Medicinal Chemistry of Anthelmintic Agents

1. Anthelmintics
Dr. Somdutt Mujwar
(Associate Professor)
M.M. College of Pharmacy,
Maharishi Markandeshwar (Deemed to be University)
Mullana, Ambala- Haryana, India
Mobile: +91-9827813303

2. Anthelmintics
Helminth- It is a general term for worms (vermi).
• Helminths (worms) are multicellular organisms that infect very large
numbers of humans and cause a broad range of diseases.
• Over 1 billion people are infected with intestinal nematodes, and many
millions are infected with filarial nematodes, flukes, and tapeworms.
• They are an even greater problem in domestic animals.

3. Anthelmintics
Anthelmintics
• Anthelmintics or antihelminthics are a group of antiparasitic drugs that
expel parasitic worms and other internal parasites from the body by either
stunning or killing them and without causing significant damage to the
host.
• They may also be called vermifuges or vermicides.

4. Classification
Anthelmintics
Benzimidazoles Piperazines Heterocyclic Amides Natural Product
 Albendazole  Diethylcarbamazine
citrate
 Oxamniquine  Niclosamide  Ivermectin
 Mebendazole  Praziquantal
 Thiabendazole

5. I. Benzimidazole
Mebendazole
• It is a benzimidazole anthelmintic used to treat helminth infections.
• Mebendazole is a (synthetic) broad-spectrum anthelmintic.
• The principal mode of action for Mebendazole is by its inhibitory effect
on tubulin polymerization which results in the loss of cytoplasmic
microtubules.

6. Classification
Albendazole
It is a benzimidazole anthelmintic used to treat parenchymal
neurocysticercosis and other helminth infections.
Thiabendazole
It is a benzimidazole used in the treatment of strongyloides (threadworm),
cutaneous larva migrans, visceral larva migrans, and trichinosis infections.

7. II. Piperazines
Diethylcarbamazine citrate
• It is an anthelmintic used to treat filarial infections like Wuchereria
bancrofti and Loa loa.
• The mechanism of action of diethylcarbamazine is thought to involve
sensitizing the microfilariae to phagocytosis.

8. III. Heterocyclic
Oxamniquine
• Oxamniquine is an anthelmintic with schistosomicidal activity against
Schistosoma mansoni, but not against other Schistosoma species.
• Oxamniquine may associate with an irreversible inhibition of the nucleic
acid metabolism of the parasites.
Praziquantal
• Praziquantel is an anthelmintic medication used to treat a number of
parasitic worm infections such as schistosomiasis.

9. IV. Amides
Niclosamide
• Niclosamide is an antihelminthic used for the treatment of tapeworm infections.
• It works by killing tapeworms on contact.
• Adult worms are rapidly killed, presumably due to uncoupling of oxidative
phosphorylation or stimulation of ATPase activity.

10. V. Natural Product
Ivermectin
• Ivermectin is an anti parasite medication used to treat head lice, onchocerciasis,
strongyloidiasis, ascariasis, trichuriasis, and enterobiasis.
• Ivermectin binds selectively and with high affinity to glutamate-gated chloride
ion channels in invertebrate muscle and nerve cells of the microfilaria.
• This binding causes an increase in the permeability of the cell membrane to
chloride ions and results in hyperpolarization of the cell, leading to paralysis
and death of the parasite.

11. Thank you!!!