It is important as per PCI Syllabus Medicinal Chemistry-III subject sem-VI

1. Ms. Mandakini Sampat Holkar
(M.Pharm)
Dept. of Pharmaceutics
Shri Vithal Education and Research Institute’s
College of Pharmacy, Pandharpur

2. 'Helminth' is a general term meaning worm. All helminths are invertebrates with
long, flat or round bodies. There are many different kinds of helminth ranging in
length from less than one millimetre to over one metre. Helminths infect a range
of hosts, including humans.

4. Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel
parasitic worms (helminths) 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 (those that stun) or vermicides (those that
kill). Anthelmintics are used to treat people who are infected by helminths, a
condition called helminthiasis. These drugs are also used to treat infected
animals.

5. Classification based upon chemical structure
Benzimidazoles-Albendazole,Mebendazole,Thiabendazole
Piperazines-Diethylcarbamazine citrate(DEC),Piperazine citrate
Heterocyclics- Oxamniquine,Praziquantel
Natural Product –Ivermectin, Avermectin
Vinyl pyrimidines- pyrantel,oxantel
Amide-Niclosamide
Nitro derivative-Niridazole
Imidazo thiazole- Levamisole

7. Benzimidazoles
Mebendazole
Bind with
parasite Beta
tubulin
Inhibit its
polymerization
Inhibiting
Microtubule
synthesis
Blocks glucose
uptake in
parasite
Depletes its
glycogen
stores
Mechanism of action

8. Albendazole
Albendazole is a broad-spectrum antihelminthic agent of the
benzimidazole type.
Albendazole, also known as albendazolum, is a medication used for
the treatment of a variety of parasitic worm infestations. It is useful
for giardiasis, trichuriasis, filariasis, neurocysticercosis, hydatid
disease, pinworm disease, and ascariasis, among others.
It is taken by mouth.

9. Mebendazole
Mebendazole is a broad-spectrum antihelminthic agent of the
benzimidazole type.
Mebendazole (MBZ) is a medication used to treat a number of
parasitic worm infestations. This includes ascariasis, pinworm
disease, hookworm infections, guinea worm infections, hydatid
disease, and giardia, among others.

10. Tiabendazole
As an antiparasitic, tiabendazole is able to control
roundworms (such as those causing strongyloidiasis),
hookworms, and other helminth species which infect
wild animals, livestock, and humans

11. Mechanism of action Tiabendazole
-
It reversibly inhibits
neuromuscular
transmission in the worm
Paralysed worms
Probably by mimicking
GABA, at GABA-gated
chloride channels in
nematode muscle
Expelled alive by normal
intestinal peristaltic
movement

13. Diethylcarbamazine citrate(DEC)
It is made from 4-methyl-piperazine Diethylcarbamazine
(DEC) is a medication used in the treatment of filariasis
including lymphatic filariasis, tropical pulmonary
eosinophilia, and loiasis. It may also be used for prevention of
loiasis in those at high risk. It is taken by mouth.

15. Praziquantel
It is a medication used to treat a number of types of parasitic worm
infections.Specifically it is used for schistosomiasis, clonorchiasis,
opisthorchiasis, tapeworm infections, cysticercosis, hydatid
disease, and other fluke infections

16. Mechanism of action Praziquantel
Praziquantel disrupts Calcium
haemostasis in parasite
Induces an influx of ion
By binding to proteinkinase
C-binding site in beta subunit
of schistosome voltage-gated
calcium channels
Paralysis
Rapid contraction of
musculature
Death of Worm

18. Ivermectin
Ivermectin is a medication used to treat many types of parasite
infestations. This includes head lice, scabies, river blindness
(onchocerciasis), strongyloidiasis, trichuriasis, ascariasis, and
lymphatic filariasis. It can be taken by mouth or applied to the skin
for external infestations. Use in the eyes should be avoided
It works by causing the parasite's cell membrane to increase in
permeability, resulting in paralysis and death

19. Ivermectin

21. Pyrantel
Pyrantel is a medication used to treat a number of parasitic
worm infections. This includes ascariasis, hookworm
infections, enterobiasis (pinworm infection),
trichostrongyliasis, and trichinellosis

22. Mechanism of action- Pyrantel
depolarizing neuromuscular
blocking agent
followed by paralysis of
worm
there by causing sudden
contraction

24. Niclosamide
Niclosamide, sold under the brand name Niclocide among
others, is a medication used to treat tapeworm infestations.
This includes diphyllobothriasis, hymenolepiasis, and
taeniasis.
Mechnism of action-
Niclosamide inhibits glucose uptake, oxidative
phosphorylation, and anaerobic metabolism in the tapeworm

26. Niridazole is a schistosomicide. It is used to treat schistosomiasis, the
helmintic disease caused by certain flatworms (trematodes) from the
genus Schistosoma
Niridazole is rapidly concentrated in the parasite and inhibits oogenesis
and spermatogenesis. The compound also inhibits the
phosphofructokinase enzyme, leading to glycogen depletion
Niridazole

27. Imidazo thiazole

28. Levamisole
Levamisole is effective in infections with the common
roundworm
Mechanism of action
It has a nicotine- like action,stimulating & subsquently blocking
the neuromuscular junctions.
Paralysed worms are then expelled in faeces.Ova are not killed.

29. References
▪Foye’s Principles of Medicinal chemistry fifth edition
▪Rang and Dale’s Pharmacology seventh edition