Toxicodynamics There are two types of pyrethroids: those with and without α-cyanogroup. The neurotoxicity of<unk>  is based on the affinity to the voltage-gated sodium channels (in insects as well as mammals). The pyrethroids with an α-cyanogroup block the sodium-channel permanently, causing the membrane to be permanently depolarized. The resting potential will not be restored, and no further action potential can be generated. The pyrethroids without an α-cyanogroup, to which<unk>  belongs, are only able to bind to the sodium channel transiently. This will result in after potentials and eventual continuous firing of axons. The resting potential is not affected by these pyrethroids.<unk>  will open the sodium channel for a shorter period than other pyrethroids. The mechanism in mammals and invertebrates is not different, but the effect on mammals is much less due to higher body temperature, higher body volume, and lower affinity of<unk>  to sodium channels. Toxicokinetics Numerous studies have been conducted on the half life of<unk>  in soil, water, and air under different conditions, such as aerobic or anaerobic, and at different temperatures and pH. It is more likely to remain in the soil and not so much in water (it is hydrophobic), nor in the air (it is unlikely to volatize because of its physical properties). Because of the water-insolubility of<unk> , it will not rapidly cause contamination of ground water. However, some contamination might occur by soil-bound<unk>  to surface water through runoff. For an overview of the environmental degradation of<unk> , see figure below. The main path of degradation results in 4’-hydroxy<unk> . Biotransformation Pyrethroids are much less toxic in mammals than they are in insects and fish, because mammals have the ability to rapidly break the ester bond in<unk>  and break the substance into its inactive acid and alcohol components: In humans and rats,<unk>  is degraded by the cytochrome p450-family. Toxicology Toxicity in animals ;Mosquitoes<unk>  is an effective pesticide to use against malaria and filaria vector mosquitoes. It is still effective when a resistance to other pyrethroids is found. Mosquito nets and indoor walls can be treated with<unk>  to keep more mosquitoes away.<unk>  is an effectively used insecticide, but the risk is high of it working only for a short time. Mosquitoes can develop a resistance to it, as well. ;Aquatic life<unk>  is hardly soluble in water, so nearly all<unk>  will stay in the sediment, but it is very harmful to aquatic life. Even in small concentrations, fish and other aquatic animals are affected by<unk> . One of the reasons for the high sensitivity of fish is fish have a slow metabolism.<unk>  will stay longer in the system of the fish. Another reason for the high sensitivity of fish is the effect of<unk>  as ATPase-inhibitor. The gills need ATP to control the osmotic balance of oxygen. If the fish is no longer capable of taking up oxygen because ATP can no longer be used, the fish will die. In cold water,<unk>  is even more dangerous. pH and calcium concentration are also factors that influence the toxicity. Vertebrates are less sensitive to the effects of<unk>  as ATPase-inhibitor. ;Bees In bees, the lethal concentration (LC50) of<unk>  is about 17 mg/l. At sublethal concentrations,<unk>  reduces the fecundity of bees, decreases the rate at which bee larvae develop into adults, and increases their immature periods. ;Table of LD50 values Species LD50 Female rats 54 mg/kg Male rats 70 mg/kg Mice 43 mg/kg Mallard ducks 1280 ppm Bobwhite quail 4450 ppm Rainbow trout 0.00015 mg/l Bluegill 0.00035 mg/l Daphnia 0.0016 mg/l Toxicity in humans<unk>  and other synthetic pyrethroids are being used in agriculture in increasing amounts because of the high efficiency of these substances in killing insects, the low toxicity for mammals, and good biodegradability. However, because of its success, they are being used more often (also indoors) and high exposure of<unk>  to humans can occur. Carcinogenicity The U.S. EPA classified<unk>  as a Category C, possible human carcinogen. This rating is based on an increased rate of urinary bladder tumors in mice, adenoma and adenocarcinoma of the liver in male mice, and bronchoalveolar adenomas and adenocarcinomas of the lung in some female mice. Potential for neurotoxicity<unk>  can be absorbed by humans either by skin contact or ingestion. Skin contact is not toxic, causing only a slight tingling sensation on the specific location of contact. Ingestion in concentrations below 10−4 M is not toxic. However, commercially available<unk>  products formulated for household use (such as Ortho Home Defense Max, sold as a liquid pump spray), can induce toxic effects due to other chemicals added to improve the sustainability of<unk>  or are toxic on their own. Symptoms of excessive exposure are nausea, headaches, hypersensitivity for touch and sound, and irritation of the skin and the eyes.
Bifenthrin
Beclamide
Atogepant
Brimonidine
Brinzolamide
Bolazine
Mebanazine
Veristrat