Absorption, Distribution and Excretion
Groups of 5 Crl:CD BR VAF/Plus rats/sex per group were dosed daily for 14 days by gavage (in 2 mL/kg corn oil vehicle) with fosthiazate at 2 mg/kg. Rats were then administered 2 mg/kg labeled fosthiazate, and were killed after 24 hrs or 168 hrs, at which time tissues (including blood) were collected for radiolabel analyses. Urine, feces, and expired air were collected at intervals after dosing. Unlabeled fosthiazate was 99% pure, and ring-labeled fosthiazate was >99% pure. There was no apparent effect of pre-treatment on metabolism... Patterns of excretion and tissue residues over time were comparable to single dose treatment. Fosthiazate is rapidly absorbed, metabolized, and excreted. Urine was the major route of excretion, whereas feces and expired air were minor routes. Neither sex-related differences in route or rate of excretion were observed. Excretion was essentially complete by 24 hrs after dosing. At 24 hrs, 75 to 82% of administered dose was eliminated. By 168 hrs after termination, 70% and 13.2% of administered dose was excreted in urine and feces, respectively. About 5.3% was eliminated as CO2.
Groups of 5 Crl:CD BR VAF/Plus rats/sex per group were dosed once by gavage (in 2 mL/kg corn oil vehicle) with fosthiazate, either 2 or 20 mg/kg. Unlabeled fosthiazate was 99% pure, and ring-labeled fosthiazate was >99% pure. Excreta and exhaled air were sampled throughout the 7-day post-exposure period. Major tissues were examined at termination for label. Expired air contained 5-6% of administered dose (in 1 N NaOH traps, presumed to be CO2), regardless of sex or dose level. Most of this was collected in the first 12 hrs. Amounts of volatile organics collected downstream from the CO2 traps were minuscule. Urinary metabolites accounted for 66-67% of administered dose in males, and 71- 73% in females. There was no apparent difference between the dose levels. Over one-half of the urinary label was collected within 6 hrs of dosing in all cases. Fecal metabolites constituted 11-12% of administered dose, regardless of sex or dose. Most of this label was collected within 48 hrs. Total percentage of administered dose found in all body tissues combined were 11.0 and 9.4% in 2 mg/kg/day and 20 mg/kg/day males, respectively; and 8.2 and 6.8% in respective females, suggesting appreciable retention. Tissue label was widely distributed at 1 week post-treatment. Highest concentrations of label at 2 mg/kg were in liver, lung, and heart. Radioactivity was clearly not concentrated in points of entry (g.i. tract) or circulation (blood), nor in the fat. This appreciable tissue retention, coupled with the significant CO2 production of labeled carbon from metabolism of the ring component, suggests that carbon from the thiazolidinyl ring is substantially assimilated into the body's carbon pool. ...
Ten Crl:CD BR VAF/Plus rats/sex/group were dosed once daily by gavage (in 2 mL/kg corn oil vehicle) with unlabeled fosthiazate at 2 mg/kg/day. On Day 15, rats were administered 2 mg/kg S-sec-butyl-labeled fosthiazate. Five/sex were sacrificed at 24 hr after dosing with label: the other 5/sex were sacrificed after 7 days. ... There was no apparent effect of the pre-treatment on distribution and excretion patterns. Fate of label in the 7-day rats in this study in percent of administered dose was: urine (73 and 74% in M and F, respectively), feces (8 and 9% in M and F), expired air as CO2 (9 and 8% in M and F), expired air as volatile organics (0.5 and 0.6% in M and F), and all tissues combined (1.8 and 1.2% in M and F). ... no sampled organ had specific radioactivity higher than 2x that of whole blood at day 7 sacrifice. Tissue sampling at 24-hr sacrifice (excluding g.i. tract, due to insufficient time for normal passage of labeled lumenal contents) found liver to have the highest specific radioactivity relative to whole blood (liver/blood ratio 4.4 in M and 2.3 in F), followed by lung (lung/blood ratio 2.0 in M and 1.6 in F), with kidney and adrenal specific concentrations slightly lower than lung, and most organs or tissues similar to or lower label concentration than whole blood. ...

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Metabolism / Metabolites
Groups of 7 Crl:CD BR VAF/Plus rats/sex were dosed once by gavage (in 2.5 mL/kg corn oil vehicle) with fosthiazate at 18 mg/kg. Non-radiolabeled fosthiazate, which contained 13C on 50% of each of the methyl carbons of the butyl group, was 99.3% pure. S-sec-butyl-2-14C-labeled fosthiazate was 97.7% pure (by MS). Investigators evaluated fate of fosthiazate in tissues and excreta over 48 hrs, and characterized major metabolites found in urine. S-sec-butyl-2-14C-labeled group in the present study produced about the same distribution of label in excreta as had been observed in /another study/ which utilized ring-labeled 14C. This suggests that both the ring and the butyl substituents undergo degradation to release appreciable CO2 (about 10% of administered dose). Identified large MW metabolites (excluding glutathione products) underwent ring opening, often with subsequent methylation of the ring sulfur. Products of oxidation of this ring sulfur, such as sulfonic acids, sulfoxides, and sulfones, constituted about 20% of administered dose. There were several observed residues of hydrolysis of the S-sec-butyl group, similarly displaying oxidation of the sulfur, with or without methylation of the sulfur. Some of the S-secbutyl group residues underwent glutathione conjugation and were manifest as N-acetyl cysteine products (not further characterized). ...
Seven Crl:CD BR VAF/Plus rats/sex were dosed once by gavage (in 2.2 mL/kg corn oil) with 22 mg/kg ring-14C-fosthiazate prior to ... identifying major metabolites. ... Nine peaks /were observed/ migrating near to the solvent front formed the largest cluster of radio-labeled components, none of which were characterized. They were considered to be small, polar, and apparently uncharged based on their mobility on a reverse-phase HPLC column and the minimal influence of a basic ion-pairing agent on their mobilities. These constituted 42% of administered dose in males, and 27% of administered dose in females. It appears that ring carbons were substantially assimilated into the carbon pool, considering together the appreciable labeled CO2 output, substantial label retention in tissues, and the presence of many small MW labeled components in urine. Three metabolites retained the S-butyl substituent and underwent opening of the thiazolidinyl ring. Together these constituted about 7% of administered label in males and 18% in females. The most abundant of these was (RS)-S-sec-butyl O-ethyl N-(2-methylsulfinylethyl) phosphoramidothioate (designated BESxP). A couple of analogous metabolites had undergone loss of the S-sec-butyl group; O-ethyl S-hydrogen N-2(methylsulfonyl)ethyl phosphoramidothioate (DBSoS) in particular (4.6% of administered dose in males, and 3.0% in females). Acetamide (a rat liver carcinogen at levels about 1000 x larger than levels observed in this study) constituted 3% and 2% of administered dose in males and females, respectively. ...
Paraoxonase (PON1) is a key enzyme in the metabolism of organophosphates. PON1 can inactivate some organophosphates through hydrolysis. PON1 hydrolyzes the active metabolites in several organophosphates insecticides as well as, nerve agents such as soman, sarin, and VX. The presence of PON1 polymorphisms causes there to be different enzyme levels and catalytic efficiency of this esterase, which in turn suggests that different individuals may be more susceptible to the toxic effect of OP exposure.

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Biological Half-Life
Groups of 5 Crl:CD BR VAF/Plus rats/sex per group were dosed once by gavage (in 2 mL/kg corn oil vehicle) with fosthiazate, either 2 or 20 mg/kg. Unlabeled fosthiazate was 99% pure, and ringlabeled fosthiazate was >99% pure. ... Median initial half-life estimates (defined as peak blood concentration time to 12 hrs post-dosing) were 14.9 or 11.5 hrs for low dose males and females, respectively. High dose initial half-life estimates were 8.6 hrs for both males and females. Median half-life values for the later phase of 18 to 168 hrs were 76 and 66 hrs for 2 mg/kg males and females, respectively; and 92 and 87 hrs for 20 mg/kg males and females, respectively. ...

Toxicity Summary
Fosthiazate is a cholinesterase or acetylcholinesterase (AChE) inhibitor. A cholinesterase inhibitor (or 'anticholinesterase') suppresses the action of acetylcholinesterase. Because of its essential function, chemicals that interfere with the action of acetylcholinesterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death. Nerve gases and many substances used in insecticides have been shown to act by binding a serine in the active site of acetylcholine esterase, inhibiting the enzyme completely. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop. Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds, which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate), and a terminal oxygen.

[1]. Chiral organophosphorous pesticide fosthiazate: absolute configuration, stereoselective bioactivity, toxicity, and degradation in vegetables. J Agric Food Chem. 2020 Jul 22;68(29):7609-7616.

Fosthiazate is a phosphonic ester, an organic phosphonate and an organothiophosphate insecticide. It has a role as an EC 3.1.1.7 (acetylcholinesterase) inhibitor, an agrochemical and a nematicide.
Fosthiazate has been reported in Capparis spinosa with data available.
Fosthiazate is a member of the organophosphate class of pesticides or nematicides and is used to control nematodes species on tomatoes.

C9H18NO3PS2

283.35

283.046

98886-44-3

91758

White to off-white <25°C powder,>25°C liquid

1.3±0.1 g/cm3

371.3±25.0 °C at 760 mmHg

178.3±23.2 °C

0.0±0.8 mmHg at 25°C

1.541

0.94

0

5

6

16

301

0

CCC(C)SP(=O)(N1CCSC1=O)OCC

DUFVKSUJRWYZQP-UHFFFAOYSA-N

InChI=1S/C9H18NO3PS2/c1-4-8(3)16-14(12,13-5-2)10-6-7-15-9(10)11/h8H,4-7H2,1-3H3

3-[butan-2-ylsulfanyl(ethoxy)phosphoryl]-1,3-thiazolidin-2-one

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.)