Absorption, Distribution and Excretion
Pregnant Syrian golden hamsters were injected with 20 uCi (4.8 mg/kg body weight) of 14C-nitrosodibutylamine (14C-NDBA). Animals were sacrificed 20 minutes or 1 hour later for whole-body autoradiography. For in vitro experiments, tissue sections from fetal mice (days 12 and 15 of gestation), juvenile mice (4, 10, or 20 days old), or adult hamsters (non-pregnant females) were incubated at 37°C for 1 hour in a solution containing 14C-NDBA (34 μmol/mL; 0.12 uCi/mL). Autoradiography showed fetal absorption of the radioactive material, with higher levels of radiolabeling in the fetal nasal, tracheal, and bronchial mucosa than in most other fetal tissues. These tissues from 15-day-old fetuses exhibit a strong metabolic capacity, capable of converting 14C-labeled NDBA into 14C-carbon dioxide (14CO2) and tissue-bound 14C, a capacity not found in tissues from 12-day-old fetuses. In juvenile hamsters, the levels of 14CO2 and tissue-bound 14C in respiratory tissues were, in some cases, higher than in adult animal tissues. Adult hamster tissue culture results showed that the nasal mucosa produced the highest levels of (14)CO2 and tissue-bound (14)C.

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Metabolisms/Metabolites
...Following oral administration of NDBA to guinea pigs, glucuronide of N-nitroso-n-butyl-n-(3-hydroxybutyl)amine and trace amounts of N-nitroso-n-butyl-n-(2-hydroxy-3-carboxypropyl)amine were excreted.
This study demonstrates that the putative and identified metabolites of dipropylnitrosamine and dibutylnitrosamine can reach Syrian hamster fetuses after subcutaneous injection in maternal rats (day 14 of gestation). These compounds include [2-hydroxypropylpropylnitrosamine, HPPN; 2-oxopropylpropylnitrosamine, OPPN; methylpropylnitrosamine, MPN]; N-nitrosobis(2-hydroxypropyl)amine (BHP) and 4-hydroxybutylbutylnitrosamine (HBBN) were still detected in the tested tissues (maternal blood, placenta, fetus, amniotic fluid) 4–6 hours after subcutaneous injection. The overall incidence of transplacental tumor induction in F1 offspring was lower than that in P-generation, and the latency period in F1 offspring was also relatively longer. However, in some groups, tumors not occurring in the mother were found (e.g., nasal cavity: BHP, HBBN; trachea: HBBN; lung: HPPN, BHP, HBBN; liver: OPN, MPN, BHP, HBBN). The carcinogenic effect was enhanced transplacentally on day 14 of gestation compared to early pregnancy exposure. Tumors originating from other organs were not associated with the placental transport effect of the nitrosamines studied. This study investigated the effects of butylated hydroxyanisole (BHA) on the P-450-dependent ω-hydroxylation of N,N-dibutylnitrosamine (NDBA) to N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), and the further oxidation of BBN by an alcohol/aldehyde dehydrogenase system to N-butyl-N-(3-carboxypropyl)nitrosamine (BCPN), using liver homogenate supernatant from animals pretreated with acute or chronic BHA (S9) or from untreated rats supplemented with BHA (S9). Acute oral administration of BHA (50 and 250 mg·kg⁻¹) did not alter the ω-oxidation of NDBA; only when 0.5% BHA was added to the diet for 3 weeks did the ω-oxidation of NDBA decrease by 35%. The process of BBN to BCPN was not affected by acute or chronic BHA pretreatment. To verify whether BHA or its metabolites have a direct effect on the oxidation of NDBA and BBN, we added different concentrations of BHA to the S9 fraction of untreated rats. Only when the BHA concentration was equimolar to or 10-fold excess of the substrate concentration did we observe a 30-50% inhibition of BBN production and a decrease in BCPN production (60-80% of the control group). Therefore, only at extremely high BHA concentrations could we confirm that BHA inhibits the activity of P-450-dependent mixed-function oxidases and alcohol dehydrogenases involved in NDBA and BBN metabolism. N-nitrosodi-((1-14)C)butanylamine (NDBA) has been shown to have a high first-pass metabolic rate in isolated perfused rat small intestine segments. The ω-hydroxylation metabolites of NDBA, namely the bladder carcinogens N-nitrosobutyl-(4-hydroxybutyl)amine (NB4HBA) and N-nitrosobutyl-(3-carboxypropyl)amine (NB3CPA), account for over 90% of the total absorbed radioactivity. This study used perfused rat small intestine segments to confirm the high first-pass metabolism of NDBA under near-in vivo conditions, although its absorption rate was much higher than in vitro experiments. At the end of the 36-minute experiment, 70-80% of the dose was absorbed via portal vein blood, while only 1-10% was absorbed 2 hours after in vitro perfusion. ω-hydroxylation again emerged as the most important metabolic pathway. However, the relationship between NB3CPA and NB4HBA tilted towards NB4HBA, indicating that the further metabolism of NB4HBA to NB3CPA is concentration- and rate-dependent. For more complete metabolite/metabolite data on N,N-dibutylnitrosamines (16 metabolites in total), please visit the HSDB record page.
The known human metabolites of N-nitrosodibutylamine include N-butyl-N-(1-hydroxybutyl)nitrosamide.

Toxicity Summary
Identification and Uses: N,N-Dibutylnitrosamine (DBNA) is a pale yellow liquid. It was previously used in the synthesis of di-n-butylhydrazine, but there is no evidence that it has been used commercially. Human Studies: No data available. Animal Studies: DBNA can induce tumors in various experimental animals in a variety of tissues and via various pathways. A single dose is carcinogenic, particularly to the bladder, causing benign and/or malignant bladder tumors in mice, rats, hamsters, and guinea pigs after oral administration, and benign and/or malignant bladder tumors in mice, rats, hamsters, and rabbits after subcutaneous administration. DBNA can induce respiratory tumors in hamsters after oral or prenatal exposure, in rats, hamsters, adult mice, and newborn mice after subcutaneous injection, and in male and female hamsters after intraperitoneal injection. Benign or malignant liver tumors have been observed in mice, rats, and guinea pigs after oral exposure, and in newborn mice after subcutaneous exposure. Upper gastrointestinal tumors were induced in mice, rats, and hamsters after oral exposure, and in rats and hamsters after subcutaneous injection. Intravenous injection of DBNA induced leukemia in both male and female mice. Gavage administration of DBNA to male rats via gastric tube induced forestomach cancer, as well as liver and bladder cancer. DBNA induced metabolic reversion mutations in Salmonella Typhimurium strains TA 100, TA 1530, and TA 1535, and in Escherichia coli.

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Interactions
This study investigated the target organ specificity of the carcinogen dibutylnitrosamine (DBN) in Syrian golden hamsters. Male hamsters were divided into groups and injected with the carcinogen weekly for 8 weeks. They were then fed a basal diet, a diet supplemented with 1% butylated hydroxyanisole (BHA), or the corresponding carcinogen was added to their drinking water until sacrifice at week 34. …DBN induced lesions in the bladder, forestomach, and trachea, and a small number of precancerous lesions appeared in the liver and lungs. In all the organs studied, precancerous lesions and tumor cell populations were largely similar to those observed in other experimental animals, while colonic and tracheal lesions showed alterations in polysaccharide metabolism. While BHA administration inhibited the development of hepatocellular lesions… and itself induced widespread papillary forestomach hyperplasia; it did not significantly regulate tumorigenesis in other organs. This study investigated the moderating effect of concomitant antioxidant treatment on N,N-dibutylnitrosamine (DBN)-induced carcinogenesis. Male F344 rats were fed drinking water supplemented with 0.05% DBN for 16 weeks, along with a powdered diet containing either 2.0% butylated hydroxyanisole (BHA) or 0.7% butylated hydroxytoluene (BHT) for 16 weeks. Control group animals drank drinking water containing 0.05% DBN but did not receive antioxidant treatment. The final incidence of hepatocellular carcinoma in the DBN combined with BHA group, the DBN combined with BHT group, and the DBN monotherapy group were 100%, 100%, and 40%, respectively, with statistically significant differences (P<0.001). Lung metastasis was observed only in the DBN combined with BHT group and the DBN combined with BHA group (50%, P<0.001; 7%, respectively). The incidence of papillary or nodular hyperplasia of the bladder was significantly higher in the DBN combined with BHA group than in the control group (P<0.05). In addition, esophageal cancer and papilloma were observed in all DBN treatment groups, with no significant difference in incidence between groups. On the other hand, DBN combined with BHA or BHT significantly reduced the incidence of forestomach hyperplasia. The results clearly demonstrate that the concurrent use of antioxidants, especially BHT, can alter the carcinogenic effects of DBN. This study aimed to determine the effects of vitamin C, diallyl disulfide (DADS), and dipropyl disulfide (DPDS) on apoptosis induced by N-nitrosopiperidine (NPIP) and N-nitrosodibutylamine (NDBA) in human leukemia (HL-60) and hepatocellular carcinoma (HepG2) cell lines using a terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay. Selected concentrations of vitamin C (5–50 μM), DADS, and DPDS (1–5 μM) did not induce a significant proportion of apoptosis. Under simultaneous treatment, vitamin C, DADS, and DPDS reduced NPIP and NDBA-induced apoptosis in HL-60 and HepG2 cells (by approximately 70%). We also investigated the scavenging activity of vitamin C against reactive oxygen species (ROS) generated by NPIP and NDBA in both cell lines using 2',7'-dichlorodihydrofluorescein diacetate. Vitamin C (5–50 μM) reduced ROS generation induced by both N-nitrosamines to control levels in a dose-dependent manner. However, DADS (5 μM) increased NPIP and NDBA-induced ROS levels in HL-60 cells (40% and 20%, respectively) and HepG2 cells (18%), while DPDS at the lowest concentration (1 μM) showed greater efficiency in scavenging ROS in HL-60 cells (52% and 25%, respectively) and HepG2 cells (24%). These data suggest that the scavenging capacity of vitamin C and DPDS may contribute to the inhibition of NPIP and NDBA-induced apoptosis. However, the protective effect of dietary antioxidants against NPIP and NDBA-induced apoptosis in HL-60 and HepG2 cells may involve multiple mechanisms, such as inhibition of phase I enzymes and/or induction of phase II enzymes. This study aimed to investigate the protective effects of myricetin, quercetin, (+)-catechin, and (-)-epicatechin against N-nitrosodibutylamine (NDBA) and N-nitrosopiperidine (NPIP)-induced DNA damage in human hepatocellular carcinoma cells (HepG2). DNA damage (strand breaks and purine/pyrimidine oxidation) was assessed using alkaline single-cell gel electrophoresis or a comet assay. The lowest concentration (10 μM) of (+)-catechin showed the greatest inhibitory effect on NDBA- or NPIP-induced DNA strand breaks (23%), endonuclease III (19-21%), and the formation of formamide pyrimidine-DNA glycosidase (Fpg, 28-40%) sensitive sites. (-)-epicatechin also reduced NDBA- or NPIP-induced DNA strand breaks (10 μM, 20%) and pyrimidine/purine oxidation (33-39%). The lowest concentration (0.1 μM) of myricetin showed weak inhibitory effects on NDBA- or NPIP-induced DNA strand breaks (10-19%, respectively). Myricetin also reduced NDBA-induced levels of oxidized purines (0.1 μM, 17%) and pyrimidines (0.1 μM, 15%), but had no effect on NPIP-induced levels of oxidized pyrimidines. Quercetin did not protect DNA from NDBA-induced damage, but it reduced NPIP-induced formation of endonuclease III and Fpg-sensitive sites (0.1 μM, 17-20%, respectively). In summary, our results indicate that at the tested concentrations, (+)-catechins and (-)-epicatechins can protect human cells from NDBA- and NPIP-induced oxidative DNA damage. However, at the tested concentrations, myricetin only protected human cells from NDBA-induced oxidative DNA damage, while quercetin only protected human cells from NPIP-induced oxidative DNA damage. For more complete data on interactions of N,N-dibutylnitrosamines (9 in total), please visit the HSDB record page.

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Non-human toxicity values
Hamster subcutaneous LD50: 561 mg/kg
Hamster intraperitoneal LD50: 1200 mg/kg
Hamster oral LD50: 2150 mg/kg
Rat subcutaneous LD50: 1200 mg/kg
For more complete data on non-human toxicity of N,N-dibutylnitrosamines (6 in total), please visit the HSDB record page.

[1]. Chao Zhao, et al. Distribution of N-nitrosamines in Drinking Water and Human Urinary Excretions in High Incidence Area of Esophageal Cancer in Huai'an, China. Chemosphere. 2019 Nov;235:288-296.

According to an independent committee of scientific and health experts, N-nitrosodi-n-butylamine is a potential carcinogen. N-nitrosodi-n-butylamine is a pale yellow liquid. N-nitrosodi-n-butylamine is a nitrosamine compound. N-nitrosodi-n-butylamine is a yellow, viscous, oily nitrosamine that is extremely unstable under light. N-nitrosodiethanolamine is widely present in the environment and is a pollutant formed by the reaction of nitrites with ethanolamines in various products, including tobacco, pesticides, antifreeze, and personal care products. This substance is used only for research purposes to induce tumors in laboratory animals. N-nitrosodiethanolamine is reasonably expected to be a human carcinogen. (NCI05)

C8H18N2O

158.24

158.142

924-16-3

N-Nitrosodibutylamine-d18;1219798-82-9;N-Nitrosodibutylamine-d9

13542

Pale yellow liquid
Yellow oil

0.91 g/cm3

250.6ºC at 760 mmHg

<25℃

105.3ºC

1.456

2.57

0

3

6

11

88.1

0

O=NN(CCCC)CCCC

YGJHZCLPZAZIHH-UHFFFAOYSA-N

InChI=1S/C8H18N2O/c1-3-5-7-10(9-11)8-6-4-2/h3-8H2,1-2H3

N,N-dibutylnitrous amide

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: 100 mg/mL (631.95 mM)

Solubility in Formulation 1: ≥ 6.25 mg/mL (39.50 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 62.5 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 6.25 mg/mL (39.50 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 62.5 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 6.25 mg/mL (39.50 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 62.5 mg/mL clear DMSO stock solution to 900 μL corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)