Fipronil

Description

Fipronil is a white powder with a mouldy odour. It has a low solubility in water and is a slow-acting poison. It does not bind strongly with soil, and the half-life of fipronil– sulphone is 34 days. Fipronil is a broadspectrum insecticide of the phenylpyrazole group. Fipronil was first used extensively for the control of ants, beetles, cockroaches, fleas; ticks, termites, mole crickets, thrips, rootworms, weevils, flea of pets, field pest of corn, golf courses, and commercial turf, and other insects. Fipronil was first used in the United States in 1996. Fipronil is a topical insecticide. It kills adult fleas and larvae, ticks, and chewing lice. As a liquid, fipronil is applied on the back side skin of dogs and cats. Reports indicate that some animals do become hypersensitive (allergic) to fipronil.

Description

Fipronil is a broad-spectrum insecticide. It disrupts insects’ central nervous systems by blocking chloride channels that are gated by γ-aminobutyric acid (GABA) or glutamate. These receptors are weaker or nonexistent in mammals.
Fipronil has a chiral center at the sulfur atom in the sulfoxide group; the two enantiomers have been isolated and verified. The article of commerce is a racemic mixture of the two.
Fipronil formulations sold worldwide include flea-control products for pets, cockroach traps, and insecticides for agrciultural crops, lawns, golf courses, and the like. But despite its wide range of uses and relative harmlessness toward mammals, fipronil is a significant environmental hazard. It is highly toxic to fish and other waterborne wildlife, birds, and beneficial insects. It has been cited as one of the primary causes of honeybee die-off.
In 2017, fipronil was the culprit in a food-contamination scandal in the Netherlands. Molecule of the Week’s Dutch reader who suggested this molecule provided this narrative:
A recent article in the Dutch newspaper De Stentor chronicles the fipronil scandal, including the subsequent legal fallout and a better way to combat red mites. (Note: The article is in Dutch, but it is easily translated by major Web browsers.)

Chemical properties

White SOlid

Chemical properties

White crystalline solid.

The Uses of Fipronil

Fipronil is used for the control of a wide range of insect species in rice, cereals, corn, cotton, top fruit, sugar beet, sugar cane, oilseed rape, many vegetables and other high-value crops. It also has a veterinary use as an ectoparasiticide.

The Uses of Fipronil

A broad spectrum insecticide which actively disrupts the CNS of contacted insects by blocking the passage of chloride ions through GABA receptors.

The Uses of Fipronil

antifungal

The Uses of Fipronil

Pesticide.

What are the applications of Application

Fipronil is a GluCl and GABA-gated-Cl channel blocker

Definition

ChEBI: 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile is a member of the class of pyrazoles that is 1H-pyrazole that is substituted at positions 1, 3, 4, and 5 by 2,6-dichloro-4-(trifluoromethyl)phenyl, cyano, (trifluoromethyl)sulfinyl, and amino groups, respectively. It is a nitrile, a dichlorobenzene, a primary amino compound, a member of pyrazoles, a sulfoxide and a member of (trifluoromethyl)benzenes.

Agricultural Uses

Insecticide, Veterinary medicine: Not approved for use in EU countries. Fipronil was introduced into the U.S. in 1996 for use in animal health and indoor pest control. It is the constituent of many products for controlling a wide spectrum of domestic animal and residential pests.

Trade name

BES® 602; CEASEFIRE®; CHIPCO®; COMBAT®; FRONTLINE; MB-46030®; H&G®; ICON®; MAXFORCE® ANT STATION; MAXFORCE® ROACH STATION; REGENCY SOFION®; REGENT®; REGENT® 500-FS; TERMIDOR® L VI-NIL

Pharmacology

Fipronil is a phenylpyrazole, the mode of action of which is to inhibit nerve transmission in arthropods by blocking γ -aminobutyric acid-gated chloride channels. Fipronil is available as spray and spot-on formulations to control fleas and ticks on cats and dogs. The adulticidal activity of fipronil accounts for the majority of its activity, although additional activity against flea eggs and larvae results from the presence of fipronil on hairs and debris shed into the environment from treated pets.
Autohistoradiography studies (11) into the cutaneous distribution of 14C-fipronil in the cat and dog following spot-on administration demonstrated that radioactivity was restricted principally to the stratum corneum, the viable epidermis, and the pilosebaceous units. Following its slow release from sebaceous glands, fipronil migrates in the sebum covering the skin and hairs by passive diffusion and was shown to persist on hair for up to 2 months after treatment.

Potential Exposure

Pyrazole/phenylpyrazole/organofluor ine insecticide; veterinary medicine. Fipronil was intro duced into the United States in 1996 for use in animal health and indoor pest control. It is the constituent of many products for controlling a wide spectrum of domestic ani mal and residential pests. Banned for use in EU.

Metabolic pathway

Through the abiotic degradation of fipronil in aqueous solution and on the soil surface, 5-amino-3- carbamoyl-1-[2,6-dichloro-4-(trifluoromethyl)-phenyl]-4- [(trifluoromethyl)sulfinyl]pyrazole is the only hydrolysis product detected. Fipronil in acidic aqueous solution exposed under a xenon lamp degrades with the concomitant appearance of 5-amino-3-cyano-1-[2,6- dichloro-4-(trifluoromethyl)-phenyl]-4- (trifluoromethyl)pyrazole and 5-amino-3-cyano-1-[2,6- dichloro-4-(trifluoromethyl)phenyl]pyrazole-4-sulfonic acid. Under field conditions, when fipronil is applied in formulation, four metabolites which include one product resulting from reduction on the sulfur atom of fipronil are detected.

Shipping

UN2588 Pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN2902 Pesticide, liquid, toxic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Degradation

Fipronil is stable in water at pH 5 and 7 but is slowly hydrolysed at pH 9 (DT₅₀ 28 days) to the amide (2). It undergoes rapid aqueous photolysis with a DT₅₀ of ﹤0.5 day. The major photodecomposition product in water and on soil surfaces is desulfinyl-fipronil(3) which is formed by extrusion of the SO group. A minor photoproduct in water, on soil and on plant surfaces is the sulfonic acid (4). The mechanisms of these reactions are discussed in a recent paper by Bobe et al. (1998).

Toxicity evaluation

Acute oral LD₅₀ for rats: 100 mg/kg

Waste Disposal

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 haz ardous 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 fol low all regional, national, state and local hazardous waste laws to ensure complete and accurate classification and dis posal methods.