A Full Evaporation Static Headspace Gas Chromatography Method with Nitrogen Phosphorous Detection for Ultrasensitive Analysis of Semi-volatile Nitrosamines in Pharmaceutical Products

Analytical Methodologies to Detect N-Nitrosamine Impurities in Active Pharmaceutical Ingredients, Drug Products and Other Matrices

Since 2018, N-nitrosamine impurities have become a widespread concern in the global regulatory landscape of pharmaceutical products. This concern arises due to their potential for contamination, toxicity, carcinogenicity, and mutagenicity and their presence in many active pharmaceutical ingredients, drug products, and other matrices. N-Nitrosamine impurities in humans can lead to severe chemical toxicity effects. These include carcinogenic effects, metabolic disruptions, reproductive harm, liver diseases, obesity, DNA damage, cell death, chromosomal alterations, birth defects, and pregnancy loss. They are particularly known to cause cancer (tumors) in various organs and tissues such as the liver, lungs, nasal cavity, esophagus, pancreas, stomach, urinary bladder, colon, kidneys, and central nervous system. Additionally, N-nitrosamine impurities may contribute to the development of Alzheimer's and Parkinson's diseases and type-2 diabetes. Therefore, it is very important to control or avoid them by enhancing effective analytical methodologies using cutting-edge analytical techniques such as LC-MS, GC-MS, CE-MS, SFC, etc. Moreover, these analytical methods need to be sensitive and selective with suitable precision and accuracy, so that the actual amounts of N-nitrosamine impurities can be detected and quantified appropriately in drugs. Regulatory agencies such as the US FDA, EMA, ICH, WHO, etc. need to focus more on the hazards of N-nitrosamine impurities by providing guidance and regular updates to drug manufacturers and applicants. Similarly, drug manufacturers should be more vigilant to avoid nitrosating agents and secondary amines during the manufacturing processes. Numerous review articles have been published recently by various researchers, focusing on N-nitrosamine impurities found in previously notified products, including sartans, metformin, and ranitidine. These impurities have also been detected in a wide range of other products. Consequently, this review aims to concentrate on products recently reported to contain N-nitrosamine impurities. These products include rifampicin, champix, famotidine, nizatidine, atorvastatin, bumetanide, itraconazole, diovan, enalapril, propranolol, lisinopril, duloxetine, rivaroxaban, pioglitazones, glifizones, cilostazol, and sunitinib.

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.

Selection of yeast strains in naturally fermented cured meat as promising starter cultures for fermented cured beef, a traditional fermented meat product of northern China

BACKGROUND

Fermented meat products are meat products with a unique flavor, color, and texture as well as an extended shelf life under natural or artificially controlled conditions. Microorganisms or enzymes are used to ferment the raw meat so that it undergoes a series of biochemical and physical changes. Common fermentation strains are lactic acid bacteria, yeasts, staphylococci, molds, and so forth. Studies on the inhibitory effect of yeast fermentation strain on N-nitrosamines in fermented meat products have not been reported. Two excellent yeast starters were identified to solve the problem of nitrosamines in fermented meat products.

RESULTS

Meyerozyma guilliermondii and Debaryomyces hansenii led to weak acid production, strong resistance to NaCl and NaNO2 , and high tolerance to low acidic conditions. The inoculated fermented beef exhibited decreased lightness, moisture content, water activity, pH, protein content, nitrite content, and N-nitrosamine content in comparison with the control group fermented bacon. M. guilliermondii had a better effect, reducing pH from 5.69 to 5.41, protein content from 254.24 to 221.92 g·kg-1 , nitrite content from 28.61 to 25.33 mg·kg-1 and N-nitrosamine by 18.97%, and giving the fermented beef the desired meat color, mouthfeel, odor, taste, and tissue quality.

CONCLUSION

In this study, two strains of yeast fermenters that can degrade N-nitrosamine precursors were identified, which to some extent solves the problem of the high risk of generating nitrosamines such as N-nitrosodiethylamine (NDEA) by processing fermented meat products with nitrites as precursors. These two strains are likely to be used as starter cultures for fermented meat products. © 2023 Society of Chemical Industry.

LC-MS/MS Investigation of nitrosamine impurities in certain Sartan group medicinal products available in Istanbul, Türkiye

Nitrosamines (NAs) are molecules that include the nitroso functional group. In 2018, the US Food and Drug Administration (FDA) received its first report of NAs in pharmaceuticals. The fact that NA impurities are likely human carcinogens is relevant to these compounds. Furthermore, prolonged exposure to NA contaminants above safe limits may raise the risk of cancer. The goal of this article was to assess the amounts of six different NAs in Sartan group medicines purchased from formal pharmacies in Istanbul, Türkiye, using a validated LC-MS/MS assay. An LC-MS/MS-based analytical assay was undertaken. The separation was performed with a HR ODS 150mm×3.0mm and 5-analytical columns, providing effective separation of major peaks from NA impurities. In mobile phase A, formic acid was 0.10% in water, while in mobile phase B, formic acid was 0.10% in methanol. The flow rate was 0.4mL/minute, and the total runtime was 18minutes with the gradient elution mode. The validation was conducted in line with ISO/IEC 17025 requirements. Up to 100μg/L, linearity was determined using correlation coefficients (r2>0.995) for all NAs. The limit of quantification values for all NAs analyses were below 1.0μg/L. The mean recovery value obtained during the spike experiment was 95.18%, demonstrating the accuracy of the procedure. In addition, the accuracy was shown by a certified reference analysis, which yielded relative standard deviation and relative error values of 1.82% and 3.34%, respectively. During the intermediate precision testing, bias and relative standard deviation were 0.96 and 2.87%, respectively. Of the 75 study samples involving Sartan group medical products, no nitrosamine impurities were detected, demonstrating that pharmaceutical companies have adequate medication safety precautions in place in accordance with FDA and European Medicines Agency (EMA) regulations published to prevent NA contaminants in human medicinal products.

Revisiting the Landscape of Potential Small and Drug Substance Related Nitrosamines in Pharmaceuticals

N-Nitrosamines are a class of indirect acting mutagens, as their metabolic degradation leads to the formation of the DNA-alkylating diazonium ion. Following up on the in-silico identification of thousands of nitrosamines that can potentially be derived from small molecule drugs and their known impurities described in a previous publication, we have now re-analyzed this dataset to apply EMA's Carcinogenic Potency Categorization Approach (CPCA) introduced with the 16th revision of their Q&A document for Marketing Authorization Holders. We find that the majority of potential nitrosamines from secondary amine precursors belongs to potency categories 4 and 5, corresponding to an acceptable daily intake of 1500 ng, whereas nitrosamines from tertiary amine precursors distribute more evenly among all categories, resulting in a substantial number of structures that are assigned the more challenging acceptable intakes of 18 ng/day and 100 ng/day for potency categories 1 and 2, respectively. However, the nitrosative dealkylation pathway for tertiary amine is generally far slower than the direct nitrosation on secondary amines, with a direct nitrosation mechanism suspected only for structures featuring electron-rich (hetero)aromatic substituents. This allows for greater focus towards those structures that require further review, and we demonstrate that their number is not substantial. In addition, we reflect on the nitrosamine risk posed by secondary amine API impurities and demonstrate that based on the ICH Q3A/B identification threshold unknown impurities may exist that could be transformed to relevant amounts of NA. We also demonstrate that the analytical sensitivity required for the quantification of high potency nitrosamines can be problematic especially for high dose APIs. In summary, the regulatory framework rolled out with the latest Q&A document represents a substantial improvement compared with the previous situation, but further refinement through interaction between manufacturers, regulators, not-for-profit and academic institutions will be required to ensure patient access to vital medicines without compromising safety.

Bumetanide as a Model NDSRI Substrate: N-nitrosobumetanide Impurity Formation and its Inhibition in Bumetanide Tablets

Nitrosamine compounds are classified as potential human carcinogens, the origin of these impurities can be broadly classified in two categories, nitrosamine impurity found in drug products that are not associated with the Active Pharmaceutical Ingredient (API), such as N-nitrosodimethylamine (NDMA) or nitrosamine impurities associated with the API, such as nitrosamine drug substance-related impurities (NDSRIs). The mechanistic pathway for the formation of these two classes of impurities can be different and the approach to mitigate the risk should be tailored to address the specific concern. In the last couple of years number of NDSRIs have been reported for different drug products. Though, not the only contributing factor for the formation of NDSIRs, it is widely accepted that the presence of residual a nitrites/nitrates in the components used in the manufacturing of the drug products can be the primary contributor to the formation of NDSRIs. Approaches to mitigate the formation of NDSRIs in drug products include the use of antioxidants or pH modifiers in the formulation. The primary objective of this work was to evaluate the role of different inhibitors (antioxidants) and pH modifiers in tablet formulations prepared in-house using bumetanide (BMT) as a model drug to mitigate the formation of N-nitrosobumetanide (NBMT). A multi-factor study design was created, and several bumetanide formulations were prepared by wet granulation with and without sodium nitrite spike (100 ppm) and different antioxidants (ascorbic acid, ferulic acid or caffeic acid) at three concentrations (0.1%, 0.5% or 1% of the total tablet weight). Formulations with acidic and basic pH were also prepared using 0.1 N hydrochloric acid and 0.1 N sodium bicarbonate, respectively. The formulations were subjected to different storage (temperature and humidity) conditions over 6 months and stability data was collected. The rank order of N-nitrosobumetanide inhibition was highest with alkaline pH formulations, followed by formulations with ascorbic acid, caffeic acid or ferulic acid present. In summary, we hypothesize that maintaining a basic pH or the addition of an antioxidant in the drug product can mitigate the conversion of nitrite to nitrosating agent and thus reduce the formation of bumetanide nitrosamines.

Simultaneous analysis of carcinogenic N-nitrosamine impurities in metformin tablets using on-line in-tube solid-phase microextraction coupled with liquid chromatography-tandem mass spectrometry

Contamination of active pharmaceutical ingredients (APIs) and pharmaceutical preparations with carcinogenic N-nitrosamines has led to recalls of these products and supply shortages to patients. The present study describes the development of a highly sensitive method for simultaneous analysis of seven N-nitrosamines using on-line in-tube solid-phase microextraction (IT-SPME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine their actual contamination in metformin tablets. Using a Carboxen 1006 PLOT capillary as the extraction device for IT-SPME, these compounds were efficiently extracted and concentrated 6‒24-fold by subjecting 40 µL of sample to 25 repeated draw/eject cycles at a rate of 0.2 mL/min. The seven N-nitrosamines were separated within 11 min by gradient elution with 0.1 % formic acid solution and acetonitrile as the mobile phase using a CAPCELL PAK C18 MGII column and detected by multiple reaction monitoring in positive ion mode. The calibration curve showed linearity in the range 0.2‒50 ng/mL and detection limits (S/N = 3) in the range 3‒112 pg/mL. The intra-day and inter-day precisions were less than 5.5 % and 7.0 % (n = 6), respectively, with accuracies ranging from 93‒117 %. Following ultrasonic extraction with water, centrifugation and filtration of the supernatant liquid through a membrane filter, the N-nitrosamine impurities in metformin tablets could be analyzed by IT-SPME/LC‒MS/MS. Their limits of quantification (S/N = 10) were 0.1‒5.1 pg/mg API and recoveries ranged from 87‒102 %. Analysis of eight metformin tablets from eight manufacturers showed that 5.8‒7.5 pg/mg N-nitrosodimethylamine were present in three tablets, with no other N-nitrosamines detected in any of the eight tablets. This method may be useful in testing for N-nitrosamine impurities in pharmaceutical preparations.

Nitrosamine Impurities in Herbal Formulations: A Review of Risks and Mitigation Strategies

Nitrosamines are a class of chemical compounds that have been found to be impurities in a variety of pharmaceutical products. These impurities have raised concerns due to their potential carcinogenic effects. Recent studies have identified nitrosamines as impurities in a number of pharmaceutical products including angiotensin II receptor blockers (ARBs) and proton pump inhibitors (PPIs). The presence of nitrosamines in these products has led to recalls and market withdrawals. In addition to pharmaceuticals, nitrosamines have also been found in some herbal medicines particularly those containing traditional Chinese medicinal ingredients. The presence of nitrosamines in herbal formulations poses a significant risk to public health and highlights the need for quality control and regulations in the herbal drug industry. The present review article aims to discuss nitrosamine impurities (NMI) prominent causes, risks and scientific strategies for preventing NMI in herbal formulations. The primary objective of this study is to examine the origins of nitrosamine contamination in herbal formulations, the risks associated with these contaminants, and the methods for reducing them. The significance of thorough testing and examination before releasing herbal products to the public is also emphasized. In conclusion, the presence of nitrosamines is not limited to pharmaceutical products and poses a significant threat to the safety of herbal drugs as well. Adequate testing and extensive research are crucial for producing and distributing herbal medicines to the general population.

On the Risk of Nitrosamine Contamination During Drug Product Blister Packaging

Most N-Nitrosamine compounds are found to be genotoxic in several animal species. Some are classified as probable or possible human carcinogens and very low acceptable daily intake has been established such as 96 ng/day for N-nitrosodimethylamine (NDMA) and 26.5 ng/N-nitrosodiethylamine (NDEA). The pharmaceutical industry has considered all processing areas for potential formation or contamination of N-nitrosamine. One risk is the potential contamination of nitrosamine during drug product blister packaging using lidding foils containing nitrocellulose, and different approaches have been used by pharmaceutical companies to evaluate and mitigate this risk. Herein we share a perspective from IQ Consortium N-nitrosamine Working Group on some of the approaches and corresponding results. From these assessments, it was concluded that the risk of nitrosamine contamination during blister packaging is negligible. The approaches shared in this perspective can be incorporated into risk assessment for nitrosamine contamination during drug product packaging at other pharmaceutical companies.

Method for trace determination of N-nitrosamines impurities in metronidazole benzoate using high-performance liquid chromatography coupled with atmospheric-pressure chemical ionization tandem mass spectrometry

Genotoxic impurity control has been a great concern in the pharmaceutical industry since the recall of the large round of sartans worldwide in 2018. In these sartans, N-nitrosamines were the main contaminants in active pharmaceutical ingredients and formulations. Numerous analytical methods have been developed to detect N-nitrosamines in food, drugs, and environmental samples. In this study, a sensitive method is developed for the trace determination of N-nitrosamine impurities in metronidazole benzoate pharmaceuticals using high-performance liquid chromatography/atmospheric-pressure chemical ionization tandem mass spectrometry in the multiple reaction monitoring mode. The method was validated regarding system suitability, selectivity, linearity, accuracy, precision, sensitivity, solution stability, and robustness. The method showed good linearity with R² ≥ 0.999 and F_Mandel  < F_tab(95%) ranging from 0.33 to 8.00 ng/ml. The low limits of detection of N-nitrosamines were in the range of 0.22-0.80 ng/ml (0.0014-0.0050 ppm). The low limits of quantification were in the range of 0.33-1.20 ng/ml (0.0021-0.0075 ppm), which were lower than the acceptable limits in metronidazole benzoate pharmaceuticals and indicated the high sensitivity of the method. The recoveries of N-nitrosamines ranged from 84% to 97%. Thus, this method exhibits good selectivity, sensitivity, and accuracy. Moreover, it is a simple, convenient, and scientific strategy for detecting N-nitrosamine impurities in pharmaceuticals to support the development of the pharmaceutical industry.

Current status and prospects of development of analytical methods for determining nitrosamine and N-nitroso impurities in pharmaceuticals

Nitrosamine impurities in pharmaceuticals have recently been concerned for several national regulatory agencies to avoid carcinogenic and mutagenic effects in patients. The demand for highly sensitive and specific analytical methods with LOQs in the ppb and sub-ppb ranges is among the most significant challenges facing analytical scientists. In addition, artifactual nitrosamine formation during sample preparation and injection leading to overestimation of nitrosamines has received considerable attention. Numerous analytical methodologies have been reported for quantifying nitrosamine impurities in active pharmaceutical ingredients and medicinal products at the interim limit criteria as preventive measures. In this review, we meticulously discuss those reported gas and liquid chromatographic methods for nitrosamine determination in pharmaceuticals in aspects of chromatographic conditions and sensitivity of detection. We also introduce the potential of novel fluorescence-based methods recently developed to rapidly screen nitrosamine impurities. In addition, the review assesses the nitrosation assay procedure (NAP test), which is expected to be a future preventive measure for screening potential nitrosation and identifying suspected contamination with N-nitroso or other potential mutagenic impurities during the drug development process.

Investigation of Carcinogenic Impurities of N-Nitrosamines in Sartan Pharmaceutical Products Marketed in Brazil: Development and Validation of Method Based on High-Performance Liquid Chromatography-Tandem Mass Spectrometry

N-nitrosamines (NA) impurities have unexpectedly been found in sartan products, angiotensin II receptor antagonists that are used to control hypertension, representing an urgent concern for industry, global regulators and for the patients. In this study, an HPLC-MS/MS method was developed and validated for the quantification of six NA (N-nitrosodimethylamine, N-Nitroso-N-methyl-4-aminobutyric acid, N-Nitrosodiethylamine, N-ethyl-N-nitroso-2-propanamine, N-nitroso-diisopropylamine and N-nitroso-di-n-butylamine) in losartan, valsartan, olmesartan, irbesartan, candesartan and telmisartan products. The method was validated in terms of sensitivity, linearity, accuracy, precision, robustness and stability. The limits of quantification were 100, 31.25, 250, 33, 312.5 and 125 µg kg^-1 in losartan, valsartan, olmesartan, irbesartan, candesartan and telmisartan samples, respectively, which met the sensitivity requirements for the limits set by Food and Drug Administration of the United States. The standard curves showed good linearity. The recoveries ranged from 93.06 to 102.23% in losartan matrix, 83 to 85.9% in valsartan, 96.1 to 101.2% in olmesartan, 89.2 to 97.5% in irbesartan, 93.4 to 132.0% in candesartan and 62.3 to 106.2% in telmisartan matrix. The other parameters met the validation criteria, the good sensitivity and precision, high accuracy and simple and fast analysis provides a reliable method for quality control of NA in sartan pharmaceutical products. The developed method was successfully applied for the determination of N-nitrosamines in 71 sartan products marketed in Brazil.

Thymol-Based Hydrophobic Deep Eutectic Solvents as a Green Approach for Screening Polar Nitrosamines in Sartans Pharmaceutical Products by Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Combined with HPLC-DAD

Nitrosamines are carcinogens substances firstly detected in sartans drugs in 2018, leading to new regulations and monitoring programmes that raised the costs and challenges to the pharmaceutical industry. Therefore, reliable and cost-effective methods for screening nitrosamines in medicines are highly desirable. Hydrophobic deep eutectic solvents (HDES), a novel "eco-friendly" alternative to solvents commonly used in microextraction techniques, can meet these requirements. In this study, a simple and rapid method of ultrasound-assisted dispersive liquid-liquid microextraction using thymol-based HDES followed by HPLC-DAD detection was developed for the determination of n-nitrosodimethylamine (NDMA) and n-nitroso-n-methylamino butyric acid (NMBA) from candesartan, irbesartan, losartan, olmesartan, telmisartan and valsartan drug substances, and from losartan tablets. Various influencing factors (such as HDES type, HDES:sample ratio, salt addition and sample pH) were investigated. Best extraction efficiencies were achieved with thymol:benzyl alcohol HDES. Under optimal conditions, the linearities ranged from 15 to 1000 ng mL^-1 for both NDMA and NMBA (R² > 0.99), with recoveries between 81.8-104.2% and precision from 0.2 to 14.6%. The limits of detection were 17.3 - 220.0 ng g^-1 and 16.3 - 290.0 ng g^-1 for NDMA and NMBA, consecutively. Finally, the proposed method was successfully applied in spiked sartans drug substances and in losartan potassium tablets collected in the market.

Absolute Quantitation of N-Nitrosamines by Coulometric Mass Spectrometry without Using Standards

Carcinogenic N-nitrosamines were recently found in the sartan family of drugs and caused many drug recalls. Both of their detection and quantification are therefore important. Methods reported for N-nitrosamine quantitation rely on the use of standards and are just applicable to simple N-nitrosamines. There is an urgent need to quantify N-nitrosamines derived from drugs with a complicated structure that lack standards. To tackle the issue, this study describes a novel absolute quantitation strategy for N-nitrosamines using coulometric mass spectrometry (CMS) without standards. In our approach, N-nitrosamine is first converted into electrochemically active hydrazine via zinc reduction under acidic condition and the resulting hydrazine can then be easily quantified using CMS. To validate our method, six simple N-nitrosamines, N-nitrosodiethylamine (NDEA), N-nitroso-4-phenylpiperidine (NPhPIP), N-nitrosodiphenylamine (NDPhA), N-nitrosodibutylamine (NDBA), N-nitrosodipropylamine (NDPA), and N-nitrosopiperidine (NPIP), were chosen as test samples, and they all were quantified with excellent measurement accuracy (quantitation error ≤1.1%). Taking this one step further, as a demonstration of the method utility, a drug-like N-nitrosamine, (R)-N-(2-(6-chloro-5-methyl-1'-nitroso-2,3-dihydrospiro[indene-1,4'-piperidin]-3-yl)propan-2-yl)acetamide (VII), was also synthesized and successfully quantified using our method at 15 ppb level in a complex formulation matrix, following solvent extraction, N-nitrosamine isolation, and reductive conversion. Because of the feature of requiring no standards, CMS provides a simple and powerful approach for N-nitrosamine absolute quantitation and has great potential for analysis of other drug impurities or metabolites.