出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2016/11/14 21:42:47」(JST)
Names | |
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IUPAC name
(±)-3-Phenoxybenzyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate
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Identifiers | |
CAS Number
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52645-53-1 Y |
ChEBI | CHEBI:34911 Y |
ChEMBL | ChEMBL1525 Y |
ChemSpider | 36845 Y |
DrugBank | DB04930 Y |
ECHA InfoCard | 100.052.771 |
Jmol 3D model | Interactive image |
KEGG | C14388 Y |
PubChem | 40326 |
UNII | 509F88P9SZ Y |
InChI
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SMILES
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Properties | |
Chemical formula
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C21H20Cl2O3 |
Molar mass | 391.29 g·mol−1 |
Appearance | Colorless crystals |
Density | 1.19 g/cm3, solid |
Melting point | 34 °C (93 °F; 307 K) |
Boiling point | 200 °C (392 °F; 473 K) |
Solubility in water
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5.5 x 10−3 ppm |
Pharmacology | |
ATC code
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P03AC04 (WHO) QP53AC04 (WHO) |
Hazards | |
Main hazards | Irritating to skin and eyes, damaging to lungs |
Related compounds | |
Related pyrethroids
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Bifenthrin Deltamethrin |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Y verify (what is YN ?) | |
Infobox references | |
Permethrin is a medication and chemical widely used as an insecticide, acaricide, and insect repellent. Permethrin is a first-line treatment for scabies when used as a cream.
It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to rapidly harm most mammals or birds, but is toxic to fish and cats. In cats it may induce hyperexcitability, tremors, seizures, and death.[1] In general, it has a low mammalian toxicity and is poorly absorbed by skin.[2]
It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.[3]
Permethrin is used:
Permethrin is available for topical use as a cream or lotion. It is indicated for the treatment and prevention in exposed individuals of head lice and treatment of scabies.[4]
For treatment of scabies: Adults and children older than 2 months are instructed to apply the cream to the entire body from head to the soles of the feet. Wash off the cream after 8–14 hours. In general, one treatment is curative.[5]
For treatment of head lice: Apply to hair, scalp, and neck after shampooing. Leave in for 10 minutes and rinse. Avoid contact with eyes.[6]
In agriculture, permethrin is mainly used on cotton, wheat, maize, and alfalfa crops. Its use is controversial because, as a broad-spectrum chemical, it kills indiscriminately; as well as the intended pests, it can harm beneficial insects including honey bees, and aquatic life.[7]
Permethrin kills ticks on contact with treated clothing. A method of reducing deer tick populations by treating rodent vectors involves stuffing biodegradable cardboard tubes with permethrin-treated cotton. Mice collect the cotton for lining their nests. Permethrin on the cotton instantly kills any immature ticks feeding on the mice.
Permethrin is used in tropical areas to prevent mosquito-borne disease such as dengue fever and malaria. Mosquito nets used to cover beds may be treated with a solution of permethrin. This increases the effectiveness of the bed net by killing parasitic insects before they are able to find gaps or holes in the net. Military personnel training in malaria-endemic areas may be instructed to treat their uniforms with permethrin, as well.
Permethrin is the most commonly used insecticide worldwide for the protection of wool from keratinophagous insects such as Tineola bisselliella.[8]
Permethrin application can cause mild skin irritation and burning. Discontinue use if hypersensitivity occurs.
Permethrin has little systemic absorption, and is considered safe for topical use in adults and children over the age of 2 months. The FDA has assigned it as pregnancy category B. Animal studies have shown no effects on fertility or teratogenicity, but studies in humans have not been performed. The excretion of permethrin in breastmilk is unknown, and breastfeeding is recommended to be temporarily discontinued during treatment.[6]
Absorption of topical permethrin is minimal. One in vivo study demonstrated 0.5% absorption in the first 48 hours based upon excretion of urinary metabolites.[9]
Distribution of permethrin has been studied in rat models, with highest amounts accumulating in fat and the brain.[10] This can be explained by the lipophilic nature of the permethrin molecule.
Metabolism of permethrin occurs mainly in the liver, where the molecule undergoes oxidation by the cytochrome P450 system, as well as hydrolysis, into metabolites.[9] Elimination of these metabolites occurs via urinary excretion.
To better protect soldiers from the risk and annoyance of biting insects, the US[11] and British[12] armies are treating all new uniforms with permethrin.
Permethrin has four stereoisomers (two enantiomeric pairs), arising from the two stereocenters in the cyclopropane ring. The trans enantiomeric pair is known as transpermethrin.
Permethrin acts as a neurotoxin, slowing down the nervous system through binding to sodium channels. This action is negatively correlated to temperature, thus, in general, showing more acute effects on cold-blooded animals (insects, fish, frogs, etc.) over warm-blooded animals (mammals and birds):
Permethrin is listed as a "restricted use" substance by the US Environmental Protection Agency (EPA)[14] due to its high toxicity to aquatic organisms,[15] so permethrin and permethrin-contaminated water should be properly disposed. Permethrin is quite stable, having a half life of 51–71 days in an aqueous environment exposed to light. It is also highly persistent in soil.[16]
According to the Connecticut Department of Public Health, permethrin "has low mammalian toxicity, is poorly absorbed through the skin, and is rapidly inactivated by the body. Skin reactions have been uncommon."[17]
Excessive exposure to permethrin can cause nausea, headache, muscle weakness, excessive salivation, shortness of breath, and seizures. Worker exposure to the chemical can be monitored by measurement of the urinary metabolites, while severe overdose may be confirmed by measurement of permethrin in serum or blood plasma.[18]
Permethrin does not present any notable genotoxicity or immunotoxicity in humans and farm animals, but is classified by the EPA as a likely human carcinogen, based on reproducible studies in which mice fed permethrin developed liver and lung tumors.[19] Carcinogenic action in nasal mucosal cells due to inhalation exposure is suspected, due to observed genotoxicity in human tissue samples, and in rat livers the evidence of increased preneoplastic lesions raises concern over oral exposure.[20][21]
Animal studies by Bloomquist et al.[22] suggest a possible link of permethrin exposure to Parkinson's disease, including very small exposures:
However, a 2007 study by the same researcher concluded "little hazard to humans" existed.
A 2006 study in South Africa found residues of permethrin in breast milk in an area that experienced the use of pyrethroids in small-scale agriculture.[26]
Pesticide-grade permethrin is toxic to cats. Many cats die after being given flea treatments intended for dogs, or by contact with dogs having recently been treated with permethrin.[27]
Toxic exposure of permethrin can cause several symptoms, including convulsion, hyperaesthesia, hyperthermia, hypersalivation, and loss of balance and coordination. Exposure to pyrethroid-derived drugs such as permethrin requires treatment by a veterinarian, otherwise the poisoning is often fatal.[28][29] This intolerance is due to a defect in glucuronosyltransferase, a common detoxification enzyme in other mammals (that also makes the cat intolerant to paracetamol and many essential oils).[30] The use of any external parasiticides based on permethrin is contraindicated for cats. (Cat ecotoxicology : cutaneous 100 mg/kg - oral 200 mg/kg.)[medical citation needed]
Permethrin was first synthesized in 1973.[31]
Numerous synthetic routes exist for the production of the DV-acid ester precursor. The pathway known as the Kuraray Process uses four steps.[32] In general, the final step in the total synthesis of any of the synthetic pyrethroids is a coupling of a DV-acid ester and an alcohol. In the case of permethrin synthesis, the DV-acid cyclopropanecarboxylic acid, 3-(2,2-dichloroethenyl)-2,2-dimethyl-, ethyl ester, is coupled with the alcohol, m-phenoxybenzyl alcohol, through a transesterification reaction with base. Tetraisopropyl titanate or sodium ethylate may be used as the base.[32]
The alcohol precursor may be prepared in three steps. First, m-cresol, chlorobenzene, sodium hydroxide, potassium hydroxide, and copper chloride react to yield m-phenoxytoluene. Second, oxidation of m-phenoxytoluene over selenium dioxide provides m-phenoxybenzaldehyde. Third, a Cannizzaro reaction of the benzaldehyde in formaldehyde and potassium hydroxide affords the m-phenoxybenzyl alcohol.[32]
It is marketed by Johnson & Johnson under the name Lyclear. In Nordic countries and North America, it is marketed under trade name Nix, often available over the counter.
Human lice and pediculosis
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Species |
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Infestation |
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Treatment |
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Other terms of interest |
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Ectoparasiticides / arthropod (P03A)
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Insecticide/pediculicide |
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Acaricide/miticide/scabicide |
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Pest control: Insecticides
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Carbamates |
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Inorganic compounds |
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Insect growth regulators |
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Neonicotinoids |
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Organochlorides |
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Organophosphorus |
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Pyrethroids |
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Ryanoids |
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Other chemicals |
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Metabolites |
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Biopesticides |
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リンク元 | 「ペルメトリン」「ambush」「パーメトリン」 |
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