Avermectin class of endectocides

Emamectin benzoate is a semi-synthetic avermectin. Avermectins are macrocyclic compounds produced by the soil microorganism Streptomyces avermitilis and are characterised by a 16 membered lactone ring with an attached dioleandrosyl group.

The precise mechanism by which emamectin benzoate kills the various sea lice species has not been elucidated. However, extensive research on the mode of action of avermectin compounds against invertebrate species has shown that the avermectins competitively bind to glutamate-gated chloride channels on invertebrate nerves. The distribution of glutamate-gated chloride channels in the invertebrate may be localised to specific muscles such as those of the pharyngeal pump.

Emamectin benzoate is relatively slowly absorbed but it is also widely distributed to the tissues. Excretion is also relatively slow.