Permethrin

Permethrin (cyclopropanecarboxylic acid, 3-(2,2-dichloroethenyl)2,2-dimethyl-(3-phenoxyphenyl)methyl ester) 

Permethrin is classified as a restricted use pesticide (RUP) because of high toxicity to fish and aquatic organisms. Permethrin is used to control Nantucket pine tip moths, coneworms, seed bugs, and range caterpillars.4,5 

Toxicity Permethrin has an acute oral LD50 of a wide range (430 to 4,000 mg/kg) in rats. The acute dermal LD50 is greater than 2,000 mg/kg in rabbits. It has demonstrated mild skin irritation in rabbits and slight irritation to eyes in rabbits. The 

2-Dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (3-phenoxyphenyl) methyl ester, 3-(phenoxyphenyl) methyl (+)-cis, Irons 3 (2,2-dichloroethenyl) 2,2-dimethylcyclopropanecarboxylate, Ambush, Pounce. 

Colorless crystals to a pale yellow viscous liquid, mp, 35°C, bp, 220°C (0.05 mm)1 

Solubility in water below 1 ppm. Soluble or miscible with organic solvents, except ethylene glycol.1 Easily hydrolyzed. Noncorrosive. Degraded by UV light.2 

Mild irritant to the skin and eyes.1 LD50 (oral rat) 3800 mg/kg. LD50 (dermal rabbit) above 2000 mg/kg.2 LC50 (rainbow trout, 48 hours) 5.4 pg/L.3 

To each 500 mg of permethrin is added 100 mL of 10% sodium hydroxide solution and 4.7 g of potassium permanganate. The mixture is stirred at room temperature for 18 hours. Excess permanganate is reduced with sodium bisulfite and the solution is neutralized with dilute hydrochloric acid (1 volume of concentrated acid added to 5 volumes of water). The solution is poured into the drain and any residual brown manganese dioxide is discarded with regular garbage.4 

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Permeability coefficient Permeation Permenorm 5000 H2 Permenorm 3601 K2 Permenorm Z PermeOx Permethrin... 

The horn fly Haematobia irritans an important bloodsucking pest of catde, was found to be completely controlled by ear tags which slowly released permethrin and fenvalerate. These were found to give almost 100% control for 24 weeks. However, following almost universal appHcation of this ideal control measure, control failures of the pyrethroid insecticides were widely reported in North America in 1982 ndash 1983 and the practice is now abandoned. 

The pyrethroid permethrin is an effective repeUent for biting flies, mosquitoes, and ticks. A 30% permethrin cream is a general-purpose repeUent used by the U.S. Armed Forces. 

Encapsulated fonofos, a soil insecticide, was developed to coat seeds before they were planted (72). Encapsulation reduces oral toxicity 100-fold and dermal toxicity 10-fold while extending activity of the fonofos. Other encapsulated pesticides available include permethrin and parathion (69). Significantly, all commercial encapsulated pesticides are prepared by interfacial polymeri2ation. 

DEET-treated net jackets also provide good protection, but an additional appHcation of 10—25% solutions of repellent to the unprotected face is necessary for maximum protection. Clothing treated with permethrin [52645-53-1] (9) does not provide the protection expected against these insects. Because sandfly behavior and resistance to quick knockdown are responsible for the numbers of bites recorded, maximum protection from bites thus requires appHcation of DEET or another suitable repellent to the exposed skin when wearing permethrin-treated clothing (35). 

Alternatively, fabric patches treated with permethrin have been evaluated against natural and laboratory strains of human body flee in Pern. Permethrin-treated fabric is toxic to flee on contact and quickly affects feeding behavior, even when washed up to 20 times. Thus permethrin-treated clothing intermpts disease transmission, and offers a passive louse control not previously feasible (39). 

The specialities of chromatographic behaviour of cypermethrin, permethrin, X-cyhalothrin, deltamethrin and fenvalerate were investigated in this work. Gas chromatographic determination was cai ry out with use of packed column with stationai y phase of different polarity (OV-101, OV-210 OV-17) and capillary and polycapillary columns with non-polai ic stationary phase. Chromatographic peak identification was realized with attraction GC-MS method. 

Gas ehromatography mass-mass aequisition was used for the pyrethroid determination. Pyrethroids investigated were Allethrin, Prallethrin, Tetramethrin, Bifenthrin, Phenothrin, X-Cyhalothrin, Permethrin, Cyfluthrin, Cypermethrin, Flueythrinate, Fsfenvalerate, Fluvalinate and Deltamethrin. Piperonyl butoxide, main synergist eompound for pyrethroid eompounds, was also studied. 

Although statutory standards for List II substances have yet to be set in UK legislation, the Government Advice note Circular 7/89 sets out EQSs for a number of List II substances which are being applied as if they were statutory. Cyfluthrin and permethrin have agricultural approvals, but their detection in the environment is mainly associated with discharges from the moth-proofing industry. 

Alusuisse Lonza Group (Algroup) Ltd., 147 ALZA Corporation, 216 Amano Enzyme Inc., 180 Amantech Chemicals Pvt. Ltd., 168 Amber Chemical Company, 206 AMBUSH , permethrin, 12 AMCOL International Corporation, 216 Amerada-Hess Corporation, 216... 

Permethrin, a pyrethrin pesticide, decreased the inhibition of brain cholinesterase activity by methyl parathion, but methyl parathion decreased the LD50 of permethrin when the two pesticides were simultaneously administered to rats (Ortiz et al. 1995). The potentiation of permethrin lethality may be due to the inhibition by methyl parathion of carboxylesterase, which metabolizes permethrin. 

Johnson, SJ USDA To determine the resistance by soybean looper insects to methyl parathion and permethrin. 

Ortiz D, Yanez L, Gomez H, et al. 1995. Acute toxicological effects in rats treated with a mixture of commercially formulated products containing methyl parathion and permethrin. Ecotoxicol Environ Safety 32 154-158. 

Schimmel SC, Gamas RE, Patrick JM, et al. 1983. Acute toxicity, bioconcentration and persistence of AC 222,705, benthiocarb, chlorpyrifos, fenvalerate, methyl parathion and permethrin in the estuarine environment. J Agric Food Chem 31 104-113. 

Pednekar MD, Gandhi SR, Netrawali MS. 1987. Evaluation of mutagenic activities of endosulfan, phosalone, malathion, and permethrin, before and after metabolic activation, in the Ames Salmonella test. Bull Environ Contam Toxicol 38 925-933. 

The structures of some pyrethroid insecticides are shown in Figure 12.1. They are all lipophilic esters showing some structural resemblance to the natural pyrethrins. They can all exist in a number of different enantiomeric forms. Permethrin, cypermethrin, and deltamethrin, for example, all have three asymmetric carbon atoms... 

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