Pyriproxyfen

Pyriproxyfen is a novel kind of insect growth regulator which was successfully developed by Sumitomo Chemical Industry Co., Ltd (Japan) It has the same effect on the insect as juvenile hormone and has various kinds of effects such as inhibiting the mosquitoes, pupating of the flies larvae and its feathering. Upon being exposed to this drug agent, the larvae of mosquitoes and flies will mostly die in the pupal stage without being able to get into feathering. The duration of this agent will persist up to a month or so. Moreover, it is convenient for using with no odor and is a good kind of drugs for killing of mosquito and fly.

According to our pesticide toxicity grading standards, pyriproxyfen belongs to low toxicity pesticides. The acute LD50 of rat subject to oral administration of the original drug acute is larger than 5000 mg/kg body weight. For acute percutaneous administration of rats, the LD50 is larger than 2000 mg/kg body weight. For acute inhalation of rat, the LC50 is larger than13000 mg/m3 (4h). It has slight irritation effect on eye without causing sensitization. Test dose has no mutagenic effect and teratogenic response. The non-effect dose of rats subject to 6-month of feeding study is 400mg/kg body weight. Non-effect dose of rat subject to inhalation within 28 day is 482mg/m3. It is absorbed, distributed and excreted rapidly by animal.
The above information is edited by the Chemicalbook of Dai Xiongfeng.

Pyriproxyfen can be used for controlling the larvae of mosquitoes and flies and some other pests. For prevention and control of mosquito larvae, apply 20 g of 0.5 % pyriproxyfen granules (active ingredient: 100 mg) per cubic meter directly into the water (water depth should be kept at about 10 cm which is best); for control of housefly larvae, apply 20 to 40 g of 0.5% pyriproxyfen granules (active ingredient 100~200 mg) per cubic meter for spreading on the surface of the housefly breeding ground. It has excellent inhibitory effect on the larvae of mosquitoes and flies.

1. It should be kept in dark, cool place and kept away from fire.
2. Upon contacting with it on the skin, we should use soap and clean water for washing thoroughly.

For rat: acute oral administration: LD50> 5000mg/kg; acute percutaneous administration: LD50> 2000mg/kg.

The pure product is crystal with m.p. being 45~47 ℃, the vapor pressure being 0.29 × 10-3Pa (20 ℃), and the relative density being 1.23 (20 ℃). Solubility: xylene 50%, hexane: 40%, and methanol: 20%.

1. It is a kind of benzyl ethers class insect growth regulator and is a kind of juvenile hormone type inhibitor of chitin synthesis. It is characterized by its high efficiency, less medication, long duration, crop safety, low toxicity to fish, and the small impact on the ecological environment. It can be used to control Homoptera, Thysanoptera, Diptera, and Lepidoptera pests. Its inhibitory inhibition on insects is related to its influence on the molting and reproduction of insect. For mosquito class sanitation pests, applying low-dose of this product for 4th instar larvae in late phase that can result in larvae’s death at the pupation stage and inhibition of the formation of adults. For the application, apply the granules directly to the sewage pond or dispersing it in the breeding ground of mosquitoes and flies. It can also be used for prevention of sweetpotato whitefly and scale insects. Pyriproxyfen also has an inner suction transfer activity which can affect the larvae hidden in the back of the blade.
2. It is used for the control of public health pests.

Pyriproxyfen is a pyridine insecticide that mimics juvenile growth hormone, which prevents larvae from developing into reproduction-capable adults. The LD₅₀ of pyriproxyfen in rats is >5,000 mg/kg, >1,300 mg/cubic meter/4 hours, and >2,000 mg/kg through oral, inhalation, or percutaneous dosing, respectively. It is used as a larvicide in the drinking water of 11 municipalities in Brazil and rumors suggested it may be correlated with the increase in cases of microcephaly in Brazil. The acceptable daily intake determined by the World Health Organization is 0.3 mg/L. The prevalence of microcephaly in Brazil is not higher in municipalities that use pyriproxyfen in the water supply, compared with municipalities that use the larvicide Bti. In addition, in zebrafish, even very high doses (0.1 μg/ml, compared with 0.01 μg/ml used in practice for pest control) pyriproxyfen does not induce microcephaly or other brain malformations. Formulations containing pyriproxyfen are used for flea control in dogs and as an insecticide for ants.

Pyriproxyfen is a pyridine compound and, in common with fenoxycarb, is a juvenile hormone mimic whose structure is unrelated to natural juvenile hormone. It is an insect growth regulator. Fleas absorb pyriproxyfen either by direct contact or by ingesting blood from a treated animal.

Gray to white crystalline solid or powder. Also described as a pale yellow, waxy solid or liquid. Commercial product is available as an emulsifiable concen- trate or wettable powders.

Insecticide.

Pyriproxyfen is used for control of public health pests (flies, beetles, midges, mosquitoes) by application to breeding sites.

Pyriproxyfen is a pyridine-based pesticide used against a variety of arthropoda, in particular to protect cotton crops against whitefly.

ChEBI: An aromatic ether that consists of propylene glycol having a 2-pyridyl group at the O-1 position and a 4-phenoxyphenyl group at the O-3 position.

Insect growth regulator, Insecticide, Veterinary medicine: Pyriproxyfen is found in a number of household products as sprays, powders, baits, mists and shampoos for the control of fleas, ticks, mites and flying insects on pets, in the air, and in carpets and rugs. It’s a larvicidal agent that mimics juvenile insect hormone.

ARCHER®; DALAR®; DISTANCE®; ESTEEM®; NYLAR®; S-9318®; S 31183®; SUMILARV® Pyriproxyfen

Pyriproxyfen is an unclassified insect growth regulator, insecticide, veterinary medicine found in a number of household products as sprays, powders, baits, mists and shampoos for the control of fleas, ticks, mites, and flying insects on pets, in the air, and in carpets and rugs. It’s a l larvicidal agent that mimics juvenile insect hormone.

Pyriproxyfen is not persistent in soils and sediments and is rapidly metabolised by a variety of organisms. In rats and mice, the major metabolic pathways were hydroxylation of the aromatic ring, hydroxylation at the 5-position of the pyridyl ring, loss of the aromatic ring, cleavage of ether linkages and conjugation of the resultant phenols with glucuronic or sulfuric acid. The general pathways in soils, sediments and a variety of organisms involve fission of ether linkages and hydroxylation of the phenoxyphenol group.

UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous haz- ardous material, Technical Name Required.

[¹⁴C]Pyriproxyfen was dissolved in distilled water or sterile river water at a concentration of 0.2 mg kg^-1 and exposed to natural sunlight from November to December at 40°N latitude. The DT₅₀ values were 17.5 and 21 days in distilled water and sterile river water respectively. Photodegradation involved cleavage at the three ether linkages and the major products were carbon dioxide (11-29% of the applied radioactivity) and a product formed by loss of the phenoxyphenyl group (9) (16-30%). When [¹⁴C]pyriproxyfen was exposed to sunlight for 8 weeks on sandy loam and silty loam soils, the DT₅₀ values were 11 and 13 weeks respectively. Photodegradation involved cleavage at the three ether linkages to give products 4,6 and 10 but the major product was carbon dioxide, representing 9.5-13% of the applied radioactivity. Bound radioactivity accounted for 11-26% of the applied radioactivity at week 8 (Miyamoto et al., 1993). Degradation products are shown in Scheme 1.

This material is combustible. Dust may form an explosive mixture in air. Incompatible with oxidi- zers (chlorates, nitrates, peroxides, permanganates, perchlo- rates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

It is the responsibility of chemical waste generators to determine the toxicity and physical properties and of a discarded chemical and to properly identify its classification and certification as a hazardous waste and to determine the disposal method. United States Environmental Protection Agency guidelines for the classification determination are listed in 40 CFR Parts 261.3. Additionally, waste generators must consult and follow all regional, national, state and local hazardous waste laws to ensure complete and accurate classification and disposal methods. Follow recommendations for the disposal of pesticides and pesticide containers. Containers must be disposed of properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.