Dihydroavermectin B1b (CAS 70209-81-3)

Dihydroavermectin B1b, a component of the anthelmintic compound ivermectin, is known for its anthelmintic effects by selectively binding to glutamate-gated chloride channels found in nematode neurons and pharyngeal muscle cells. Compared to the 25-sec-butyl (B1a) analogue, the B1b (25-iso-propyl) analogue has been found to be slightly more potent in inhibiting nematode larval development and paralysis, making it a sensitive probe for studying ivermectin resistance. Dihydroavermectin B1b belongs to the macrocyclic lactone class of avermectins. The compound exhibits efficacy against ectoparasites such as ticks, mites, fleas, lice, and nematodes. The mechanism of action of Dihydroavermectin B1b involves its binding to glutamate-gated chloride channels present in parasite cell membranes. This binding enhances the permeability of chloride ions, leading to their influx into the parasite cells. Consequently, the increased chloride ion concentration causes hyperpolarization, resulting in paralysis and subsequent death of the parasite.