Medicinal chemistry-Antiprotozoal agents-RGUHS syllabus

1. ANTIPROTOZOAL AGENTS
BY
SWATHI KENCHA

2. INTRODUCTION
• Protozoal diseases are highly prevalent in tropical countries.
• They infect both human and animal populations.
• They are malaria,Amoebiasis, Balantidiasis,Giardiasis,
Trichomoniasis,Tripanosoniasis, Leishmaniasis etc..,
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3. PROTOZOAL DISEASES
Amoebiasis is caused by Entamoeba histolytica.This
protozoa try to invade the colon and affects other parts like
liver & lungs.
Giardiasis –Giardia lamblia
Tripanosoniasis – Chronic tropical disease caused by
pathogenic member of family of trypanosomidae.
Tripanosoniasis is commonly called as sleeping sickness.
Leishmaniasis – Chronic tropical disease caused by flagette
protozoa of leishmania species.
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4. ENTAMOEBA HISTOLYTICA
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5. ANTIPROTOZOAL AGENT-CLASSIFICATION
• Drugs which used for the treatment of protozoal diseases are
called as Antiprotozoal agents.
Based on chemical structure:Antiprotozoal agents are classified
as:
1.Natural compounds-Emetine Hcl
2.Imidazole derivatives- Metronidazole,Ornidazole,Tinidazole
3.8-Hydroxy quinolines-Clioquinol,Iodoquinol
4.Miscellaneous compounds –Diloxanide Furoate ,Carbarsone
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6. EMETINE
Uses: Alkaloid obtained by the separation of Ipecac extracts.
Mainly used in amoebiasis and exerts direct
microbicidal action on various forms of entameoba
histolytica.
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7. • It is also called as protozoal poison as it prevents protein
synthesis &protein elongation.
• Also used to treat balantidial dysentery &Fluke infestations
such as fascioliasis & paragonimiasis.
Toxicity:
Gastrointestinal distress like nausea,diarrhoea.
Cardiovascular effects like hypotension and arrythmias
Neuromuscular effects like pain &weakness.
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8. MOA OF EMETINE
• Emetine exerts direct microbicidal action on all forms of
entameoba histolytica.
• It is considered as protozoal poison because it prevents
protein synthesis and protein elongation.
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9. METRONIDAZOLE
Uses: For the treatment of trichomonal vaginalis,vaginitis.
It is effective for the treatment of both intestinal and hepatic
amoebiasis.
It is used in the treatment of Giardiasis,Balantidiasis
Used for the treatment of serious infections like
septisemia,pneumonia,apses and meningitis.
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10. ORNIDAZOLE TINIDAZOLE
Uses:Tinidazole is used in the treatment of Giardiasis and
amoebiasis.
Ornidazole is used to treat infections caused by protozoa and
strains of anaerobic bacteria.,infections of stomach,intestine and
UTI’s. Swathi PharmaJnan

11. MOA OF METRONIDAZOLE
• Metronidazole undergoes microbial reduction of 5-nitro
group.
• The reactive intermediate metabolic products produced are
nitroso group,hydroxylamino group,nitroxide,amino group.
• These groups will covalently binds with DNA of the
microorganism and causes lethal effect to the protozoa.
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12. CLIOQUINOL IODOQUINOL
Uses: Clioquinol is used internally for intestinal amoebiasis.
Iodoquinol is used for the treatment of acute &chronic
intestinal amoebiasis.
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13. MOA OF CLIOQUINOL &IODOQUINOL
• This class of compounds have antifungal and antibacterial
property.
• They have ability to chelate with bacterial metal ions.
• I₂ improves the antimicrobial property.
• An introduction of I₂ at 5th & 7th position improves the
activity.
• It has broad spectrum amoebicidal activity.
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14. DILOXANIDE FUROATE
Uses: In the treatment of asymptomatic treatment of
Entamoeba histolytica.
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15. CARBARSONE
Uses: Antiamoebic drug
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16. SYNTHESIS OF METRONIDAZOLE
RADZISZEWSKI REACTION
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