Derquantel

Derquantel, a spirocyclic anthelmintic, is a competitive, orally active nicotinic acetylcholine receptor (nAChR) antagonist. Derquantel inhibits ACh-induced depolarization with an IC50 of 0.22 μM. By selectively antagonizing nAChRs on the somatic muscles of nematodes, Derquantel causes flaccid paralysis of muscles, thereby dislodging parasites from the host's gastrointestinal tract. Derquantel is applicable to research related to Haemonchus contortus infection and Ascaris suum infection^[1][2]. In Vitro:Derquantel (1 μM) acts as a competitive antagonist of acetylcholine-induced contractions in Ascaris suum somatic muscle strips, shifting the acetylcholine EC₅₀ from 7 μM to 52 μM^[2].
Derquantel (0.1-30 μM; 0-4 min) potently and reversibly inhibits acetylcholine-induced depolarizations in Ascaris suum somatic muscle flap preparations with an IC₅₀ of 200 nM, acting as a competitive antagonist^[2].
Derquantel (1 μM; 30 min pre-incubation) shifts the acetylcholine EC₅₀ from 4.5 μM to 10.2 μM and reduces the maximum depolarization response in Ascaris suum somatic muscle flap preparations, consistent with competitive antagonism^[2]. In Vivo:Combination treatment with Derquantel (2 mg/kg; p.o.; single dose) and Avermectin yields limited efficacy in sheep infected with highly multidrug-resistant Haemonchus contortus^[1].