New innovations in active material science technologies enable an active packaging-based solution that can react with nitrosating agents (NO_X gases) in the packaging headspace to inhibit nitrosamine formation. Not only can these technologies stop nitrosamine formation, but they can be adjusted to serve as an additional “insurance policy” by adsorbing or scavenging N-nitrosamines post-formation, providing a holistic risk mitigation solution. Such novel active polymer platforms, deployed as nitrosamine scavenging technology, can be seamlessly integrated into existing packaging formats and processes to address nitrosamine risks without disrupting manufacturing workflows.
 
Introduction
N-nitrosamines are classified as probable human carcinogens. After N-nitrosamine contaminants were detected in pharmaceutical products in 2018, regulatory authorities set a framework for the risk assessment, testing, and mitigation of N-nitrosamines in drug products (1-3). In response to the unexpected presence of N-nitrosamine impurities in several widely used pharmaceutical products, the FDA released a Guidance for Industry document in September 2020 (3). The background and possible mitigation strategies were outlined in the report. The updated FDA guidance matches the EMA’s three-step procedures, and includes deadlines for drug manufacturers to complete each step for approved and pending drug applications. In addition, a document listing possible N-nitrosamine mitigation strategies specifically mentions ascorbic acid and α-tocopherol as common antioxidants that significantly inhibit N-nitrosamines in drug products (4).
 
In general, N-nitrosamine formation requires the presence of three factors: 
 
1. A nitrosating agent or precursor thereof, particularly nitrite. Nitrite does not directly nitrosate amines; however, they are precursors of nitrosating agents. 
 
2. A vulnerable secondary or tertiary amine, which may be a moiety within the drug substance. 
 
3. Conditions amenable for the reaction to occur, such as elevated temperatures, acidic conditions, or the presence of a liquid phase.
 
These three factors may not be sufficient for N-nitrosamine formation to occur, as the kinetics of N-nitrosamine formation can vary significantly, depending on the structure and environment (5, 6).
 
One strategy to inhibit the formation of N-nitrosamines during the manufacture and storage of drug products involves the use of nitrosating agent scavengers. In screening studies, diverse molecules – including the antioxidant vitamins ascorbic acid and α-tocopherol, amino acids, and other antioxidants used in foods or drugs – have been tested for inclusion in drug products to mitigate N-nitrosamine formation (7, 8). The use of nitrosating agent scavengers that are currently listed as inactive ingredients in drug products by the FDA offers advantages from a regulatory perspective, and also in terms of the development time needed to establish N-nitrosamine mitigation. 
 
Recently, as part of compound screening, 19 structurally-diverse compounds with an acceptable toxicological profile were evaluated by Homšak et al (7). These included certain amino acids (L-cysteine, histidine, lysine), general antioxidants (propyl gallate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), ammonia-related compounds (urea, ammonium sulfate and ammonium chloride), the pyrone maltol, para-aminobenzoic acid (PABA), and vitamins with antioxidant properties (ascorbic acid, α-tocopherol). Likewise, the use of ascorbic acid and α-tocopherol to inhibit N-nitrosamine formation in pharmaceutical products has been specifically mentioned by the FDA (4).
 
Ascorbic acid has wide applicability across many nitrosating agents and is nontoxic at effective amounts in drug products (9, 10). It is particularly suited to aqueous and weakly acidic conditions, and can react with N₂O₃, H₂NO₂+, and NO_X, converting them to NO (9, 10). However, under aerobic conditions, NO can oxidize to NO₂ and subsequently convert back to nitrosating agents (i.e. N₂O₃ or N₂O₄). Good scavenging efficiency of redox scavengers such as ascorbic acid is thus expected under anaerobic conditions, although their efficiency is already strong in the presence of oxygen (11). 
 
As mentioned above, until now most research has focused on the prevention of nitrosation by adding the nitrosating agent scavengers directly to drug formulations. Nevertheless, the same principles can be applied by adding the active material directly into the packaging framework, avoiding time and costs associated with mitigation via drug reformulation. The work described in this paper outlines key considerations for the incorporation of an innovative nitrosamine scavenging technology, which contains nitrosating agent scavengers directly inside pharmaceutical packaging. This includes a particular emphasis special focus on NO_X scavenging, as NO_X is a nitrosating agent common to drug packaging.
 
Methods
More than 260 diverse NO_X mitigant raw materials were identified from literature, with 52 tested in screening studies – including different categories of organic and inorganic materials (antioxidants, adsorbers, pH modifiers, moisture controllers and other innovative agents, etc.) (see Figure 1).

The results of the screening were used to formulate various mitigation films with the best active candidates. These raw active materials were then engineered for inclusion into a polymer matrix to form  the active polymer (Figure 2) nitrosamine scavenging technology, which is capable of mitigating N-nitrosamine formation by scavenging nitrosating agents. The obtained nitrosamine scavenging technology – deployed in various scenarios as active film solutions (Figure 3), heat-staked films (active blister packaging), blown films and blown bottles – were tested to determine their ability to reduce nitrite and NO_X concentration, in order to avoid or limit N-nitrosamine formation. 



Mitigants (in powder or shaped film formats) were put with a NO_X– and nitrite-provider (when needed) in a vial, blister or bottle and aged for different periods of time. The different compounds were detected and quantified using various analytical equipment such as gas chromatography mass spectroscopy headspace, etc. Each active raw material and film formulation was tested three and 30 times, respectively, to achieve high confidence in the results.
 
Results & Discussion
A total of 52 active raw materials were tested. Figure 2 shows the NO_X percentage reduction with the best 46 mitigant raw materials after 24 hours at 60°C. Of the 52 mitigants identified and tested, 10 mitigants reduced 50% or more of NO_X present in the vial headspace (Figure 4). 

The five materials demonstrating the highest adsorption capacities were then incorporated into a specially designed active film material, compatible with traditional blister packaging. Each film formulation and its corresponding controls were analyzed 30 times, yielding high-confidence results that can be used for further evaluation and determination of the best performing nitrosamine scavenging films. The controls averaged 9.63 ppm after seven days of aging at 60°C. All five mitigant films reduced NO_X overall concentration dramatically, with “N-Sorb F” and “N-Sorb H” films averaging complete removal of NO_X (below 0.1 ppm) in the headspace (Figure 5). 

By offering a targeted, efficient, and easily implementable solution, nitrosamine scavenging technology can empower drug developers to ensure the safety and quality of their products while streamlining compliance with regulatory requirements.
 
Conclusion 
Innovative active polymer platforms, engineered as nitrosamine scavenging technology, offers pharmaceutical developers a promising alternative to current nitrosamine mitigation strategies (based on drug reformulation) by actively removing or decreasing nitrosamine concentration in the headspace of sealed drug packaging. The key findings from this study demonstrate the potential of nitrosamine scavenging technology as a potent scavenger of nitrosating agents, addressing the root cause of N-nitrosamine formation. Promisingly, nitrosamine scavenging technology can be seamlessly integrated into existing packaging formats and processes, mitigating risk while minimizing disruption to manufacturing workflows. 
 
References
1. S. Baertschi, J. Daou, J. Pratt, Mitigating N-Nitrosamine Risks with Novel Active Material Science Innovations. White Paper, Aptar CSP Technologies, May 2023.
 
2. I. Comer I, J. Daou, M. Gaston, A. Murph, J. Pratt, Targeting Nitrosamine precursors with novel active material science scavenger technologies” White Paper, Aptar CSP Technologies, Feb 2024. 
 
3. U.S. Food and Drug Administration, Control of Nitrosamine Impurities in Human Drugs: Guidance for Industry, Report number: FDA-2020-D-1530, 2020. 
 
4. U.S. Food and Drug Administration, Updates on Possible Mitigation Strategies to Reduce the Risk of Nitrosamine Drug Substance-Related Impurities in Drug Products, 2021.
 
5. International Pharmaceutical Excipients Council (IPEC) Federation, The Role of Excipients in Determining N-Nitrosamine Risks for Drug Products, 2022. 
 
6. R. López-Rodríguez, J.A. McManus, N.S. Murphy, M.A. Ott, M.J. Burns, Pathways for N-nitroso compound formation: secondary amines and beyond, Org Process Res Dev, 24 (9) 2020, pp. 1558-1585. 
 
7. M. Homšak, M. Trampuž, K. Naveršnik, et al., Assessment of a diverse array of nitrite scavengers in solution and solid state: a study of inhibitory effect on the formation of alkyl-aryl and dialkyl N-nitrosamine derivatives, Processes, 10 (11) 2022, p. 2428. 
 
8. K.K. Nanda, S. Tignor, J. Clancy, M.J. Marota, L.R. Allain, S.M D’Addio, Inhibition of N-nitrosamine formation in drug products: a model study, J Pharm Sci, 110 (12) 2021, pp. 3773-3775. 
 
9. W.J. Mergens, H.L. Newmark, Antioxidants as blocking agents against nitrosamine formation, MG Simic, M Karel (Eds.), Autoxidation in Food and Biological Systems, Springer US 1980, pp. 387-403. 
 
10. S.R. Tannenbaum, J.S. Wishnok, C.D. Leaf, Inhibition of nitrosamine formation by ascorbic acid, Am J Clin Nutr, 53 (1 Suppl) 1991, pp. 247S-250S. 
 
11. A.F. Holleman, N. Wiberg, Lehrbuch Der Anorganischen Chemie, De Gruyter, Berlin, Boston, 2008.
 

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Ivy Comer, a Scientist III in the Applications and Research Development Team at Aptar CSP Technologies, holds a Bachelor of Science in Biochemistry from Auburn University. Her expertise in innovation, analytical methodologies, and strategic problem-solving has driven impactful solutions in the medical and packaging industries.

 






Amanda Murph is a Scientist II in the Research and Applications Development division at Aptar CSP Technologies. With a Bachelor’s degree in Materials Engineering, she demonstrates a strong commitment to innovation and collaborative problem-solving by consistently exploring novel material applications and focusing on achieving tangible results.




 
Jason D. Pratt is Director of Material Science at Aptar CSP Technologies with a passion for bringing innovative solutions to commercial opportunities. Skilled at bringing together and mentoring high power teams to tackle impossible problems, he is a green chemist with over 40 patents across the food, cosmetics, pharma and construction industries.



 



After earning a Ph.D. in material chemistry from the University of Louis Pasteur, Jean joined the University of Haute Alsace as assistant professor and was promoted to full professor in 2016. In 2021, he joined Aptar CSP Technologies as R&D manager where his research activities focus on the synthesis of porous materials, the study of their properties and their shaping to meet pharmaceutical packaging demands for molecular decontamination. He is the author of 137 publications in international journals and 18 patents.