detail study of anti-amoebic drug i.e.life cycle of entamobia histolytica,classification and all drugs

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

2. Overview
 Introduction
Life cycle of Entamoeba histolytica
 Classification
Detail study of following drugs-
Metronidazole*, Tinidazole, Ornidazole,
Diloxanide, Iodoquinol, Pentamidine Isethionate,
Atovaquone,

3. Introduction
Antiprotozoals are used to treat protozoal infections, which include
amebiasis, giardiasis, cryptosporidiosis, microsporidiosis, malaria,
babesiosis, trypanosomiasis, leishmaniasis, and toxoplasmosis
Amoebiasis, also known amoebic dysentery, is an infection caused
by any of the amoebae of the Entamoeba group. Symptoms are most
common during infection by Entamoeba histolytica.
Symptoms may include abdominal pain, diarrhea, or bloody diarrhea.
Complications can include inflammation and ulceration of the colon
with tissue death or perforation, which may result in peritonitis .People
affected may develop anemia due to loss of blood.

4. Life cycle of
Entamoeba histolytica
Entamoeba histolytica exists in two forms:
1.Cysts form (That can survive out side the body)
2.Trophozoites form (That are labile and don’t Persist outside the body)

5. 1.Ingestion of cysts
Cysts are ingested through faeces, contaminated food or water
2.Formation of trophozoites
Cysts are passed in to the lumen of intestine, where the trophozoites
are librated.
3.Penetration and multiplication of trophozoites
Trophozoites are penetrated in intestinal wall and multiply within
colon wall. They either invade and ulcerate the mucosa of large
intestine or simply feed on intestinal bacteria.
Life cycle consist of following steps:

6. 4.Systemic invasion
Large numbers of trophozoites within the colon wall can also
lead to systemic invasion and caused liver abscess.
5.Cysts discarded
The trophozoites within the intestine are slowly carried toward
the rectum , where they return to cyst form and are excreted in
faeces

8. Classification
A. Tissue amoebicides-
1. For both intestinal and extra intestinal amoebiasis
Nitroimdazoles-Metronidazole,Tinidazole,Ornidazole
Alkaloids –Emetine
2. For extra intestinal amoebiasis only-Chloroquine
B.Luminal amoebiasis-
a. Amide-diloxanide furate
b. 8-hydroxyquinolones-Idoquinol
c. Antibiotics-Tetracycline

9. Metronidazole
Metronidazole, marketed under the brand name Flagyl , is an antibiotic
and antiprotozoal medication.
Metronidazole is primarily used to treat: bacterial vaginosis, pelvic
inflammatory disease , pseudomembranous colitis, aspiration pneumonia,
rosacea (topical), fungating wounds (topical), intra-abdominal infections,
lung abscess, periodontitis, amoebiasis, oral infections, giardiasis,
trichomoniasis

10. Mechanism of action of Metronidazole
Metronidazole
enter in to cell by
diffusion
Highly reactive
nitro radical
Nitro group is
reduced by
Which exerts
cytotoxicity
Energy
metabolism of
anaerobes is
disrupted
redox
protein
operative
only in
anaerobic

11. Tinidazole
Tinidazole is a drug used against protozoan infections. It is widely known
throughout Europe and the developing world as a treatment for a variety of
amoebic and parasitic infections. It was developed in 1972 and is a
prominent member of the nitroimidazole antibiotic class
use of tinidazole for infections from amoebae, giardia, and trichomonas, just
like metronidazole

12. Ornidazole
Ornidazole is an antibiotic used to treat protozoan infections. A
synthetic nitroimidazole, it is commercially obtained from an acid-
catalyzed reaction between 2-methyl-5-nitroimidazole and
epichlorohydrin. Antimicrobial spectrum is similar to that of
metronidazole .

13. Diloxanide
Diloxanide furoate works only in the digestive tract and is a
lumenal amebicide.It is considered second line treatment for
infection with amoebas when no symptoms are present but the
person is passing cysts, in places where infections are not
common.
Paromomycin is considered the first line treatment for these
cases. For people who are symptomatic, it is used after
treatment with ambecides that can penetrate tissue, like
metronidazole or tinidazole

14. Iodoquinol is an amebocide used against Entamoeba
histolytica, and it is active against both cyst and trophozoites
that are localized in the lumen of the intestine. It is considered
the drug of choice for treating asymptomatic or moderate
forms of amebiasis
Iodoquinol

15. Pentamidine
Pentamidine is an antimicrobial medication used to treat African
trypanosomiasis, leishmaniasis, babesiosis, and to prevent and treat
pneumocystis pneumonia

16. Atovaquone
Atovaquone (alternative spelling: atavaquone) is a chemical
compound that belongs to the class of naphthoquinones
Uses-
pneumocystis pneumonia (PCP)
toxoplasmosis
malaria
babesia