Gastrointestinal agents Acidifiers: Ammonium chloride* and Dil. HCl Antacid: Ideal properties of antacids, combinations of antacids, Sodium Bicarbonate*, Aluminum hydroxide gel, Magnesium hydroxide mixture Cathartics: Magnesium sulphate, Sodium orthophosphate, Kaolin and Bentonite Antimicrobials: Mechanism, classification, Potassium permanganate, Boric acid, Hydrogen peroxide*, Chlorinated lime*, Iodine and its preparations

1. UNIT III
Gastrointestinal tract

2. INTRODUCTION

3. DISEASE

14. 2.ANATCID

19. T
able : Marketed Anatcid
Preparation
Brand Name Ingredients
Gelusil Al(OH)3 and Mg(OH)2
Digene Al(OH)3 and Mg(OH)2
Siloxogene Al(OH)3 and Mg(OH)2 and Simethicone
Almacarb Al(OH)3 with liquorice
Cogel Al(OH)3 with MgCO3
Solacid Al(OH)3, Mg(OH)2 and magnesium
trisilicate

20. Cathartics :
These are the drugs which brings about
defecation.
They are beneficial in constipation
and for expulsion of intestinal
parasites.
Constipation can also be due to many
factors like weakness of intestine,
intestinal spasm, injury or use of certain
drugs & diets, etc.
Cathartics or purgatives generally act by
four different mechanisms.

21. Cathartics or purgatives generally act by four different mechanisms.
Stimulants
Saline
Cathartics
Lubricants
Bulk
Purgatives
Cathartics

22. Stimulants :
These are the drugs or chemicals which act by local irritation on
intestinal tract and bring about stimulation of peristaltic activity.
As they are directly act on intestine & stimulate peristalsis, they are
termed as stimulants.
Eg.- Senna, Castor oil, rhubarb, etc.
Bulk Purgatives :
These are the agents which are able to increase bulk of intestinal
contents.
These are soluble or non-digestable type of materials.
Eg.- Methylcellulose, sodium carboxymethylcellulose, gum, isapgol, etc.
Lubricants :
In constipation, contents of intestine become hard because of
absorption of water by body, there results in difficulty in clearing
bowels.
Eg.- Liquid paraffin, glycerin, etc.

23. Saline Cathartics :
 These act by increasing the osmotic load of intestine by absorbing
large quantity of water & thereby stimulate peristalsis.
 Poorly absorable cations like calcium, magnesium, & anions like
phosphate, sulphate, tartrate are contributing to this effect.
 Saline cathartics are water soluble and they are taken with plenty of
water.
 This is helpful in restricting excessive loss of body fluid & reduces
nausea and vomitting.
 They may be administered by oral route in the form of suspension,
tablet or in other suitable formulations.
 Eg.- magnesium hydroxide, Magnesium sulphate, etc. & tartrate salts
of Na & K.

24. Protectives andAdsorbents
 Protectives and adsorbents are the chemically inert substances which are used in
the treatment of diarrhoea.
 Diarrhoea is defined as the frequent passage of watery stools or liquid faeces.
 It may be mild or chronic diarrhoea.
 Mild diarrhoea is due to bacterial infections with their toxins, side effects of
some drugs, hypersensitivity, accidental or intestinal poisoning while chronic
diarrhoea is due to the GIT disturbances, absorption and inflammation.
 Excess discharge of intestinal content leads to the loss of electrolyte which give
rise to Dehydration or Electrolyte Imbalance.
 Inorganic compounds such as Bismuth Subcarbonate, Kaolin, Bentonite, etc. are
insoluble salts which are used as protectives and adsorbents.

25. ANTIMICROBIAL AGENTS
 An antimicrobial (disinfectant & Antiseptic) is a substance that
kills or inhibits the growth of microorganisms such as bacteria,
fungi or protozoans.
 Antimicrobial agents either kill microbes (microbiocidal) or
prevents the growth of microbes (microbiostatic).

26. CLASSIFICATION OF ANTIMICROBIAL AGENTS
1. Antiseptics
2. Disinfectants
3. Germicides
4. Bacteriostatics
5. Sanitizers

27. ANTISEPTICS
These are the substances that are able to kill or prevent the growth of
microorganisms.
It acts by inhibiting their activity or destroying them specially by applying
to the living tissues like surface of skin, application of antiseptic dressings
on wounds.
The drugs like phenol, iodine, boric acid, cetrimide are the examples of
antiseptics.
Disinfectants
These are the substances that are used to prevent growth or multiplication
of microorganisms.
It is used to apply on inaminate objects (non-living objects)
Disinfectants are widely used for home & hospital sanitation.
All disinfectant solutions undergo deterioration under storage & elevated
temperature. Ex- cresol, phenol

28. Germicides :
These are the substances which kills
microorganisms.
Specific terminology like “ Bactericide”(against bacteria), “ fungicide”
(against fungi), “ virucide”(against virus), etc. denotes exact action.
Bacteriostatics :
These are substances which inhibits the growth of bacteria.
Thus, bacteriostatics drugs or agents do not kill but arrest the growth
of bacteria.
Sanitizers :
Disinfectants that are used to maintain general public health standards, ae termed as
Sanitizers.
Sanitation is mainly concerned with cleaning or washing away the organic matter(saliva,
mucous, etc.)
Sanitation can be achieved only with surfaces & articles that are physically clean.
High concentration of sanitizers also cause local cellular damage.

29. Mechanism of action
 The mechanism of action of antimicrobial agents may range from
a mild astringent to powerful oxidative processes.
 Inorganic compounds exhibits antimicrobial action by involving
either of the following three mechanisms
i) Oxidation
ii) Halogenation
iii) Protein binding or precipitation

30. Oxidation mechanism
 Examples of compounds acting by this mechanism are
peroxides of peroxy acids, oxygen liberating compounds
like potassium permagnate.
 They bring about oxidation of active functional groups
present in proteins and enzymes vital to the growth and
survival of microorganisms.
 This causes a change in the confirmation of the proteins &
thereby alters it’s function.

31. 2. Halogenation mechanism
 Examples of compounds acting by this mechanism are the compounds
which are able to liberate chlorine or hydrochloride or iodine.
 This category of agents act on the peptide linkage & alter it’s potential
& property.
 The destruction of specific function of protein causes death of micro-
organisms.
 Most of the enzymes are proteinous in nature.
 Aprotein molecule is composed of a variety of amino acids connected
through a peptide (--CONH--) linkage.

32. Protein precipitation :
 Examples of compounds acting by this mechanism are metal
ions(eg.-Astringents)
 Polar group of proteins binds with metal ions to form complex.
 The complex formed may be strong chelate leading to
inactivation of proteins

33. Characteristics ofAntimicrobial agents
1. It should possess antiseptic/germicide activity .
2. It should have rapid onset of action.
3. It should not cause local cell damage.
4. It should not interfere with body defence.
5. It should show no systemic toxicity from topical applications.

34. IODINE
Chemical formula : I2 Molecular wt. – 126.9
Iodine compounds are very common in nature.
Sea water is also having traces of combined iodine, which gets absorbed by some specific plants and
sea weeds, like Laminaria digitata.
Iodine also occurs in the form of sodium iodate.
Preparation :
 It is manufactured by extracting kelp(seaweed’s ash) with water.
 When the sulphate and chloride of sodium and potassium gel crystalised out, the solution is
concentrated, leaving freely soluble sodium and potassium iodide in the mother liquor.
 Sulphuric acid is added to mother liquor, small amount of thiosulphate and sulphide are allowed to
settle down.
 Mother liquor is decanted and to this MnO2 is added and iodine distills over.

35. Various Iodine preparations
1. Aqueous iodine solution
2. Weak iodine solution
3. Strong iodine solution
4. Povidone iodine solution
5. Tincture of iodine

36. Note on composition of various iodine preparations
1) Aqueous iodine praparation:
Synonym : Lugol’s solution
It is having 5% w/v of iodine and 10% w/v of potassium iodide in purified water.
Composition :
Iodine
Potassium iodide
Purified water
50 g
100 g
1000 ml
2) Weak iodine preparation :
Synonym : Tincture of iodine
It is having 2% w/v of iodine and 2.5 % w/v of potassium iodide.
Composition :
Iodine
Potassium iodide
Alcohol(50%)
20 g
25 g
1000 ml

37. Hydrogen peroxide
Chemical formula : H2O2
It is an aqueous preparation of hydrogen peroxide.
Method of preparation :
1. it is obtained by adding a thick paste of Barium peroxide (BaO2
ice cold dilute sulphuric acid. The barium sulpahte will formed.
) in ice cold water to a
BaO2 + H2SO4 -------------- BaSO4 + H2O2
Barium
Peroxide
Sulphuric
acid
Barium
sulphate
Hydrogen
peroxide
2.It is also manufactured by electrolysis of ice cold 50% sulphuric acid.
2H2SO4 ----------- 2HSO4 + 2 H+
Perdisulphuric acid is formed, which on distillation under reduced pressure gives
hydrogen peroxide
2HSO4 + 2 H+ ----------- H2S2O8 (Predisulphuric acid)
H2SO4 + 2H2O ----------- H2SO4 + H2O2
3. Prepared by passing CO2 through Barium peroxide in water.
BaO2 + CO2 + H2O --------- H2O2 + BaCO3

38. Properties :
 It is colourless and odurless liquid having slightly acidic taste.
 It is a strong oxidising agent.
 The solution decomposes in contact with oxidizable matter or
when made alkaline.
Uses :
 It is a strong oxidising agent and it gives nascent oxygen.
 It is used in cleaning cuts and wounds as it is antiseptic and
germicide.
 It is used as deodorant.
 Used in bleaching the hair.
 Effective antidote in phosphurus and cyanide poisoning.

39. Storage:
 It is stored in a light resistant container with a stopper made up
of glass or plastic resistant to hydrogen peroxide.
 It is kept in cool and dark place.

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