IC50: fungi[1]

Absorption, Distribution and Excretion
In a single-dose study, male and female rats were administered 0.5 or 25 mg/kg of metalaxyl via gavage. Over 60% of the low or high dose was excreted in urine or feces within 24 hours. The amount excreted in exhaled air was negligible. Low tissue residues were observed 6 days after treatment, indicating no significant bioaccumulation. Female rats excreted the majority of the dose (55-65%) in urine, while male rats excreted the majority (60-70%) in feces. Although no metabolites were identified, chromatograms were similar across sexes and dose groups.

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Metabolic/Metabolic Substances
A recent comprehensive study evaluated the pharmacokinetics of metalaxyl in male and female Sprague-Dawley rats following a single intravenous injection (1 mg/kg), a single oral low-dose (1 mg/kg), a single oral high-dose (200 mg/kg), or repeated oral low-dose (1 mg/kg/day for 14 consecutive days). Absorption, distribution, and elimination patterns were consistent with previous findings. No significant dose or sex differences were observed, except that females were primarily excreted in the urine, while males were primarily excreted in the feces. Metalaxyl is readily absorbed (similar elimination curves for intravenous and oral administration), extensively metabolized (<1% of the parent compound in excrement), and rapidly eliminated (70-80% eliminated within 24 hours). Ten metabolites were identified. Urinary metabolites were predominantly in conjugated form (glucuronide or sulfate), while fecal metabolites were mostly in unconjugated form. The main metabolite in both urine and feces is N-(2,6-dimethylphenyl)-N-(hydroxyacetyl)alanine. Three major metabolic pathways and one minor pathway were identified. One pathway involves the hydrolysis of ethers, followed by oxidation, ester hydrolysis, or N-dealkylation of the ester chain into the resulting alcohol. The second pathway involves the oxidation of aromatic methyl groups to benzyl acid or ester hydrolysis. The third major pathway is ester hydrolysis, sometimes accompanied by the formation of benzyl acid. The minor pathway involves meta-hydroxylation of the benzene ring. Two major metabolites in urine have not yet been identified.

Interactions
Because metalaxyl is used in tobacco, a 90-day smoke inhalation study was conducted. Male and female Fischer 344 rats were exposed to cigarette smoke containing 0, 130, 3900, or 13000 ppm metalaxyl for 4 hours daily, 5 days a week. The highest concentration of metalaxyl in the air was 5 μg/L. The concentrations in the test cigarettes were 100–1000 times the average residual level and 30–100 times the expected maximum residual level. Although this study had limitations in simulating human exposure, the results were sufficient to suggest that exposure other than that associated with heavy smoking is unlikely to produce toxicological effects. Analysis of the inhalable smoke residues showed that 30% was metalaxyl, 4% was 2,6-dimethylaniline, and 65% was unidentified substances.

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Non-human toxicity values
Oral LD50 in rats: 669 mg/kg
Oral LD50 in mice: 788 mg/kg
Oral LD50 in hamsters: 7120 mg/kg
Dermal LD50 in rabbits: >6000 mg/kg

[1]. Yinjun Zhang, et al. Bio-preparation of (R)-DMPM using whole cells of Pseudochrobactrum asaccharolyticum WZZ003 and its application on kilogram-scale synthesis of fungicide (R)-metalaxyl. Biotechnol Prog

Metalaxyl-M is an N-(2,6-dimethylphenyl)-N-(methoxyacetyl)alanine methyl ester, a more flexible R-enantiomer of metalaxyl. It is a systemic fungicide effective against downy mildew pathogens and is used to control Pythium spp. in various vegetable crops. It is an agricultural chemical. Metalaxyl-M is an N-(2,6-dimethylphenyl)-N-(methoxyacetyl)alanine methyl ester, a D-alanine derivative, belonging to the acyl amino acid class of fungicides and the aniline class of fungicides. Functionally, it is related to D-alanine. It is the enantiomer of (S)-metalaxyl.

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Mechanism of Action
Intraperitoneal injection of metalaxyl (250 mg/kg) causes a decrease in heart rate in anesthetized rats for more than 60 minutes.
Pretreatment of rats with phentolamine (a non-selective α-adrenergic receptor antagonist, intraperitoneally at a dose of 20 mg/kg) and prazosin (an α1-adrenergic receptor antagonist, intraperitoneally at a dose of 5 mg/kg) significantly reduced metalaxyl-induced bradycardia. Yohimbine (an α2-adrenergic receptor antagonist, intraperitoneally at a dose of 10 mg/kg) did not affect the effect of metalaxyl on heart rate. These results indicate that α2-adrenergic receptors mediate the bradycardic effect of metalaxyl. The effects of metalaxyl… on specific biomarkers associated with non-genotoxic co-carcinogenicity were investigated. This study investigated several CYP-dependent responses in the liver, kidneys, and lung microsomes of male and female Swiss albino CD1 mice treated with a single intraperitoneal injection (200 or 400 mg/kg body weight) or repeated injections (200 mg/kg body weight for 3 consecutive days) of the bactericide. No significant changes in absolute or relative weight were observed in the liver, kidneys, and lungs after metalaxyl treatment. While a single dose had no significant effect on monooxygenases, selective induction of CYP3A was observed in different tissues after repeated administration. An approximately 3-fold increase in CYP3A isoenzyme activity was observed in the liver (both male and female), and an approximately 5-fold increase in the oxidase activity was observed in the kidneys (male and female average). No significant changes in selected biomarkers were observed in the lungs. Furthermore, a slight but significant decrease in CYP2B1 activity was recorded in the liver (male). Overexpression of CYP3A in the liver and kidneys was confirmed by Western blot analysis… Northern blot analysis using a biotin-labeled probe of CYP3A cDNA showed that the expression of this isoenzyme in the liver is regulated at the mRNA level. Overall, these data appear to suggest that this fungicide has synergistic toxicity and synergistic carcinogenicity. The effects of metalaxyl on nucleic acid and protein synthesis in liquid cultures of Phytophthora tobacco were investigated. Metalaxyl does not inhibit the uptake of nucleic acid and protein synthesis precursors—32P, 3H-uridine, 3H-thymidine, and 14C-leucine—by mycelia. At a concentration of 0.5 μg/ml, metalaxyl strongly inhibited RNA synthesis indicated by 3H-uridine incorporation (approximately 80%). This inhibition was observed within minutes of toxin addition. Since the inhibition of 3H-thymidine incorporation into DNA and 14C-leucine incorporation into proteins became significant only after 2–3 hours, metalaxyl primarily interfered with RNA synthesis. Ribosomal RNA synthesis was most significantly affected (over 90%), while tRNA (approximately 55%) and poly(A)-containing RNA were less affected. Furthermore, mRNA synthesis was weakly inhibited, at least in the early stages of metalaxyl action. The molecular mechanism by which metalaxyl inhibits transcription remains unclear. This fungicide did not inhibit the activity of partially purified RNA polymerase isolated from fungi. On the other hand, RNA synthesis (14C-UTP incorporation) in cell homogenates and isolated nuclear components was significantly inhibited. The molecular mechanism of action of metalaxyl is discussed in this paper. RNA synthesis in certain plant systems (tomato cell cultures, nuclei isolated from the same cell cultures, and RNA polymerase purified from spinach chloroplasts) was not inhibited by metalaxyl, even at high concentrations.

C15H21NO4

279.33

279.147

70630-17-0

Metalaxyl-M-d6;1398112-32-7

11150163

Fine, white powder
... Colorless crystals ... .

1.117 g/cm3

394.3ºC at 760 mmHg

38.7ºC

192.3ºC

1.527

1.844

0

4

6

20

335

1

CC1=C(C(=CC=C1)C)N([C@H](C)C(=O)OC)C(=O)COC

ZQEIXNIJLIKNTD-GFCCVEGCSA-N

InChI=1S/C15H21NO4/c1-10-7-6-8-11(2)14(10)16(13(17)9-19-4)12(3)15(18)20-5/h6-8,12H,9H2,1-5H3/t12-/m1/s1

methyl (2R)-2-(N-(2-methoxyacetyl)-2,6-dimethylanilino)propanoate

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 : ~250 mg/mL (~895.00 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.)