Faecal Excretion Profile of Moxidectin and Ivermectin after Oral Administration in Horses

A study was undertaken to evaluate and compare faecal excretion of moxidectin and ivermectin in horses after oral administration of commercially available preparations. Ten clinically healthy adult horses, weighing 390–446 kg body weight (b.w.), were allocated to two experimental groups. Group I was treated with an oral gel formulation of moxidectin at the manufacturer’s recommended therapeutic dose of 0.4 mg/kg b.w. Group II was treated with an oral paste formulation of ivermectin at the recommended dose of 0.2 mg/kg b.w. Faecal samples were collected at different times between 1 and 75 days post-treatment. After faecal drug extraction and derivatization, samples were analysed by High Performance Liquid Chromatography using fluorescence detection and computerized kinetic analysis.