Understanding the molecular-pharmaceutical basis of sartan recalls focusing on valsartan

A collaborative study of the impact of N-nitrosamines presence and ARB recall on ARB utilization - results from IQVIA™ Disease Analyzer Germany

PURPOSE

Regulators are increasingly concerned with  the impact of recalls on drug adherence. In 2018, N-nitrosamines impurities were detected in valsartan containing medical products. Concerned products were immediately recalled in July 2018 by regulatory agencies internationally. In Germany, recalls were issued for valsartan, losartan and irbesartan from July 2018 to March 2019. This study examined angiotensin II receptor blocker (ARB) utilization trends and switching patterns in Germany before and after July 2018.

METHODS

Patients prescribed ARBs from January 2014 to June 2020 in general practices in Germany were included in a collaborative framework common protocol drug utilization study led by the US Food and Drug Administration. Trends in monthly and quarterly proportions of total ARB prescribing were analysed for individual ARBs using descriptive statistics and interrupted time series analysis. The rate of switching to an alternative ARB was analysed before and after the recalls.

RESULTS

The proportion of valsartan prescriptions immediately decreased from 35.9 to 17.8% following the first recalls in July 2018, mirrored by an increased proportion for candesartan. Increased switching from valsartan to candesartan was observed. No increased switching was observed after losartan recalls, whereas for irbesartan, increased switching was observed 6-12 months after the last recall. Increased switching from ARBs to angiotensin-converting enzyme (ACE) inhibitors or ARB treatment discontinuations were not observed.

CONCLUSION

This study showed that patients were able to continue ARB treatment despite the July 2018-March 2019 recalls, although many patients needed to switch to an alternative ARB. The duration of the impact of ARB recalls appeared to be limited.

Does the Red Shift in UV-Vis Spectra Really Provide a Sensing Option for Detection of N-Nitrosamines Using Metalloporphyrins?

N-nitrosamines are widespread cancerogenic compounds in human environment, including water, tobacco products, food, and medicinal products. Their presence in pharmaceuticals has recently led to several recalls of important medicines from the market, and strict controls and tight limits of N-nitrosamines are now required. Analytical determination of N-nitrosamines is expensive, laborious, and time-inefficient making development of simpler and faster techniques for their detection crucial. Several reports published in the previous decade have demonstrated that cobalt porphyrin-based chemosensors selectively bind N-nitrosamines, which produces a red shift of characteristic Soret band in UV-Vis spectra. In this study, a thorough re-evaluation of metalloporphyrin/N-nitrosamine adducts was performed using various characterization methods. Herein, we demonstrate that while N-nitrosamines can interact directly with cobalt-based porphyrin complexes, the red shift in UV-Vis spectra is not selectively assured and might also result from the interaction between impurities in N-nitrosamines and porphyrin skeleton or interaction of other functional groups within the N-nitrosamine structure and the metal ion within the porphyrin. We show that pyridine nitrogen is the interacting atom in tobacco-specific N-nitrosamines (TSNAs), as pyridine itself is an active ligand and not the N-nitrosamine moiety. When using Co(II) porphyrins as chemosensors, acidic and basic impurities in dialkyl N-nitrosamines (e.g., formic acid, dimethylamine) are also UV-Vis spectra red shift-producing species. Treatment of these N-nitrosamines with K₂CO₃ prevents the observed UV-Vis phenomena. These results imply that cobalt-based metalloporphyrins cannot be considered as selective chemosensors for UV-Vis detection of N-nitrosamine moiety-containing species. Therefore, special caution in interpretation of UV-Vis red shift for chemical sensors is suggested.

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

The ubiquitous presence of mutagenic and potentially carcinogenic N-nitrosamine impurities in medicines has become a major issue in the pharmaceutical industry in recent years. Rigorous mitigation strategies to limit their amount in drug products are, therefore, needed. The removal of nitrite, which is a prerequisite reagent for the N-nitrosation of amines, has been acknowledged as one of the most promising strategies. We have conducted an extensive literature search to identify nineteen structurally diverse nitrite scavengers and screened their activity experimentally under pharmaceutically relevant conditions. In the screening phase, we have identified six compounds that proved to have the best nitrite scavenging properties: ascorbic acid (vitamin C), sodium ascorbate, maltol, propyl gallate, para-aminobenzoic acid (PABA), and l-cysteine. These were selected for investigation as inhibitors of the formation of N-methyl-N-nitrosoaniline (NMA) from N-methylaniline and N-nitroso-N’-phenylpiperazine (NPP) from N-phenylpiperazine in both solution and model tablets. Much faster kinetics of NMA formation compared to NPP was observed, but the former was less stable at high temperatures. Vitamin C, PABA, and l-cysteine were recognized as the most effective inhibitors under most studied conditions. The nitrite scavenging activity does not directly translate into N-nitrosation inhibitory effectiveness, indicating other reaction pathways may take place. The study presents an important contribution to identifying physiologically acceptable chemicals that could be added to drugs to prevent N-nitrosation during manufacture and storage.

Implications of an epidemiological study showing an association between in utero NDMA exposure and childhood cancer

Exposure to N-nitrosodimethylamine (NDMA) has recently been linked to a childhood cancer cluster in Wilmington, MA, which is home to the Olin Chemical Superfund Site. When it was discovered in the 1990's that 22 children in a town of under 22,000 people got cancer, the community took action and pressed for an investigation into the possibility that chemicals from the Olin Chemical site had contaminated their water. This led to the eventual discovery that NDMA was present in the town water supply. NDMA has long been known for its potent carcinogenicity in animal models, and so the community pointed to NDMA as a possible cause. This led to an investigation by the Massachusetts Department of Public Health, which, in 2021, released its findings showing an association between NDMA exposure in utero and childhood cancer. The mission of the NIEHS Superfund Research Program is to protect human health from hazardous substances. In 2017, in response to community concerns, a team at MIT created the MIT Superfund Research Program Center with a focus on research related to NDMA. Just 1 week prior to the release of the Department of Public Health study, the MIT Superfund Research Program Center published a manuscript in Cell Reports that identifies the Alkyladenine DNA glycosylase (AAG) as a possible genetic susceptibility factor. This commentary provides an author's perspective on the context and implications of this and related research.