Imazapic targets acetohydroxyacid synthase (AHAS) / acetolactate synthase (ALS), a key enzyme in the biosynthesis of branched-chain amino acids (valine, leucine, and isoleucine) in plants. By inhibiting this enzyme, the compound blocks protein synthesis and plant growth, leading to weed death. This target is specific to plants and certain microorganisms, making imazapic selective for herbicidal activity.

In vitro, imazapic inhibits AHAS/ALS activity in plant extracts. The enzyme is extracted from plant tissues and incubated with varying concentrations of the compound and its substrates (pyruvate or 2-ketobutyrate). ALS activity is measured by quantifying the production of acetolactate or acetohydroxybutyrate using colorimetric or radiometric methods. IC₅₀ values are calculated from dose-response curves.

In vivo, imazapic is used as a selective herbicide for the control of annual grass weeds and some broadleaf weeds. It is applied post-emergence and is absorbed by both foliage and roots. The compound is systemic and translocates throughout the plant, accumulating in meristematic tissues where it inhibits growth. Its herbicidal activity has been demonstrated in various field and greenhouse studies.

For in vitro enzyme assays, imazapic is tested against plant AHAS/ALS. The enzyme is extracted from plant tissues such as leaves or seedlings. The enzyme preparation is incubated with varying concentrations of the compound and the substrate (pyruvate) in the presence of cofactors (Mg²⁺, TPP, FAD). ALS activity is measured by quantifying acetolactate production using colorimetric detection with creatine and alpha-naphthol. IC₅₀ values are determined from dose-response curves.

For in vitro cell-based assays, imazapic is typically tested on plant cell cultures, such as tobacco or Arabidopsis cell suspension cultures. Cells are treated with the compound at various concentrations (typically 0.1-100 µM) for 24-72 hours. Cell growth and viability are assessed by measuring fresh weight, dry weight, or using vital stains. Branched-chain amino acid levels can be measured by HPLC or LC-MS to confirm target inhibition.

For in vivo plant experiments, imazapic is applied to target weeds in greenhouse or field settings. The compound is typically applied as a foliar spray at rates ranging from 50-200 g active ingredient per hectare. Weed control efficacy is assessed by visual scoring of phytotoxicity, measurement of plant height and biomass, and determination of the percentage of weed biomass reduction compared to untreated controls.

Absorption, Distribution and Excretion
Imidazopyridine does not bioaccumulate in animals; if ingested, it is rapidly excreted in urine and feces. 5 Crl:CD BR rats (half male and half female in each group) received a single dose of (14)C-imidazopyridine (CL 263,222) via gavage or intravenous injection at a dose of 10 or 1000 mg/kg. One group of rats received daily oral administration of non-radiolabeled imidazopyridine for 14 consecutive days, followed by a single oral administration of (14)C-labeled imidazopyridine (10 mg/kg). After radiolabeled administration, the animals were housed alone in metabolic cages and sacrificed after 7 days. Radioactivity was analyzed in feces, urine, cage cleaning/rinsing fluid, cage wiping fluid (methanol extraction), blood, fat, heart, spleen, ovaries, uterus, bones (femur), brain, kidneys, liver, lungs, muscles (thigh), testes, and the remaining carcass using liquid scintillation counting (LSC). Metabolite profiles in urine, dissolved urinary precipitate, and fecal extract (ether) were determined using thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The primary route of excretion of the administered radioactive material was urine. The mean percentage of total dose (including cage cleaning and wiping fluid) ranged from 94.0% to 102% in males and 94.5% to 102% in females. The mean percentage of total dose excreted in feces ranged from 0.79% to 3.44% in males and 0.59% to 3.50% in females. Most of the radioactive material was eliminated from the body within 6 hours of administration. Seven days after a single dose of 10 mg/kg, the average concentration of radioactive material in the blood was undetectable. At a dose of 1000 mg/kg, the concentration of radioactive material in the blood of male animals was 0.127 ppm, and the concentration of radioactive material in the blood of female animals was less than 0.1 ppm. At doses of 10 mg/kg and 1000 mg/kg, the average concentration of radioactive material in tissues was generally undetectable (less than 0.01 ppm). The residual radioactive material concentration in the carcass ranged from less than 0.001 ppm to 0.043 ppm. The unmodified test compound (14)C-imidazopyridine acid showed radioactivity in urine (94% to 102% of the total dose) and feces (0.59% to 3.50% of the total dose) at ≥ 93.5% and ≥ 65.9% of the total radioactivity, respectively…

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Metabolites/Metabolites
Five Cr1:CD BR rats of each sex were administered (14)C-imidazopyridine acid (CL 263,222) via gavage or intravenous injection as a single dose. One group of rats received non-radioactively labeled (14)C-imidazopyridine acid orally for 14 consecutive days, followed by a single oral administration of (14)C-labeled (14)C-imidazopyridine acid (10 mg/kg). Animals were housed in metabolic cages after being radiolabeled with the drug and sacrificed 7 days later… Metabolites CL 303,459 and CL 263,284… as well as several trace radioactive components were also detected (<5% of the total radioactivity in the sample). Metabolites CL 303,459 (4.29% (male) to 5.38% (female) of the sample radioactivity), CL 263,284 (1.96% (male) and 0.85% (female)) and CL 290,610 (0.69% (male) and 0.70% (female)) were detected in feces. The absolute content of each metabolite was less than 0.2% of the administered dose. Several unknown metabolites accounted for less than 6% of the total radioactivity in the fecal sample. (14) The proposed metabolic pathway of C-imidazolic acid is based on components identified in excrement. (14) The oxidation of the methyl group on the pyridine ring of C-imidazolium acid produces metabolites CL 263,284. The presence of CL 303,459 indicates that the initial step is cyclization, which is reduced to intermediate CL 280,442, followed by hydrolysis to CL 303,459, and further hydrolysis to CL 290,610.
Pharmacokinetic data for imazapic in animals are limited, as it is primarily used as a herbicide. In plants, the compound is absorbed through foliage and roots and translocated systemically. It is metabolized in plants via hydroxylation and conjugation pathways. The compound has a molecular weight of 275.30 g/mol and formula C₁₄H₁₇N₃O₃. In soil, it has moderate persistence with a half-life of 60-120 days.

Non-Human Toxicity Values
Rabbit dermal LD50 >2000 mg/kg; Rat oral LD50 >5000 mg/kg
Toxicological data for imazapic indicate that it has low acute toxicity in mammals. The oral LD₅₀ in rats is greater than 5000 mg/kg. It is not a skin sensitizer or irritant. However, it may be toxic to aquatic organisms and should be used with caution near water bodies. The compound is classified as a research-grade herbicide and is not for human therapeutic use.

5-Methyl-2-[4-methyl-5-oxo-4-(propyl-2-yl)-4,5-dihydro-1H-imidazol-2-yl]pyridine-3-carboxylic acid is a pyridine monocarboxylic acid, formed by substituting 4,5-dihydroimidazol-2-yl at the 2-position of 5-methylpyridine-3-carboxylic acid, which is then further substituent at the 4, 5, and 6 positions with isopropyl, methyl, and oxo groups, respectively. It is a pyridine monocarboxylic acid, belonging to the imidazolinone class of compounds, and also a methylpyridine class of compounds. Imidazole acid is a chemical substance used as a herbicide. It can control a variety of broadleaf weeds and control or suppress certain grass weeds in pastures, grasslands, and certain types of lawns. Its half-life in soil is approximately 120 days.

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Mechanism of Action
Imidazolidinyl acid (IMZR), imidazolidinyl acid (IMZC), imidazolium acetonicotinic acid (IMZT), imidazolium acetonicotinic acid (IMZX), and imidazolium quinolinic acid (IMZQ)... all belong to the imidazolinone (IMI) class of herbicides. Their mechanism of action is to inhibit acetylhydroxy acid synthase (AHAS), which is involved in the biosynthesis of amino acids such as leucine, isoleucine, and valine.
Imazapic is a research-use only compound and has not been approved for human clinical applications. It is also known as imazamethapyr. Its molecular weight is 275.30, and its formula is C₁₄H₁₇N₃O₃. The compound has a melting point of 206.0-210.0°C. It is available from various research chemical suppliers for herbicidal and plant science research.

C14H20N4O3

292.33

275.126

104098-48-8

91770

White to off-white solid powder

1.3±0.1 g/cm3

434.2ºC at 760 mmHg

208 °C

216.4ºC

5.72E-10mmHg at 25°C

1.621

0.97

2

5

3

20

461

0

PVSGXWMWNRGTKE-UHFFFAOYSA-N

InChI=1S/C14H17N3O3/c1-7(2)14(4)13(20)16-11(17-14)10-9(12(18)19)5-8(3)6-15-10/h5-7H,1-4H3,(H,18,19)(H,16,17,20)

5-methyl-2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl)pyridine-3-carboxylic acid

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 : ≥ 100 mg/mL (~363.24 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (9.08 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 (9.08 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
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.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (9.08 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.)