Monthly Archives: February 2023

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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