Avermectins

Avermectins — macrocyclic lactone natural products with potent antiparasitic, insecticidal, and antihelmintic properties — are gaining increasing use in veterinary, medical, and agricultural applications. Extraction and instrumental analysis methods for avermectins are complex, lengthy, and expensive, making immunoassay a desirable alternative. Using ivermectin 4"-hemisuccinate-protein conjugates as immunogens, we prepared 20 monoclonal antibodies (MAbs) that detect avermectins at 3 to 400 ppb in competition enzyme immunoassay (EIA). The EIA tolerates up to 20% (v/v) of several organic solvents, and detects avermectins A2, B1, B2, and B1 monosaccharide and aglycone. The MAbs recognize major substituents and structural differences associated with biological activity. We are currently developing simplified methods to extract avermectins for EIA of environmental samples and commercial formulations.