Trace Aldehydes in Solid Oral Dosage Forms as Catalysts for Nitrosating Secondary Amines

Nitrosamine Drug Substance-Related Impurities (NDSRIs) in Pharmaceuticals: Formation, Mitigation Strategies, and Emphasis on Mutagenicity Risks

OBJECTIVES

To investigate the formation, detection, mutagenicity, and control strategies of nitrosamine drug substance-related impurities (NDSRIs) in pharmaceutical formulations, emphasizing regulatory compliance, risk mitigation, and the establishment of acceptable intake (AI) limits for enhanced drug safety.

METHODS

This study reviews the NDSRI formation and mutagenicity assessment methods, including in silico, in vitro, and in vivo assays. It also explores mitigation strategies and approaches for determining AI limits.

RESULTS

The findings indicate that NDSRIs are primarily formed through the nitrosation of APIs containing amine groups, with key risk factors including reactive functional groups and interactions between drugs and excipients. Mutagenicity evaluation revealed that while in silico and in vitro assays provide initial insights, in vivo assays offer more comprehensive and biologically relevant data by capturing complex metabolic processes and systemic interactions. Effective mitigation strategies, such as optimizing the manufacturing conditions and using nitrosation inhibitors, are crucial in reducing NDSRI formation. Approaches like the carcinogenic potency categorization (CPCA) and read-across methods are proposed for determining AI limits, facilitating safer exposure thresholds and supporting regulatory compliance.

CONCLUSION

A multifaceted approach is vital for managing NDSRIs in pharmaceuticals. Comprehensive mutagenicity testing, especially in vivo assays, provides biologically relevant insights into NDSRI-associated risks. Implementing control strategies and, determining AI limits are key to minimizing exposure. Strengthening regulatory frameworks and industry practices improves drug safety, quality, and public health protection.

NDSRIs Crisis in Pharmaceuticals; Insights on Formation Pathways, Root Causes, Risk Management, and Novel Analytical Techniques

The discovery of a new class of nitrosamine impurities called nitrosamine drug substance related impurities (NDSRIs) in pharmaceuticals has emerged as a significant challenge for the pharmaceutical sector due to their significant genotoxic and mutagenic effects. Regulatory bodies globally in active collaboration with all the concerned stake holders, are taking effective measures to prevent and control NDSRIs. This comprehensive review on NDSRIs discusses formation pathways, root cause analysis, acceptable intake limits, case studies, control strategies and regulatory responses pertaining to recent NDSRI incidents. This review discusses the novel liquid chromatographic techniques (LC-MS/MS, GC-MS/MS) used to identify and quantify of NDSRIs. This review would aid pharmaceutical professionals, R&D analytical and formulation scientists, and regulatory bodies in gaining deeper insights into the NDSRIs crisis, controlling NDSRIs in drug products, and ensuring their sensitive detection with accurate risk evaluation.

Investigation of the Formaldehyde-Catalyzed NNitrosation of Dialkyl Amines: An Automated Experimental and Kinetic Modelling Study Using Dibutylamine

The potential for drug substances and drug products to contain low levels of N-nitrosamines is of continued interest to the pharmaceutical industry and regulatory authorities. Acid-promoted nitrosation mechanisms in solution have been investigated widely in the literature and are supported by kinetic modelling studies. Carbonyl compounds, particularly formaldehyde, which may be present as impurities in excipients and drug product packaging components or introduced during drug substance manufacturing processes are also known to catalyze nitrosation, but their impact on the risk of N-nitrosamine formation has not been systematically investigated to date. In this study, we experimentally investigated the multivariate impact of formaldehyde, nitrite and pH on N-nitrosation in aqueous solution using dibutylamine as a model amine. We augmented a published kinetic model by adding formaldehyde-catalyzed nitrosation reactions. We validated the new kinetic model vs. the experimental data and then used the model to systematically investigate the impact of formaldehyde levels on N-nitrosamine formation. Simulations of aqueous solution systems show that at low formaldehyde levels the formaldehyde-catalyzed mechanisms are insignificant in comparison to other routes. However, formaldehyde-catalyzed mechanisms can become more significant at neutral and high pH under higher formaldehyde levels. Model-based sensitivity analysis demonstrated that under high nitrite levels and low formaldehyde levels (where the rate of formaldehyde-catalyzed nitrosation is low compared to the acid-promoted pathways) the model can be used with kinetic parameters for model amines in the literature without performing additional experiments to fit amine-specific parameters. For other combinations of reaction parameters containing formaldehyde, the formaldehyde-catalyzed kinetics are non-negligible, and thus it is advised that, under such conditions, additional experiments should be conducted to reliably use the model.

Nitrosamines crisis in pharmaceuticals - Insights on toxicological implications, root causes and risk assessment: A systematic review

The presence of N-nitroso compounds, particularly N-nitrosamines, in pharmaceutical products has raised global safety concerns due to their significant genotoxic and mutagenic effects. This systematic review investigates their toxicity in active pharmaceutical ingredients (APIs), drug products, and pharmaceutical excipients, along with novel analytical strategies for detection, root cause analysis, reformulation strategies, and regulatory guidelines for nitrosamines. This review emphasizes the molecular toxicity of N-nitroso compounds, focusing on genotoxic, mutagenic, carcinogenic, and other physiological effects. Additionally, it addresses the ongoing nitrosamine crisis, the development of nitrosamine-free products, and the importance of sensitive detection methods and precise risk evaluation. This comprehensive overview will aid molecular biologists, analytical scientists, formulation scientists in research and development sector, and researchers involved in management of nitrosamine-induced toxicity and promoting safer pharmaceutical products.

N-nitrosamine Mitigation with Nitrite Scavengers in Oral Pharmaceutical Drug Products

N-nitrosamines are likely 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. One strategy to inhibit the formation of N-nitrosamines during the manufacture and storage of drug products involves the incorporation of nitrite scavengers in the formulation. Diverse molecules have been tested in screening studies including the antioxidant vitamins ascorbic acid and α-tocopherol, amino acids, and other antioxidants used in foods or drugs, for inclusion into drug products to mitigate N-nitrosamine formation. This review article outlines key considerations for the inclusion of nitrite scavengers in oral drug product formulations.

Current Threat of Nitrosamines in Pharmaceuticals and Scientific Strategies for Risk Mitigation

The current global situation of nitrosamine contamination has expanded from angiotensin-II receptor blockers (ARBs) to wide range of medicines as the risk of contamination via the drug substances, formulation, manufacturing process, and packaging is possible for many drug products. The understanding of chemistry, toxicology, and root causes of nitrosamines are mandatory to effectively evaluate and mitigate the risks associated with the contaminated mutagen. Lessons learnt and scientific findings from previously identified root causes are good examples on how to perform effective risk assessments and establish control strategies. Addressing the risk of nitrosamine contamination in pharmaceuticals requires significant knowledge and considerable resources to collect the necessary information for risk evaluation. Examples of the resources required include a reliable laboratory facility, reference material, highly specific and sensitive instrumentation able handle trace levels of contamination, data management, and the most limited resource - time. Therefore, the supporting tools to assist with risk assessment e.g., shared databases for drug and excipients in concern, screening models for the determination of nitrosamine formation potential, and an in silico model to help with toxicity estimation, have proven to be beneficial to tackle the risk and concern of nitrosamine contamination in pharmaceuticals.

Ranitidine: A Proposed Mechanistic Rationale for NDMA Formation and a Potential Control Strategy

The formation of N-nitrosodimethylamine (NDMA) in ranitidine hydrochloride drug substance (DS) and drug products has attracted considerable attention over the last few years. The drug structure is unusual in that it contains a vinyl nitro moiety. Although a variety of studies have been carried out to understand how NDMA is formed in the DS solids, a mechanistic description of NDMA formation has remained elusive. A new mechanistic view of NDMA formation is detailed here. Autoxidation of ranitidine can rationalize nitrite ion and dimethylamine liberation from ranitidine. The subsequent nitrosation is argued to be due to conversion of nitrite ion to the gas phase nitrosating agent nitrosyl chloride, NOCl. Oxygen scavenging packaging systems should be able to stop the autoxidation, and thus shut down the nitrite release from ranitidine. Without nitrite release NDMA cannot form. This may provide a practical means to stabilize ranitidine DS and solid dosage formulations against NDMA formation.