

A special thanks to Matt Webberley, Associate Director Analytical Research and Development at our sister company, SK biotek Ireland Limited, for his assistance with the profiles of AAS, ICP-OES, ICP-MS, and XRD. 

A Definition of These Newsmakers
Elemental impurities in food have been in the news recently, with reports of everything from lead being found in baby food to arsenic, cadmium, and assorted heavy metals in dark chocolate and other foods.1-8 Of course, the FDA and Congress are taking notice.3 The US Pharmacopeia definition of elemental impurities states they “include catalysts and environmental contaminants that may be present in drug substances, excipients, or drug products. These impurities may occur naturally, be added intentionally, or be introduced inadvertently (e.g., by interactions with processing equipment and the container closure system).”9 As recent news reports show, the concern can be expanded beyond drugs and APIs (active pharmaceutical ingredients) to include food and beverages. 

Classifying Elemental Impurities
In addition to the recalls and resources, there are a variety of impurity classification levels, too. In the following table, the FDA and EMA sort them by elements.12,13 They are classified into three categories based on their toxicity and also based on occurrence in the drug product (note: this is usually assumed to be the same as for the drug substance but not always). 

ELEMENT CLASSIFICATION 
Class 1: The elements, As, Cd, Hg, and Pb are human toxicants that have limited or no use in the manufacture of pharmaceuticals. Their presence in drug products typically comes from commonly used materials (e.g., mined excipients). Because of their unique nature, these four elements require evaluation during the risk assessment across all potential sources of elemental impurities and routes of administration. The outcome of the risk assessment will determine those components that may require additional controls, which may, in some cases, include testing for Class 1 elements. It is not expected that all components will require testing for Class 1 elemental impurities; testing should only be applied when the risk assessment identifies it as the appropriate control to ensure that the PDE will be met.  
Class 2: Elements in this class are generally considered as route-dependent human toxicants. Class 2 elements are further divided into sub-classes 2A and 2B based on their relative likelihood of occurrence in the drug product.  
• Class 2A elements have [a] relatively high probability of occurrence in the drug product and thus require risk assessment across all potential sources of elemental impurities and routes of administration (as indicated). The class 2A elements are: Co, Ni, and V.  
• Class 2B elements have a reduced probability of occurrence in the drug product related to their low abundance and low potential to be co-isolated with other materials. As a result, they may be excluded from the risk assessment unless they are intentionally added during the manufacture of drug substances, excipients, or other components of the drug product. The elemental impurities in class 2B include: Ag, Au, Ir, Os, Pd, Pt, Rh, Ru, Se, and Tl.  
Class 3: The elements in this class have relatively low toxicities by the oral route of administration (high PDEs, generally > 500 μg/day) but may require consideration in the risk assessment for inhalation and parenteral routes. For oral routes of administration, unless these elements are intentionally added, they do not need to be considered during the risk assessment. For parenteral and inhalation products, the potential for inclusion of these elemental impurities should be evaluated during the risk assessment unless the route-specific PDE is above 500 μg/day. The elements in this class include: Ba, Cr, Cu, Li, Mo, Sb, and Sn.  
Other elements: Some elemental impurities for which PDEs have not been established due to their low inherent toxicity and/or differences in regional regulations are not addressed in this guidance. If these elemental impurities are present or included in the drug product, they are addressed by other guidance and/or regional regulations and practices that may be applicable for particular elements (e.g., Al for compromised renal function; Mn and Zn for patients with compromised hepatic function), or quality considerations (e.g., presence of W impurities in therapeutic proteins) for the final drug product. Some of the elements considered include: Al, B, Ca, Fe, K, Mg, Mn, Na, W, and Zn. 
Key: 
Ag, Silver; Al, Aluminum; As, Arsenic; Au, Gold;  B, Boron; Ba, Barium; Ca, Calcium;
Cd, Cadmium; Co, Cobalt; Cr, Chromium;
Cu, Copper; Hg, Mercury; Fe, Iron;  		 Ir, Iridium; K, Potassium; Li, Lithium;
Mg, Magnesium; Mn, Manganese;
Mo, Molybdenum; Na, Sodium; Ni, Nickel;
Os, Osmium;  		 Pb, Lead; Pd, Palladium; Pt, Platinum;
Rh, Rhodium; Ru, Ruthenium; Sb, Antimony; Se, Selenium; Sn Tin; Tl, Thallium; V, Vanadium;
W, Tungsten; Zn, Zinc 

Tools for Testing Elemental Impurities 

Beyond the FDA, EMA, and the USP, other assets are available to industries, including testing for and mitigating these elemental impurities.  Detection by testing plays a crucial role in ensuring the quality and safety of food, beverages, and medical products. In a very relevant article in Pharmaceutical Technology, published two years ago, Felicity Thomas states, “The most commonly used techniques to analyze elemental impurities are inductively coupled plasma–mass spectrometry (ICP–MS) or inductively coupled plasma–optical emission spectroscopy (ICP–OES).” Both systems utilize high-energy plasma charges that ionize any elements present in the sample preparation and detect them using elemental masses or emission bands. The authors quote Paul Kippax, Pharmaceutical Sector director at Malvern Panalytical, who says, “The advantage of using ICP is that it can detect a wide range of elemental impurities at very low concentrations. This [capability] enables the product safety requirements for the main product types (oral solid dose, inhaled, and injectable products) to be assessed.”14 However, elemental impurity testing is not limited to ICP-MS or ICP-OES. Other techniques available include material characterization (including particle size and thermal analysis), chromatography, x‐ray diffraction and foreign matter identification, and NMR (nuclear magnetic resonance) spectroscopy, each with specific advantages or limitations depending on factors such as time, budget, material or impurities and levels being tested. Here is each profile:  

Atomic Absorption Spectroscopy (AAS)
Atomic absorption spectrometry (AAS) detects elements in either liquid or solid samples through the application of characteristic wavelengths of electromagnetic radiation from a light source. Individual elements will absorb wavelengths differently, and these absorbances are measured against standards. In effect, AAS takes advantage of the different radiation wavelengths that are absorbed by different atoms. In AAS, analytes are atomized by an Air/Acetylene or Nitrous oxide/Acetylene flame so that their characteristic wavelengths are emitted and recorded. When a hollow cathode lamp is passed into the cloud of atoms, the selected metals to monitor absorb the light from the lamp, and the concentration is measured by a detector. Most of the elements reach excitation temperature using this source, which has a maximum temperature of 2,600 °C. For a few elements, such as V, Zr, Mo, and B, the source temperature is not sufficient to atomize the molecules, and as a result, sensitivity is reduced. Moderate detection limits and not all elements can be determined by AAS are some of the limitations of atomic absorption spectroscopy. 

Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES or ICP-AES)
The source in ICP-OES is plasma at temperatures as high as 10,000 °C, where all elements, including refractory elements, atomize with higher efficiencies than in AAS. As a result, elements can be determined more precisely, and lower limits of detection levels are possible. There are two variants in ICP-OES, radial and axial. Axial viewing increases the path length and reduces the plasma background signal [over radial viewing], resulting in lower detection limits. ICP-OES is a multi-element technique. Under the source of plasma, the sample dissociates into its atoms and ions. At their excitation level, they emit light at characteristic wavelengths. The concentration of a particular element in the sample can be measured from the intensity of the emitted light with a detector. However, the detection limits in ICP-OES are moderate to low. 

Inductively Coupled Plasma-Mass Spectrometry ICP-MS (ICP-MS)
The same source as in ICP-OES is used to dissociate a sample into atoms and ions. It is also a multi-element technique. The basic difference between ICP-OES and ICP-MS is that ions are directly detected by an MS detector rather than by emission of light, as in the case of ICP-OES. The ions are separated by a Quadrupole based on the mass-to-charge ratio. The best detection limits are available for most of the elements in ICP-MS as the number of ions produced is high, and although some spectral interference is seen, these are defined and limited. 

X-ray fluorescence (XRF)
X-ray fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. Analyzers determine the chemistry of a sample by measuring the fluorescent (or secondary) X-rays emitted from a sample when it is excited by a primary X-ray source. Each element in a sample produces a set of characteristic fluorescent X-rays (“a fingerprint”) unique for that specific element, which is why XRF spectroscopy is an excellent technology for qualitative and quantitative analysis of material composition. The ICP-OES technique has better sensitivity and lower detection limits compared to XRF. Therefore, using XRF for determining lower levels has higher errors, and the correlation with ICP-OES is weaker. 

Recalls and Resources
The FDA’s actions on contamination from elemental impurities range from issuing guidance to product recalls. There are three class recall levels (I-III) and two related activities: a market withdrawal and a medical device safety alert.10 The former of these are voluntary, while the latter can be considered, in some cases, a recall.

Additionally, the FDA has a range of resources available for both consumers and manufacturers.  For consumers, these include:  

For industry resources, the offerings consist of the following: 

The European Medicines Agency also provides numerous guides and requirements on their site, including the International Council for Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use’s ICH Q3D Elemental impurities – Scientific Guideline.11 

 Final Thoughts on Elemental Impurities 

Whether it is in food and beverages or drug products, there is increased scrutiny by regulatory agencies and consumers on the presence of elemental impurities. Industries hoping to avoid costly product withdrawals, recalls, and possible litigation is advised to safeguard the quality and safety of food, beverages, and medical products by testing for elemental impurities. AMPAC Analytical has decades of experience and the full array of equipment and methods to ensure our products avoid these worst-case scenarios. Furthermore, these analytical services are accompanied by a devoted customer focus, with communication and guidance at each step to assist with all regulatory and filling requirements. 

References 

  1. https://cen.acs.org/safety/consumer-safety/FDA-seeks-limit-lead-baby 
  2. https://www.nytimes.com/2023/01/26/health/baby-food-metals-lead.html 
  3. https://oversightdemocrats.house.gov/sites/democrats.oversight.house.gov/files/ECP%20Second%20Baby%20Food%20Report%209.29.21%20FINAL.pdf 
  4. https://www.nytimes.com/2023/02/09/well/eat/dark-chocolate-metal-lead.html 
  5. https://www.reuters.com/business/retail-consumer/consumer-reports-urges-dark-chocolate-makers-reduce-lead-cadmium-levels-2023-01-23/ 
  6. https://www.npr.org/2022/12/30/1146254933/hersheys-lawsuit-dark-chocolate-heavy-metals-lead 
  7. https://www.usnews.com/news/health-news/articles/2023-02-08/how-are-toxins-like-lead-arsenic-getting-into-baby-foods 
  8. https://www.consumerreports.org/health/food-safety/lead-and-cadmium-in-dark-chocolate-a8480295550/ 
  9. https://www.usp.org/sites/default/files/usp/document/our-work/chemical-medicines/key-issues/c232-usp-39.pdf 
  10. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/recall-resources 
  11. https://www.ema.europa.eu/en/documents/scientific-guideline/international-conference-harmonisation-technical-requirements-registration-pharmaceuticals-human-use_en-16.pdf 
  12. https://www.fda.gov/media/148474/download 
  13. https://www.ema.europa.eu/en/documents/scientific-guideline/international-conference-harmonisation-technical-requirements-registration-pharmaceuticals-human-use_en-32.pdf 
  14. https://www.pharmtech.com/view/approaching-elemental-impurity-analysis 

Resources, Related Topics, and Further Reading 

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