N-Nitrosodimethylamine formation in metformin hydrochloride sustained-release tablets: Effects of metformin and hypromellose used in drug product formulation

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.

Exploiting of Green Synthesized Metal Oxide Nanoparticles in the Potentiometric Determination of Metformin Hydrochloride in Pharmaceutical Products

The advanced and highly functional properties of Al2O3 and NiO nanoparticles promote the widespread use of metal oxides as remarkable electroactive materials for sensing and electrochemical applications. The proposed study describes a comparison of the sensitivity and selectivity of two modified wire membrane sensors enriched with Al2O3 and NiO nanoparticles with conventional wire membranes for the quantification of the antidiabetic drug metformin hydrochloride (MTF). The results show linear relationships of the enriched Al2O3 and NiO nanosensors over the concentration ranges 1.0 × 10-10-1.0 × 10-2 mol L-1 and 1.0 × 10-6-1.0 × 10-2 M for both the modified sensors and the conventional coated wire membrane sensors. The regression equations were EmV = (52.1 ± 0.5) log (MTF) + 729 for enriched nanometallic oxides, EmV = (57.04 ± 0.4) log (MTF) + 890.66, and EmV = (58.27 ± 0.7) log (MTF) + 843.27 with correlation coefficients of 0.9991, 0.9997, and 0.9998 for the aforementioned sensors, respectively. The proposed method was fully validated with respect to the recommendations of the International Union of Pure and Applied Chemistry (IUPAC). The newly functionalized sensors have been successfully used for the determination of MTF in its commercial products.

Simple and Practical Method for the Quantitative High-Sensitivity Analysis of N-Nitroso Duloxetine in Duloxetine Drug Products Utilizing LC-MS/MS

The high-sensitivity analytical method for the determination of N-nitroso duloxetine (NDXT), which can be carcinogenic and harmful in duloxetine drug products, was successfully developed utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS). Tandem mass spectrometric detection at positive electrospray ionization in multiple reaction monitoring (MRM) mode was then employed for the determination of NDXT. The quantitative range for NDXT was found in 0.075-3.75 ng/mL in terms of concentration in the dilution solvent for duloxetine active pharmaceutical ingredient (API) and capsules and 0.075-1.875 ng/mL for duloxetine tablets, and the recovery rates were in the range of 82.5-91.6% for the API, 91.0-113.4% for capsules, and 70.6-109.1% for tablets, respectively. The repeatability was 6.9% with a %RSD of n = 9 for the API, 10.9% with a %RSD of n = 9 for capsules, and 21.6% with a %RSD of n = 9 for tablets, respectively. For reproducibility, the %RSD of the n = 6 measurements between the two sites was 3.5%. The calibration curve of NDXT in the concentration range of 0.075-3.75 ng/mL was carried out, and the correlation coefficient (R) was found to be 1.000. The sample solution was stable for 7 days. The applicability of the determination of the content of NDXT in a variety of duloxetine drug products was demonstrated. This manuscript seeks to aid the risk assessment process of NDXT in duloxetine drug products through providing a fast and reliable quantitative LC-MS/MS analytical method.

Patient In-Use Stability Testing of FDA-Approved Metformin Combination Products for N-Nitrosamine Impurity

Between February 2020 and January 2022, the Food and Drug Administration (FDA) recalled 281 metformin extended-release products due to the presence of N-nitrosodimethylamine (NDMA) above the acceptable daily intake (ADI, 96 ng/day). Our previous studies indicated presence of NDMA levels above ADI in both metformin immediate and extended-release products. When metformin products have NDMA impurities, it is indispensable to check for the same impurities in metformin combination products. Therefore, the objective of the present study was to evaluate in-use stability of commercial metformin combination products for NDMA. For this purpose, metformin products in combination with glyburide (GB1-GB12), glipizide (GP1-GP8), pioglitazone (P1-P3), alogliptin (A1, A2), and linagliptin (L1, L2) were repacked in pharmacy vials, stored at 30°C/75% RH for 3 months, and monitored for NDMA impurity. The NDMA level varied from 0 to 156.8 ± 32.8 ng/tablet initially and increased to 25.4 ± 5.1 to 455.0 ± 28.4 ng/tablet after 3 months of exposure to in-use condition. Initially, 18 products have NDMA level below ADI limit before exposure which decreased to 7 products (GB5, GP3, GP5, A1, A2, L1, and L2) meeting specification. In conclusion, in-use stability study provides quality and safety risk assessment of drug products where nitroso impurities are detected in the probable condition of use.

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.

Dispersant-First Dispersive Liquid-Liquid Microextraction (DF-DLLME), a Novel Sample Preparation Procedure for NDMA Determination in Metformin Products

Since December 2019, global batch recalls of metformin pharmaceutical products have highlighted an urgent need to control N-nitrosodimethylamine (NDMA) contamination to demonstrate patient safety and maintain supply of this essential medicine. Due to their formulation, the metformin extended-release products present difficult analytical challenges for conventional sample preparation procedures, such as artefactual (in-situ) NDMA formation, gelling, and precipitation. To overcome these challenges, a new version of dispersive liquid-liquid microextraction (DLLME) termed dispersant-first DLLME (DF-DLLME) was developed and optimized for the analysis of NDMA in metformin extended-release products using a detailed Design of Experiments (DoE) to optimize sample preparation. Gas chromatography-high resolution accurate mass-mass spectrometry (GC-HRAM-MS) combined with automated DF-DLLME were successfully applied to monitor the NDMA levels of two different metformin extended-release AstraZeneca products to ultra-trace levels (parts per billion). The additional benefits associated with DF-DLLME, which include automation, time/costs saving, and greener sample preparation, make this novel technique easier to transfer from a development to Quality Control (QC) environment. In addition, this also offers an attractive candidate for the wider platform analysis of N-nitrosamines in pharmaceutical drug products.

Modeling the Impact of Excipients Selection on Nitrosamine Formation towards Risk Mitigation

Risk control for nitrosamine impurities in drug products is currently a major challenge in the industry. Nitrosamines can form during drug product manufacturing and storage through the reaction of nitrites with amine-containing APIs or impurities. The level of nitrites in excipients and the rate of reaction often control the build-up of nitrosamine. Although the variability in nitrite levels across excipient types and suppliers is well recognized, the impact of excipient selection on the level of nitrosamine formed has not been systematically studied. This gap of knowledge is addressed in the current work. We present theoretical case studies of formulations where microcrystalline cellulose (MCC), or lactose supplier, or superdisintegrant type are changed in pursuit of lower levels of nitrite. The impact of the average, maximum, and minimum levels of nitrites in each excipient on nitrosamine formation in the dosage form is calculated. The input data for this calculation are the formulation composition, nitrosamine molecular weight (MW), percentage of conversion, and nitrite levels per excipient. The percentage of conversion (based on the formulation and manufacturing variables) and nitrite levels were taken from the recent literature. We show that changing the supplier of a single excipient, or of the three most critical excipients, can reduce nitrosamine formation by up to -59% and -89%, respectively. We also show that high-risk formulations, e.g., high MW nitrosamines, high dosage weights, and high percentages of conversion (e.g., wet granulation), can often be de-risked below regulatory acceptable daily intake via careful excipient selection. Finally, we provide an open-access tool that enables users to calculate the theoretical formation of nitrosamines in their specific formulations. This calculation template can be used for (i) the preliminary screening of the risk of nitrosamine formation in drug products and (ii) the preliminary assessment of the impact of excipient selection for risk mitigation.

Nitrosated Active Pharmaceutical Ingredients - Lessons Learned?

The occurrence of N-nitrosodialkylamines in active pharmaceutical ingredients (APIs) and drug products in the last years was a kind of eye opener with regard to quality of drugs. We became aware of the fact that quality control tests described in the international pharmacopoeias might not be sufficient. The N-nitrosodialkylamines found were neither so-called (structurally) related substances, nor residual solvents or heavy metals; hence they were not limited by a compendial test, but by the ICH guideline M7 of mutagenic impurities. Additionally, nitrosamine drug-substance-related impurities (NDSRIs) were detected, mostly within the process of risk assessment required by regulatory authorities. Here, the APIs containing a vulnerable amino moiety had reacted with nitrites being a contaminant of an excipient. This review deals with the formation, toxicity, and mitigation of NDSRISs.

The Landscape of Potential Small and Drug Substance Related Nitrosamines in Pharmaceuticals

This article reports the outcome of an in silico analysis of more than 12,000 small molecule drugs and drug impurities, identifying the nitrosatable structures, assessing their potential to form nitrosamines under relevant conditions and the challenges to determine compound-specific AIs based on data available or read-across approaches for these nitrosamines and their acceptance by health authorities. Our data indicate that the presence of nitrosamines in pharmaceuticals is likely more prevalent than originally expected. In total, 40.4 % of the analyzed APIs and 29.6 % of the API impurities are potential nitrosamine precursors. Most structures identified through our workflow could form complex API-related nitrosamines, so-called nitrosamine drug substance related impurities (NDSRIs), although we also found structures that could release the well-known small and potent nitrosamines NDMA, NDEA, and others. Due to common structural motifs including secondary or tertiary amine moieties, whole essential drug classes such as beta blockers and ACE inhibitors are at risk. To avoid the risk of drug shortages or even the complete loss of therapeutic options, it will be essential that the well-established ICH M7 principles remain applicable for nitrosamines and that that the industry and regulatory authorities keep an open communication not only about the science but also to make sure there is a good balance between risk and benefit to patients.