Absorption, Distribution and Excretion
Four beagle dogs (four per group, half male and half female) were administered 96.6% pure sulfamethoxazole via gavage at doses of 0, 1, 3, or 6 mg/kg/day for one year. Blood and urine samples were collected periodically to assess tissue clearance and excretion patterns of sulfamethoxazole. The no-adverse-effect level (NOEL) was determined to be 3 mg/kg/day based on decreased food intake in males and females, increased soft or watery stools in males, and a slight increase in brownish vomit in both males and females during the first 2–3 weeks of the study. Peak plasma concentrations of sulfamethoxazole were reached approximately 2 hours after administration, with approximately 40% of the peak concentration remaining after 24 hours; sex had no significant effect on plasma concentrations. The terminal plasma half-life of sulfamethoxazole was estimated to be approximately 20 hours (applicable to both males and females). Typically, approximately 60% to 80% of the administered dose was recovered from urine collection over 24 hours, excreted as maternal sulfamethoxazole.
When rats were orally administered labeled sulfafluoride, approximately 93% of the dose was excreted in urine and feces as maternal sulfafluoride. The major metabolite in urine was a glucuronide conjugate of the sulfafluoride metabolite X11721061, accounting for approximately 2% to 4% of the administered dose. Several other unidentified trace components were also present in urine and fecal samples, each at less than 1% of the administered dose…
/Milk/ When lactating goats were orally fed labeled sulfafluoride at a concentration of 12.2 ppm, approximately 4% of the dose appeared in milk and 3% in tissues.
Rats were given sulfafluoride with a purity of 95.6%…containing appropriate amounts of C14 ring-labeled sulfafluoride with a purity of 97.6% and more than 2% of XR-208 ketone byproducts. Grouping was as follows: (1) a single low-dose (5 mg/kg) gavage; (2) a single high-dose (100 mg/kg) gavage; (3) daily low-dose (5 mg/kg) unlabeled sulfaflutole, followed by 5 mg/kg labeled sulfaflutole on day 15; or (4) a single intravenous injection of 5 mg/kg. The time to sacrifice was 168 hours. Kinetics were typically assessed by detecting markers in blood, excreta, and tissues. Metabolic residues were determined in urine and feces. Tissue residues were very low or below the limit of detection. Within 12 hours of administration, approximately 65-70% of the administered dose was excreted in the urine and rapidly cleared. Within 24 hours, 4-5% of the administered dose remained in the feces. Carbon capture results were typically below the limit of detection. No significant effect was observed with 14 days of low-dose pretreatment. In all these cases, approximately 92% of the administered dose was excreted in the urine and 5-7% in the feces, with no significant gender difference and regardless of dose level. Following intravenous administration, 97-101% of the estimated dose is excreted in urine and 6-9% in feces. Similar to gavage administration, very little residue remains in the blood or visceral organs after 7 days. The estimated time to peak plasma concentration (Tmax) after a single gavage administration is typically 1-2 hours. Regardless of dose or route of administration, the half-life (t1/2) of the first phase of plasma elimination is 4-6 hours, and the second phase elimination lasts approximately 40 hours. A similar pattern is observed based on erythrocytes, except that the t1/2 of the second phase is approximately 50-75 hours. Two adjacent large peaks were identified as two diastereomers of the parent sulfafluoride, constituting the majority of the radioactive material in the excrement. The first peak eluted in urine (“peak F”) accounts for approximately 53% of the administered dose, while the second peak (“peak G”) accounts for approximately 37%. This ratio of small amounts of radioactive material in feces is typically greater than 2:1. These results suggest that the labeled test substance is not a racemic mixture, and that the metabolism of one isomer may preferentially over the other. Except for one glucuronide (X11721061), the levels of other metabolites did not exceed 1% of the administered dose. This glucuronide apparently involves the cleavage between the sulfur atom and the methylene carbon atom of sulfafluoride, followed by a binding reaction at the cleavage site. Other smaller peaks were not characterized. This conjugate was quantified only in urine…
For more complete data on the absorption, distribution, and excretion of sulfafluoride (7 in total), please visit the HSDB record page.

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Metabolism/Metabolites
During days 3–4 of the administration phase, residual levels in milk plateaued at approximately 0.2 mg/kg equivalent. Similar ¹⁴C levels were also found in the liver, kidneys, milk, and muscle; while lower levels were observed in adipose tissue. This study indicates that X11719474 is not metabolized in goats: no metabolites were detected, and all radioactivity detected in tissues was derived from X11719474. When 11.8 ppm of the labeled sulfadiazine metabolite X11719474 was added to laying hen feed for oral administration, approximately 0.5% of the administered dose was recovered in eggs, fat, and tissues. Sup>14C levels were similar in liver, muscle, and eggs; levels were lower in adipose tissue. Approximately 92% of the dose was recovered from feces, and 0.3% from cage flushing fluid. Residual levels in eggs plateaued on day 4 of the administration period, with no other compounds detected except for X11719474. This study indicates that X11719474 is not metabolized in hens: no metabolites were detected, and all radioactivity detected in tissues was derived from X11719474. /Sulfamethoxam Metabolites/ Except for X11519540, all tested metabolites were less toxic than the parent compound. X11519540 exhibited higher acute and short-term toxicity than the parent compound.
The plant and animal (rat) metabolite X11721061 of sulfafluoride has low acute oral toxicity in rats (LD50 > 2000 mg/kg body weight) and has not shown genotoxicity in mammalian or microbial in vitro test systems. In a 28-day oral toxicity study in rats, the NOAEL was determined to be 3000 ppm (equivalent to 236 mg/kg body weight/day) based on the reduction in feed consumption at 8000 ppm (equivalent to 622 mg/kg body weight/day). /Sulfafluoride metabolites/

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Biological half-life
Four beagle dogs (each group of different sexes) were administered sulfafluoride by gavage at doses of 0, 1, 3, or 6 mg/kg/day for 1 year… The estimated terminal plasma half-life of sulfafluoride is approximately 20 hours (applicable to both sexes).
…In F344/DuCrl rats… Plasma samples were evaluated, and an elimination half-life of 8–9 hours was found.
Rats were administered sulfamethoxazole with a purity of 95.6%...containing an appropriate amount of C14 ring-labeled sulfamethoxazole (purity 97.6%) and more than 2% of XR-208 ketone byproducts. The groups were as follows: (1) a single low-dose (5 mg/kg) gavage; (2) a single high-dose (100 mg/kg) gavage; (3) daily low-dose (5 mg/kg) unlabeled sulfamethoxazole, followed by 5 mg/kg labeled sulfamethoxazole on day 15; (4) a single intravenous injection of 5 mg/kg. ...Regardless of dose or route of administration, the plasma elimination phase I half-life (t1/2) was 4-6 hours, and phase II elimination lasted approximately 40 hours. The erythrocyte-based elimination pattern was similar, except the phase II half-life was approximately 50-75 hours. ...

Toxicity Summary
Identification and Uses: Sulfafluridine is a white powder with a pungent odor and is registered as an insecticide in the United States. However, approved insecticide uses may change periodically, so it is essential to consult federal, state, and local authorities for information on currently approved uses. Sulfafluridine is the first member of the novel insecticide class—sulfonyl imines—and is a potent activator of the nicotinic acetylcholine receptor (nAChR) in insects. Human Exposure and Toxicity: Studies have shown that sulffafluridine has no agonistic effect on nAChR in human fetal or adult muscle. Data support the conclusion that the effects of sulffafluridine on rat development are mediated by sustained activation of fetal muscle nAChR during late fetal development and are considered irrelevant to humans. Animal Studies: Toxicity and mechanistic studies in rats, rabbits, dogs, and mice have shown that sulffafluridine is also an activator of nAChR in mammals, but to a much lower degree than in other animals and exhibits species specificity. The nervous system and liver are target organs for sulfafluoride and its major metabolites, which can cause hepatotoxicity, including changes in liver weight and enzymes, hypertrophy, proliferation, and hepatocellular adenocarcinoma observed in subchronic and chronic rodent studies. Developmental toxicity, manifested as skeletal abnormalities and neonatal death, has been observed only in rats. Skeletal abnormalities, including forelimb flexion, clavicle bending, and hindlimb rotation, are likely due to skeletal muscle contraction caused by intrauterine skeletal muscle nAChR activation. Diaphragmatic contraction (also associated with skeletal muscle nAChR activation) can impair normal neonatal breathing and lead to increased mortality in reproductive studies. Oral administration of medium and high doses of sulfafluoride resulted in reduced food intake, leading to weight loss and alterations in the male reproductive system. Changes in male reproductive organs were observed in rat carcinogenicity studies, including increased testicular and epididymal weight, seminiferous tubule atrophy, and reduced secretions from the coagulating glands, prostate, and seminal vesicles. Furthermore, an increased incidence of interstitial cell (Leydig cell) tumors was also observed, which is thought to be due to testicular dysfunction. At the highest test dose, muscle tremors and twitches, seizures, hind limb abduction, increased lacrimation and salivation, pupillary constriction and decreased tactile response, gait abnormalities, and decreased rectal temperature were observed. Decreased motor activity was also observed in the medium and high dose groups. No chromosomal aberrations were detected with sulfafluoride before and after metabolic activation, and it was also negative for Salmonella typhimurium strains TA 1535, TA 100, TA 1537, and TA 98 and Escherichia coli strain WP2 uvrA in the standard reverse mutation assay.

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Interaction
Researchers prepared isolated phrenic nerve-hemiegia specimens from newborn rats. The system included a muscle strain gauge sensor, a stimulating electrode fixed to the phrenic nerve, and a tissue specimen fixed in a container that could be replaced with test solutions as needed. Researchers hypothesize that sulfafluoride is an agonist of embryonic nicotinic acetylcholine receptor (nAChR). Preliminary tests confirmed that 100 μM acetylcholine (ACh) can induce muscle contraction and reduce muscle twitching responses induced by phrenic nerve stimulation, which return to normal after rinsing. 10 μM tubocurarine can rapidly reduce muscle tone and muscle twitching responses. Sulfaflurane-induced muscle contraction is similar to that induced by ACh: 100 μM sulffaflurane has no significant effect on muscle twitching induced by nerve stimulation, while 1 mM sulffaflurane reduces the muscle twitching response to approximately 34% of normal levels. Simultaneous administration of 10 μM tubocurarine and 1 mM sulffaflurane can block approximately 50% of muscle contraction. Pre-incubation with 10 μM tubocurarine can essentially eliminate muscle contraction induced by 1 mM sulffaflurane. Prolonged exposure to 1 mM sulffaflurane (7 minutes) results in sustained muscle contraction and reduced muscle twitching responses, which recover after rinsing. The test results support the hypothesis that neonatal death may be due to respiratory impairment caused by diaphragmatic failure.

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Non-human toxicity values
Oral LD50 in rats: 1000 mg/kg body weight
Dermal LD50 in rats: >5000 mg/kg body weight
Inhalation LC50 in rats: >2.09 mg/L (4 hours, nasal exposure only)

[1]. Mode of Action of Sulfoxaflor on α-bungarotoxin-insensitive nAChR1 and nAChR2 Subtypes: Inhibitory Effect of Imidacloprid. Neurotoxicology. 2019 Sep;74:132-138.

[Methyl(oxide){1-[6-(trifluoromethyl)pyridin-3-yl]ethyl}-λ(6)-sulfinyl]cyanamide belongs to the pyridine class of compounds, with the structure 5-ethyl-2-trifluoromethylpyridine, wherein the ethyl group at position 1 is replaced by an N-cyano-S-methylsulfonylimide group. The insecticide sulfone chloride is a mixture of four possible stereoisomers generated from two tetrahedral stereocenters. It belongs to the pyridine, sulfonylimide, nitrile, and organofluorine compounds classes.

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Mechanism of Action
This report effectively utilizes the mechanism of action sequence… to explain the non-significantly increased incidence of preputial adenocarcinoma in a combined rat study. The proposed sequence is as follows: (1) Increased release of dopamine from the hypothalamus leads to (2) decreased secretion of prolactin from the pituitary gland, which in turn leads to (3) reduced stimulation of prolactin receptors on testicular interstitial cells, thereby reducing the density of luteinizing hormone (LH) receptors in testicular interstitial cells, leading to (4) downregulation of LH receptor gene expression, leading to (5) a transient decrease in serum testosterone, leading to (6) an increase in serum LH levels, leading to (7) an increase in serum testosterone through the hypothalamic/pituitary/gonadal feedback loop, leading to (8) an increase in preputial adenocarcinoma due to a slight increase in circulating testosterone. The authors noted that item (3) appears to be irrelevant to humans (a statement consistent with published literature)...
The novel agricultural molecule sulfamethoxazole (X11422208) can cause adverse reactions (forelimb flexion, hindlimb rotation, and clavicle bending) and neonatal death in rat fetuses at high doses (400 ppm in feed); however, such adverse reactions were not observed in rabbit dietary studies despite similar maternal and fetal plasma exposure levels. To verify the hypothesis that the effects of sulfamethoxazole on rats are due to a single mechanism of action (MoA) induced by its activation of fetal rat muscle nicotinic acetylcholine receptors (nAChR), researchers conducted Mechanism of Action (MoA) studies. These studies included cross-fostering and critical exposure window studies in rats, in vitro nAChR agonist experiments in fetal and adult rats and humans, and studies on phrenic nerve-hemiethorrhea contracture in newborn rats. The substantial evidence from these studies supports a novel mechanism of action: sulfamethoxazole is an agonist of nAChR in fetal rat muscle but has no agonist effect on nAChR in adult rat muscle. In fetal/newborn rats, sustained agonist activity of this receptor with sulfamethoxazole leads to persistent rhabdomyos contractures accompanied by decreased muscle responsiveness to physiological neural stimulation. Fetal effects are induced with only one day of exposure in late pregnancy but are rapidly reversed after birth, consistent with the pharmacological mechanism of action. Regarding human relevance, the studies indicate that sulfamethoxazole has no agonist effect on nAChR in human fetal or adult rat muscle. In summary, the data support the hypothesis that the developmental effects of sulfamethoxazole in rats are mediated by sustained agonist activity of fetal muscle nAChR in late fetal development and are independent of human involvement.

C10H10F3N3OS

277.2652

277.05

946578-00-3

16723172

White to off-white solid powder

1.34g/cm3

363.8ºC at 760 mmHg

112 °C (99.7% purity)

173.8ºC

1.519

3.605

0

7

2

18

459

0

ZVQOOHYFBIDMTQ-UHFFFAOYSA-N

InChI=1S/C10H10F3N3OS/c1-7(18(2,17)16-6-14)8-3-4-9(15-5-8)10(11,12)13/h3-5,7H,1-2H3

N-(methyloxido(1-(6-(trifluoromethyl)-3-pyridinyl)ethyl)-lambda4-sulfanylidene)cyanamide

Sulfoxaflor GF 2372 XDE-208GF-2032XDE 208GF 2032

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)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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