Theoretical and Experimental Study of Molecular Interactions of Fluralaner with Lipid Membranes

Abstract

Fluralaner is a relatively new insecticide belonging to the isoxazoline group, whose action mechanism involves the blocking of GABA A -receptors in the insect nervous system. Because of its high hydrophobicity, fluralaner could bioaccumulate and reach toxic local concentrations. Since there are no data available about the penetration and persistence of isoxazolines in biological membranes, we intend to evaluate fluralaner permanence as a pollutant by using model membranes. We used experimental and in silico models to characterize the incorporation of fluralaner into the lipid phase at different packing states. We determined its impact in the membrane structure and organization. Our results confirm that fluralaner is capable of penetrating, holding, and accumulating in the lipid membrane and provide details on its precise location and orientation. These properties would allow fluralaner to reach high local concentrations in different membranes and organs, which could be dangerous for vertebrate organisms if its handling is not properly controlled.

Topical, contact, and oral susceptibility of adult Culicoides biting midges (Diptera: Ceratopogonidae) to fluralaner

“…An adulticide product formulated to these concentrations is more effective as demonstrated by the bioassays, but environmental contamination is of critical concern for this application type. To date, fluralaner is classified as “persistent/very persistent in soil and aerobic freshwater sediments,” indicating significant concern for ground water and soil contamination if applied using this method [ 50 , 57 ]. Notably, droplet size is a limitation of the assay used here as 20 nl is on the larger end of ULV sprayer droplet size and is not the ideal size for effective control [ 55 , 56 ].…”