Safety vs price in the generic drug market: metformin.

OBJECTIVES: Generic medications represent 90% of prescriptions in the US market and provide a tremendous financial benefit for patients. Recently, multiple generic drugs have been recalled due to the presence of carcinogens, predominantly N-nitrosodimethylamine (NDMA), including an extensive recall of extended-release (ER) metformin products in 2020. STUDY DESIGN: Primary pharmaceutical quality testing and database analysis. METHODS: We tested marketed metformin immediate-release (IR) and ER tablets from a wide sample of generic manufacturers for the presence of carcinogenic impurities NDMA and N,N-dimethylformamide (DMF). We examined the association of level of impurity with drug price and the impact of the 2020 FDA recalls on unit price and prescription fill rate. RESULTS: Postrecall NDMA levels were significantly lower in metformin ER samples (standardized mean difference = -2.0; P = .01); however, we found continued presence of carcinogens above the FDA threshold in 2 of 30 IR samples (6.67%). Overall, the presence of contaminant levels was not significantly associated with price for either IR (NDMA: R2 = 0.142; P = .981; DMF: R2 = 0.382; P = .436) or ER (NDMA: R2 = 0.124; P = .142; DMF: R2 = 0.199; P = .073) samples. Despite recalls, metformin ER prescription fills increased by 8.9% while unit price decreased by 19.61% (P < .05). CONCLUSIONS: Recalls of metformin ER medications were effective in lowering NDMA levels below the FDA threshold; however, some samples of generic metformin still contained carcinogens even after FDA-announced recalls. The absence of any correlation with price indicates that potentially safer products are available on the market for the same price as poorer-quality products.

Development and validation of high-performance liquid chromatography-Orbitrap mass spectrometric method for quantification of NDMA in ranitidine drug products and evaluation of antioxidants as inhibitors of classical nitrosation reaction.

RATIONALE: N-Nitroso dimethylamine (NDMA) is a mutagenic impurity detected in several ranitidine products. The amino functional group of ranitidine is a risk factor for classical nitrosation-induced NDMA formation in ranitidine drug products during storage conditions. The United States Food and Drug Administration (US FDA) recommended the use of antioxidants to control NDMA in drug products. Considering the need for sensitive analytics, a liquid chromatography/high-resolution mass spectrometry (LC-HRMS) method was developed and validated to detect NDMA in this pilot study to demonstrate the antioxidants as inhibitors of nitrosation reactions. METHODS: The method, utilizing an EC-C18 column and tuned to atmospheric pressure chemical ionization/selected ion monitoring (APCI/SIM) mode, separated NDMA (m/z: 75.0553; tR: 3.71 min) and ranitidine (m/z: 315.1485; tR: 8.61 min). APCI mode exhibited four times higher sensitivity to NDMA than electrospray ionization (ESI) mode. Classical nitrosation of the dimethyl amino group of ranitidine was studied with sodium nitrite in solid pellets. Antioxidants (alpha-tocopherol, ascorbic acid, and trolox) were evaluated as NDMA attenuators in ranitidine pellets under vulnerable storage conditions. The developed method quantified NDMA levels in samples, extracted with methanol through vortex shaking for 45 min. RESULTS: The method achieved a limit of detection (LOD) and limit of quantitation (LOQ) of 0.01 and 0.05 ng/mL, respectively, with linearity within 1-5000 ng/mL (R1: 0.9995). It demonstrated good intra-day and inter-day precision (% RSD [relative standard deviation]: <2) and accuracy (96.83%-101.72%). Nitrosation of ranitidine induced by nitrite was significant (p < 0.001; R2 = 0.9579) at various sodium nitrite levels. All antioxidants efficiently attenuated NDMA formation during ranitidine nitrosation. Ascorbic acid exhibited the highest NDMA attenuation (96.98%), followed by trolox (90.58%). This study recommends 1% ascorbic acid and trolox as potent NDMA attenuators in ranitidine drug products. CONCLUSIONS: This study compared the effectiveness of antioxidants as NDMA attenuators in ranitidine under storage conditions susceptible to NDMA generation. The study concluded that ascorbic acid and trolox are potent inhibitors of NDMA formation and nitrosation attenuators in ranitidine drug products.

Animal Feedlots and Domestic Wastewater Discharges are Likely Sources of N-Nitrosodimethylamine (NDMA) Precursors in Midwestern Watersheds.

N-nitrosodimethylamine (NDMA) precursor concentrations along four major rivers in Minnesota, USA were quantified and correlated with watershed land cover types, anthropogenic activity, and organic matter characteristics. River water samples (36 in total) were chloraminated under uniform formation conditions (UFC) before and after lime-softening treatment, and the resulting NDMA concentrations were quantified (NDMAUFC). Regarding land cover, NDMAUFC in raw river water exhibited weak positive correlations with urban land (ρ = 0.33, p = 0.05) and cropland coverage (ρ = 0.35, p = 0.04). For anthropogenic activity, NDMAUFC in raw river water positively correlated with the number of feedlots (ρ = 0.57), total weight of animals (ρ = 0.68), and total number of domestic wastewater treatment plants (WWTPs; ρ = 0.63) with p < 0.01. NDMAUFC positively correlated with region IV fluorescence intensity from fluorescence excitation-emission spectra (ρ = 0.70, p < 0.01). Lime softening of river water typically increased NDMAUFC and preferentially removed organic matter that fluoresces in region V, suggesting that the organic matter in this region decreases NDMAUFC by competing for available chloramines. Overall, animal feedlots, along with domestic WWTPs, are predominant sources of NDMA precursors in the studied watersheds, while croplands and urban runoff are of lesser importance.

Impact of agricultural activities on the occurrence of N-nitrosamines in an aquatic environment.

N-Nitrosamines, nitroso compounds with strong carcinogenic effects on humans, have been frequently detected in natural waters. In agricultural areas, there is typically a lack of drinking water treatment processes and distribution systems. As a result, residents often consume groundwater as drinking water which may contain N-nitrosamines, necessitating the investigation of the occurrence, sources, and carcinogenic risk of N-nitrosamines within the groundwater of agricultural areas. This study identified eight N-nitrosamines in groundwater and river water in the Jianghan Plain, a famous agricultural region in central China. N-Nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosomorpholine (NMOR), N-nitrosopyrrolidine (NPYR), and N-nitrosodi-n-butylamine (NDBA) were detected in groundwater, with NDMA being the main compound detected (up to 52 ng L-1). Comparable concentrations of these N-nitrosamines were also found in river water. From laboratory experiments, we found a tremendous potential for the formation of N-nitrosamines in groundwater. Principal component analysis and multiple linear regression analysis results showed that the primary sources of N-nitrosamines in groundwater were the uses of nitrogen fertilizers and pesticides carrying specific N-nitrosamines such as NPYR. The average total carcinogenic risk values of detected N-nitrosamines were higher than the acceptable risk level (10-5), suggesting a potential carcinogenic risk of groundwater. Further research is urgently needed to minimize N-nitrosamine levels in the groundwater of agricultural areas, particularly in those where pesticides and fertilizers are heavily used.

Oxidation of amine-based pharmaceuticals with unactivated peroxymonosulfate: Kinetics, mechanisms, and elimination efficiency of NDMA formation.

Amine-based pharmaceuticals are a significant class of N-nitrosodimethylamine (NDMA) precursors. This study investigated the use of unactivated peroxymonosulfate (PMS) to control amine-based pharmaceuticals and their NDMA formation potential. Kinetic analysis and product identification revealed that sumatriptan and doxylamine primarily underwent reactions at their tertiary amine group, while ranitidine and nizatidine had both tertiary amine and thioether group as reaction sites. The NDMA formation from sumatriptan and doxylamine during post-chloramination was significantly reduced with the abatement of the parent contaminants, while the formation of NDMA remained high even if full abatement of ranitidine and nizatidine was achieved. Product formation kinetics and reference standard tests revealed the great contribution of transformation products to NDMA formation. Ranitidine could be oxidized to sulfoxide-type product ranitidine-SO and N-oxide type product ranitidine-NO. Ranitidine-SO exhibited a high NDMA yield comparable to that of ranitidine (>90%), while ranitidine-NO showed a low NDMA yield (2%). With further oxidation of ranitidine-SO at the tertiary amine group, NDMA formation was reduced by more than 90%. The underlying mechanism for the importance of the tertiary amine group in NDMA formation was demonstrated by quantum chemical calculation. These findings underscore the potential of PMS pre-oxidation on NDMA control.

Comparative Evaluation of Chemical and Photolytic Denitrosation Methods for Chemiluminescence Detection of Total N-Nitrosamines in Wastewater Samples.

N-Nitrosamines form as byproducts during oxidative water treatment and occur as impurities in consumer and industrial products. To date, two methods based on chemiluminescence (CL) detection of nitric oxide liberated from N-nitrosamines via denitrosation with acidic triiodide (HI3) treatment or ultraviolet (UV) photolysis have been developed to enable the quantification of total N-nitrosamines (TONO) in environmental water samples. In this work, we configured an integrated experimental setup to compare the performance of HI3-CL and UV-CL methods with a focus on their applicability for TONO measurements in wastewater samples. With the use of a large-volume purge vessel for chemical denitrosation, the HI3-CL method achieved signal stability and detection limits comparable to those achieved by the UV-CL method which utilized a microphotochemical reactor for photolytic denitrosation. Sixty-six structurally diverse N-nitroso compounds (NOCs) yielded a range of conversion efficiencies relative to N-nitrosodimethylamine (NDMA) regardless of the conditions applied for denitrosation. On average, TONO measured in preconcentrated raw and chloraminated wastewater samples by the HI3-CL method were 2.1 ± 1.1 times those measured by the UV-CL method, pointing to potential matrix interferences as further confirmed by spike recovery tests. Overall, our comparative assessment of the HI3-CL and UV-CL methods serves as a basis for addressing methodological gaps in TONO analysis.

Occurrence and transport of N-nitrosamines in the urban water systems of the Pearl River Delta, southern China.

The discharge of substantial amounts of N-nitrosamines-contained wastewater into receiving rivers can significantly deteriorate water quality, as these carcinogenic compounds can be easily transported into groundwater and drinking water systems. This study investigated the distribution of eight species of N-nitrosamines in river water, groundwater, and tap water located in the center of the Pearl River Delta (PRD), China. The results showed that three major N-nitrosamines, including N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and N-nitrosodibutylamine (NDBA), with concentrations of up to 64 ng/L, were observed in river water, groundwater, and tap water, whereas the other compounds occurred sporadically. In river water and groundwater, high concentrations of NDMA, NDEA, N-nitrosomorpholine (NMOR), and NDBA were found in industrial and residential lands as compared to agricultural lands owing to the influence of various human activities. The primary sources of N-nitrosamines in river water were industrial and domestic wastewater, and the infiltration of river water was responsible for the high levels of N-nitrosamines in groundwater. Among the target N-nitrosamines, NDEA and NMOR with long biodegradation half-lives (>4 days) and low LogKow values (<1) displayed the highest potential for groundwater. N-nitrosamines in groundwater and tap water pose significant potential cancer risks to residents, especially children, and juveniles, with lifetime cancer risks of over 10-4, necessitating advanced water treatments for drinking water and critical controls on primary industrial discharge in urban areas.

Changes in N-nitrosamines, Residual Nitrites, Lipid Oxidation, Biogenic Amines, and Microbiota in Chinese Sausages Following Treatment with Tea Polyphenols and Their Palmitic Acid-modified Derivatives.

This study aimed to investigate the effects of tea polyphenol (TP), epigallocatechin gallate (EGCG), and their palmitic acid-modified derivatives palmitoyl-TP (pTP) and palmitoyl-EGCG (pEGCG) on the accumulation of N-nitrosamine and biogenic amines (BAs), residual nitrites, and lipid oxidation in Chinese sausages. The microorganisms, color, and texture properties of sausages were evaluated. TP, EGCG, pTP, or pEGCG significantly inhibited the accumulation of N-nitrosodimethylamine (NDMA) and BAs, residual nitrites, and lipid oxidation, but enhanced the redness, hardness, and chewiness of sausages. The concentration of NDMA in sausages was reduced by 58.11%, 63.51%, 36.49%, and 44.59%, respectively, after treatment with TP, EGCG, pTP, and pEGCG. Both EGCG and pEGCG exhibited excellent inhibitory effects on the predominant BAs, including putrescine, tyramine, cadaverine, histamine, and 2-phenylethylamine. Palmitoyl-EGCG was found to be the strongest inhibitor of lipid oxidation. Besides, the four antioxidants weakly affected the population of total aerobic bacteria and lactic acid bacteria but totally suppressed the growth of undesirable Enterobacteriaceae. The principal component and correlation analyses proved that BAs, nitrites, lipid oxidation, and microbiota were responsible for the formation of NDMA. The results indicated that palmitic acid-modified TPs and similar derivatives might serve as potential preservatives to improve the safety and quality of fermented meat products.

Study on characteristic and mechanism involved in the formation of N-nitrosodimethylamine precursors during microbial metabolism of amino acids.

Amino acid metabolism by microorganisms is a new but important pathway for the formation of NDMA precursors in water. We investigated the properties of nitrosamine precursors produced through microbial metabolism of amino acids by polarity rapid assessment method and molecular weight fractionation by ultrafiltration method. The PRAM results showed that the positively charged fraction and the non-polar fraction accounted for most (45 %-79 % and 6 %-82 %, respectively) of the NDMA precursors. The MW fractionation results also indicate the dominant precursors had MWs <1 kDa or over 10 kDa. NDMA precursors produced through amino acid metabolism were identified and quantified. Dimethylamine, N-methyl-alanine and alanine methyl ester were produced during the metabolism of alanine and peptone. Together, N-methyl-alanine and dimethylamine averagely contributed 24 % (12 %-44 %) of the NDMA precursors in the alanine medium. The NDMA precursor formation pathway during alanine metabolism involves the methylation of alanine to form N-methyl-alanine and the decomposition of alanine anabolism products to form dimethylamine. Nitrosamine precursors are generally formed through anabolism or methylation, but biogenic amines or NH3 can be produced through catabolism before nitrosamine precursor synthesis. Microbial community analysis was performed and Ralstonia was found to be a likely key genus contributing to NDMA precursor formation during alanine metabolism.

Release regularity and cleaning measures of magnetic anion exchange resin during application.

Anion exchange resin is responsible for removing harmful anionic contaminants in drinking water treatment, but it may become a significant source of precursors for disinfection byproducts (DBPs) by shedding material during application without proper pretreatment. Batch contact experiments were performed to investigate the dissolution of magnetic anion exchange resins and their contribution to organics and DBPs. Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) released from the resin were highly correlated with the dissolution conditions (contact time and pH), in which 0.7 mg/L DOC and 0.18 mg/L DON were distributed at exposure time of 2 h and pH 7. The formation potential of four DBPs in the shedding fraction was also revealed that trichloromethane (TCM), dichloroacetonitrile (DCAN), nitrosodimethylamine (NDMA), and dichloroacetamide (DCAcAm) concentrations could reach 21.4, 5.1, 12.1 µg/L, and 69.6 ng/L, respectively. Furthermore, the hydrophobic DOC that preferred to detach from the resin mainly originated from the residues of crosslinkers (divinylbenzene) and porogenic agents (straight-chain alkanes) detected by LC-OCD and GC-MS. Nevertheless, pre-cleaning inhibited the leaching of the resin, among which acid-base and ethanol treatments significantly lowered the concentration of leached organics, and formation potential of DBPs (TCM, DCAN, and DCAcAm) below 5 µg/L and NDMA dropped to 10 ng/L.

N-nitrosamines in Qingdao dried aquatic products and dietary risk assessment.

N-nitrosamines are human carcinogens commonly present in dried aquatic products. A method of gas chromatography - mass spectrometry combined with steam distillation was developed for the determination of 9 N-nitrosamines in dried aquatic products in Qingdao, China, with which 300 samples of fish, squid, shrimp and sea cucumber collected from Qingdao were analysed. A health risk assessment was conducted based on determined levels of N-nitrosamines by using estimated daily intake and slope factors. Results showed that fish products was the category with the highest content of N-nitrosamines, whereas squid and shrimp products were the categories with the highest frequency of presence of N-nitrosamines. The average estimated cancer risk of N-nitrosamines in dried aquatic products in Qingdao ranged from 3.57 × 10-8 to 3.53 × 10-5. Nitrosodimethylamine, N-Nitrosodiethylamine and N-Nitrosodibutylamine could be considered to pose a potential cancer risk to residents in Qingdao.

Maternal exposure to nitrosamines in drinking water during pregnancy and birth outcomes in a Chinese cohort.

Maternal exposure to regulated disinfection by-products (DBPs) during pregnancy has been linked with adverse birth outcomes. However, no human studies have focused on drinking water nitrosamines, a group of emerging unregulated nitrogenous DBPs that exhibits genotoxicity and developmental toxicity in experimental studies. This cohort study included 2457 mother-infant pairs from a single drinking water supply system in central China, and maternal trimester-specific and entire pregnancy exposure of drinking water nitrosamines were evaluated. Multivariable linear and Poisson regression models were used to estimate the associations between maternal exposure to nitrosamines in drinking water and birth outcomes [birth weight (BW), low birth weight (LBW), small for gestational age (SGA) and preterm delivery (PTD)]. Elevated maternal N-nitrosodimethylamine (NDMA) exposure in the second trimester and N-nitrosopiperidine (NPIP) exposure during the entire pregnancy were associated with decreased BW (e.g., ß = -88.6 g; 95% CI: -151.0, -26.1 for the highest vs. lowest tertile of NDMA; p for trend = 0.01) and increased risks of PTD [e.g., risk ratio (RR) = 2.16; 95% CI: 1.23, 3.79 for the highest vs. lowest tertile of NDMA; p for trend = 0.002]. Elevated maternal exposure of N-nitrosodiethylamine (NDEA) in the second trimester was associated with increased risk of SGA (RR = 1.80; 95% CI: 1.09, 2.98 for the highest vs. lowest tertile; p for trend = 0.01). Our study detected associations of maternal exposure to drinking water nitrosamines during pregnancy with decreased BW and increased risks of SGA and PTD. These findings are novel but require replication in other study populations.

Fluorescent paper-based sensor integrated with headspace thin-film microextraction for the detection of acyclic N-nitrosamines following in situ photocatalytic decomposition.

BACKGROUND: In this work, a novel analytical approach based on the photocatalytic decomposition of N-nitrosamines combined with headspace thin-film microextraction of the generated nitrogen oxides such as NO has been developed for the determination of the acyclic N-nitrosamine fraction in drinking water samples. A hydrophilic cellulose substrate modified with fluorescent silver nanoclusters (Ag NCs) was used both as extractant and sensing platform. A quenching effect of Ag NCs fluorescence occurs as the concentration of N-nitrosamines increases. Front-face fluorescence spectroscopy with a solid sample holder was employed for directly measuring the fluorescence quenching onto the cellulose substrate. RESULTS: In order to achieve an optimal analytical response, different parameters involved in the photocatalytic reaction as well as those concerning the microextraction step were fully investigated. It is demonstrated that the photodegradation rate of cyclic N-nitrosamines at acidic pH is much lower than that of acyclic ones, which can be the basis for the determination of the later fraction in waters. Under optimal conditions, a detection limit for the acyclic N-nitrosamine fraction around 0.08 µg L-1 using N-nitrosodimethylamine (NDMA) as model compound for calibration was obtained. Several drinking waters were spiked with acyclic N-nitrosamines showing recoveries in the range of 98-102% with a relative standard deviation of 3-4% (N = 3). SIGNIFICANCE AND NOVELTY: N-nitrosamines generated as by-products during disinfection processes applied to water cause multiple adverse effects on human health being classified as potential human carcinogens. This study highlights the suitability of a fluorescent paper-based sensor for the rapid analysis of the acyclic N-nitrosamine fraction (i.e. the most abundant fraction) as a total index in drinking water, being useful as screening tool before exhaustive chromatographic analysis, which saves costs, time and reduces waste generation.

Analysis of N-nitrosodimethylamine in metformin hydrochloride products by high-resolution accurate mass gas chromatography mass spectrometry.

RATIONALE: The high resolving power of the Orbitrap mass spectrometer in a high-resolution accurate mass gas chromatography (HRAM-GC-MS) system provides greater selectivity and sensitivity for the identification and quantification of volatile analytes at low parts per billion (ppb) levels. Hence, it can be applied for the analysis of pharmaceutical impurities like N-nitrosodimethylamine (NDMA) in metformin hydrochloride products (METs). METHODS: Different METs extracted by a dichloromethane/aqueous system were analyzed by HRAM-GC-MS under softer electron ionization (EI) at 30 eV. The accurate masses of NDMA and its internal standard NDMA-d6 were analyzed by full scan and targeted selected ion monitoring modes under 60 000 and 30 000 full width at half maximum at m/z 200, respectively. Data acquisition and processing were managed by Xcalibur and Trace Finder software, respectively. RESULTS: Limits of detection (LOD) and quantification (LOQ) at 10 and 20 ng/g were achieved, which is below the allowed daily intake of 32 ng/g. The mass errors measured from experimental data were within ±2 ppm of the theoretical values over a period of a week. Sample analysis showed that 180 out of 212 samples (85%) were below LOD and 15 out of 212 samples (7 %) were within LOD and LOQ. Only 17 samples (8%) were found to be above LOQ, comprising one active pharmaceutical ingredient (API), five immediate-release METs and 11 extended-released METs. Amongst these, seven extended-release METs and one API exceeded the daily allowed intake, 32 ng/g. CONCLUSIONS: The validated method has been successfully applied for NDMA analysis in various forms of METs. The method is rather straightforward without an additional clean-up step. The scope can also be extended to other volatile impurities in finished pharmaceutical products.

Setting limits for N-nitrosamines in drugs: A defined approach based on read-across and structure-activity relationship for N-nitrosopiperazine impurities.

This paper describes DARAN (Defined Approach for Risk Assessment of New Nitrosamines), an new defined approach that uses lines of reasoning based on structure-activity relationship (SAR) patterns and Read-Across (RAx) to set transparent and acceptable limits for new N-nitrosamines for which no toxicological data exist. We selected the compound 1-methyl-4-nitrosopiperazine (MeNP) as a target to calculate a new acceptable limit on the basis of a more transparent and scientifically reasoned RAx. We used publicly available databases and datasets to retrieve experimental in vitro mutagenicity and in vivo carcinogenicity data for N-nitrosopiperazine compounds and to form the chemical category for an RAx. We carried out SAR analyses to try to understand patterns and to obtain interpretable inferences of variation in carcinogenic potency among the N-nitrosopiperazines compounds and their differences with the potent nitrosamines NDMA (N-nitrosodimethylamine) and NDEA (N-nitrosodiethylamine). To estimate an acceptable limit for the target MeNP, we used the scientifically based hypotheses and the evidence lines of about the influence of structural attributes for a robust RAx. On the basis of the criteria proposed in the Assessment Report EMA/369136/20202 and by using the SAR hypotheses obtained by the analysis, we obtained a robust RAx, scientifically supported assumptions, which resulted in TD50 values predicted from the closest structurally related compounds and a worst-case approach.

Development of dispersive inclusion complex microextraction for the analysis of nitrosamines in medicinal products.

A new dispersive inclusion complex microextraction (DICM) approach coupled with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for the determination of n-nitrosamine impurities in different medicinal products is demonstrated for the first time. The proposed DICM procedures consist of a dispersive liquid phase microextraction steps employing cyclodextrin as an inclusion complex agent to extract n-nitrosamines namely N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodiisopropylamine (NDIPA), N-ethyl-N-nitrosoisopropylamine (NEIPA) and N-nitroso-di-n-butylamine (NDBA) present in the medicinal products. The sample solutions were prepared by mixing 5% (m/v) NaCl solution with 1.5 mM ß-cyclodextrin and 20 mM sodium dodecyl sulphate to form a stable inclusion complex and subsequently extracted into dichloromethane as an extraction solvent. The enriched solution was reconstituted into aqueous solution prior to UPLC-MS/MS analysis. The method showed good linearity in the range of 0.036-1 ng/mL with a correlation coefficient of at least 0.995, acceptable reproducibility (RSD 0.5-5.8%, n=5), low limits of detection (0.011-0.018 ng/mL), and satisfactory relative recoveries (96-105%). The results obtained were found to be at least 10-fold more sensitive comparable to those obtained using validated direct sample dissolutions coupled with UPLC-MS/MS approach.

Pharmacoepidemiological Research on N-Nitrosodimethylamine-Contaminated Ranitidine Use and Long-Term Cancer Risk: A Population-Based Longitudinal Cohort Study.

N-Nitrosodimethylamine (NDMA), a carcinogenic chemical, has recently been identified in ranitidine. We conducted a population-based study to explore ranitidine use and cancer emergence over time. Using the Taiwan National Health Insurance Research Database, a population-based cohort study was conducted. A total of 55,110 eligible patients who received ranitidine between January 2000 and December 2018 were enrolled in the treated cohort. We conducted a 1:1 propensity-score-matching procedure to match the ranitidine-treated group with the ranitidine-untreated group and famotidine controls for a longitudinal study. The association of ranitidine exposure with cancer outcomes was assessed. A multivariable Cox regression analysis that compared cancer risk with the untreated groups revealed that ranitidine increased the risk of liver (hazard ratio (HR): 1.22, 95% confidence interval (CI): 1.09-1.36, p < 0.001), lung (HR: 1.17, CI: 1.05-1.31, p = 0.005), gastric (HR: 1.26, CI: 1.05-1.52, p = 0.012), and pancreatic cancers (HR 1.35, CI: 1.03-1.77, p = 0.030). Our real-world observational study strongly supports the pathogenic role of NDMA contamination, given that long-term ranitidine use is associated with a higher likelihood of liver cancer development in ranitidine users compared with the control groups of non-ranitidine users treated with famotidine or proton-pump inhibitors.

Evaluation and optimization of a HS-SPME-assisted GC-MS/MS method for monitoring nitrosamine impurities in diverse pharmaceuticals.

The probable carcinogenic nitrosamine impurities, such as N-nitrosodiethylamine (NDEA) and N-nitrosodimethylamine (NDMA), have been detected from various pharmaceuticals in recent years. The sensitive chromatographic methods, including liquid chromatography (LC) and gas chromatography (GC), have been applied for analyzing nitrosamines in the pharmaceutical substrates, such as sartans, ranitidine and metformin. In comparison of LC, the efficacy of GC for analyzing multiple nitrosamines in diverse pharmaceuticals will be limited or attenuated owing to the chemical properties of target analytes or matrix hinderance of pharmaceutical substrates. To extend the applicability of GC analysis for multiple nitrosamines in pharmaceuticals, this study presented a gas chromatograph tandem mass (GC-MS/MS) method for monitoring 14 nitrosamines within 44 pharmaceuticals, whereas the headspace-solid phase microextraction (HS-SPME) sampling mode was introduced. Chromatographic separation was achieved on a DB-heavyWax column (30 m × 0.25 mm; i.d., 0.25 µm), whereas the HS-SPME sampling mode with a 50/30 µm DVB/CAR/PDMS extracting fiber was applied for comparison of the direct injection mode. Meanwhile, the HS-SPME conditions were optimized to evaluate the effects of the parameters on analyzing total nitrosamines in pharmaceuticals by GC-MS/MS. The optimal conditions of HS-SPME were as follows: extracting solution of 90% NaCl, HS incubation time 1 min, SPME adsorbing at 80 â„ƒ for 30 min, and desorbing at 250 â„ƒ for 5 min. The limit of quantification (LOQ) for 14 nitrosamines in pharmaceutical matrices under the optimal conditions was 0.05 µg/g for the optimal HS-SPME, whereas the value was 0.05-0.25 µg/g for direct injection.

Analysis of genotoxic N-nitrosamines in active pharmaceutical ingredients and market authorized products in low abundance by means of liquid chromatography - tandem mass spectrometry.

In 2018, high levels of the IARC class IIA carcinogen N-nitrosodimethylamine (NDMA) were analytically verified in the active pharmaceutical ingredient (API) valsartan, resulting in extensive regulatory action on angiotensin-II-receptor antagonists and recall of finished drug products by the pharmaceutical industry to ensure patient safety. The root cause of contamination was the unintended reaction of common reagents utilized during drug synthesis. This lead to serious effects on drug quality and immediate regulatory action. Thus, routine analysis of drug product contents are inevitable and necessitate thoroughly performed work up procedures of the product as well as adequate validated analytical methods. The nature of N-nitrosamines (NA), ranging from small, semi-volatile compounds up to highly polar molecules, effort sophisticated requirements in terms of instrumental analysis. Up today, gas as well as liquid chromatographic devices coupled to mass spectrometers are the most widespread systems for analysis. Gas chromatographic - mass spectrometric (GC-MS) systems, obviously superior towards liquid chromatography - mass spectrometry (LC-MS) for detecting small volatile compounds like NDMA, reach their limits for broadly designed studies including polar or acidic NA. In this study, a complementary and highly sensitive approach by means of liquid chromatography - tandem mass spectrometry (LC-MS/MS) is presented, including detection of 13 NA deduced from major classes of secondary amines. Thereby, the fully validated approach was performed in accordance to ICH and European Medicines Agency (EMA) guidelines. Quantitative proof-of-concept measurements with various APIs and market authorized tablets as representative drug formulations conclude applicability for further presumably contaminated substances. The approach employs organic or inorganic extraction steps with solid phase extraction (SPE). The limit of detection for the most prominent NA, NDMA and N-diethylnitrosamine (NDEA), were both 0.025 parts-per-billion (ppb) per matrix, respectively.

Development of a fully automated analytical platform based on static headspace-gas chromatography-tandem mass spectrometry for the analysis of five N-nitrosamines in dried aquatic products of animal origin.

BACKGROUND: The development of rapid and sensitive monitoring methods for trace N-nitrosamines (NAs) in foodstuffs is essential for mitigating the potential health risks to consumers. In the present study, an analytical platform based on one step fully automated static headspace sampling and gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed and validated for the analysis of N-nitrosamines in dried aquatic products of animal origin. The samples and sodium chloride solution mixture were incubated in a heated headspace vial for analyte evaporation, coupled to automatic sampling and online GC-MS/MS analysis. The proposed method requires minimal sample preparation and organic solvent consumption. Five N-nitrosamines including N-nitroso dimethylamine, N-nitroso methyl ethylamine, N-nitroso pyrolidine, N-nitroso piperidine and N-nitroso diphenylamine were selected as model compounds to optimize the significant factors by a using Box-Behnken design. RESULTS: The optimum conditions achieved limits of detections in the range 0.08-0.29 µg kg-1 , with correlation coefficient over 0.998. Relative recoveries in dried aquatic product sample were in the range 76.9-92.4%, with relative SDs of 1.9-7.2%. CONCLUSION: These results confirm the reliability of the developed method for further application in trace level monitoring of the target analytes in foodstuffs. © 2022 Society of Chemical Industry.