Development of non-sedating antischistosomal benzodiazepines

Area of Science:

• Medicinal Chemistry
• Parasitology
• Drug Discovery

Background:

• Schistosomiasis affects over 200 million people globally, with praziquantel as the sole broad-spectrum antiparasitic drug.
• Emerging drug resistance and treatment failures necessitate the development of alternative schistosomiasis therapies.
• Meclonazepam, a benzodiazepine, demonstrated antiparasitic efficacy but was limited by sedative side effects.

Approach:

• Synthesized 18 meclonazepam derivatives, modifying the benzodiazepine ring system.
• Assessed in vitro antiparasitic activity of synthesized compounds.
• Evaluated promising derivatives in vivo using a murine model and assessed sedative effects via rotarod testing.

Key Points:

• Five meclonazepam derivatives exhibited antiparasitic activity, with two progressing to in vivo testing.
• Two derivatives demonstrated efficacy comparable to meclonazepam in a murine schistosomiasis model.
• The two most potent derivatives showed significantly reduced sedative effects compared to meclonazepam.

Conclusions:

• Meclonazepam analogs can be designed to possess an improved therapeutic index for schistosomiasis treatment.
• The C3 position of the benzodiazepine ring is a key site for optimizing antiparasitic activity and reducing sedation.
• This study provides a proof of concept for developing safer and effective schistosomiasis drugs based on the meclonazepam scaffold.