In vivo activities of the new anthelmintic depsipeptide PF 1022A.

PF 1022A is a member of a new class of cyclic depsipeptides with antiparasitic activity. Following in vitro and laboratory animal studies it was tested for its anthelmintic efficacy in companion and livestock animals against a wide spectrum of intestinal nematodes and lungworms. Studies were carried out in rats, dogs, horses, sheep, and cattle. Animals were either naturally or experimentally infested. The efficacy of PF 1022A was investigated against the following parasite species: Strongyloides ratti and Nippostrongylus brasiliensis in rats, Ancylostoma caninum in dogs, small strongyles (cyathostomes) in horses, Trichostrongylus colubriformis and Haemonchus contortus in sheep, and Dictyocaulus viviparus in cattle. Doses varied from 1 to 10 mg/kg body weight for oral, subcutaneous or intravenous application in companion and livestock animals. High degrees of efficacy were found in all the above-cited examinations, and no clinical signs of intolerability were observed.