Tag Archives: Threshold of Toxicological Concern

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Some Background and Concerns About PFAS

PFAS

The Background and Concerns of PFAS

PFSA structure(Per- and) PolyFluoroAlkyl Substances (PFAS) are a class of ubiquitous chemicals that have been found in water, air, fish, and soil across the nation and worldwide. Known as “Forever Chemicals,” there are thousands of different PFAS, and they are present in consumer, commercial, and industrial products.1 Having one of the strongest bonds in organic chemistry, their structures proved to be resistant to heat, water, oil, and degradation.2 They are found in “food packaging and non-stick cookware, cosmetics, waterproof and stain-proof textiles and carpet, aqueous film forming foam (AFFF) to fight Class B fires, and as part of metal plating processes.”3 Teflon and Scotchgard were two of the pioneering products to utilize these fluoropolymers. The two most common PFAS are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS).

Health Concerns of PFAS

Some of the most frequently cited health concerns associated with PFAS include adverse cardiovascular, immunity, developmental, and hepatic effects.3,4The most commonly heard refrain to minimize these concerns is that if they are so prevalent, why are there
not more health issues associated with them? In fact, “The Lancet Commission on Pollution and Health reported that pollution was responsible for 9 million premature deaths in 2015, making it the world’s largest environmental risk factor for disease and
premature death.” This was updated in 2019, and those numbers held steady, accounting for one in six deaths worldwide.5/i> While this number includes all types of pollution, the impacts are clear.

The Exposure Concerns of PFAS Are Regulatory and Legal

Due to their combination of persistence, pervasiveness, mobility, and the ability of some to bioaccumulate (or build up in animals and humans), they have been in the news recently too.6 Predictably, they are also now moving through the courts.7-9 Some of the most common areas of litigation are directed at PFAS found in drinking water and firefighting foam. The regulatory initiatives are also increasing. These address a range from water and soil to numerous manmade products including food packaging.10,11 The European Chemicals Agency (ECHA) and the NIH have a wealth of guidance and regulations that apply to PFAS.12,13

PFAS Detection

The EPA has useful direction for analytical methods development and sampling research that outlines the “laboratory validation process following a particular rulemaking or guidance effort and are available to support regulatory or guidance activities.”14 For
technique and equipment, PFAS are typically analyzed by mass spectrometry, coupled with gas chromatography or liquid chromatography (GCMS and LCMS), which enables detection in the low parts per billion.

AMPAC Analytical has years of experience and numerous experts in trace analysis by mass spectrometry who can assist with method development for high-volume analyses for both common and atypical sample matrices that will allow you to stay ahead of evolving regulatory concerns. Please contact us with specific questions or to receive a quote for PFAS quantitation.

References

  1. PFAS Explained | US EPA
  2. Understanding Organofluorine Chemistry. An Introduction to the C–F bond – Chemical Society Reviews (RSC Publishing)
  3. PFAS Health Effects Database: Protocol for a Systematic Evidence Map – ScienceDirect
  4. Toxicological Profile for Perfluoroalkyls (cdc.gov)
  5. Pollution and Health: a Progress Update – The Lancet Planetary Health
  6. ‘Forever Chemicals’ Are Everywhere. What Are They Doing to Us? – The New York Times (nytimes.com)
  7. PFAS Settlements: Future of PFAS Litigation Landscape to be Determined by Upcoming Decision | Reuters
  8. PFAS: The New Frontier of Product Liability – ProQuest
  9. DuPont, Corteva, and Chemours Announce Resolution of Legacy PFAS Claims | DuPont
  10. Trends in the Regulation of Per- and Polyfluoroalkyl Substances (PFAS): A Scoping Review
  11. PFAS in Food Packaging: State-by-State Regulations – September 2023 | Bryan Cave Leighton Paisner – JDSupra
  12. Per- and Polyfluoroalkyl Substances (PFAS) – ECHA (europa.eu)
  13. Guidance on PFAS Exposure, Testing, and Clinical Follow-Up – NCBI Bookshelf (nih.gov)
  14. PFAS Analytical Methods Development and Sampling Research | US EPA

Resources

Blog

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

TCB* With Your TTC Needs

Triple Quad HPLC

Triple Quad HPLC“The dose makes the poison” – Paracelsus (c. 1493– 1541), born Theophrastus von Hohenheim

The Threshold of Toxicological Concern (TTC) refers to levels of mutagenic impurities expected to pose a negligible carcinogenic risk.1 The US FDA, the EMA (European Medicines Agency), and the European Food Safety Authority (EFSA) all have TTC values and regulations in place for food and active pharmaceutical ingredients (APIs), along with numerous other products.2,3 Originally, these standards were applied to TTC levels from oral ingestion but have expanded to even include cosmetics and fragrances.4,5

One tool to assess risk is the use of Cramer classes for organic impurities. They range from I-III, indicating a low, medium, or high probability of toxicity.5

There are numerous tools and techniques to assess TTC, depending on the product (food, water, and other beverages, APIs, or cosmetics) and the mutagenic impurity. AMPAC Analytical can utilize TTC guidelines and risk assessments to establish method development and validation targets that ensure acceptable levels of mutagenic impurities in your API or food products. Contact us today to learn more about analytical strategies to control mutagenic impurities.

*Taking Care of Business

References

  1. https://www.fda.gov/media/85885/download
  2. https://www.ema.europa.eu/en/ich-m7-assessment-control-dna-reactive-mutagenic-impurities-pharmaceuticals-limit-potential
  3. https://www.efsa.europa.eu/en/topics/topic/threshold-toxicological-concern
  4. https://www.sciencedirect.com/science/article/abs/pii/S0278691507002207
  5. https://www.sciencedirect.com/science/article/abs/pii/S0273230015300660

Resources

  • https://www.fda.gov/media/85885/download
  • https://www.frontiersin.org/articles/10.3389/ftox.2021.655951/full
  • https://academic.oup.com/toxsci/article/86/2/226/1653574
  • https://www.sciencedirect.com/science/article/abs/pii/S027869159600049X