I. Basic Information
- Chemical Formula: C48H72O14 (B1a)·C47H70O14 (B1b)
- Molecular Weights:
- CAS Number: 71751-41-2
- Appearance: White or light yellow crystalline powder
- Boiling Point: 875.9 to 1005.9°C (at 760 mmHg)
- Water Solubility: Slightly soluble
- Density: 1.19 to 1.21 g/cm³
- Flash Point: 240.3 to 295.9°C
II. R&D and Production
- Source: Derived from fermentation of Streptomyces avermitilis, a soil actinomycete.
- Composition: Approximately 80% avermectin B1a and 20% B1b, with B1a being more bioactive.
- Biological Activities: Potent insecticidal, acaricidal, and nematicidal effects.
III. Mechanism of Action
- Mode of Action:
- Functions as both a stomach poison and a contact insecticide.
- Interacts with glutamate-gated chloride channels and GABA receptors, enhancing chloride ion influx.
- Leads to hyperpolarization and paralysis in insects.
- Symptoms appear within 2 to 4 days; does not affect insect eggs, allowing potential population resurgence.
IV. Main Uses
- Agricultural:
- Controls pests such as spider mites, fruit flies, and crop-specific insects (e.g., leaf miners, cotton bollworms).
- Veterinary:
- Treats parasitic diseases like heartworm in dogs and nematode infections in livestock.
V. Formulations and Methods of Use
- Available in several formulations, including:
- Emulsifiable concentrates (EC)
- Water emulsions (EW)
- Water-dispersible granules (WDG)
- Application Methods: Tailored to specific pests and crops.
VI. Safety and Precautions
- Toxicity:
- Highly toxic to aquatic life and bees.
- Lower toxicity to birds.
- Precautions:
- Protective measures during application are essential to prevent accidental exposure.
- Sensitive to light and extreme pH, which can degrade efficacy.
VII. Extraction Method for Avermectin B2a
- Process Steps:
- Filtration: Fermentation liquid of single-component avermectin B2a is filtered to collect bacterial cells.
- Extraction: An ethanol and toluene mixed organic solvent (ethanol:toluene = 1:5) is used for extraction over 2 to 6 hours. The resulting solution is the avermectin B2a extract.
- Decolorization: Activated carbon is added to the extract, heated to 50-80°C, decolorized, and filtered.
- Freeze-drying: The decolorized extract is freeze-dried to obtain crystallized avermectin B2a.
- Benefits: The process uses inexpensive activated carbon, ethanol, and toluene, making it simple and cost-effective while achieving purity requirements for crystallized avermectin B2a.
References
Abamectin promotes behavior changes and liver injury in zebrafish.
Chemosphere, Volume 311, Part 1, January 2023, 136941 DOI: 10.1016/j.chemosphere.2022.136941
In our study, the toxicological effects of a commercial formulation containing abamectin on the liver and behavior of zebrafish (D. rerio) were investigated. The animals were submitted to acute and short-term exposure to distinct concentrations of the drug. Our major findings evidenced behavior and hepatic alterations due to abamectin's toxic effect.
The key factors of solid nanodispersion for promoting the bioactivity of abamectin
Pesticide Biochemistry and Physiology, Volume 201, May 2024, 105897 DOI: 10.1016/j.pestbp.2024.105897
We prepared abamectin SND consisted of 8% abamectin, 1% antioxidant BHT, 12% complex surfactants and 79% sodium benzoate (w/w) as carrier by self-emulsifying-carrier solidifying technique. The SND had excellent storage stability at low, thermal and ambient temperatures. The pseudo-solubility of abamectin was raised at least 3300 times and the particle size was >667 times smaller than that of EW and WDG.