Mite

Absorption, Distribution and Excretion
Following oral administration of fenpyroximate, rats absorbed it well. Absorbed fenpyroximate was primarily excreted via bile, with a small amount excreted via urine. Low residual levels in organs and tissues were observed 168 hours later. No evidence of bioaccumulation was found. Four male Sprague-Dawley CD rats were randomly divided into four groups and treated with a single application of 14C-pyrazole-fenpyroximate aqueous solution to a 10 cm² area of skin at doses of 0.1, 1.0, or 5.2 mg/mL for 0.5, 1, 2, 4, 10, or 24 hours, respectively, and were sacrificed at the end of the exposure period. The concentration of the radiolabeled substance in the blood was very low after all administrations. Urinary excretion was minimal but increased with prolonged exposure; 0.7–0.9% of the administered dose was excreted 24 hours after exposure. Radiolabeled fenpyroximate was detected in feces 10 and 24 hours after treatment. The fecal excretion rate was 1.4% in the 1 mg dose group, 0.5% in the 10 mg dose group, and 0.2% in the 52 mg dose group. These results indicate that fenpyroximate is hardly absorbed through the skin and is mainly excreted via bile-fecal and urinary routes. Six male and six female Sprague-Dawley rats (all with bile duct cannulation) were administered a single oral dose of 2 mg/kg of (14)C-pyrazole- or (14)C-benzyl-fenpyroximate. Within 48 hours of treatment with pyrazole-labeled fenpyroximate, 47% (female) to 55% (male) of the radiolabeled fenpyroximate was excreted via bile, 5% (male) to 10% (female) via urine, and 17% (female) to 28% (male) via feces. The total excretion rate at 48 hours after treatment was approximately 88% in males and approximately 73% in females. The Tmax, Cmax, and half-life of the radiolabeled fenpyroxime in the blood of cannulated rats were similar to those in uncannulated rats. Within 48 hours after oral administration of benzyl-labeled fenpyroxime, 47% (female) to 51% (male) of the radiolabeled fenpyroxime was excreted in bile, 6% (male) to 8% (female) in urine, and 28% (female) to 40% (male) in feces. Six male and six female Sprague-Dawley (Crl;CD) rats in each group were administered a single dose of (3-(14)C)-pyrazole- (radiochemical purity 96.4-99.9%) or (U-(14)C)-benzyl-fenpyroxime (radiochemical purity 99.2-99.5%) suspended in 1% Tween 80 aqueous solution by gavage. Blood was collected from the tail vein of five rats in each group at different time points. 168 hours post-administration. In rats given a 2 mg/kg body weight dose, the concentration of the radiolabeled substance in the blood peaked within 1 hour post-administration and then plateaued, lasting approximately 18 hours… In the group given a 400 mg/kg body weight dose, absorption was delayed, and the radiolabeled substance was undetectable in the blood within 12 hours post-administration. Near-maximal levels were reached 12–24 hours post-administration; the plateau lasted 80–100 hours…
For more complete data on the absorption, distribution, and excretion of fenpyroxime (7 compounds), please visit the HSDB record page.

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Metabolism/Metabolites
Fenpyroxime is extensively metabolized in rats; 23 metabolites have been identified. The parent compound was not detected in urine; metabolites found in feces accounted for 0–11% of the administered dose. Fenpyroxime is metabolized via multiple pathways, including oxidation, hydroxylation, demethylation, hydrolysis, and isomerization.
Fenpyroxime is extensively metabolized through hydrolytic cleavage of the oxime ether bond, hydrolysis of tert-butyl ester, oxidation of tert-butyl, hydroxylation of the phenoxy ring and 3-methyl, isomerization, N-demethylation and conjugation reactions, producing a large number of metabolites. The major metabolites identified are (E)-4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoic acid, (Z)-4-[(1,3-dimethyl-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoic acid, (E)-4-{[1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-yl]methyleneaminooxymethyl}benzoic acid, 1,3-dimethyl-5-phenoxypyrazole-4-carboxylic acid, 4-hydroxymethylbenzoic acid, terephthalic acid, 4-cyano-1-methyl-5-phenoxypyrazole-3-carboxylic acid, and (E)-2-{4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoyloxy}-2-methylpropionic acid. (E)-2-{4-[1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazol-4-yl]methyleneaminooxymethyl}benzoyloxy]-2-methylpropionic acid, and (E)-2-[{4-[3-hydroxymethyl-1-methyl-5-phenoxypyrazol-4-yl]methyleneaminooxymethyl}benzoyloxy]-2-methylpropionic acid. Six male and six female Sprague-Dawley rats (all with bile duct cannulation) were orally administered 2 mg/kg (14)C-pyrazole-labeled fenpyroximate. The parent compound benzypyroxime was not detected in bile, but the metabolites (E)-4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)-methyleneaminooxymethyl]benzoic acid, (Z)-4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)-methyleneaminooxymethyl]benzoic acid, (E)-4-{[1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-yl]methyleneaminooxymethyl}benzoic acid, (E)-2-{4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoyloxy}-2-methylpropionic acid, 1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-carboxaldehyde, and 1,3-dimethyl-5-phenoxypyrazole-4-carboxylic acid were detected. 3-Methyl-5-phenoxypyrazole-4-carboxaldehyde, 1,3-dimethyl-5-(4-hydroxyphenoxy)-pyrazole-4-nitrile, (E)-1,3-dimethyl-5-phenoxypyrazole-4-carboxaldehyde oxime, 3-methyl-5-(4-hydroxyphenoxy)-pyrazole-4-carboxaldehyde, and (E)-2-[4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoyloxy]-2-methylpropionic acid, and (E) (Z)-4-{[1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoic acid and (Z)-4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoic acid conjugates were detected as (E)-4-{[1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-yl]methyleneaminooxymethyl}benzoic acid and 1,3-dimethyl-5-phenoxypyrazole-4-carboxylic acid. The total radiolabeled amount was less than 2% of the dose. The hypothesized metabolic pathway of fenpyrazinoxime in rats is: ester bond cleavage, phenoxypyrazole group hydroxylation, tert-butyl oxidation, and binding to sulfate and glucuronide. Four male Sprague-Dawley (SLC) rats were divided into four groups and administered a single oral dose of 1.5 mg/kg body weight of (14)C-pyrazole or (14)C-benzoyl-labeled fenpyroxime (radioactive purity >99%). Urine and fecal samples were collected from 0 to 72 hours. Six urinary metabolites and 17 fecal metabolites were identified by thin-layer chromatography and co-separation from standard samples. ... The main urinary metabolites were 1,3-dimethyl-5-phenoxypyrazole-4-carboxylic acid (7.3% of the dose), 4-cyano-1-methyl-5-phenoxypyrazole-3-carboxylic acid (2.5%), and terephthalic acid (3.8%). The main fecal metabolites were (E)-4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)-methyleneaminooxymethyl]benzoic acid (4.1-11.0% of the dose), (E)-4-{[1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-yl]methyleneaminooxymethyl}benzoic acid (2.9-4.2%), and (E)-2-[4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoyloxy]-2-methylpropionic acid (3.5-4.3%); 4-hydroxymethylbenzoic acid (7.5%) was found to be a precursor of terephthalic acid, and (E)-2-[4-[1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-yl]methyleneaminooxymethyl}benzoyloxy]-2-methylpropionic acid (2.0-9.7%). And (E)-2-[{4-[3-hydroxymethyl-1-methyl-5-phenoxypyrazole-4-yl]methyleneaminooxymethyl}benzoyloxy]-2-methylpropionic acid (3.3-4.5%) is the hydroxylated product of (E)-2-[4-[(1,3-dimethyl-5-phenoxypyrazole-4-yl)methyleneaminooxymethyl]benzoyloxy]-2-methylpropionic acid. Urinary metabolites include 1,3-dimethyl-5-(4-hydroxyphenoxy)-pyrazole-4-onitrile and 3-methyl-5-(4-hydroxyphenoxy)-pyrazole-4-carboxaldehyde, while fecal metabolites include tert-butyl(E)-4-[(1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-yl)methyleneaminooxymethyl]benzoate and (E)-2-[4-[(1,3-dimethyl-5-phenoxy-pyrazole-4-yl)methyleneaminooxymethyl]benzoyloxy The concentrations of (E)-2-[{4-[1,3-dimethyl-5-(4-hydroxyphenoxy)pyrazole-4-yl]methyleneaminooxymethyl]benzoyloxy]-2-methylpropionic acid, and (E)-2-[{4-[3-hydroxymethyl-1-methyl-5-phenoxypyrazole-4-yl]methyleneaminooxymethyl}benzoyloxy]-2-methylpropionic acid could be increased by enzymatic hydrolysis of excreta by β-glucuronidase or sulfatase. In this study, at least three rats/sex/dose/time interval combinations were given a single oral dose of (pyrazole-(14)C) fenpyroxithiolate (NNI-850, purity: 99.6%) before urine, feces, volatile organic compounds, and carbon dioxide were collected. Preliminary studies showed no detection of carbon dioxide and no or below-quantitative levels of volatile organic compounds. …Single oral doses were administered at low (2 mg/kg) and high (400 mg/kg) doses. Following radiolabeled fenpyroximate treatment, the sacrifice intervals for the low-dose group were 12, 24, and 168 hours, and for the high-dose group, they were 12, 24, 96, 120, and 168 hours. The repeat-dose group received unlabeled fenpyroximate at 2 mg/kg/day for 14 days, followed by a single dose of labeled fenpyroximate at 2 mg/kg. This group was maintained for 168 hours before sacrifice. Five males and five females were used in each of the 168-hour groups, and excretory samples were collected periodically throughout the treatment period. Metabolite identification was performed by comparing the migration rates of excretory extracts using two-dimensional thin-layer chromatography with the migration rates of a range of candidate metabolites in both solvent systems (i.e., comparing standard chromatograms developed under UV light with autoradiography of fecal or urine extracts). At a single 2 mg/kg dose, approximately 8% of the fecal metabolites were the parent compound, approximately 13% were presumed to be ester hydrolysis products, and other identified metabolites accounted for approximately 5% or less of the fecal radioactivity. Unidentified metabolites remaining in situ on the thin-layer chromatography plate from 0 to 24 hours accounted for 47-50% of the fecal radioactivity in the 2 mg/kg group, compared to only 2-4% in the 400 mg/kg group, indicating that most of the drug was absorbed and metabolized after low-dose administration. The major metabolite identified in urine was clearly 1,3-dimethyl-5-phenoxypyrazole-4-carboxylic acid. This compound (designated M-8) is primarily bound in the form of a glucuronide. ...

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Biological Half-Life
Six male and six female Sprague-Dawley (Crl;CD) rats in each group were administered a single dose by gavage of 2 or 400 mg/kg body weight of (3-(14)C)-pyrazole (radiochemical purity 96.4-99.9%) or (U-(14)C)-benzylphenylpyroxime (radiochemical purity 99.2-99.5%), suspended in 1% Tween 80 aqueous solution. Five rats from each group were used, and blood was collected from the tail vein at different time points within 168 hours after administration. In rats given a dose of 2 mg/kg body weight...elimination was slow, with a half-life of 6-9 hours. In the group given 400 mg/kg body weight...the elimination phase half-life was 35-49 hours.
Two studies used five male and female rats in each group, who were administered either pyrazole-(14)C fenpyroxime ester (NNI-850) or benzyl-(14)C fenpyroxime ester (NNI-850) by gavage at doses of 2 or 400 mg/kg, dissolved in 1% Tween 80 aqueous solution. Tail vein blood was collected at intervals over 7 consecutive days. Pyrazole-(14)C study: At a dose of 2 mg/kg, the blood half-life in both male and female rats was 8.9 hours. In contrast, at a dose of 400 mg/kg, the half-lives in the blood of males and females were 49 hours and 45 hours, respectively. ... Benzyl-(14)C study: At a dose of 2 mg/kg, the half-lives in the blood of males and females were 6.1 hours and 7.9 hours, respectively. ... In contrast, at a dose of 400 mg/kg, the half-lives in the blood of males and females were 47 hours and 35 hours, respectively.

Non-Human Toxicity Values
Rat inhalation LC50 (female): 0.33 mg/L/4 hours/nasal exposure only/
Rat inhalation LC50 (male): 0.21 mg/L/4 hours/nasal exposure only/
Rat inhalation LC50 (female): 0.36 mg/L/4 hours/systemic exposure/
Rat inhalation LC50 (male): 0.33 mg/L/4 hours/systemic exposure/
For more complete non-human toxicity data for fenpyroximate (9 items in total), please visit the HSDB record page.

[1]. Demographic analysis of fenpyroximate and thiacloprid exposed predatory mite Amblyseius swirskii (Acari: Phytoseiidae). PLoS One. 2018 Nov 15;13(11):e0206030.

[2]. Fenpyroximate binds to the interface between PSST and 49 kDa subunits in mitochondrial NADH-ubiquinone oxidoreductase. Biochemistry. 2012 Mar 6;51(9):1953-63.

Fenpyroxetine is a pyrazole acaricide belonging to the tert-butyl ester class. It functions as an inhibitor of mitochondrial NADH: ubiquinone reductase. Fenpyroxetine is derived from the hydride of 1H-pyrazole. Fenpyroxetine is being investigated in the clinical trial NCT02533336 (Efficacy of durable wall lining treated with non-pyrethroid insecticides as a method of malaria control in rural areas of Tanzania, an endemic region of malaria). Mechanism of Action: The high specificity of fenpyroxetine as an acaricide is not primarily based on differences in target site sensitivity, as its inhibitory potency against mitochondrial complex I in rat liver and spider mites differs by less than 10-fold. The primary mechanism of selectivity has been shown to depend on differences in metabolic detoxification rates, particularly through the removal of the tert-butyl group to generate a free carboxylic acid analog. This metabolite does not possess complex I inhibitory activity. This apparent hydrolysis is primarily catalyzed by cytochrome PA50, via hydroxylation of the tert-butyl group followed by intramolecular ester bond cleavage. In several mammals, fish, and insects tested, oxidative ester bond cleavage occurred rapidly, but not in mites. The brains of Parkinson's disease (PD) patients showed evidence of mitochondrial respiratory complex I deficiency, oxidative stress, and neuronal death. Complex I inhibitors, such as the insecticide rotenone, cause neuronal death and Parkinson's disease in animal models. We have previously demonstrated that overexpression of DJ-1 in astrocytes enhances their ability to protect neurons from rotenone damage, while knockdown of DJ-1 attenuates astrocyte-mediated neuroprotection against rotenone, and both processes involve factors released by astrocytes. To further explore the mechanisms behind these findings, we developed a high-throughput, microplate-based bioassay to assess how genetic manipulation of astrocytes affects their ability to protect co-cultured neurons. Using this bioassay, we showed that impaired astrocyte-mediated neuroprotection caused by DJ-1 deficiency occurred only in the presence of insecticides that inhibit complex I (rotenone, pyridaben, benzoxazole, and benzimidox); while substances that inhibit complex II-V, primarily induce oxidative stress, or inhibit the proteasome did not produce this impairment. This finding may be relevant to Parkinson's disease, as epidemiological studies have shown that insecticide exposure is associated with an increased risk of Parkinson's disease. Further studies of our model showed that the astrocyte glutathione (GSH) and heme oxygenase-1 antioxidant system are not central to the neuroprotective mechanism. In this study, we investigated the in vitro toxicity and mechanism of action of several commonly used insecticides (such as terbufenpyridine) putative complex I inhibitors. Except for pyridaben (PYR), the other inhibitors showed a similar order of potency in reducing ATP levels and competitively binding (3)H-dihydrorotenone (DHR) to complex I. Neuroblastoma cells stably expressing NADH dehydrogenase (NDI1) insensitive to rotenone (ROT) in Saccharomyces cerevisiae are resistant to these pesticides, indicating that inhibition of complex I is a necessary condition for toxicity. …PYR is a more potent inhibitor of mitochondrial respiration than ROT and causes more severe oxidative damage. NDI1, or the antioxidants α-tocopherol and coenzyme Q10, can mitigate oxidative damage. PYR also exhibits strong toxicity to organoid sections of the midbrain. These data suggest that, in addition to ROT, several commercially available pesticides can directly inhibit complex I, leading to oxidative damage, and highlight the need for further investigation into the potential role of environmental factors inhibiting complex I in Parkinson's disease.

421.2

111812-58-9

(E)-Fenpyroximate;134098-61-6

9576412

White crystalline powder

1.1±0.1 g/cm3

546.2±60.0 °C at 760 mmHg

101.1 to 102.4 °C

284.1±32.9 °C

0.0±1.5 mmHg at 25°C

1.561

6.44

0

6

9

31

592

0

YYJNOYZRYGDPNH-MFKUBSTISA-N

InChI=1S/C24H27N3O4/c1-17-21(22(27(5)26-17)30-20-9-7-6-8-10-20)15-25-29-16-18-11-13-19(14-12-18)23(28)31-24(2,3)4/h6-15H,16H2,1-5H3/b25-15+

tert-butyl 4-[[(E)-(1,3-dimethyl-5-phenoxypyrazol-4-yl)methylideneamino]oxymethyl]benzoate

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)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

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.)