Terbuthylazine is an inhibitor of acetolactate synthase (ALS), a key enzyme in the biosynthesis of branched-chain amino acids (valine, leucine, and isoleucine) in plants. By inhibiting ALS, the herbicide disrupts protein synthesis and plant growth, leading to the death of susceptible weeds. It belongs to the triazine class of herbicides and functions by inhibiting photosynthesis in target plants.

In vitro studies have demonstrated that terbuthylazine inhibits acetolactate synthase (ALS) activity in plant extracts. The compound is active against a variety of broadleaf and grass weeds, including A. retroflexus, D. stramonium, S. nigrum, and S. halepense. Its herbicidal activity has been characterized in biochemical assays measuring ALS enzyme inhibition and in growth inhibition studies using target weed species.

In vivo, terbuthylazine is applied as a pre- and early post-emergent herbicide in agricultural fields. It is absorbed by plant roots and foliage and translocated throughout the plant. The compound inhibits photosynthesis and ALS activity in target weeds, resulting in growth inhibition and plant death. It has been found in surface groundwater and soil samples. Formulations containing terbuthylazine are used for weed control in agriculture and as algicides in water coolant systems.

The in vitro enzyme assay for terbuthylazine involves measuring the inhibition of acetolactate synthase (ALS) activity. Plant extracts or purified ALS enzyme are incubated with varying concentrations of terbuthylazine (typically 0.001-100 uM) in assay buffer containing pyruvate, thiamine pyrophosphate, and FAD at 37degC for 30-60 minutes. The reaction is stopped by acidification, and acetoin produced from acetolactate is measured colorimetrically at 525 nm after incubation with creatine and alpha-naphthol. The IC50 is determined by fitting inhibition data to a dose-response curve.

In vitro cellular assays for terbuthylazine are conducted using plant cell cultures or isolated chloroplasts to assess photosynthetic inhibition. Chloroplasts are isolated from leaf tissues and incubated with varying concentrations of terbuthylazine (typically 0.01-100 uM). Photosynthetic electron transport is measured by monitoring oxygen evolution or by measuring the reduction of 2,6-dichlorophenolindophenol (DCPIP) spectrophotometrically at 600 nm. The compound's effects on chloroplast membrane integrity and photosynthetic efficiency are assessed. Cell viability in plant cell cultures is monitored using vital stains.

In vivo animal studies for terbuthylazine typically involve administration to rodents for toxicological assessment. The compound is administered by oral gavage at varying doses (typically 1-1000 mg/kg), and clinical signs, mortality, and biochemical parameters are monitored over 14-28 days. Tissue distribution and residue analysis are performed using LC-MS/MS. The compound's presence in environmental samples (groundwater, soil) is monitored using standard analytical methods. Environmental fate studies assess the compound's degradation and persistence in agricultural ecosystems.

Absorption, Distribution and Excretion
In a rat metabolism study, Wistar rats were orally administered (14)C-tertidine (3.6 mg). Tertidine was rapidly and completely metabolized (50% excreted within 16–17 hours) and did not accumulate in tissues. Male rats excreted the radioactive material in urine and feces in equal amounts, while approximately 66% of the radiolabeled material was excreted in urine in female rats. In mammals, following oral administration, 72–84% of tertidine was excreted in urine and feces within 24 hours, and almost all was excreted within 48 hours. Tertidine (TBA) is a widely used herbicide in maize cultivation. This study evaluated the determination of TBA content in hair as an exposure biomarker. Five Sprague Dawley rats were administered TBA by gavage for three consecutive days, followed by shaving of the back hair and analysis of TBA content. In addition, at the end of the application season, hair samples were collected from 10 maize farmers, 9 rural residents, and 6 urban residents. TBA in the hair was detected by solvent extraction using liquid chromatography-triple quadrupole mass spectrometry (LC-MS). TBA was detected in all rat samples, with an average concentration of 0.92 (± 0.26) ng/mg, equivalent to an incorporation rate of 0.12%. TBA was detected in all farmer samples (median: 0.67 ng/mg), in 75% of rural resident samples (0.01 ng/mg), and was not detected in any urban resident samples (<0.01 ng/mg), with statistically significant differences among groups (P<0.01). Our results indicate that TBA enters the hair, thus warranting further investigation into the potential use of hair TBA as a biomarker of cumulative exposure.

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Metabolism/Metabolites
Tetraazine's metabolism in rats is similar to that of other chlorotriazine herbicides. The main metabolic pathway is hydrolysis of the chlorinated moiety followed by mono- or di-dealkylation. Hydroxylation may also occur at the dealkylated amino group.
Up to 25 and 15 identified metabolites were detected in urine and feces, respectively, most of which are polar metabolites. The triazine ring was not degraded.
Two common dechlorination and dealkylation/hydroxylation metabolites found in all triazine herbicides—aminoamines and aminoamino esters—were present in low concentrations in feces.
In mammals, following oral administration, a deethylated metabolite is rapidly formed, followed by a complex of products formed by the oxidation of a methyl group of the tert-butyl moiety. All of these metabolites are rapidly excreted. In the leaves of maize, sorghum, and sugarcane, tert-butylethazine is rapidly metabolized into water-soluble compounds; however, in susceptible barley, the metabolism is slower due to the substitution of a 2-chloro group by glutathione or γ-glutamylcysteine. The metabolism of atrazine (and three other triazine herbicides: tert-butylethazine, atrazine, and tert-butylethazine) in the liver microsomes of rats, pigs, and humans has been studied in vitro. The major Phase I reactions in all three species were N-monoalkylation, isopropyl or tert-butyl hydroxylation, and substrate sulfoxideization. Although all species produced the same types of metabolites, the proportions of these metabolites differed species-specifically. Subsequent studies have shown that cytochrome P450 1A2 is the major Phase I enzyme in the metabolism of triazines in human liver microsomes. /Triazine Herbicides/
The known human metabolites of tert-butylamine include 1-[[4-(tert-butylamino)-6-chloro-1,3,5-triazin-2-yl]amino]ethanol and 2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylprop-1-ol.

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Pharmacokinetic properties of terbuthylazine are characteristic of a triazine herbicide. The compound has a molecular weight of 229.71 and a molecular formula of C9H16ClN5. It is soluble in DMF and DMSO at 30 mg/mL and in ethanol at 1 mg/mL. The compound is absorbed through plant roots and foliage and translocated systemically. In mammals, it is metabolized primarily in the liver and excreted via urine and feces. The compound is stable under normal storage conditions at -20degC.

Toxicity Data
LC50 (Rat) > 3,510 mg/m³/4h

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2000 mg/kg LD50 (Rats, Transdermal Contact): >2000 mg/kg LC50 (Rats, Inhalation): >5.3 mg/L Air/4 hours

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The toxicological profile of terbuthylazine is characteristic of triazine herbicides. The compound is a selective herbicide that is relatively low in toxicity to mammals but can be toxic to aquatic organisms. The compound has been found in surface groundwater and soil samples, raising environmental concerns. The product is not for human or veterinary use. Standard safety precautions should be followed when handling the compound, including the use of appropriate personal protective equipment.

[1]. Does the effect of herbicide pulse exposure on aquatic plants depend on Kow or mode of action? Aquat Toxicol. 2005 Feb 10;71(3):261-271.

Terbutaline is a diamino-1,3,5-triazine compound with the chemical formula N-tert-butyl-N'-methyl-1,3,5-triazine-2,4-diamine, with a chlorine substitution at the 6-position. It is a herbicide, environmental pollutant, and exogenous substance. It is both a diamino-1,3,5-triazine and a chloro-1,3,5-triazine compound. Its function is similar to 6-chloro-1,3,5-triazine-2,4-diamine. Mechanism of action: Inhibition of photosynthetic electron transport at the photosystem II receptor site. Maize's tolerance to triazine compounds is attributed to their binding to glutathione. ... Herbicide, primarily absorbed by the roots.

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Terbuthylazine (CAS 5915-41-3) is a chloro-s-triazine herbicide used for pre- and early post-emergent weed control in crops including maize and sorghum. It inhibits acetolactate synthase (ALS) and photosynthesis in target plants. The compound is also used as an industrial algicide. It is available for research purposes only and is not for human or veterinary use.

C9H16N5CL

229.70984

229.109

5915-41-3

Terbuthylazine-d5;222986-60-9

22206

White to off-white solid powder

1.3±0.1 g/cm3

290.8±23.0 °C at 760 mmHg

177-179ºC

129.7±22.6 °C

0.0±0.6 mmHg at 25°C

1.580

1.26

2

5

4

15

193

0

FZXISNSWEXTPMF-UHFFFAOYSA-N

InChI=1S/C9H16ClN5/c1-5-11-7-12-6(10)13-8(14-7)15-9(2,3)4/h5H2,1-4H3,(H2,11,12,13,14,15)

2-N-tert-butyl-6-chloro-4-N-ethyl-1,3,5-triazine-2,4-diamine

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 : ~23 mg/mL (~100.13 mM)

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.)