Trace Level Quantification of 4-Methyl-1-nitrosopiperazin in Rifampicin Capsules by LC-MS/MS

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.

Investigation into the genotoxic impurity, 1-methyl-4-nitrosopiperazine, in rifampicin

This study assessed the presence of the genotoxic impurity 1-methyl-4-nitrosopiperazine (MNP) in 27 batches of rifampicin capsules obtained from 11 manufacturers in China. While they were below the temporary limit of 5 ppm set by the US Food and Drug Administration, the observed levels (0.33-2.36 ppm) exceeded the acceptable threshold of 0.16 ppm. Building upon preliminary findings and degradation experiments, we concluded that MNP is a by-product of the oxidative degradation of rifampicin or is introduced via oxidation or nitrosation during the synthesis process involving 1-methyl-4-aminopiperazine. The pathways of MNP formation were confirmed in this study. Furthermore, we observed that the addition of antioxidants, sealed storage, and selection of dominant crystal forms can aid in controlling MNP levels.

Quantification of oxaliplatin- and ioversol-related compounds in pharmaceutical formulations using novel HPLC-ICP-MS methods

PURPOSE

Accurate quantifying of drug-related compounds in medicines is vital for safety. Commonly used structure-dependent methods rely on analytical standards. High-performance liquid chromatography coupled with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) offers a promising solution, being structure-independent and not requiring standards. In this study, we aim to develop HPLC-ICP-MS methods for the determination of related compounds in oxaliplatin and ioversol injections.

RESULTS

The target analytes were eluted on an XSelect HSS T3 column (2.1 ×50 mm, 5 µm). Specifically, oxaliplatin injection was eluted isocracially for 3.5 min, and ioversol injection was eluted gradient with a total chromatographic run time of 12 min. The measurements to determine dihydroxy oxaliplatin-Pt(IV) and two related compounds of ioversol were performed by monitoring at m/z for 195Pt and 127I, respectively. The calibration curves were established over the range of 0.05-1 μM for Pt and 0.3-15 μM for I with the correlation coefficients greater than 0.999. The limits of quantification were 0.004 μM for dihydroxy oxaliplatin-Pt(IV), 0.022 μM for ioversol related compound A and 0.026 μM for ioversol related compound B. The accuracy (recovery between 93-105%) and precision (repeatability ≤ 6.1% RSD) were fit-for-purpose for dihydroxy oxaliplatin-Pt(IV), and the accuracy (recovery between 95-107%) and precision (repeatability ≤ 3.9% RSD) were also fit-for-purpose for both ioversol related compound A and ioversol related compound B.

CONCLUSION

The quantitation accuracy of HPLC-ICP-MS closely matched that of the standard HPLC-UV approach. HPLC-ICP-MS can be used as a complementary analytical technique for quantitative determination of drug-related compounds.

Determination of Aflatoxin B1 in Grains by Aptamer Affinity Column Enrichment and Purification Coupled with High Performance Liquid Chromatography Detection

Aflatoxin B1 (AFB1) is a highly teratogenic and carcinogenic secondary metabolite produced by Aspergillus. It is commonly detected in agricultural products such as cereals, peanuts, corn, and feed. Grains have a complex composition. These complex components severely interfere with the effective extraction and separation of AFB1, and also cause problems such as matrix interference and instrument damage, thus posing a great challenge in the accurate analysis of AFB1. In this study, an aptamer affinity column for AFB1 analysis (AFB1-AAC) was prepared for the enrichment and purification of AFB1 from grain samples. AFB1-AAC with an AFB1-specific aptamer as the recognition element exhibited high affinity and specificity for AFB1. Grain samples were enriched and purified by AFB1-AAC, and subsequently analyzed by high performance liquid chromatography with post-column photochemical derivatization-fluorescence detection (HPLC-PCD-FLD). The average recoveries of AFB1 ranged from 88.7% to 99.1%, with relative standard deviations (RSDs) of 1.4-5.6% (n = 3) at the spiked levels of 5.0-20.0 μg kg-1. The limit of detection (LOD) for AFB1 (0.02 μg kg-1) was much below the maximum residue limits (MRLs) for AFB1. This novel method can be applied to the determination of AFB1 residues in peanut, corn, and rice.

A comprehensive LC-UHPLC-MS/MS method for the monitoring of N-nitrosamines in lipophilic drugs: A case study with rifampicin

In the last five years, the presence of N-nitrosamines in commonly used medicines has become a significant concern for patients, physicians, and the pharmaceutical industry, due to their carcinogenic properties, even at low concentrations. Analytical methods that enable the unequivocal monitoring of these compounds, with low detection limits and covering a range of drugs, are indispensable. The present work proposes a bidimensional liquid chromatography-tandem mass spectrometry method capable of quantifying eleven N-nitrosamines in lipophilic active pharmaceutical ingredients (APIs). The API is retained in the first chromatographic dimension, while the fraction containing the N-nitrosamines is transferred to the second chromatographic dimension and, after separation, to the mass spectrometer. The logP values for the APIs and N-nitrosamines enabled prediction of the APIs that could be separated from the target analytes. The method was validated and successfully applied for the quantification of 1-methyl-4-nitroso piperazine (MNP) and N-nitrosodimethylamine (NDMA) in rifampicin, a drug used to treat tuberculosis. Although NDMA was not detected in two pharmaceutical analyzed, MNP was found at concentrations of 0.44 ± 0.05 and 2.1 ± 0.3 µg g-1. Given the ability to apply the method to various APIs, together with its reliance solely on logP values for determining suitability, the proposed technique could be extended to the determination of N-nitrosamines in other drugs besides rifampicin.

Development and Validation of LC-MS/MS Method for the Determination of 1-Methyl-4-Nitrosopiperazine (MNP) in Multicomponent Products with Rifampicin-Analytical Challenges and Degradation Studies

Rifampicin is an essential medicine for treating and preventing tuberculosis (TB). TB is a life-threatening infectious disease and its prevention and treatment are public health imperatives. In the time of a global crisis of nitrosamine contamination of medicinal products, patient safety and a reduction in the number of drug recalls at the same time are crucial. In this work, the LC-MS/MS method was developed for the determination of the 1-methyl-4-nitrosospiperazine (MNP), a genotoxic nitrosamine impurity in various products containing rifampicin at a 5.0 ppm limit level according to Food and Drug Administration (FDA). Extraction with neutralization was necessary due to the matrix and solvent effect associated with the complexity of the rifampicin product. The developed method was validated in accordance with regulatory guidelines. Specificity, accuracy, precision, limit of detection, and limit of quantification parameters were evaluated. The recovery of the MNP was 100.38 ± 3.24% and the intermediate precision was 2.52%. The contamination of MNP in Rifampicin originates in the manufacturing process of the drug. Furthermore, the results of the forced degradation experiments show that the formation of MNP is possible by two mechanisms: through degradation of rifampicin and the oxidation of 1-amino-4-methyl-piperazine. This article points out that it is necessary to monitor and describe degradation products and the mechanism of degradation of potentially affected active pharmaceutical ingredient (API) with respect to the formation of nitrosamines during stress testing, as it was done in the following work for rifampicin in multicomponent products.

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.

Development of a Sensitive Screening Method for Simultaneous Determination of Nine Genotoxic Nitrosamines in Active Pharmaceutical Ingredients by GC-MS

A worldwide crisis with nitrosamine contamination in medical products began in 2018. Therefore, trace-level analysis of nitrosamines is becoming an emerging topic of interest in the field of quality control. A novel GC-MS method with electron ionization and microextraction was developed and validated for simultaneous determination of nine carcinogenic nitrosamines (NDMA, NMEA, NDEA, NDBA, NMOR, NPYR, NPIP, NDPA, and N-methyl-npz) in active pharmaceutical ingredients (APIs): cilostazol, sunitinib malate, and olmesartan medoxomil. The method was validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines, demonstrating good linearity in the range of LOQ up to 21.6 ng/mL (120% of specification limit). The limits of detection for the nine nitrosamines were determined to be in the range 0.15–1.00 ng/mL. The developed trace level GC-MS method turned out to be specific, accurate, and precise. The accuracy of all the tested APIs ranged from 94.09% to 111.22% and the precision evaluated by repeatability, intermediate precision, and system precision was RSD ≤ 7.65%. Nitrosamines were not detected in cilostazol and sunitinib, whereas in olmesartan medoxomil NDEA was detected at the level of LOQ. The novel protocol was successfully applied for nitrosamines determination in selected APIs and can be used for the routine quality control of APIs under Good Manufacturing Practices rules, ensuring the safety and effectiveness of pharmaceutical products.