The primary targets of trimethyl phosphate are not well-defined, as the compound is not a drug but rather an industrial chemical. Its biological effects are mediated through its methylating activity, which can alkylate DNA, proteins, and other macromolecules. Trimethyl phosphate may affect the nervous system, causing paralytic gait and decreased motor activity in rats. The compound has been shown to be carcinogenic in female B6C3F1 mice, inducing adenocarcinomas of the uterus/endometrium. It is also associated with the induction of benign fibromas of the subcutaneous tissue in male Fischer 344 rats. The compound may cause genetic defects.

Trimethyl phosphate exhibits potent toxicological effects in vitro. The compound is genotoxic and may cause genetic defects. It is a strong irritant to the skin, eyes, and respiratory tract. The compound's methylating activity allows it to alkylate DNA and proteins, which can lead to mutations and cell death. In cell-based assays, trimethyl phosphate has been shown to induce cytotoxicity and genotoxicity. The compound's effects on the nervous system include neurotoxicity, with symptoms such as paralytic gait and decreased motor activity observed in animal studies.

In vivo studies of trimethyl phosphate have demonstrated significant toxicity in animal models. In repeat dose toxicity studies, twelve males and one female given 250 mg/kg died during the 4th to 6th week of the dosing period, showing progressive development of a paralytic gait and decreased motor activity before death. The compound was found to be carcinogenic in female B6C3F1 mice, inducing adenocarcinomas of the uterus/endometrium. It was associated with the induction of benign fibromas of the subcutaneous tissue in male Fischer 344 rats. The NOEL is estimated to be less than 40 mg/kg/day for both repeated dose and reproductive toxicity.

Non-cell-based assays for trimethyl phosphate include genotoxicity testing using the Ames test (bacterial reverse mutation assay) to assess mutagenic potential. The compound's methylating activity can be measured using chemical assays that detect the transfer of methyl groups to nucleophilic substrates. Enzyme inhibition studies may be performed to assess effects on acetylcholinesterase and other enzymes. Physicochemical properties such as solubility, volatility, and stability are determined using standard OECD guidelines for chemical characterization. Analytical methods including GC-MS and HPLC are used for identification and quantification.

Cell-based assays for trimethyl phosphate assess cytotoxicity, genotoxicity, and mutagenicity. Various cell lines (e.g., CHO, V79, human lymphocytes) are treated with the compound at various concentrations, and cell viability is measured using MTT or similar assays. Genotoxicity is assessed using the micronucleus test, comet assay, or sister chromatid exchange assay. Mutagenicity is evaluated using the Ames test or mouse lymphoma assay. The compound's effects on DNA methylation and gene expression can be studied using epigenetic assays. Neurotoxicity is assessed in neuronal cell lines by measuring neurite outgrowth and cell viability.

In vivo animal studies for trimethyl phosphate have been conducted in rats and mice. Repeat dose toxicity studies involve administration of the compound via oral gavage at various doses for several weeks. Animals are monitored for clinical signs, body weight, and survival. Hematological and biochemical parameters are measured. Histopathological examination of tissues is performed to assess organ toxicity. Carcinogenicity bioassays have been conducted in B6C3F1 mice and Fischer 344 rats. Reproductive toxicity studies assess effects on fertility and fetal development.

Absorption, Distribution and Excretion
Most organophosphate compounds…are absorbed via the skin, conjunctiva, gastrointestinal tract, and lungs. /Organophosphate Compounds/

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Metabolism/Metabolites Rats were orally administered 100 mg/kg, and mice were intraperitoneally injected with 1000 mg/kg of 32P-labeled trimethyl phosphate. Dimethyl phosphate was primarily excreted in the urine. Only trace amounts of the parent compound were detected, and only in rats within 6 hours of administration. S-methylcysteine and S-methylcysteine N-acetate were also isolated. A small amount of S-methylglutathione was detected, presumably the initial methylation product of this series of metabolites… Trimethyl phosphate was metabolized faster in mice than in rats, but no evidence of further conversion to monomethyl phosphate was found in either animal group…

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Trimethyl phosphate has a molecular weight of 140.08 g/mol and a molecular formula of C₃H₉O₄P. The compound is a colorless liquid that is soluble in water and organic solvents. It is volatile and can be absorbed through inhalation, ingestion, and dermal exposure. The compound decomposes on burning, producing toxic fumes including phosphorus oxides. It reacts with strong bases and strong oxidants and may explode on heating during large-scale atmospheric pressure distillation. It should be stored in a cool, well-ventilated area away from incompatible materials.

Toxicity Summary
Identification and Uses: Trimethyl phosphate (TMP) is a colorless liquid. It is used as a gasoline additive to control surface ignition and spark plug carbon buildup; a methylating agent, a chemical intermediate in the production of polymethyl polyphosphate; a flame-retardant solvent for paints and polymers; and a catalyst in the preparation of polymers and resins. Human Exposure and Toxicity: The neurotoxic effects of TMP include weakness and paralysis. Animal Studies: TMP is irritating to the rabbit eyes. In rabbits, oral or dermal administration can cause flaccid and spastic paralysis. TMP is neurotoxic in Peg dogs. After 4 weeks, neurotoxicity in jumping, tactile localization, and ataxia gait was observed. Electrophysiological tests showed prolonged neuromuscular impulse conduction latency after 9 weeks, followed by a decrease in the maximum conduction velocity of sensory fibers. Peripheral nerve fibers also exhibit abnormalities at this time, including paranodecal and internodecal swelling, paranodecal demyelination, and distal rupture. TMP can cause infertility in mice, rats, and rabbits. Trimethyl phosphate primarily affects epididymal sperm, possibly by influencing sperm motility. Trimethyl phosphate can cause azoospermia in male fruit flies. Larval testicular cell studies indicate that the chemically infertile effect of this chemical targets early primary spermatocytes. In mouse developmental studies, F1 male offspring were infertile or semi-infertile due to heritable chromosomal translocations. Therefore, trimethyl phosphate can cause chromosomal damage in mouse sperm cells. In NTP carcinogenicity studies, trimethyl phosphate was associated with the development of benign fibromas in the subcutaneous tissue of male Fischer rats. No evidence of carcinogenicity of this compound was found in female rats. Trimethyl phosphate is carcinogenic in female mice, inducing uterine/endometrial adenocarcinoma. No carcinogenicity of this compound was found in male mice. Ecotoxicity studies: Oral administration of trimethyl phosphate to Japanese quail resulted in a rapid decrease in the percentage of fertilized eggs within 10 days of the first dose. Another study reported that only 81% of eggs laid by male quails treated with trimethyl phosphate within 1 to 35 days were fertilized, significantly lower than the control group.

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Non-human toxicity values
Rabbit dermal LD50: 3388 mg/kg
Rat oral LD50: 840 mg/kg
Rabbit oral LD50: 1050 mg/kg
Mouse oral LD50: 1470 mg/kg
For more non-human toxicity values (complete data) for trimethyl phosphate (8 values in total), please visit the HSDB record page.

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Trimethyl phosphate is toxic by ingestion and inhalation. It is a strong irritant to the skin, eyes, and respiratory tract. The compound is classified as Acute Toxicity Category 4 (Harmful if swallowed) and may cause genetic defects. It is a potential carcinogen (Carcinogenicity Category 1B) and reproductive toxicant (Reproductive Toxicity Category 1). The compound may cause effects on the nervous system, including paralytic gait and decreased motor activity. Vapors may cause drowsiness and dizziness. It should be handled with extreme caution using appropriate personal protective equipment.

According to the U.S. Environmental Protection Agency (EPA), trimethyl phosphate may be carcinogenic. Trimethyl phosphate is a pale straw-colored liquid. Inhalation may irritate the respiratory tract. Vapors or the liquid may irritate the skin or eyes. Ingestion may irritate the gastrointestinal mucosa. Trimethyl phosphate is a trialkyl phosphate ester, a trimethyl ester of phosphoric acid. It is used as an insect attractant and a nuclear magnetic resonance chemical shift reference compound.

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Trimethyl phosphate is an organophosphorus compound used as a methylating agent, solvent, and flame retardant in various industrial applications. It is of toxicological interest due to its neurotoxic, genotoxic, and carcinogenic effects. The compound has been classified as a potential carcinogen and reproductive toxicant. It is used as a reference standard for analytical chemistry and environmental monitoring. The compound's mechanism of toxicity involves its methylating activity, which can alkylate DNA, proteins, and other macromolecules. The compound is for research and industrial use only and is not intended for human consumption.

C3H9O4P

140.07

140.023

512-56-1

10541

Liquid
Colorless liquid

1.2±0.1 g/cm3

197.2±0.0 °C at 760 mmHg

-51 °F (NTP, 1992) ; -46 °C ; -46 °C

83.7±38.8 °C

0.5±0.3 mmHg at 25°C

1.379

-0.52

0

4

3

8

82.4

0

COP(=O)(OC)OC

WVLBCYQITXONBZ-UHFFFAOYSA-N

InChI=1S/C3H9O4P/c1-5-8(4,6-2)7-3/h1-3H3

trimethyl phosphate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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 (713.93 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.)