Permethrin

Structural formula
Structural formula without stereochemistry
General
Surname	Permethrin
other names	Permitrin 3- (2,2-Dichloroethenyl) -2,2-dimethylcyclopropanecarboxylic acid (3-phenoxyphenyl) methyl ester 3- (Phenoxy-1-yl) benzyl 3- (2,2-dichloroethen-1-yl) -2,2-dimethylcyclopropanecarboxylate
Molecular formula	C 21 H 20 Cl 2 O 3
Brief description	light brown solid (crystals, powder)
External identifiers / databases
CAS number 52645-53-1 EC number 258-067-9 ECHA InfoCard 100.052.771 PubChem 40326 DrugBank DB04930 Wikidata Q411635
Drug information
ATC code	P03 AC04
Drug class	Antiparasitic agent (external), repellent
properties
Molar mass	391.3 g mol −1
Physical state	firmly
density	1.19–1.27 g cm −3 (20 ° C)
Melting point	34-35 ° C
boiling point	> 290 ° C
Vapor pressure	2.15 · 10 −8 mmHg
solubility	almost insoluble in water (0.2 mg l −1 at 20 ° C)
safety instructions
Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution H and P phrases H: 302 + 332-317-410 P: 273-280-501
Toxicological data	383 mg kg −1 ( LD 50 ,  rat ,  oral ) > 2000 mg kg −1 ( LD 50 ,  rabbit ,  transdermal ) 0.0072 mg l −1 ( LC 50 ,  fish , 96 h; median from 146 studies ) 0.00275 mg l −1 ( LC 50 ,  crustaceans , 48 h; median from 27 studies )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Permethrin is an insecticide and acaricide from the group of pyrethroids . It acts as a contact and food poison; its spectrum of activity is very broad. Permethrin was developed by Michael Elliott's group of Rothamsted Research for the British National Research Development Corporation and has been on the market since around 1977. It is a type I pyrethroid , so it does not have a cyano-3-phenoxybenzyl group.

Areas of application

Human medicine

In humans, permethrin is effective against adult lice and their nits. It is considered better tolerated than natural pyrethrum extracts or preparations containing lindane . However, in a study in Denmark, most lice were resistant to permethrin (and malathion ).

Permethrin has been approved in Germany as a remedy for scabies since 2004 . Here it is considered an effective and well-tolerated active ingredient.

Permethrin is also used in the form of a 5% cream for rosacea .

Veterinary medicine

Veterinary medicine uses permethrin as a spot-on active ingredient to combat lice , fleas , mites and ticks in powders, sprays, shampoos, emulsions and solutions. If used correctly, it kills all of an animal's fleas within an hour, for example, with the effect lasting between two weeks and five months. However, permethrin can also be contained in preventive products such as ear tags, collars, etc., where the repellent effect of permethrin on insects, which triggers a foot-retraction effect (→ repellent ), predominates. However, resistance to the active ingredient has already been observed in the brown dog tick .

Toxicity in cats

In contrast to dogs, spot-on products containing permethrin must never be used in cats, as they lack an enzyme necessary to break down the active ingredient and it is therefore much more toxic for these animals than for other warm-blooded animals. Typical symptoms of poisoning by permethrin in cats are central nervous symptoms such as tremors, profuse salivation, cramps, shortness of breath, but also vomiting, diarrhea, fever or low temperature. Accidentally applied permethrin-containing solutions should therefore be washed out immediately with mild detergents and then consulted a veterinarian immediately.

Agriculture and Forestry

The approval of the active ingredient permethrin for plant protection was revoked by the EU Commission in 2000. In Germany, Austria and Switzerland, permethrin is no longer approved as a plant protection product.

Wood protection

In the construction industry , permethrin is used as a preventive or combating wood preservative against wood-destroying insects such. B. the longhorn beetle or the common rodent beetle used.

Use in aircraft

Certain airlines such as the South African generally use permethrin every 8 weeks (often in 2% concentrations), sometimes in the presence of passengers, to combat any insects that may have been introduced; Overall, the use of the agent in locked aircraft cabins is viewed as controversial. The Federal Institute for Risk Assessment generally rejects the use of pyrethroids or permethrin in aircraft cabins because of possible health complications and the (long-term) resistance of the active ingredients and rather recommends the application of short-term toxins that degrade within a few days or can be easily removed with cleaning agents are.

Occurrence and use in households

Textiles and carpets

As protection against clothes moths and the carpet beetle , permethrin is sometimes used for finishing wool carpets. It then gets into the house dust with the carpet abrasion. In a study, the Federal Institute for Risk Assessment was unable to identify any health risk from carpets treated with permethrin.

Textiles impregnated with permethrin are designed to protect those who wear them from dangerous insects and parasites . When the Bundeswehr is deployed abroad, soldiers wear uniforms treated with them.

Using mosquito nets treated with permethrin is considered good protection against malaria .

Indoor pest control

At the end of the 1990s, the Fraunhofer Institute for Toxicology investigated the persistence of several pest control products containing pyrethroids of type I and type II or the synergist piperonyl butoxide. The concentrations of the active ingredients were monitored in the gas phase, for suspended particles, house dust and on furniture surfaces over a period of 24 months. Permethrin was only detected in the gas phase immediately after use. High concentrations of permethrin were found on suspended particles immediately after application. This concentration decreased rapidly within two days, but a much slower rate of degradation was observed in the following 24 months. The concentration level in house dust decreased within the first 12 months, but remained almost constant from then on, which indicates long-term pollution of indoor areas.

A more recent study from 2019 shows that permethrin, which was applied both in a test house and under laboratory conditions, is degraded by around 10% within 112 days after pest control, which indicates a comparable persistence of the active ingredient under indoor conditions.

The Federal Institute for Risk Assessment recommends that pesticides should not be used by laypeople, or at most in exceptional cases. Use should be reserved for professionally trained pest controllers.

decontamination

The success of a decontamination of permethrin depends on the surface properties, the cleaning agent and the cleaning technique. Smooth surfaces such as tiles tend to be easier to decontaminate than plastic or wooden surfaces. Porous and particularly absorbent materials or surfaces such as carpets, wallpaper or clothing are difficult to decontaminate.

High-pressure or low-pressure spraying and extraction cleaning devices with which the cleaning liquor can be applied and the contaminated dirty water sucked off the surface are well suited . As a rule, a permethrin reduction of at least 85% (without taking into account the active ingredient migrated into the materials) could be achieved with one-off cleaning processes. Bioindication tests using flies, on the other hand, showed that even with strong reductions in active ingredients on surfaces, high mortality rates of insects were sometimes observed.

Stereochemistry

Due to the two stereocenters in the cyclopropane ring, permethrin has four stereoisomers (two pairs of enantiomers ). The trans enantiomer pair is known as transpermethrin .

• 

  (1 S , 3 R ) - trans enantiomer

• 

  (1 R , 3 S ) - trans enantiomer

• 

  (1 S , 3 S ) - cis enantiomer

• 

  (1 R , 3 R ) - cis enantiomer

Mode of action in insects

Insects absorb permethrin through the surface of their bodies, and it is then distributed throughout the insect's body. It is a neurotoxin and causes the Na ⁺ channels of the nerve cells to no longer close. Na ⁺ ions flow unhindered into the inside of the cell and uncontrollable nerve impulses occur. This initially leads to states of excitement with cramps, then to coordination disorders and finally to paralysis. The insect is unable to move within a few minutes, which is known as a "knock-down" effect. Death only occurs after a while. If the dose is insufficient, many of the insects affected can enzymatically detoxify permethrin and recover. By adding synergists such as piperonyl butoxide , enzymatic degradation can be prevented.

Analytics

For reliable determination of permethrin are, after an appropriate sample preparation the HPLC and gas chromatography coupled with the mass spectrometry The methodology is also suitable for the detection of Permethrin in eggs. and in adulterated spices such as oregano

toxicology

Permethrin has low acute toxicity to warm-blooded animals. The cis isomer in the mouse (intravenously and orally administered) is 10 times more toxic than the trans isomer. Therefore, the toxicity of a permethrin preparation also depends on the cis: trans mixture ratio. Permethrin is comparatively poorly absorbed through the gastrointestinal tract . Orally administered permethrin dissolved in oil is 10 times more toxic than when given with water. The LD ₅₀ in rats is given orally with a cis: trans mixture ratio of 40:60 and dissolved in corn oil as 400 mg / kg body weight. Permethrin is rapidly broken down in the body through hydrolysis . In animal experiments, the substance did not have a negative effect on the course of pregnancies and did not cause any malformations in the offspring.

As part of the evaluation of active substances according to the EU Biocidal regulation was evaluated in 2014 permethrin with the result that a substance is not genotoxic and carcinogenic and not on reproduction owns and developmental toxic potential. The US EPA has classified permethrin as a likely carcinogen if ingested orally . This was done on the basis of reproducible studies with mice that developed lung and liver tumors after feeding with permethrin.

Humans can experience different symptoms depending on the form of contact with permethrin. Contact with the skin can cause irritation and itching in the affected area. These symptoms rarely last more than 24 hours. Inhalation can cause headache, nasal and respiratory irritation, difficulty breathing, dizziness, nausea, or vomiting. Ingestion may cause a sore throat, stomach ache, nausea, and vomiting. In the 1990s, various cases of permethrin or pyrethroid poisoning including the associated long-term damage to the human nervous system were reported, including in TV reports: on the one hand, such cases were based on overdoses and repeated use of the toxic substances, on the other hand misuse, such as spraying carpets, seats and sleeping places.

Permethrin is oxidatively broken down in the liver and quickly excreted. If the synergist piperonyl butoxide is consumed at the same time , the oxidative degradation is delayed.

So far, no information or scientific studies on toxicological long-term effects are available.

Environmental impact

In the environment, permethrin can be decomposed to a certain extent by sunlight (but only by the UVC component), whereby manufacturers and studies attribute this effect to a rather insignificant role. In the soil, it binds to clay minerals and humus components; its half-life here is around 30 days. The half-life on the surfaces of plants is around 10 days. Permethrin is only slightly toxic to birds, but it is highly toxic to fish. In laboratory tests, permethrin is very toxic to bees. In the wild, bees avoid permethrin because it is repellent ( i.e. repellent ) to them.

Trade names

Worldwide: Ambush

Monopreparations

InfectoPedicul (D), NoBite (D), Infectoscab (D, A), Loxazol (CH)

Veterinary medicine: Advantix (A), Defendog (CH), Duowin (A), exspot (CH, D), Fletic (D), Permit (CH), Preventic¹ Spot-on Permethrin (D), Pulvex Spot (F, NL)
¹ Virbac sells another product called Preventic that contains Amitraz

Combination preparations

• with cypermethrin : Contra Insect (D)
• with piperonyl butoxide (PBO): Ardap vermin spray, Ardap silver fish spray, Ardap flea fogger, various Gerobug products, Indorex Defense Fogger, Trixie Fogger (fleas / vermin)
• with tetramethrin : Rubin bug spray (D), Ida Fogger
• with pyriproxyfen : Ardap long-term flea spray and Ardap Fogger (D)

Web links

• National Pesticide Information Center fact sheet

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on permethrin in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
2. ↑ EPA: Reregistration Eligibility Decision (RED) for Permethrin. United States Environmental Protection Agency, Washington DC 2007, Retrieved July 26, 2017.
3. ↑ Entry on m-phenoxybenzyl-3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropanecarboxylate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can use the harmonized classification and labeling expand .
4. ^ Richter, Müller-Stöver, Walter, Mehlhorn, Häussinger: Head lice - dealing with a resurgent parasitosis . Deutsches Ärzteblatt 102, September 9, 2005, p. A-2395.
5. ↑ M. Kristensen et al .: Survey of permethrin and malathion resistance in human head lice populations from Denmark. J Med Entomol. 43/3/ 2006 . Pp. 533-538. PMID 16739412 .
6. ↑ Haustein, Paasch: Scabies still common: Endemics in nursing homes require consistent synchronous treatment . Deutsches Ärzteblatt 102, January 10, 2005, p. A-45.
7. ↑ Guideline of the German Dermatological Society Rosacea Guideline of the German Dermatological Society - Rosacea ( Memento from May 12, 2013 in the Internet Archive )
8. ↑ ^{a b} Entry on permethrin at Vetpharm, accessed on February 15, 2018.
9. ↑ AL Eiden et al .: Determination of metabolic resistance mechanisms in pyrethroid-resistant and fipronil-tolerant brown dog ticks. In: Medical and veterinary entomology. Volume 31, number 3, 09 2017, pp. 243-251, doi : 10.1111 / mve.12240 , PMID 28639697 .
10. ↑ Richard Malik, Michael P. Ward, Aine Seavers, Anne Fawcett, Erin Bell, Merran Govendir, Stephen Page: Permethrin spot-on intoxication of cats: Literature review and survey of veterinary practitioners in Australia , Journal of Feline Medicine & Surgery, Vol 12, Issue 1, January 2010, pp. 5–14, doi : 10.1016 / j.jfms.2009.12.002 .
11. ↑ General Directorate Health and Food Safety of the European Commission: Entry on permethrin in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; Retrieved February 19, 2016.
12. ^ WHO report on aircraft and permethrin. Accessed in 2018 . 
13. ↑ BfR: Be careful when using pesticides on airplanes! 1996, accessed in 2019 . 
14. ↑ BfR (2008): No health risk from permethrin in wool carpets. BfR Opinion No. 011/2008 of December 18, 2007, accessed on July 7, 2017.
15. ↑ Klaus E. Appel, Ursula Gundert-Remy, Horst Fischer, Michael Faulde, Klaus G. Mross, Stephan Letzel, Bernd Rossbach: Risk assessment of Bundeswehr (German Federal Armed Forces) permethrin-impregnated battle dress uniforms (BDU) , In: International Journal of Hygiene and Environmental Health , Volume 211, Ed. 1-2, 2008, pp. 88-104, doi : 10.1016 / j.ijheh.2007.10.005 .
16. ↑ RW Snow, SW Lindsay, RJ Hayes, BM Greenwood: Permethrin-treated bed nets (mosquito nets) prevent malaria in Gambian children , Transactions of the Royal Society of Tropical Medicine and Hygiene, Volume 82, Issue 6, November-December 1988 , Pp. 838-842, doi : 10.1016 / 0035-9203 (88) 90011-9 .
17. ↑ TGT Jaenson, MJ Gomes, RCBarreto dos Santos, V. Petrarca, D. Fortini, J. Évora, J. Crato: Control of endophagic Anopheles mosquitoes and human malaria in Guinea Bissau, West Africa by permethrin-treated bed nets , Transactions of the Royal Society of Tropical Medicine and Hygiene, Volume 88, Issue 6, November-December 1994, pp. 620-624, doi : 10.1016 / 0035-9203 (94) 90197-X .
18. ↑ Edith Berger-Preiess, Alfred Preiess, Kriemhild Sielaff, Mechthild Raabe, Bert Ilgen, Karsten Levsen: The Behavior of Pyrethroids Indoors: A Model Study. In: Indoor Air. 7, 1997, p. 248, doi : 10.1111 / j.1600-0668.1997.00004.x .
19. ↑ LE Nakagawa, CM do Nascimento, AR Costa, R. Polatto, S. Papini: Persistence of indoor permethrin and estimation of dermal and non-dietary exposure. In: Journal of exposure science & environmental epidemiology. Volume 30, Number 3, May 2020, pp. 547-553, doi : 10.1038 / s41370-019-0132-7 , PMID 30926895 .
20. ↑ BfR: From the handling of chemical pesticides. Retrieved June 3, 1996, in 2019 . 
21. ↑ K. Buhl, C. Bond: Cleaning Up After Indoor Pesticide Misuse. National Pesticide Information Center, Oregon State University Extension Services, 2016, accessed 2020 . 
22. ^ Gerhard Winter, Rainer Sonneck: Decontamination of insecticides from various surfaces. In: International conference on urban pests. 1999, accessed in 2020 . 
23. ↑ Thomas Leiblein: Cleaning and decontamination of surfaces after insecticide applications: Comparative biological and chemical studies on the success of decontamination. 2011, accessed in 2020 . 
24. ↑ Reichert B, P Nunes MDG, Pizzutti IR, Costabeber IH, Fontana MZ, Jänich BD, Panciera MP, Arbusti D, Cardoso CD, Chim JF: Pesticide residues determination in common bean using optimized QuEChERS approach followed by solvent exchange and GC-MS / MS analysis. , J Sci Food Agric. 2020 Jan 13, PMID 31943212
25. ↑ Personne S, Marcelo P, Pilard S, Baltora-Rosset S, Corona A, Robidel F, Lecomte A, Brochot C, Bach V, Zeman F: Determination of maternal and fetal distribution of cis- and trans-permethrin isomers and their metabolites in pregnant rats by liquid chromatography tandem mass spectrometry (LC-MS / MS). , Anal Bioanal Chem. 2019 Dec; 411 (30): 8043-8052, PMID 31748895
26. ↑ Song NE, Lee JY, Mansur AR, Jang HW, Lim MC, Lee Y, Yoo M, Nam TG: Determination of 60 pesticides in hen eggs using the QuEChERS procedure followed by LC-MS / MS and GC-MS / MS. Food Chem. 2019 Nov 15; 298: 125050, PMID 31260955
27. ↑ Drabova L, Alvarez-Rivera G, Suchanova M, Schusterova D, Pulkrabova J, Tomaniova M, Kocourek V, Chevallier O, Elliott C, Hajslova J: Food fraud in oregano: Pesticide residues as adult markers. , Food Chem. 2019 Mar 15; 276: 726-734, PMID 30409655
28. ↑ BfR (2017): Allergies: Sensitization to permethrin in textiles is unlikely. , Federal Institute for Risk Assessment, April 25, 2017, p. 4, accessed on June 30, 2017 (PDF).
29. ↑ EPA (2009): Permethrin Facts. , United States Environmental Protection Agency, Washington DC 2009, accessed June 30, 2017 (PDF).
30. ↑ ARD: ARD contribution to insecticide / permethrin poisoning. Retrieved 1997 . 
31. ↑ Mirror report on insecticide use. 1997, accessed 2019 . 
32. ^ Karl Ernst von Mühlendahl: Pyrethrum and synthetic pyrethroids, page 344. In: Poisoning in childhood. 2003, accessed in 2019 . 
33. ↑ K. Toynton, B. Luukinen, K. Buhl, D. Stone: Permethrin Technical Fact Sheet. National Pesticide Information Center, March 2009, accessed July 28, 2017.
34. ^ WHO report in coordination with Bayer and Tagros India. Accessed in 2011 . 
35. ↑ FAQs - Signs & Symptoms of Pesticide Poisoning , (English).

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !