Anti-Amoebic
Introduction:
People living in the tropical countries with poor sanitizations
from:
• Infection due to microbe’s viz. Bacteria, fungi, protozoa virus
and rickettisia.
• Infection due to paralytic worms and insects.
Antiamoebic
drugs:
• Amoebiasis is the parasitic protozoal infection caused by
entamoeba hysstolytica, with or without clinical manifestations.
• This disease is due to poor hygienic condition and transmitted by
faecal –oral route. Amoebae are present in the lumen or wall of the gut of
human beings.
Classification of Antiamoebic drugs:
A) Chemical
classification of Antiamoebic drugs:
• Alkaloid: -e.g.
Emetine and Dihydro emetine.
• Amaroids: – Quassin
• Antibiotics: – Promomycine
• Quinoline derivatives:
a) Halogenated hydroxy Quinoline :-diiodohydroxyquinoline
(Iodoquinol) ,Iodochlorhyquinoline (clioquinol)
b) Amino Quinoline: chloroquine, amodiaquine.
• Heterocyclic compound:
a) Furan derivatives: Diloxanide
b) Imidazole derivatives: Metronidazole.
• Organometalic compound: Acetarsol
• Miscellaneous:-Diloxanide
B) On the basis of site of action they are
grouped as follows:
• Luminal amoebicides: e.g. Diloxinide furoate, Paromomycin
Halogenated hydroquinolines.
• Tissue or systemic amoebicides:-Emetine and its derivatives.
• Mixed amoebicide: Metronidazole.
Emetine
• Emetine is an alkaloid obtained from ipecacuhana.
• It can be obtained by methylation of cephaeline; the other
alkaloid is also present which can be prepared by synthetically.
• It contains tetra hydro Quinoline heterocycle.
Physical properties of Emetine:
• Emetine hydro chloride is a dihydro salt
of emetine.
• It is white or slightly yellow
crystalline powder.
• It is odourless.
• It is tasteless.
• It is soluble in water and alcohol.
• Emetine is levo rotetory
Chemical properties of Emetine:
• It gives bright green colour when a
mixture of molybdenum trioxide and sulphuric acid is sprinkled on it.
• It contains two basic nitrogen atom
.hence it form salt quite readily with two molecules of hydrochloric acid gives
an emetine hydro chloride.
Stability and storage of Emetine:
• It becomes faintly yellow on exposure to
light .it is stored in tightly closed light resistant containers.
Uses of Emetine:
• Intestinal Amoebiasis (amoebic dysentery)
• Hepatic Amoebiasis (amoebic hepatitis)
• Amoebic infection of lung, brain and other tissues
Pharmaceutical formulations: Emetine
injection
Brand names: Stembin,
Hemometina
Metronidazole
Structure of Metronidazole:
Chemical names:
2-(2methyl, 5 nitro imidazole -1 Yl)
ethanol. OR 1-(2-hydroxy ethyl), 2 methyl, 5 nitro imidazole.
Chemistry of Metronidazole:
• It is 5 nitro imidazole derivatives.
• It contains 2-hydroxy ethyl group and methyl group at 1 and 2
position respectively.
• Activation of either the group leads to inactivation.
Physical Properties of Metronidazole:
• It is white or creamy white crystalline powder.
• It having slightly odour.
• It has bitter and saline test.
• It is slightly soluble in water.
• It is soluble in alcohol.
Chemical properties of Metronidazole:
• When its solution in sulphuric acid is treated with picric acid,
it gets precipitate as its Picrate which melts at 150 degree Celsius.
• Nitro group of Metronidazole on reduction with Zn/HCl is converted
in to amino group which undergo diazotiastion with HNO2 diazotised product on
coupling with Beta Naphthol in NAOH gives orange red colour.
Pharmaceutical formulations: Metronidazole
tablets, injection, suppositories.
Brand names: Flagyl,
Metroquin, Metroquniol
Diloxanide
furoate
Physical Properties of Diloxanide furoate:
• It occurs white crystalline powder
• It is odourless and tasteless
• It is slightly soluble in water.
• It is dissolved completely in
chloroform.
Chemical properties of Diloxanide furoate:
• When its solution in pyridine is treated
with tetra butyl ammonium bromide, its enolic form reacts to form salt.
Stability and storage of Diloxanide furoate:
• It is affected by light and hence it is
stored in well closed light resistant containers.
Uses of Diloxanide furoate:
• Amoebic dysentery,
• Symptomic cyst-passer
• Hepatic abscesses in conjugation with
chloroquine or Metronidazole.
Pharmaceutical formulations: Diloxanide furoate
tablets
Brand names: Entamizole, Flagyl-DF, Diloxyl
Promomycine
Physical Properties of Promomycine:
• It is official as sulphate salt which
occurs as creamy –white to light yellow powder.
• It is odourless
• It is hygroscopic in nature
• It is very soluble in water
• It is practically insoluble in alcohol
and chloroform
Stability and storage of Promomycine:
• It is hygroscopic and hence it stored in
tightly closed containers
Uses of Promomycine:
• It has antibacterial activity .hence it
is used to suppress intestinal flora.
• It has amoebicide activity and hence is
used to treat intestinal amoebiasis (amoebic dysentery)
• It is used to treat leishmaniasis (kala
azar)
• It is used to treat balantidiasis
(diarrhea type symptoms due to balantadium coli).
• It has also Anthelmentics activity (to
treat tapeworm infection)
Pharmaceutical formulation: Promomycine
sulphate tablet, Promomycine sulphate syrup.
Brand names: Paramicina, Hamagen