Absorption, Distribution and Excretion
Following intratracheal instillation, gavage, or dermal application of 1 mg/kg body weight of (14)-chlorothiazoline in male Sprague-Dawley rats, less than 6% of the administered dose was recovered in blood or urine within 48 hours. Following a single oral administration of a low dose (1.5 mg/kg) of chlorothiazoline in rats, approximately 20-22% of the absorbed dose was excreted bile, and approximately 10% was excreted in urine. At higher doses (200 mg/kg), the proportion of absorbed dose excreted bile decreased significantly (8%), indicating a saturation process. These data suggest that total gastrointestinal absorption is approximately 30-32% of the administered dose. The majority of the drug is excreted in feces, with at least 80% of the administered dose eliminated via this route within 96 hours. Approximately 90% of the administered dose is eliminated within 34-48 hours, but elimination is slower at doses of 50 mg/kg and above. The highest drug concentration is found in the kidneys, approximately 0.1% of the administered dose. Similar metabolic characteristics were observed after repeated administration, and no evidence of bioaccumulation was found. ...Data from monkeys showed that after a single oral dose of 50 mg/kg, 1.8–4.15% of the dose appeared in the urine, with very low levels of thiol-derived metabolites in the urine. Fecal excretion was dominant, with approximately 92% of the dose excreted via this route within 96 hours. Absorption and excretion were rapid, and no evidence of bioaccumulation was found. Low concentrations of oral chlorothalonil were detected in mouse tissues, and urinary excretion indicated that at least 10% of the dose was absorbed, with the majority (70–80%) excreted in the feces. For more complete data on absorption, distribution, and excretion of chlorothalonil (12 in total), please visit the HSDB records page. Metabolites/Metabolites When yeast cells are exposed to chlorothalonil, the derivatives formed are similar to those formed by the in vitro reaction of glutathione with chlorothalonil. Coenzyme A and 2-mercaptoethanol can also form derivatives with chlorothalonil in vitro. Infrared spectroscopy and chromatographic analysis of the four derivatives showed that the halogens at positions 1-4 were replaced by 2-mercaptoethanol. Dactan decomposes in fresh rumen contents, producing two unidentified metabolites. In plants, 4-hydroxy-2,5,6-trichloroisophthalonitrile is a metabolite. This study used high-performance liquid chromatography (HPLC) to detect the metabolism of chlorothalonil in the liver and gill cytoplasm and microsomal fractions of the channel catfish (Ictalurus punctatus). All fractions catalyzed the metabolism of chlorothalonil to polar metabolites. The metabolism of chlorothalonil in the cytoplasmic fraction was significantly reduced when glutathione was not added to the reaction mixture. No chlorothalonil metabolism was observed in the microsomes in the presence of NADPH or an NADPH regeneration system, indicating that glutathione S-transferase directly catalyzes the binding of chlorothalonil to glutathione without prior oxidation by cytochrome P450. Both cytoplasmic and microsomal glutathione S-transferases from both tissues were active against the commonly used reference substrate 1-chloro-2,4-dinitrobenzene. In summary, the spotted catfish detoxifies chlorothalonil in vitro via a glutathione conjugation reaction catalyzed by glutathione S-transferases in the liver and gills. This report is the first to demonstrate the activity of microsomal glutathione S-transferases in the gills of aquatic animals against 1-chloro-2,4-dinitrobenzene and microsomal glutathione S-transferases in the liver against chlorothalonil, as well as the activity of gill cytoplasmic glutathione S-transferases against chlorothalonil. To isolate and identify urinary metabolites, male Sprague-Dawley rats were orally administered 200 mg/kg of (14)C-chlorothalonil (99.7% purity). Urine was collected at 17, 24, and 48 hours post-administration. Urinary metabolites accounted for 2.4% of the administered dose. Except for 30% of the radiolabeled substances, which could not be extracted from urine, the remaining metabolites were trimethylthiochloroisophthalonitrile and dimethylthiodichloroisophthalonitrile. These thiols are excreted in urine as free thiols and their methylated derivatives. …The hypothetical metabolic pathway is as follows: hepatic metabolism begins with binding to glutathione (GSH), followed by enzymatic degradation. Smaller conjugates are then transported via the bloodstream to the kidneys, where they are converted into thiol metabolites and excreted in urine.
For more complete metabolite/metabolite data on chloroAcibenzolar (12 metabolites in total), please visit the HSDB record page.
Organic nitriles are converted to cyanide ions in the liver by cytochrome P450 enzymes. Cyanide ions are rapidly absorbed and distributed throughout the body. Cyanide ions are primarily metabolized to thiocyanate by thiocyanate oxidase or 3-mercaptopyruvate thiotransferase. Cyanide metabolites are excreted in urine. (L96)

Toxicity Summary
Identification and Uses: Chlorothalonil is a colorless and odorless crystal in its pure form. It is a benzene-alternative fungicide used to control fungal diseases in vegetables, fruits, lawns, and ornamental plants. Chlorothalonil is registered for use in the United States, but its approved pesticide uses may change periodically; therefore, it is essential to consult federal, state, and local authorities for information on currently approved uses. Human Exposure and Toxicity: At a chlorothalonil manufacturing plant, multiple employees developed contact dermatitis. 19 out of 103 employees were affected. Approximately 60% of employees experienced some form of skin abnormality, compared to 18.5% of employees who were not exposed to chlorothalonil. After the plant's hygiene conditions improved, the overall rate of skin abnormalities decreased to approximately 20%, and no further cases of chlorothalonil contact dermatitis were reported. One report describes a Danish cabinetmaker who developed dermatitis on his hands after using a wood preservative containing chlorothalonil to coat furniture for nine consecutive months. Another report mentioned three similar cases: two patients developed facial erythema (especially around the eyes), and one patient developed eczema on both hands; all patients worked in similar occupations. Patients showed positive reactions to patch tests with 0.01% chlorothalonil acetone solution. An employee at a packaging plant experienced eye pain, mild to moderate conjunctivitis, and corneal irritation after exposure to chlorothalonil. With higher exposure levels, ocular edema was also observed. With lower exposure levels, patients recovered completely within 24 hours. With higher exposure levels, recovery time was slightly longer. No corneal opacity was observed in any of the cases. Animal studies: Instillation of 96% chlorothalonil into the eyes of rabbits caused severe irritation, resulting in persistent corneal opacity, iris lesions, and conjunctival irritation. In a rat carcinogenicity study, male rats were fed a diet supplemented with 98.1% chlorothalonil at doses up to 175 mg/kg/day for 116 weeks; female rats were fed for 129 weeks. Weight loss was observed in both the high-dose and medium-dose groups. Erosion and ulceration occurred in the non-glandular stomach. Histological examination showed that the compound affected the kidneys, esophagus, stomach, and duodenum. Chronic glomerulonephritis, cortical tubular hyperplasia, renal pelvis/papillary epithelial hyperplasia, renal tubular cysts, renal adenomas and renal carcinomas, as well as gastric papillomas, were observed in all dosage groups. No chromosomal aberrations or micronucleus induction were observed in rats or Chinese hamsters administered by gavage at doses up to 5000 mg/kg/day for 2 consecutive days, or in mice administered by gavage at doses of 2500 mg/kg/day for 2 consecutive days. In an inhalation study assessing the genotoxic potential of chlorothalonil drift in mice, there was no significant difference in DNA damage between the exposed and control groups. Ecotoxicity studies: The chronic oral toxicity of four of the most common insecticides detected in pollen and beeswax (flufenican, coumarin, chlorothalonil, and chlorpyrifos, tested individually and in all combinations) to bee larvae was evaluated using a larval rearing method. All pesticides, at residual concentrations in the honeycomb, significantly increased larval mortality, more than doubling compared to the untreated group, with a significant increase in mortality after 3 days of exposure. Among these four pesticides, bee larvae were more sensitive to chlorothalonil than adults. A bird breeding study using mallards showed that at a concentration of 100 ppm, eggshell thickness decreased. At a concentration of 250 ppm, adult body weight, food intake, and gonadal development were affected, as were egg production, embryonic development, eggshell thickness, hatching rate, and hatching survival rate. Earthworms raised in soil mixed with chlorothalonil (at five times the recommended application rate, i.e., 0.9 g per 4700 cubic centimeters of soil) experienced a lifespan reduction of approximately 50% compared to the control group after the treatment began, and reproduction almost completely ceased. Organic nitriles can decompose into cyanide ions both in vivo and in vitro. Therefore, the main toxic mechanism of organic nitriles is the production of toxic cyanide ions or hydrogen cyanide. Cyanide is an inhibitor of cytochrome c oxidase in the fourth electron transport complex (located on the mitochondrial membrane of eukaryotic cells). It forms a complex with the ferric iron atom in this enzyme. The binding of cyanide to this cytochrome prevents electrons from being transferred from cytochrome c oxidase to oxygen. As a result, the electron transport chain is disrupted, and the cell cannot perform aerobic respiration to produce ATP for energy. Tissues that rely primarily on aerobic respiration, such as the central nervous system and the heart, are particularly susceptible to this effect. Cyanide can also exert some toxic effects by binding to catalase, glutathione peroxidase, methemoglobin, hydroxycobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, succinate dehydrogenase, and copper/zinc superoxide dismutase. Cyanide binds to the iron ions in methemoglobin to form inactive cyanogenic methemoglobin. (L97)

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Toxicity Data
LC50 (Rat) = 92 mg/m3
LD50: 2500 mg/kg (intraperitoneal injection, mouse) (T14)
LD50: 3700 mg/kg (oral administration, mouse) (T14)
LD50: >2500 mg/kg (dermal contact, rat) (T14)
LC50: 310 mg/m3 (within 1 hour) (inhalation, rat) (T14)

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Interactions
…Japanese medaka (Oryzias latipes) exposed to environmentally relevant concentrations of methylpyrimidine, chlorothalonil, endosulfan, and mixtures thereof… Juvenile fish exposed to chlorothalonil and mixtures thereof exhibited reduced activity. Adult individuals showed a sex ratio bias towards females… Individuals exposed to methylpyrimidine, chlorothalonil, and pesticide mixtures showed a significantly deviated sex ratio from equilibrium. No evidence of additive or synergistic effects of pesticide mixtures was found. ...When the concentrations of atrazine and chlorothalonil were ≥25 μg/L and 33.3 μg/L, respectively, the population growth rate of D. tertiolecta was significantly reduced. At higher concentrations (≥400 μg/L), chlorpyrifos also significantly affected the population growth rate of D. tertiolecta. The EC50 values for the population growth rate of D. tertiolecta were: 64 μg/L for chlorothalonil, 69 μg/L for atrazine, and 769 μg/L for chlorpyrifos. The combination of atrazine and chlorpyrifos showed additive toxicity, while the combination of atrazine and chlorothalonil showed synergistic toxicity.

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Non-human toxicity values
Mouse intraperitoneal LD50: 2500 mg/kg
Mouse oral LD50: 3700 mg/kg
Rat dermal injection LD50: >2500 mg/kg
Rat intraperitoneal injection LD50: 2500 mg/kg
For more non-human toxicity values (complete data) for chlorothalonil (11 in total), please visit the HSDB record page.

[1]. Low Dose Chlorothalonil Impairs Mouse Spermatogenesis Through the Intertwining of Estrogen Receptor Pathways With Histone and DNA Methylation.Chemosphere. 2019 Sep;230:384-395.

[2]. The Influence of Chlorothalonil on the Activity of Soil Microorganisms and Enzymes. Ecotoxicology. 2018 Nov;27(9):1188-1202.

According to an independent committee of scientific and health experts, chlorothalonil may be carcinogenic. Chlorothalonil appears as colorless crystals, granules, or a light gray powder. Melting point: 250-251℃. Pure product is odorless; industrial grade product has a slightly pungent odor. It is a fungicide, available in water-dispersible granules, wettable powders, or powders. Chlorothalonil is a dinitrile compound, formed by the substitution of four chlorine atoms in phenyl-1,3-dianitronidazole. It is a non-systemic fungicide, first introduced in the 1960s for the control of various diseases in multiple crops. It is an antifungal pesticide. It is a dinitrile, tetrachlorobenzene, and aromatic fungicide. Functionally, it is related to isophthalonitrile. Turmeric has reportedly contained chlorothalonil, and there is supporting data. Chlorothalonil is a cyanide compound, belonging to the non-systemic fungicide class. Products containing chlorothalonil are sold under names such as Bravo, Echo, and Daconil. It is primarily used in peanuts, potatoes, and tomatoes. It is also used in golf courses and lawns, and as an additive in some paints. (L597)

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Mechanism of Action
Injection of monoglutathione conjugates into rats resulted in kidney damage similar to that of the parent chlorothalonil…In vitro studies using isolated kidney mitochondria showed that respiration was inhibited in the presence of chlorothalonil-derived synthetic monothiols and dithiols conjugates. …Differences in nephrotoxicity sensitivity among different species appear to be correlated with differences in the ability to produce these thiol-derived metabolites, as rats excrete more thiol-derived metabolites than dogs.
The effects on rodent kidneys are due to the action of renal β-lyases on cysteine S-conjugates to generate dithiols and trithiols. These dithiols and trithiols appear to originate from chlorothiazide glutathione conjugates.
Chlorothiazine (TCIN) inhibits the production of basal and stimulated superoxide anion (O₂⁻) in a dose-dependent manner. Similar results were obtained using yeast polysaccharides and phorbol 12-myristate-13-acetate. Pretreatment with sulfoxide (BSO) to inhibit glutathione synthesis enhanced the inhibition of superoxide anion (O₂⁻) generation. Dithiothreitol (DTT) alleviated TCIN-induced macrophage dysfunction. TCIN did not induce lipid peroxidation in macrophages. Existing data on the metabolism of chlorothiazoline in rats and dogs indicate that the parent compound binds to glutathione or cysteine-S-conjugates in the liver. These conjugates are subsequently absorbed by the gastrointestinal tract. Upon reaching the kidneys, cysteine-S-conjugates, glutathione conjugates, or thiouric acid come into contact with proximal tubular cells, where the thiouric acid precursor is ultimately "activated" by cysteine conjugate β-lyases present in the cytosol and mitochondria of proximal tubular cells. The nephrotoxicity of cysteine-S-conjugates, through activation into thiol metabolites, is associated with renal cortical mitochondrial dysfunction. Studies have shown that dithiol and trithiol analogs of clothiazide interfere with respiratory control. The toxic effects of clothiazide's thiol metabolites lead to changes in intracellular osmotic pressure in renal cortical tubular cells, resulting in vacuolar degeneration, followed by cell regeneration.

C8CL4N2

265.9

263.881

C, 36.14; Cl, 53.33; N, 10.54

1897-45-6

Chlorothalonil-13C2;2767332-24-9

15910

White to off-white solid powder

1.7±0.1 g/cm3

350.5±37.0 °C at 760 mmHg

250-251ºC

153.8±20.7 °C

0.0±0.8 mmHg at 25°C

1.633

2.88

0

2

0

14

284

0

ClC1C(C#N)=C(C(=C(C=1C#N)Cl)Cl)Cl

CRQQGFGUEAVUIL-UHFFFAOYSA-N

InChI=1S/C8Cl4N2/c9-5-3(1-13)6(10)8(12)7(11)4(5)2-14

1,3-Benzenedicarbonitrile, 2,4,5,6-tetrachloro-

Chlorothalonil; DAC 2787; Daconil; Daconil M;

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 : ~33.33 mg/mL (~125.34 mM）

Solubility in Formulation 1: ≥ 2.5 mg/mL (9.40 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 25.0 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: ≥ 2.5 mg/mL (9.40 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 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 3: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.5 mg/mL (9.40 mM)

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