This is chapter No 3 of Pharmaceutical Chemistry - I for Diploma in Pharmacy (D. Pharmacy) Details notes for Diploma in Pharmacy (D.Pharmacy) Students.

1. GASTROINTESTINAL AGENTS
(7-9 M)
BY
CHETAN V. JAIN
(M.PHARMACY PHARMACEUTICS)
CHAPTER 2

2. Introduction
 GIT consist of series of organs
starting from esophagus up to
the Anus. Which is followed by
stomach, small intestine &
large intestine.
 The pharmaceutical compound
used in the treatment of GIT
disorder / disturbance are
called as GI agents.

3. Classification
1) Acidified agent : the drug which increases the
formation of acid are known as acidified agents
e.g. Dil HCl
2) Antacids : The drug which neutralizes the excess of
HCl secreted in the body known as antacids. e.g.
Aluminium Hydroxide
3) Protective & Adsorbent : The drug which are used in
a treatment of various GIT disorder like dysentery &
diarrhea. e.g. Kaolin
4) Saline Cathartic : this are the agents increases the
osmotic load in GIT

4. 1) Acidified Agent
 The drug which increases the formation of acid in a stomach when
stomach is empty or stomach is fully ingested with food are
known as acidified agents.
 The epithelial cell of stomach will secrete a proper acid in body &
soften of fibrous food & helps in the secretion of photolytic
enzymes like pepsin.
 When there is no secretion of acid (HCl) in the body known as
“Achlorhydria” & its symptoms are
– Sensitivity to spicy food
– Loss of appetite
– Mild Diarrhea
– Abnormal pain
 In this condition there is use of external acid like HCl known as
acidified agents & instead of HCl capsules of glutamic acid to be
supplied in the body.

5. Dil. Hydrochloric Acid [HCl]
 Synonym : Muriatic Acid
 Limit : Not less than 35% and not
more than 38% of HCl
 Preparation : 10 ml Conc. HCl + up
to 100 ml Water

6. Dil. Hydrochloric Acid [HCl]…
 Physical Properties
 Clear Colorless Liquid.
 Pungent Odor.
 Miscible with water and alcohol.
 Fuming liquid.

7. Dil. Hydrochloric Acid [HCl]…
 Uses :
 As a Pharmaceucal Aid (Acidifying Agent)
 As a solvent in Industry
 As a reagent in Laboratory
 For manufacturing of basic Pharmaceuticals.
 Storage : temp not exceeding 30 C in a
glass stopped container.
0

8. 2) Antacids
 These are the agent which neutralizes HCl acid in the
body.
 If there is excessive secretion of HCl in a stomach is
known as “Hyperchlorhydria” & if there less secretion
of HCl in stomach is known as “Hypochlorhydria”
although hyper or hypo it is not applicable for body
mechanism but if there hyperchlorhydria it leads to
minimize acid level & the drugs which neutralizes or
minimizes acid level in the body is called as Antacids.
 E.g. aluminium hydroxide gel I.P.

9. Requirements for an ideal antacid
 It should be insoluble in water and should have fine particle size.
 The antacid should not be absorbable or cause systemic alkalosis.
 The antacid should not be a laxative or cause constipation.
 The antacid should exert its effect rapidly and over a long period
of time.
 The antacid should buffer in the pH 4-6 range.
 The reaction of the antacid with gastric hydrochloric acid should
not cause a large evolution of gas.
 The antacid should probably inhibit pepsin.

10. 1. ALUMINIUM CONTAINING ANTACIDS
I. ALUMINIUM HYDROXIDE GEL
II. ALUMINIUM PHOSPHATE GEL
DIFFERENT ANTACIDS

11. Aluminium Hydroxide Gel I.P. Al(OH)3
 Synonym : Aluminium hydroxide
powder.
 Limit : Not less than 3.5% and not
more than 4.4% of Al2O3
 Storage : Aluminium hydroxide
should be kept in a tightly closed
container.

12. Aluminium Hydroxide Gel I.P. Al(OH)3
 Preparation : a hot solution of potash
alum is added slowly with constant stirring
to a hot solution of sodium carbonate.
After complete expulsion of carbon dioxide
the ppt of aluminium hydroxide is filtered,
washed thoroughly with hot water until
free from sulphate ion
3Na2CO3 + 2KAl(SO4)2 + 3H2O  3Na2SO4 + K2SO4 + 2Al(OH)3 + 3CO2

13. Aluminium Hydroxide Gel I.P. Al(OH)3
 Properties
– White Emulsion
– Sweet in taste due to sweating agent
– Gel is insoluble in water & alcohol
– Soluble in mineral acid.
 Used : used as antacid.

14. Aluminium Phosphate Gel IP [AlPO4]
 Limit : Not less than 7% and not
more than 8% of AlPO4
 Storage : Aluminium hydroxide
should be kept in a tightly closed
container.

15. Aluminium Phosphate Gel IP [AlPO4]
 Preparation : It is prepared by interaction
between aqs. solution of aluminium salts
(Aluminium Chloride) & alkali phosphate
(sodium phosphate) with a formation of
aluminium phosphate, phosphoric acid,
salt(NaOH).
2AlCl3 + 3Na2HPO4  2AlPO4 + 6NaCl + H3PO4

16. Aluminium Phosphate Gel IP [AlPO4]
 Properties
– White Emulsion
– Sweet in taste due to sweating agent
– Gel is insoluble in water & alcohol
– Soluble in mineral acid.
 Used : used as antacid.

17. 2. CALCIUM CONTAINING ANTACIDS
I. CALCIUM CARBONATE
DIFFERENT ANTACIDS

18. Calcium Carbonate (CaCO3)
 Synonyms : Precipitated Chalk
 Limit : Not less than 98% and not more
than 100.5% of CaCO3
 Preparation : It is prepared by the
interaction of sodium carbonate and
calcium chloride. The resulting precipitate
is filtered & wash.
Na2CO3 + CaCl2  CaCO3 + 2NaCl

19. Calcium Carbonate (CaCO3)….
 Properties :
– White crystalline powder
– Odorless & tasteless compound
– Gel is insoluble in water & alcohol
– Soluble in mineral acid.
 Used :
– Used as Antacid
– Used as a cleaning & polishing agent in tooth powder.
 Storage : To be store in well closed container.

20. 3. SODIUM CONTAINING ANTACIDS
I. SODIUM BICARBONATE
DIFFERENT ANTACIDS

21. Sodium Bicarbonate (NaHCO3)
 Synonym : Backing Soda
 Limit : Not less than 99% and not more than
100.5% of NaHCO3
 Preparation : it is prepare by passing CO2 gas
through solution of sodium hydroxide. The
solution is concentrated to obtain the product.
2NaOH + CO2  Na2CO3 + H2O
Na2CO3+ H2O + CO2  2NaHCO3

22. Sodium Bicarbonate (NaHCO3)
 Properties :
– White crystalline powder
– Odorless & Saline taste compound
– Soluble in water & insoluble in alcohol
– The aqueous solution is alkaline in nature.
 Used :
– Used as Antacid
– Expectorant , eye drop , ear drop.
 Storage : To be store in well closed container.

23. 4. MAGNESIUM CONTAINING ANTACIDS
DIFFERENT ANTACIDS
I. MAGNESIUM CARBONATE
II. MAGNESIUM OXIDE
III. MAGNESIUM TRISILICATE

24. Magnesium Carbonate (MgCO3)
 Limit : Not less than 40% and not more
than 45% of MgCO3
 Preparation : it is prepared by double
decomposition of magnesium sulphate
& sodium carbonate where each
dissolve separately & mix up into the
ratio 1:1
MgSO4 + NaCO3  MgCO3 + Na2SO4

25. Magnesium Carbonate (MgCO3)
 Properties :
– White Bulky powder
– Odorless & tasteless compound
– Insoluble in water & alcohol
– Soluble in mineral acid.
 Uses :
– Antacid , mild laxative
– Adsorbent in tablet & capsules as a additives in the
prevention of formation of Eutective mixture.
 Storage : To be store in well closed container.

26. Magnesium Oxide (MgO)
 Synonym : Magnesium Powder
 Limit : Not less than and not more than
98% of MgO
 Preparation : it is preparation by heating
respective magnesium carbonate to red
hot to get formation of magnesium oxide
with the expulsion of CO2
MgCO2 MgO + CO2

27. Magnesium Oxide (MgO)
 Properties :
– White powder
– Odorless & Slightly alkaline in taste
– Insoluble in water & alcohol
– Soluble in mineral acid.
 Uses :
– Antacid , mild laxative, in dentifrices.
– Used in formation of tablet as a additives
 Storage : To be store in well closed container.

28. Magnesium Trisilicate (MgSiO3)
 Limit : Not less than 29% and not more than
32% of MgO & Not less than 65% and not more
than 68% of SiO2
 Preparation : By using sodium silicate solution
with magnesium sulphate will give magnesium
trisilicate.
MgSO4 + Na2SiO3  MgSiO3 + Na2SO4

29. Magnesium Trisilicate (MgSiO3)
 Properties :
– White slightly hydroscopic powder
– Odorless & tasteless
– Insoluble in water & alcohol
– Soluble in mineral acid.
 Uses :
– Antacid , mild laxatives
– Used in treatment of peptic ulcer
 Storage : To be store in well closed container.

30. Protective & Adsorbent
 The drug which are used in a treatment of
various GIT disorder like dysentery &
diarrhea.
 Dysentery: It is disease marketed by
frequent elimination of watery fluid with or
without mucus or blood which develops due
to amoeba known as “Entamiba Histolytica”
a small protozoa causing infection called as
amoebic dysentery

31.  Diarrhea : Diarrhea mainly result due to
improper digestion & absorption of food &
water& by the bacteria infection. In
diarrhea the frequent discharge of
intestinal content in the form of watery
fluid. The loss of fluid is accompanied by
loss of electrolytes, which frequently leads
to dehydration. The also causes electrolyte
imbalance.

32. DIFFERENT PROTECTIVE &
ADSORBENT
I. BISMUTH SUB-CARBONATE
II. KAOLIN

33. Bismuth Sub-carbonate
[(BiO2).CO3]2.H2O
 Synonym : Basic Bismuth Carbonate
 Limit : Not less than 90% and not more
than 92% of BiO2
 Preparation : Bismuth Nitrite solution can be
added with hot solution of soda ash i.e.
sodium carbonate with continuous stirring.
Wash the ppt with water & dry it in atm air
2Bi(NO3)3 + 3Na2CO3 + H2O  [(BiO2).CO3]2.H2O

34. Bismuth Sub-carbonate
[(BiO2).CO3]2.H2O
 Properties :
– White or pale yellowish powder.
– Odorless & tasteless.
– Stable in air but affected by light.
– Soluble in water, alcohol & mineral acid.
 Uses :
– Antidysentric & Anti-diarrheal
– Mild astringent
– Antiseptic & Antacid.

35. Kaolin
 Synonym : China Clay
 It is a hydrated aluminium silicate with
variable composition of calcium,
magnesium & iron.
 Preparation : it is prepared by grinding
natural china clay & pass through sieve to
get very fine kaolin powder.

36. Kaolin
 Properties:
– White soft powder.
– Odorless & Clay like taste.
– Insoluble in water.
– Soluble in mineral acid.
 Used:
– Antidysentric & Anti-diarrheal
– Used in pediatric in the form of “Kaolin Poultice”.
– As a filter.
– As a dusting powder
 Storage: To be store in well closed container.

37. Saline Cathartic
 This are the agents which decreases the rate of
constipation & increases the osmotic load in
GIT.
 Cathartic divided into 4 classes on the basis of
its mechanism
1. Stimulant
2. Bulk purgatives
3. Lubricants
4. Saline cathartics

38. 1. Stimulant : This are the agents which acts on
directly on intestine & stimulates peristaltic activity
(movement). E.g. Senna , Castor oil
2. Bulk purgatives : They are act by increasing the bulk
of intestinal contents & stimulates peristaltic activity
(movement). E.g. Methyl Cellulose, Sapgol
3. Lubricants : They act as a smooth disposal of
lubricated fecal matter through anus. E.g. Liquid
Paraffin, Glycerine.
4. Saline cathartics: This are the agents which
increases the osmotic load in GIT. E.g. Magnesium
Sulphate & Sodium Potassium Tartarate.

39. DIFFERENT SALINE
CATHARTICS
I. MAGNESIUM SULPHATE
II. SODIUM POTASSIUM TARTARATE.

40. Magnesium Sulphate (MgSO4)
 Synonym : Epsom Salt
 Limit : Not less than 99% and not more
than 100.5% of MgSO4
 Preparation : it is prepared by addition of
magnesium carbonate with sulphuric acid
with continuous agitation (stirring) till to
remove carbon dioxide gas.
MgCO3 + H2SO4  MgSO4 + H2O + CO2

41. Magnesium Sulphate (MgSO4)
 Properties:
– Colorless Crystalline powder
– Odorless
– Soluble in water, saline bitter taste
 Uses:
– Saline cathartics.
– Antidote metal poising.
 Storage: To be store in well closed container in a cool
place.

42. Sodium Potassium Tartarate
(C4H4O6.Na.K.H2O)
 Synonym : Rochelle Salt
 Limit : Not less than 99% and not more
than 104% of C4H4O6.Na.K.H2O
 Preparation: It is prepared by boiling
solution of sodium carbonate with
potassium bitartarate to get a salt with full
expultion of CO2.
Na2CO3 + 2KHC4H4O6  C4H4O6.Na.K.H2O + CO2

43. Sodium Potassium Tartarate
(C4H4O6.Na.K.H2O)
 Properties:
– White crystalline powder.
– Odorless & Saline bitter taste.
– Soluble in water & insoluble in alcohol.
 Uses:
– Saline Cathartics
– Preservatives
– Active ingredients of “Effervasant Powder”
 Storage: To be store in well closed container.

44. Question Bank
 Define & Classification of Gastrointestinal agent.
 Describe about acidified agent & give monograph of
Dilute HCl.
 Write note on Antacid with ideal requirement.
 Give monograph of aluminium, sodium, calcium &
magnesium containing antacids.
 Write note on Protective & adsorbents.
 Give monograph of Protective & adsorbents.
 Define & Classification of Cathartic.
 Give monograph of saline cathartic.