Avermectins and flea control: Structure-activity relationships and the selection of selamectin for development as an endectocide for companion animals

Evaluation of a wide range of avermectin derivatives for flea activity in a n in vitro feeding screen using the cat flea, Ctenocephalides felis, reveal ed a narrow structure-activity relationship (SAR) with activity surprisingl y associated with monosaccharides and especially their C-5-oximes. We disco vered commercially exploitable flea activity in a single compound, selamect in 33, which also possessed the necessary antiparasitic spectrum and margin of safety for development as a broad-spectrum companion animal endectocide . (C) 2000 Elsevier Science Ltd. All rights reserved.