Фипронил: свойства, применение и токсикологическая характеристика

Fipronil is a broad spectrum insecticide that belongs to the phenylpyrazole chemical family. Fipronil disrupts the insect central nervous system by blocking the ligand gated ion channel of the GABAA receptor and glutamate gated chloride (GluCl) channels. This causes hyperexcitation of contaminated insects' nerves and muscles. Fipronil's specificity towards insects is believed to be due to its greater binding affinity for the GABAA receptors of insects than to those of mammals, and for its action on GluCl channels, which do not exist in mammals. as of 2017, there does not appear to be significant resistance among fleas to fipronil. Because of its effectiveness on various pests, fipronil is used as the active ingredient in flea control products for pets and home roach baits as well as field pest control for corn, golf courses, and commercial turf. Its widespread use makes its specific effects the subject of considerable attention. Observations on possible harm to humans or ecosystems are ongoing as well as the monitoring of pesticide resistance development.

Fipronil (IUPAC name 5 amino 1 [2,6 dichloro 4 (trifluoromethyl)phenyl] 4 (trifluoromethylsulfinyl)pyrazole 3 carbonitrile) is a white, solid powder with a moldy odor. It is degraded slightly by sunlight, stable at normal temperatures for one year, and is not stable in presence of metal ions.

Fipronil is/was used against many different pests on different crops, it is used against major lepidopteran (moth, butterfly, etc.) and orthopteran (grasshopper, locust, etc.) pests on a range of field and horticultural crops and against coleopteran (beetle) larvae in soils. It is employed for cockroach and ant control as well as locust control and termite pest control. In the United States of America, fipronil was approved for use against the Rasberry crazy ant until 2022 in counties of Texas where positive identification had been made by entomologists from the Texas Department of Agriculture and the Environmental Protection Agency. In New Zealand, fipronil was used in trials to control wasps (Vespula spp. (species)), which are a threat to indigenous biodiversity. It is now being used by the Department of Conservation to attempt local eradication of wasps, and is being recommended for control of the invasive Argentine ant. Fipronil is also the active ingredient in many commercial tick and flea treatments for pets.

Fipronil is classed as a WHO Class II moderately hazardous pesticide, and has a rat acute oral of 97 mg/kg. It has moderate acute toxicity by the oral and inhalation routes in rats. Dermal absorption in rats is less than 1% after 24 hours exposure and toxicity is considered to be low. It has been found to be very toxic to rabbits. The photodegradate MB46513 or desulfinylfipronil, appears to have a higher acute toxicity to mammals than fipronil itself by a factor of about 10. Symptoms of acute toxicity via ingestion includes sweating, nausea, vomiting, headache, abdominal pain, dizziness, agitation, weakness, and tonic clonic seizures. Clinical signs of exposure to fipronil are generally reversible and resolve spontaneously. As of 2011, no data were available regarding the chronic effects of fipronil on humans. The United States Environmental Protection Agency has classified fipronil as a group C (possible human) carcinogen based on an increase in thyroid follicular cell tumors in both sexes of the rat. However, as of 2011, no human data are available regarding the carcinogenic effects of fipronil. Two Frontline TopSpot products were determined by the New York State Department of Environmental Conservation to pose no significant exposure risks to workers applying the product. However, concerns were raised about human exposure to Frontline spray treatment in 1996, leading to a denial of registration for the spray product. Commercial pet groomers and veterinary physicians were considered to be at risk from chronic exposure via inhalation and dermal absorption during the application of the spray, assuming they may have to treat up to 20 large dogs per day. Fipronil is not volatile, so the likelihood of humans being exposed to this compound in the air is low.

In 2021, the US EPA put fipronil on the Draft Fifth Contaminant Candidate List (CCL 5) which can lead to future regulation under the Safe Drinking Water Act.

Fipronil may be quantitated in plasma by gas chromatography mass spectrometry or liquid chromatography mass spectrometry to confirm a diagnosis of poisoning in hospitalized patients or to provide evidence in a medicolegal death investigation.

Fipronil was discovered and developed by Rhône Poulenc between 1985 and 1987, and placed on the market in 1993 under the Between 1987 and 1996, fipronil was evaluated on more than 250 insect pests on 60 crops worldwide, and crop protection accounted for about 39% of total fipronil production in 1997. Since 2003, BASF holds the patent rights for producing and selling fipronil based products in many countries.

The 2017 fipronil eggs contamination is an incident in Europe and South Korea involving the spread of insecticide contaminated eggs and egg products. Chicken eggs were found to contain fipronil and distributed to 15 European Union countries, Switzerland, and Hong Kong. Approximately 700,000 eggs are thought to have reached shelves in the UK alone. Eggs at 44 farms in Taiwan were also found with excessive fipronil levels.