Nitenpyram is an insecticide used in agriculture and veterinary medicine to kill outer pests, such as lice. This compound is a neurotoxin belonging to the class of neonicotinoids, which works by blocking the neural signaling of the central nervous system on special insects. It does so by irreversibly binding to the Nicotinic acetylcholine receptor (nACHr), causing the cessation of ionic flow in the postsynaptic membrane of the neuron, leading to paralysis and death. Being highly selective towards certain variations of nACHr, the type of insect they have, nitenpyram has seen extensible use in targeted insecticide applications, such as pet and agricultural care.
Known under the codename TI 304 during field testing starting in 1989, the first documented commercial use was in 1995 under the name "Bestguard" as an agricultural insecticide. Later, the expanded nitenpyram was used as a lice treatment by the Novartis company under the tradename "Capstar", with subsequent FDA approval for non-food producing animals in October 2000. The current nitenpyram manufacturer itself is a Sumitomo chemical company. Nitenpyram continues to be used commercially, although data from market surveys show a significant reduction in global use compared to other insecticides or neonicotinoids.
Because of its use as an insecticide and the treatment of animals that do not produce food, it is not considered necessary to study human toxicology during its primary use, and therefore little is known about the details of the effects of nitenpyram on humans. Looking at mouse experiments, however, the amount of lethal nitenpyram is high enough (in grams) in mammals in general, whereas invertebrates will die only with micro or nanogram of the substance.
Neonicotinoids, in general, have low degradation when used in agricultural applications, allowing long-term protection of plants against plant-sucking insects and indirectly plant diseases carried by these insects.
Video Nitenpyram
Structure
Nitenpyram ((E) -N- (6-Chloro-3-pyridylmethyl) - N-ethyl-N'-methyl-2-nitrovinylidenediamine) is an open-chain chloropyridyl neonicotinoid. Nitenpyram consists of a common hetrocyclic chloronicotinyl group for all first-generation neonicotinoids and pharmacofores, the molecular reactive group. Nitenpyram has a pharmacophore nitroamine known as the main reaction site in binding of compounds to nACh receptors, although the specificity of the reaction is not yet fully understood for neonicotinoids in general. Due to its polar group, nitenpyram is quite hydrophilic, with very high water solubility.
Maps Nitenpyram
Action mechanism
Although neonicotinoids are the largest group of insecticides used in the agricultural world today, and, prevalent in animal care, poisoning in general, genotoxicity and biotransformation remain the most controversial on the topic of neonicotinoids. This is mainly due to the lack of concrete systematic work. However, research has been done on the binding phenomenon between neonicotinoids and proteins, serving as an indicator for possible behavior in human physiological conditions.
Nitenpyram is a synthetic-related nicotine chemical (neonicotinoid), has an effect on the nicetyin nicetyin acetylcholine receptors and for this reason is thought to be similar to nicotine (agonist). Nicotinic acetylcholine receptors are involved in the sympathetic and parasympathetic nervous system, present in the muscle cells in which cells of the nervous system and muscle cells form synapses. Variations in nicotine receptor acetylcholine binding that affinity affinity persists among species.
Although nitenpyram is a nicotine agonist for nicotinic acetylcholine receptors, it has a much lower affinity for nicotine receptor acetylcholine in mammals. For most insects, nitenpyram is a very deadly compound. Nitenpyram will bind irreversibly to the nicotinic acetylcholine receptors that paralyze those exposed to the compound. Despite lower affinity levels, mammals can still get nicotine intoxication responses from too many neonicotinoids, so it is important to provide the right dose for flea-infested pets, for example, should be consulted with a veterinarian.
Nitenpyram itself and its metabolites, in addition to 6-chloronicotinic acid, have not been through deep toxicological investigations. The effects of similar genotoxicity remain ambiguous. 6-chloronicotinic acid according to the study group has non-carcinogen and not developmental toxin.
Metabolism
The literature on biotransformation of nitenpyram has been rare. However, several studies have been conducted. Toxicokinetic studies show that the human gut caco-2 cell line can absorb imidakloprid at a very high level of efficiency. Compounds completely absorb (& gt; 92%) of the gastrointestinal tract, rapidly distribute from intravascular space to tissues and peripheral organs, such as the kidneys, liver and lungs, continuing biotransformation. Veterinarians and pet owners have reported the effects of nitenpyram on pets infested with ticks beginning within 30 minutes after administration of neonicotinoids.
Nitenpyram has been reported to metabolize to 6-Chloronicotinic acid.
Nitenpyram in rats metabolized to nitenpyram-COOH, nitenpyram-deschloropyridine, desmethyl-nitenpyram, nitenpyram-CN, and nitenpyram-deschloropyridine derivatives. Metabolite nitenpyram has not been through in-depth study. However, this metabolite can be under oxidation reactions such as cyano groups into carboxylic groups. 6-chloronicotinic acid can make hydrogen bonds with hydrogen atoms from amino groups.
The Cytochrome P450 enzyme in humans can produce several metabolites with greater toxicity than the parent compounds, which are certified to cause the tumor in combination with nitrate and cause genetic damage. A precautionary approach to whatever is learned will be suggested, until the biotransformation is better and the impact is better studied and understood.
Synthesis
Nitenpyram is synthesized in a multistage reaction. The precursor compounds of this reaction are 2-Chloro-5-chloromethylpyridine, which is also used in other neonicotinoid preparations such as Imidacloprid. The reaction of this compound undergoes three steps of reaction.
The first step, 2-Chloro-5-chloromethylpyridine reacts with ethylamine at the limit of its phase to obtain the N-ethyl-2-chloro-5-pyridylmethyl amine molecule.
The synthesis can then proceed with a condensation reaction (step 2), adding a dichloromethane and trichloronitromethane solvent to produce a medium N-ethyl-2-chloro-5-pyridylmethine with an additional nitroethylene group.
In the final step methyline is added and reacted with an intermediate, replacing the pharmacofor chloride group, obtaining nitenpyram as the final product.
Derivatives
Being a first generation neonicotinoid, nitenpyram has undergone various modifications to the original structure, either to enhance the effectiveness or specificity of the compound. One such variation is in the reactive group configuration/farmakofora, from cis (E) to Trans (Z) configuration. It has been shown that this type of modification can substantially increase the nitenpyram affinity for binding to insect nACh receptors, enabling more targeted and environmentally friendly pest control. Changes to these compounds may also help to avoid increasing resistance to nitenpyram.
Toxicology
Invertebrates
In the 2015 study, the toxicity of neonicotinoids was tested on the egg parasitoid trichogramma . Special Nitenpyram is found to have the lowest toxicity, making it useful in the treatment of IPM (integrated pest management).
In 2015, researchers conducted a study on the toxicity of nitenpyram in earthworm E.fetida. E. fetida is a common earthworm, which is partly responsible for the natural aeration of the soil, including agricultural land. In a 14-day exposure period, Toxicity in LC50 nitenpyram in e.fetide was found to be 4.34 mg/kg of soil, indicating inhibition of cellulase activity and damage to epidermal cells and intestinal cells. This, however, is significantly less toxic than similar insecticides such as imidacloprid, thiacloprid and clothianidin, making a viable substitute nitenpyram for many other neonicotinoids used.
Interestingly, the ecological effects of nitenpyram in bee populations are under controversy, as conflicting studies indicate the presence of nitenpyram in their honey and honeybees, while others do not detect nitenpyram at all. This, however, may be due to a decrease in the use of nitenpyram, as global market share has steadily declined.
Nitenpyram is also commonly used in the elimination and protection of mosquitoes. Specifically, the toxicity of nitenpyram at Culex quinquefasciatus or southern house mosquitoes was tested. LC50 compounds were found to be 0.493 μg/ml.
Vertebrata
Aquatic animals
In one study, a chronic toxicity test of 60 days was performed on rare Chinese middows ( Gobiocypris rarus ) as a general fish model. Of the tested neonicotinoids (imidloprid, nitenpyram, and dinotefuran), nitenpyram is shown to have no genotoxic effects or affect the immune system, either through short or chronic exposure compared to other compounds.
In a similar study, nitenpyram proved to have adverse effects on Zebrafish DNA. Enzymes inhibit the formation of reactive oxygen species (ROS) are severely affected, causing oxidative DNA damage to increase with chronic exposure.
Mammals
The chemical security data of the oxford university documented the LD50 toxicology test in rats, both male and female, where doses were recorded as 1680 mg and 1575 mg per kg body weight respectively. Thus, the overdose limit for humans and animals is quite high, reaching into grams, and these compounds are considered safe for everyday use for animals. Human consumption is not recommended, although no side effects from indirect exposure such as eating treated plants are known to occur.
Degradation
In hopes of understanding the degradation of neonicotinoids in different types of water, an interesting finding is made. In testing groundwater, surface water and finished drinking water, the researchers found nitenpyram degradation occurred primarily in drinking water, which was associated with hydrolysis of the compound. Some of these degradation products are suspected to have toxic properties in non-target organisms, although the actual toxicity is unknown. Nitenpyram is also degraded under the influence of UV light, suggesting that sun exposure would also lower the compound into various degradation products.
Veterinary app
Nitenpyram can be used to treat pets, such as cats and dogs, with lice problems through the administration of nitenpyram tablets (also known as Capstar). This app requires that cats and dogs be treated to have a minimum weight of two pounds or more. It should also be four weeks older. Dosage is based on weight and applied orally with or without food. According to the Novartis Animal Health US, the dose for cats and dogs weighing between 2-25 pounds (1-11 kg) is 11.4 mg tablet nitenpyram, dogs weighing between 25-125 pounds (11-57 kg), should have 57, 0 mg nitenpyram tablets.
After administration of oral tablets, these drugs are easily and quickly absorbed into the blood. If a louse bites the animal it will swallow with nitenpyram blood. The nitenpyram effect can be observed half an hour after administration. At this time high concentrations in the plasma can be detected and the first tick removed from the pet host. A study showed that six hours after application of flea infestation decreased by 96.7% for dogs and 95.2% for cats. Adult lice that exist in the host is very broken, so the production of eggs is reduced. Eggs are not directly affected by nitenpyram, only after they are out. Nitenpyram administration may need to be repeated or continued until pest infestations have subsided. Half time nitenpyram is about eight hours. So, 24 hours after treatment, about 100% of adult lice are killed. Between 24 hours and 48 hours, efficacy greatly decreased and after 72 hours no effects could be demonstrated again in the study.
Side effects
One of the side effects observed was itching, suspected to be from a dislodged tick. Within five hours after the treatment, it was observed that cats more often tidied themselves, such as scratching, biting, lapping, and twitching. This will stop when the tick is dead or dead. Other reported side effects are hyperactivity, panting, lethargy, vomiting, fever, decreased appetite, anxiety, diarrhea, difficulty breathing, saliva, incoordination, seizures, dilated pupils, increased heart rate, tremor and anxiety. Other studies have no observed side effects.
Agriculture apps
Being one of the first-generation neonicotinoids, nitenpyram has seen widespread commercial use since its introduction, including pest control in agriculture. While the development of new-generation nicotinoids has led to a decline in its use, the Worldwide Integrated Assessment report (WIA) still sees it as an ecological treatment in pest control projects such as Integrated Pest Management (IPM). This is due to its lower toxicity and high uptake in soil-related plants compared to other commercially used neonicotinoids.
Nitenpyram has been used in many commercial crops, such as cotton and corn, and can be applied in various ways. The commonly used techniques are dust and seed treatment. Seed treatment allows for long-term immunity to plant-damaging insects. The use of nitenpyram has been shown to be very effective in protecting plants, as it is generally less toxic to non-target organisms, while killing plant-eating insects. Although its use is still common, unlike other neonicotinoids, the global market share for nitenpyram appears to be declining based on product sales data from 2003, 2005, 2007 and 2009. The reasons for this are not fully understood, because other first-generation neonicotinoids do not appear to follow the same trend, and nitenpyram is known to be less toxic to non-target organisms than compounds of the same generation.
However, the decrease in use can be explained through the formation of resistance in various species of insects. In a study conducted on nine commonly used nicotoids, nitenpyram was found to have the greatest increase in group resistance in brown planthopper, a common agricultural pest, between 2011-2012. A large increase in resistance is also found in Aphis gossypii or cotton lice, compared to other compounds such as Imidacloprid.
Side effects
Because of its use in plant-carrying pollen, nitenpyram has been associated with declining pollinator populations such as honeybees, wild bees and butterflies. Other non-target organisms, such as earthworms, are also reported to be negatively affected by nitenpyram. Plants themselves do not seem to have a negative response, because they do not have nicotine nicotine receptors.
References
External links
- Nitenpyram in Pesticide Properties DataBase (PPDB)
- Summary of Freedom of Information (NADA 141-053), US Food and Drug Administration
Source of the article : Wikipedia
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