Emodepside (PF 1022-221) is a cyclooctadepsipeptide with broad-spectrum anthelmintic activity.

Emodepside is a semisynthetic derivative of PF1022A, which contains a morpholine attached in para position at each of both D-phenyllactic acids. Emodepside is efficacious against a variety of gastrointestinal nematodes. Emodepside binds to a presynaptic latrophilin receptor in nematodes[1]. Emodepside produces a slow time-dependent (20 min), 4-aminopyridine sensitive, concentration-dependent hyperpolarization and increase in voltage-activated K currents. Emodepside has an inhibitory effect on spiking. Emodepside significantly inhibits the ryanodine increase in spike frequency between the 20 and 35 min period by 9.8 spikes/min[2]. In the presence of emodepside, highly increased currents are observed without depolarization up to a threshold of 0 mV and without any additional stimuli to artificially increase [Ca 2+]i levels. These novel findings confirm that Slo-1 is a direct target of emodepside[3].

Emodepside interferes with signaling at the neuromuscular junction on the body-wall muscles, pharynx and egg-laying muscles and thus inhibits three important physiological functions: locomotion, feeding and reproduction[4].

[1]. Harder A, et al. Mechanisms of action of emodepside. Parasitol Res. 2005 Oct;97 Suppl 1:S1-10. [2]. Buxton SK, et al. On the mode of action of emodepside: slow effects on membrane potential and voltage-activated currents in Ascaris suum. Br J Pharmacol. 2011 Sep;164(2b):453-70. [3]. Kulke D, et al. Characterization of the Ca2+-gated and voltage-dependent K+-channel Slo-1 of nematodes and its interaction with emodepside. PLoS Negl Trop Dis. 2014 Dec 18;8(12):e3401. [4]. Bull K, et al. Effects of the novel anthelmintic emodepside on the locomotion, egg-laying behaviour and development of Caenorhabditis elegans. Int J Parasitol. 2007 May;37(6):627-36.