Selamectin (UK-124114) is a macrocyclic lactone anthelmintic derived from ivermectin. It acts by potentiating glutamate- and GABA-gated chloride channels in parasitic nematodes, as demonstrated by its growth inhibitory effect at 0.1 µg/ml in Haemonchus contortus larval development assays. This compound is utilized in veterinary parasitology research and in vitro studies of anthelmintic mechanisms.