Moxidectin is a potent, broad-spectrum endectocide (antiparasitic that is active against endo- and ecto-parasites) with activity against nematodes, insects, and acari. It is a semi-synthetic methoxine derivative of nemadectin which is a 16-member pentacyclic lactone of the milbemycin class. Moxidectin differs by the absence of a disaccharide moiety on carbon 13, a substituted olefinic side chain at carbon 25 and a unique methoxime moiety at carbon 23. Due to these modifications, moxidectin is classified as a second generation macrocyclic lactone.