Malathion

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Malathion
Skeletal formula of malathion
3D representation of malathion
Space filling model of malathion, showing van der Waals radii for each atom
Names
IUPAC name
Diethyl 2-[(dimethoxyphosphorothioyl)sulfanyl]butanedioate
Other names
2-(Dimethoxyphosphinothioylthio) butanedioic acid diethyl ester
Malathion
Carbofos
Maldison
Mercaptothion
Ortho malathion
Identifiers
3D model (
JSmol
)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.004.089 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C10H19O6PS2/c1-5-15-9(11)7-8(10(12)16-6-2)19-17(18,13-3)14-4/h8H,5-7H2,1-4H3 checkY
    Key: JXSJBGJIGXNWCI-UHFFFAOYSA-N checkY
  • InChI=1/C10H19O6PS2/c1-5-15-9(11)7-8(10(12)16-6-2)19-17(18,13-3)14-4/h8H,5-7H2,1-4H3
    Key: JXSJBGJIGXNWCI-UHFFFAOYAK
  • O=C(OCC)C(SP(=S)(OC)OC)CC(=O)OCC
Properties
C10H19O6PS2
Molar mass 330.358021
Appearance Clear colorless liquid
Density 1.23 g/cm3
Melting point 2.9 °C (37.2 °F; 276.0 K)
Boiling point 156 to 157 °C (313 to 315 °F; 429 to 430 K) at 0.7 mmHg
145 mg/L at 20 °C[1]
Solubility Soluble in ethanol and acetone; very soluble in ethyl ether
log P 2.36 (octanol/water)[2]
Pharmacology
QP53AF12 (WHO
)
Hazards
Flash point 163 °C; 325 °F; 436 K (greater than)[3]
Lethal dose or concentration (LD, LC):
290 mg/kg (rat, oral)
190 mg/kg (mouse, oral)
570 mg/kg (guinea pig, oral)[4]
84.6 mg/m3 (rat, 4 hr)[4]
10 mg/m3 (cat, 4 hr)[4]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 15 mg/m3 [skin][3]
REL (Recommended)
 TWA 10 mg/m3 [skin][3]
IDLH
(Immediate danger)
 250 mg/m3[3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Malathion is an

USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa
as mercaptothion.

Pesticide use

Malathion is a pesticide that is widely used in agriculture, residential landscaping, public recreation areas, and in public health pest control programs such as mosquito eradication.[5] In the US, it is the most commonly used organophosphate insecticide.[6]

A malathion mixture with

Mediterranean fruit fly.[7] In Canada and the US starting in the early 2000s, malathion was sprayed in many cities to combat west Nile virus.[8] Malathion was used over the last couple of decades on a regular basis during summer months to kill mosquitoes, but homeowners were allowed an exemption for their properties if they chose.[citation needed
].

Mechanism of action

Malathion is an acetylcholinesterase inhibitor, a diverse family of chemicals. Upon uptake into the target organism, it binds irreversibly to the serine residue in the active catalytic site of the cholinesterase enzyme. The resultant phosphoester group is strongly bound to the cholinesterase, and irreversibly deactivates the enzyme which leads to rapid build-up of acetylcholine at the synapse.[9]

Production method

Malathion is produced by the addition of

racemate.[citation needed
]

Medical use

Malathion in low doses (0.5% preparations) is used as a treatment for:

Preparations include Derbac-M, Prioderm, Quellada-M[14] and Ovide.[15]

Safety

General

Malathion is of low toxicity. In arthropods it is metabolized into malaoxon[16] which is 61x more toxic,[17] being a more potent inhibitor of acetylcholinesterase.[18] According to the United States Environmental Protection Agency, no reliable information is available on adverse health effects of chronic exposure.[19]

In 1981, Malathion was sprayed over a 1,400 sq mi (3,600 km2) area to control an outbreak of Mediterranean fruit flies in California. In order to demonstrate the chemical's safety, B. T. Collins, director of the California Conservation Corps, publicly swallowed a mouthful of dilute malathion solution.[20]

Carcinogenicity

Malathion is classified by the

non-Hodgkin's lymphoma. Malathion used as a fumigant was not associated with increased cancer risk. Between 1993 and 1997, as part of the Agricultural Health Study, no clear association between malathion exposure and cancer was reported.[21]

Amphibians

Malathion is toxic to leopard frog tadpoles.[22]

Risks

General

Malathion is of low toxicity; however, absorption or ingestion into the human body readily results in its metabolism to malaoxon, which is substantially more toxic.[23] In studies of the effects of long-term exposure to oral ingestion of malaoxon in rats, malaoxon has been shown to be 61 times more toxic than malathion,[23] and malaoxon is 1,000 times more potent than malathion in terms of its acetylcholinesterase inhibition.[18] Indoor spillage of malathion can thus be more poisonous than expected, as malathion breaks down in a confined space into the more toxic malaoxon. It is cleared from the body quickly, in three to five days.[24]

Resistance

Because it is an acetylcholinesterase inhibitor, this resistance is a type of

AChEI resistance.[16] Malathion resistance is thought to always be due to either increased carboxylesterase concentrations or altered acetylcholinesterases.[16] COE because it metabolizes malathion but into non-malaoxon products, altered AChEs because we mean specifically those altered to be less sensitive to malathion and malaoxon.[16]

See also

References

  1. ^ Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11th ed., British Crop Protection Council, Surrey, England 1997, p. 755
  2. ^ Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 80
  3. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0375". National Institute for Occupational Safety and Health (NIOSH).
  4. ^ a b c "Malathion". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  5. ^ Malathion for mosquito control, US EPA
  6. PMID 17720683
    .
  7. PMID 16914134
    .
  8. PMID 12771072
    . An extensive re-evaluation of malathion was completed by the US Environmental Protection Agency in 2000. The PMRA has also re-evaluated malathion and approved its use as a mosquito adulticide.
  9. PMID 24179466
    .
  10. ^ "Guidelines for the diagnosis and treatment of pediculosis capitis (head lice) in children and adults 2008". National Guideline Clearinghouse. Archived from the original on 2013-02-26. Retrieved 2013-01-22.
  11. ISBN 978-1-57444-822-1
    . Retrieved 27 April 2010.
  12. S2CID 25087526
    .
  13. ISBN 978-0-7817-3894-1
    . Retrieved 27 April 2010.
  14. ISSN 0260-535X
  15. ^ "AHFS Drug Information". American Society of Health-System Pharmacists. 13 January 2011. Retrieved 17 January 2011.
  16. ^
    S2CID 30758188
    .
  17. ^ a b Keigwin Jr RP (May 2009). "Reregistration Eligibility Decision for Malathion (Revised)" (PDF). US Environmental Protection Agency - Prevention, Pesticides and Toxic Substances EPA 738-R-06-030 Journal: 9.
  18. ^
    S2CID 29903092
    .
  19. ^ "US Department of Health and Human Services: Agency for Toxic Substances and Disease Registry - Medical Management Guidelines for Malathion". Archived from the original on October 21, 2002. Retrieved 2008-04-02.
  20. ^ Bonfante, Jordan (1990-01-08). "Medfly Madness". TIME. Archived from the original on July 24, 2008. Retrieved May 21, 2009.
  21. ^ "Active Ingredient Fact Sheets". npic.orst.edu.
  22. ^ "Low Concentrations Of Pesticides Can Become Toxic Mixture For Amphibians". Science Daily. November 18, 2008. Retrieved December 11, 2012.
  23. ^ a b Edwards D (July 2006). "Reregistration Eligibility Decision for Malathion" (PDF). US Environmental Protection Agency - Prevention, Pesticides and Toxic Substances EPA 738-R-06-030 Journal: 9. Archived from the original (PDF) on 2008-05-21.
  24. ^ Maugh II, Thomas H. (16 May 2010). "Study links pesticide to ADHD in children". Los Angeles Times.

External links

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