Absorption, Distribution and Excretion
The overall recovery rate of mesosulfuron-methyl ester in all treatment groups was acceptable (approximately 91.6-103.8%). In rats, the primary route of excretion was urine, with urinary excretion accounting for approximately 71-95% of the total excretion in each treatment group (78-96% if cage cleaning radioactivity is considered). Fecal excretion accounted for 4.8-13.3%. Excretion was completed almost entirely within 48 hours. Based on the time course data of urinary and fecal excretion, the estimated elimination half-lives (male and female) for each group were: Group I (single low dose) 13-16 hours, Group II (21-day dietary exposure) 9-12 hours, and Group III (single high dose) 23-29 hours, indicating a significant alteration in the absorption and/or excretion process in the high-dose groups. Regardless of the exposure protocol, the radioactive load in tissues was extremely low (typically <0.1% to 1%); the highest concentrations of radioactivity were found in the gastrointestinal tract, carcass, and skin. For single or repeated low-dose groups, the radioactivity in tissues was typically >0.03 ppm. In the high-dose groups, the tissue radioactivity load in female animals (0.8 ppm in brain tissue to 7.1 ppm in liver and 8.0 ppm in kidney) was slightly higher than in male animals (0.1 ppm in blood to 1.6 ppm in liver and 2.6 ppm in kidney). No evidence of retention of the test substance or its biotransformations in vivo was found. In mammals, following oral administration of mesulfuron, mesulfuron is primarily excreted unchanged. The methoxycarbonyl and sulfonylurea groups are only partially degraded, mainly through O-demethylation and hydroxylation. Metabolites/Metabolic Substances: Four metabolites and the parent compound were detected in the urine and feces of rats in all treatment groups. The parent compound accounted for the majority of radioactivity in urine and feces (77–90% and 1.8–6.2% of the administered dose, respectively). Metabolite I was consistent with methyl 2-(((amino)sulfonyl)benzoate); metabolite II was consistent with (2-(((amino)sulfonyl)benzoic acid); and metabolite III was consistent with methyl 2-((((amino)carbonyl)amino)sulfonyl)benzoate). Metabolites I and II appear to be produced by a series of hydrolysis reactions ultimately producing saccharin, while metabolite III is formed by the breaking of two ring structures. The total metabolites in urine and feces accounted for approximately 5.4–8.2% of the administered dose in each group. The metabolite profiles of the parent compound in urine and feces were similar in nature, and all four metabolites (saccharin, metabolites I, II, and III) were found in both matrices. (Phenyl-(U)-(14)C)sulfonyl methyl ester is metabolized in isolated wheat seedlings (sensitive to sulfonyl methyl ester) to (14)C-methyl 2-(((((4-hydroxymethyl)-6-methylpyrimidin-2-yl)amino)carbonyl)aminosulfonyl)benzoic acid and its carbohydrate conjugate. This metabolic pathway is consistent with that of sulfonyl methyl ester in tolerant species such as bermudagrass. The metabolic rate of sulfonyl methyl ester in wheat is slower than that of mesosulfuron-methyl. When plants were exposed to (14)C methyl-4-hydroxy-2(((((4-methoxy-6-methyl-1,3,5-triazin-2-yl-)amino)carbonyl)amino)-sulfonyl)benzoic acid and (14)C methyl-2-(((((4-hydroxymethyl)-6-methylpyrimidin-2-yl)amino)carbonyl)amino)sulfonyl)benzoic acid (the major hydroxylated wheat metabolites of mesosulfuron-methyl and sulfomethyl, respectively), the glucose binding rate of methyl-4-hydroxy-2(((((4-methoxy-6-methyl-1,3,5-triazin-2-yl-)amino)carbonyl)amino)-sulfonyl)benzoic acid was much higher than that of methyl-2-(((((4-hydroxymethyl)-6-methylpyrimidin-2-yl)amino)carbonyl)amino)-sulfonyl)benzoic acid. Methyl 2-(((((4-hydroxymethyl)-6-methylpyrimidin-2-yl)amino)carbonyl)amino)sulfonyl)benzoate and methyl 4-hydroxy-2(((((4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino)carbonyl)amino)sulfonyl)benzoate and their parent compounds are potent inhibitors of wild-type mustard acetolactate synthase. These results indicate that wheat's intolerance to sulfamethoxam (but tolerance to the structurally similar mesulfuron-methyl) reflects not only a reduced ability to hydroxylate the parent molecule but also a reduced ability to bind the major toxic metabolite to the non-toxic portion. In mammals, after oral administration of mesulfuron-methyl, it is primarily excreted unchanged. The methoxycarbonyl and sulfonylurea groups are only partially degraded via O-demethylation and hydroxylation.

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Biological Half-Life
Based on the time course data of excretion in rat urine and feces, the estimated elimination half-lives (male and female) for each group were as follows: Group I (single low dose) 13-16 hours, Group II (21-day dietary exposure) 9-12 hours, Group III (single high dose) 23-29 hours...

Toxicity Data
LC50 (Rat) > 5,000 mg/m³/4h
Non-human Toxicity Values LC50 Rat (Male and Female) Inhalation > 5 mg/L Air/4 hours
LD50 Rat (Male and Female) Oral > 5000 mg/kg
LD50 Rabbit Dermal > 2000 mg/kg
LD50 Rabbit (Male and Female) Oral > 2000 mg/kg

Mesulfuron-methyl is an N-sulfonylurea herbicide with a sulfonyl group attached to a 2-(methoxycarbonyl)phenyl group, where a 4-methoxy-6-methyl-1,3,5-triazine-2-yl group replaces an amino hydrogen atom of the remaining urea group. It is both a herbicide and an environmental pollutant and exogenous substance. It is a benzoate, an N-sulfonylurea compound, and a methoxy-1,3,5-triazine compound. Mesulfuron-methyl is a residual sulfonylurea herbicide that kills broadleaf weeds and some annual grasses. It is a systemic compound with foliar and soil activity, inhibiting cell division in the aboveground parts and roots of plants. It has residual activity in the soil, so it can be used infrequently, but for some crops (such as sunflowers, flax, corn, or safflower), an interval of up to 22 months is required before planting. It has very low toxicity to mammals, birds, fish, and insects, but moderate eye irritation.

C14H15N5O6S

381.36

381.074

74223-64-6

52999

White crytals
White to pale yellow solid
Colorless crystals

1.473 g/cm3

647.2ºC at 760 mmHg

158°C

345.2ºC

1.593

2.03

2

9

6

26

609

0

CC1=NC(NC(OC)=N1)=NC(NS(=O)(C2=CC=CC=C2C(OC)=O)=O)=O

RSMUVYRMZCOLBH-UHFFFAOYSA-N

InChI=1S/C14H15N5O6S/c1-8-15-12(18-14(16-8)25-3)17-13(21)19-26(22,23)10-7-5-4-6-9(10)11(20)24-2/h4-7H,1-3H3,(H2,15,16,17,18,19,21)

methyl 2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoylsulfamoyl]benzoate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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 (~262.22 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.56 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 (6.56 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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 (Please use freshly prepared in vivo formulations for optimal results.)