The document discusses gastrointestinal agents and provides information about antacids. It defines antacids as alkaline substances used to neutralize hydrochloric acid in the stomach and provides relief from pain caused by excess stomach acid. The summary discusses classification of antacids as systemic or non-systemic based on absorption and criteria for an ideal antacid preparation. It also mentions combination antacid preparations can help avoid side effects of individual compounds.

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Branch: B. Pharm.
Semester: I
Subject: Pharmaceutical Inorganic Chemistry
UNIT III
Topic: Gastrointestinal agents
Ms. Vijaya Shukla
Department of Pharmaceutical Chemistry
Institute of Pharmaceutical Sciences
University of Lucknow

2. Antacid
Cathartics
Antimicrobials
Acidifiers
Stool Constipation
Purgative
Laxatives
(Strong)
(Mild)
Gastrointestinal agents

3. • Oesophagus
• Stomach
• Intestine (Small and large)
• Rectum with anus
In case, when the function of GIT is impaired, following conditions can take place:
❑ Absence or insufficient secretion of hydrochloric acid in stomach leading to achlorhydria or hypochlorhydria.
❑ Excessive secretion of hydrochloric acid in stomach leading to hyperacidity which finally causes ulcers,
inflammation and pain.
❑ Insufficient intestine motility or peristalsis leading to constipation.
❑ Accumulation of toxin, gases, toxic substance or insufficient absorption of fluid or electrolytes in intestine
stimulates the intestine motility leading to frequent stools or diarrhoea.
❑ Inadequate secretion of saliva, thereby making the food to swallow with difficulty.
Gastrointestinal tract (GIT)
The gastrointestinal tract is the tract or passageway of the digestive system that leads from the mouth to the anus (ingestion
of food to the expulsion of waste or faeces.)
The GI tract contains all the major organs of the digestive system,

4. Acidifying agents
Acidifying agents are used in a condition when there is absence or insufficient secretion of hydrochloric acid in stomach,
which leads to a disease called achlorhydria or hypochlorhydria.
Pepsinogen Pepsin
pH below 6
Pepsinogen is converted into pepsin when the gastric pH is below 6. Not only this, pepsin shows its best action below pH
3.5. Thus, the absence of gastric acid (HCI) can cause lack of pepsin activity. This finally leads to impairment of protein
digestion.
Requirement of hydrochloric acid-
• Kills the bacteria in the drink/food,
• Soften fibrous food
• Helps in the secretion of pepsin (proteolytic enzyme)

5. Ammonium Chloride
Molecular Formula: NH4Cl
Molecular Weight: 53.49 g
Synonyms: Salmiac, Amchlor, Ammonium muriate.
Standards: It contains not less than 99.5% of ammonium
chloride
The resulting solution of ammonium chloride is evaporated to
dryness.
Methods of Preparation:
1. It is prepared by neutralizing hydrochloric acid with ammonia.
NH3
HCl NH4Cl
Ammonia Hydrochloric
acid
Ammonium
chloride
+
2. It is also prepared by treating ammonium sulphate
with sodium chloride.
+
+
Sodium chloride Ammonium sulphate
2NaCl (NH4)2SO4
Ammonia Hydrochloric
acid
Sodium sulphate
2NH3 2HCI Na2SO4
+
2NH3
2HCI
+
2NH4Cl
Ammonia Hydrochloric acid
Ammonium Chloride

6. • White fine crystalline powder
• Odourless and has cooling saline taste
• Hygroscopic
• Freely soluble in water but slightly soluble in alcohol
• 0.8% w/v solution is isotonic with serum
Assay: It is assayed by acid-base titrations. The neutral formaldehyde solution is added so that ammonium chloride
will be converted to methanimine and hydrochloric acid. The liberated acid is titrated with 0.1 N NaOH using
phenolphthalein as an indicator.
+
NH4Cl HCHO CH2=NH HCl H2O
Ammonium
Chloride
Formaldehyde Methanimine Hydrochloric
acid
HCl NaOH NaCl H2O
+
+ +
+
Hydrochloric
acid
Sodium
hydroxide
Sodium
Chloride
Physical properties-

7. Incompatibility
Incompatible with alkali, alkaline earth metals, carbonates and metal salts of lead and silver.
ldentification tests
• It gives the reactions of ammonium salts and chlorides.
• A few mg of the substance is heated with sodium hydroxide solution, leading to the evolution of ammonia gas,
which is recognizable by its odour and by its action on moist red litmus paper.
+
+
+
NH4
+ OH-
NH3 H2O
Ammonium
ions
Hydroxyl
ions
Ammonia

8. The sample is tested for the presence of following impurities-
❑ Arsenic should not be more than 2 pom.
❑ Sulphate should not be more than 150 pom and calcium should not be more than 200 ppm.
❑ Iron should not be more than 20 ppm.
❑ Heavy metals should not be more than 10 ppm.
❑ Loss on drying should not be more than 1%.
Storage: It should be stored in well closed containers.
Dose: 3-6g daily in divided dose.
Uses:
• Systemic Acidifier
• Expectorant
• Diuretic
Test for Purity

9. Dilute Hydrochloric Acid, IP
Preparation : Dilute Hydrochloric Acid is prepared by mixing 274 g of Hydrochloric Acid and 726 g of Purified
Water.
Dilute Hydrochloric Acid contains not less than 9.5 per cent and not more than 10.5 per cent w/w of HCl.
Properties :
• It is a colourless liquid with a specific gravity of 1.045.
• It gives tests for strong mineral acids.
• After neutralization with alkalis it gives tests for chlorides.
• When added to potassium permanganate chlorine is evolved, detected by its characteristic pungent odour.
Assay : Weigh accurately about 6.0 g, add 30 ml of water, mix and titrate with 1 M sodium hydroxide using methyl red
solution as indicator.
1 ml of 1 M sodium hydroxide is equivalent to 0.03646 g of HCl
Uses : It is used as gastric acidifier in achlorhydria or hypochlorhydria.
The dose of 0.6 to 8 mL maybe sipped through a straw to avoid contact with teeth.
Rarely, it has also been given intravenously in metabolic alkalosis. More commonly it is employed to acidify oral liquid
preparations.
Storage : It is stored in stoppered containers of glass or other inert material, below 30°C.

10. Antacids (anti - against; acidus - acid) are alkaline substances used to neutralize hydrochloric acid in the stomach.
Gives symptomatic relief of pain due to hyperchlorhydria.
Antacids are the substances which reduce gastric acidity resulting in an increase in the pH of stomach and duodenum.
Gastric acidity occurs due to excessive secretion of HCl in stomach due to various reasons-
❑ Gastritis (A general inflammation of gastric mucosa)
❑ Peptic ulcer or oesophageal ulcer (Lower end of oesophagus)
❑ Duodenum ulcer
❑ Gastric ulcer (Stomach)
Antacids

11. Classification of Antacids
• These antacids get systemically absorbed.
These are highly soluble and potent
neutralizer.
• These are not suitable for the treatment of
peptic ulcer because of risk of ulcer
perforation which can occur due to
production of carbon dioxide in stomach.
e. g. Sodium carbonate.
Systemic
antacids
• These are insoluble and poorly absorbed
systemically. e. g. Magnesium and
Aluminium salts
Non-
systemic
antacids
(a) Aluminium containing antacids-
ex- Aluminium hydroxide,
Aluminium phosphate, Basic
Aluminium carbonate etc.
(b) Calcium containing antacids:
Calcium carbonate
(c) Magnesium containing
antacids: Magnesium carbonate,
Magnesium hydroxide,
Magnesium phosphate,
Magnesium trisilicate.
(d) Combination antacid
preparation: Aluminium
hydroxide gel and Magnesium
hydroxide, Aluminium hydroxide
gel and Magnesium silicate.

12. Criteria of an ideal antacid preparation:
❑ The antacid should not be absorbable or cause systemic alkalosis.
❑ The antacid should not be a laxative or causes 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 HCl acid should not cause a large evolution of gas.
❑ The antacid should probably inhibit pepsin.

13. Every single compound among antacid have some side effect especially when used for longer period or used in elderly
patients. To avoid certain side effects associated with antacids, combinations of antacids are used such as:
i. Magnesium and aluminium containing preparation e.g. magnesium hydroxide a fast acting antacid with aluminium
hydroxide which is a slow acting antacid.
ii. Magnesium and calcium containing preparation where one is laxative and the later one causes constipation.
Combinations of antacids therapy
Magnesium Trisilicate Oral Powder: It is having magnesium trisilicate, chalk powder, sodium bicarbonate and magnesium
carbonate.
Megaldrate: It is a chemical combination of aluminium hydroxide and magnesium hydroxide.
Algicon Tablet: It is a chewable tablet which is prepared by aluminium hydroxide and magnesium
carbonate co-dried gel, magnesium alginate, magnesium carbonate and potassium bicarbonate.
Simeco Tablets: It contains aluminium hydroxide-magnesium carbonate co-dried gel, magnesium hydroxide and activated
dimethicone.
Aluminium Hydroxide Gel-Magnesium Trisillicate Combination: Most common combinations; laxative, constipation and
protective effect.
Preparations-

14. Sodium bicarbonate
Molecular formula NaHCO3
Molar mass 84.01 g/mol
Synonym Baking soda; Bread soda, Cooking soda, Bicarbonate of soda
Preparation - NaHCO3 may be obtained by the reaction of carbon dioxide with an aqueous solution of sodium
hydroxide. The initial reaction produces sodium carbonate. Further addition of carbon dioxide produces sodium
bicarbonate
CO2 + 2 NaOH → Na2CO3 + H2O
Na2CO3 + CO2 + H2O → 2 NaHCO3
Sodium Bicarbonate contains not less than 99.0 per cent and not more than 101.0 per cent of NaHCO3.

15. Properties
Appearance : White crystalline power or granules
Odor : Odourless
Taste : Saline taste
Density : 1.1 to 1.3 g/cm3
Melting point : Decomposes to sodium carbonate starting at 500 C
Solubility in water : Freely soluble in water
Refractive index : 1.583
On an industrial scale it is obtained by Solvay process:
CO2 + H2O → H2CO3
NH3 + H2CO3 → NH4HCO3
NaCl + NH4HCO3 → NaHCO3 + NH4Cl

16. Chemical Properties-
1. Thermal decomposition: Above 500 C, sodium bicarbonate gradually decomposes into sodium carbonate,
water and carbon dioxide. The conversion is fast at 2000 C
2 NaHCO3 → Na2CO3 + H2O + CO2
2. Sodium bicarbonate reacts with acetic acid, producing sodium acetate, water, and carbon dioxide.
NaHCO3 + CH3COOH → CH3COONa + H2O + CO2
3. Sodium bicarbonate reacts with bases such as sodium hydroxide to form carbonates
NaHCO3 + NaOH → Na2CO3 + H2O
4. When mercuric chloride solution is added to a solution of sodium bicarbonate a reddish precipitated of
mercuric oxide is formed.
2 NaHCO3 + HgCl2 → 2 NaCl + H2O + HgO + 2 CO2

17. Assay - Weigh accurately about 1.5 g, dissolve in 50 ml of carbon dioxide-free water and titrate with 1 M hydrochloric
acid using 0.2 ml of methyl orange solution as indicator.
1 ml of 1 M hydrochloric acid is equivalent to 0.08401 g of NaHCO3
Uses
❑ It is used as Systemic antacid and in electrolyte replacement.
❑ It is used as systemic alkalinising agent used in the treatment of metabolic acidosis (increase in acidity).
❑ Bicarbonate of soda can also be useful in removing splinters from the skin.
❑ Sodium bicarbonate can be added to local anaesthetics, to speed up the onset of their effects and make their injection less
painful.
❑ Sodium bicarbonate may be used as a buffering agent, combined with table salt, when creating a solution for nasal
irrigation.
❑ 0.1% to 1% Sodium bicarbonate solution used as eye lotion.
❑ Used removed ear wax and lubricating fluid for contact lenses.
❑ 5% to 10% Sodium bicarbonate solution used as local applicants for burn, insect bites etc.
❑ Used in preparation of effervescent formulation.

18. Test for purity: The sample is tested for the presence of following impurities:
1. Arsenic should not be more than 2 ppm.
2. Sulphate should not be more than 150 ppm and chlorides should not be more than 200 ppm.
3. Iron should not be more than 20 ppm.
4. Heavy metals should not be more than 5ppm.
5. Other impurities to be tested include carbonates and calcium.
6. Loss on drying should not be more than 1%.
Storage Storage Conditions: it should be stored in air tight containers because of its hygroscopic nature in moist
atmosphere. It releases carbon dioxide at 50°C and gets converted to sodium carbonate at 100°C.

19. Aluminum hydroxide gel
Molecular formula: Al(OH)3
Molar mass: 78.00 g/mol
Synonym: Hydrated alumina, Ortho Aluminic acid, Aluminic acid
• Aluminium Hydroxide Gel is an aqueous suspension of hydrated aluminium oxide together with varying quantities of
basic aluminium carbonate and bicarbonate. It may contain Glycerin, Sorbitol, Sucrose or Saccharin as sweetening
agents and Peppermint Oil or other suitable flavours. It may also contain suitable antimicrobial agents. Aluminium
Hydroxide Gel contains not less than 3.5 per cent and not more than 4.4 per cent w/w of Al2O3.
• Aluminium Hydroxide Gel contains not less than 3.5 per cent and not more than 4.4 per cent w/w of Al2O3.
Preparation - It is prepared by hot solution of potash alum slowly with constant stirring to a hot solution of sodium
carbonate.
3Na2CO3 + 2KAl(SO4)2 + 3H2O →3Na2SO4 + K2SO4 + 2Al(OH)3 + 3 CO2

20. Properties
• A white, viscous suspension
• Translucent in thin layers
• Small amounts of clear liquid may separate on standing.
• Aluminium hydroxide gel gives astringent aluminium chloride when it reacts with gastric
hydrochloric acid. This results into sometimes nausea, vomiting and constipation.
Al(OH)3 + 3HCI →AlCI3 + 3H2O
When heated to red hot, it decomposes into water and aluminium oxide.
2Al(OH)3 →Al2O3 + 3H2O

21. Assay-
Weigh accurately about 5.0 g and dissolve in 3 ml of hydrochloric acid by warming on a water-
bath; cool to below 20° and dilute to 100.0 ml with water. To 20.0 ml of this solution, add 40.0 ml
of 0.05 M disodium edetate, 80 ml of water, and 0.15 ml of methyl red solution and neutralise by
the dropwise addition of 1 M sodium hydroxide. Warm on a water-bath for 30 minutes, add 3 g of
hexamine and titrate with 0.05 M lead nitrate using 0.5 ml of xylenol orange solution as indicator.
1 ml of 0.05 M disodium edetate is equivalent to 0.002549 g of Al2O3.

22. Uses
❑ Aluminium salts remain in the stomach for long periods and slowly react with stomach acid to form aluminium
chloride. Aluminium hydroxide may inhibit the action of pepsin and stimulate stomach mucus secretion.
❑ Aluminium hydroxide used as gastric antacid.
❑ Aluminium hydroxide used in treatment of Gastro esophageal reflux disorder.
❑ Ulcer Protectives-Basic aluminium hydroxide of sulfated sucrose is known as Sucralfate which promotes healing of
both duodenal and gastric ulcers.
❑ In treatment of Zollinger-Ellison Syndrome.
Storage: Store in well-closed containers and should not be allowed to freeze.
Note: Zollinger–Ellison Syndrome is a condition caused by gastrin-secreting pancreatic adenomas that lead to multiple ulcers in the stomach and
duodenum.

23. Dried Aluminium Hydroxide Gel
❑ Dried Aluminium Hydroxide Gel consists largely of hydrated aluminium oxide together with varying quantities of
basic aluminium carbonate and bicarbonate.
❑ Dried Aluminium Hydroxide Gel contains not less than 47.0 per cent and not more than 60.0 per cent of Al2O3.
❑ Description-A white, light, amorphous powder containing some aggregates; odourless; tasteless.
❑ Assay- Weigh accurately about 0.4 g and dissolve in a mixture of 3 ml of hydrochloric acid and 3 ml of water by
warming on a water-bath, cool to below 20° and dilute to 100.0 ml with water. To 20.0 ml of this solution, add
40.0 ml of 0.05 M disodium edetate, 80 ml of water, and 0.15 ml of methyl red solution and neutralise by the
dropwise addition of 1 M sodium hydroxide. Warm on a water-bath for 30 minutes, add 3 g of hexamine and titrate
with 0.05 M lead nitrate using 0.5 ml of xylenol orange solution as indicator.
1 ml of 0.05 M disodium edetate is equivalent to 0.002549 g of Al2O3

24. Magnesium Hydroxide Oral Suspension
Molecular formula: Mg(OH)2
Molar mass: 58.31 g/mol
Synonym: Magnesium Hydroxide Mixture; Milk of Magnesia; Cream of Magnesia
Magnesium Hydroxide Oral Suspension is an aqueous suspension of hydrated magnesium oxide. It may be prepared
from a suitable grade of Light Magnesium Oxide. Magnesium Hydroxide Oral Suspension contains not less than 7.0 per
cent and not more than 8.5 per cent w/w of hydrated magnesium oxide, calculated as Mg(OH)2.
Description- A white, uniform suspension, which does not separate readily on standing.

25. Methods of Preparation- Dissolve the sodium hydroxide in 150ml purified water, add the light magnesium oxide, mix
to form a smooth cream and then add sufficient purified water to produce 2500ml.
Pour this suspension in a thin stream into a solution of magnesium sulphate with continuous stirring
Allow the precipitate to subside, decant the clear liquid, transfer the residue to a calico strainer, and allow draining
and washing the precipitate with purified water until all the sulphates are washed away
Mix the washed precipitate with purified water, dissolve the chloroform in the mixture
and add sufficient purified water to produce 1000 ml.
Assay- Weigh accurately about 10.0 g, mix with 50 ml of water, add 50.0 ml of 0.5 M sulphuric acid and titrate the
excess of acid with 1 M sodium hydroxide using methyl orange solution as indicator.
1 ml of 0.5 M sulphuric acid is equivalent to 0.02916 g of hydrated magnesium oxide calculated as Mg(OH)2

26. Uses
❑ Used as weak antacid and laxative.
❑ Most commonly used antacids combine aluminum hydroxide and magnesium hydroxide. The combination
decreases the adverse effects of diarrhea (with magnesium products) and constipation (with aluminum products).
Calcium carbonate is effective in relieving heartburn, but it is infrequently used to treat peptic ulcers or GERD.
Storage- Store protected from moisture. Do not keep in a refrigerator.

27. Cathartics are the drugs, which are used to relieve constipation. They may also be given for clearing bowels
before surgery. The term "Laxative" is used for mild cathartics and the term "Purgative" is used for strong
cathartics.
Cathartics
• Normally, the peristaltic movement causes defecation (expulsion of waste out from the body) by stimulating the
bowel and finally relieve its content. The peristalsis movement normally takes place about 3-4 times a day.
Abnormality in this motion physiologically leads to constipation.
• Constipation may also result from change in environment, emotional tension, improper diet, lack of exercise or
work, side effect of drugs, weakness of intestines; intestinal injury etc.
• Low amount of watery intake daily also leads to constipation.
• Laxatives, cathartics and purgatives act by retaining fluid in the bowels. They may be administered by oral route
(suspension or powder) and by rectal route (enema or suppository).
• Prolong use of laxatives and purgative may impair the intestinal movement or activity and cause laxative habit or
dependence. Best care from constipation can be obtained by taking more fibre in the diet, including fresh fruits
and natural laxatives such as whole grains cereals, leafy vegetables like spinach, raw carrots, cucumbers, salads,
papaya, water melon etc.

28. Mild Purgatives or Laxatives: These are the substances which cause or promote defecation with minimum side
effects.
Strong Purgatives: These are the compounds which causes fast and complete evacuation of the bowels and then
bowels become inactive. These drugs generally cause constipation after their effect for which mild purgatives are
again needed. So these purgatives should not be used for constipation. These drugs are also used for killing the
intestinal worms and expel them out of the body. These purgatives cause the labor pain due to their quick action so it
should not be used in pregnancy.
Cathartics are classified as-
(a) Bulk forming drugs: These are the drugs which act by increasing the bulk of intestinal content. These materials
swell into intestine when comes in contact with water and increase the stool bulk volume, which stimulate the
peristalsis. e. g. Isapgol, agar-agar, methyl cellulose, sodium carboxy-methyl cellulose, karaya gum etc.
(b) Stool Softener (Emollients): Drugs which penetrate, lubricate and soften the stools are called as emollients. e. g.
liquid paraffin, D-octyl sodium-sulpho-succinate.

29. (c) Irritant or Stimulant Purgatives: These are the drugs which act by local irritation, on intestinal tract and bring
about stimulation of peristaltic activity. e. g. Senna, aloe, castor oil, rhubarb etc.
(d) Saline Cathartics: These drugs act by increasing the osmotic load of intestine by absorbing large quantity of
water and ultimately stimulate peristalsis. The saline cathartics are water soluble compounds mainly inorganic
chemicals and they are taken with large quantity of water. Saline cathartics are classified as:
(i) Sodium containing compounds: e. g. Sodium biphosphate, sodium phosphate, potassium sodium tartarate.
(ii) Magnesium containing compounds: e. g. Magnesium hydroxide (milk of magnesia), magnesium citrate,
magnesium sulphate.
(iii) Sulphur containing compounds.
(iv) Non-official cathartics: e. g. Sodium sulphate, potassium phosphate, potassium bi-tartarate, calomel.

30. Magnesium Sulphate
Molecular Formula: MgSO4.7H2O
Molecular Weight: 246.5 g
Synonym: Epsom salt
It is a heptahydrate salt, having not less than 99% and not more than 100% of magnesium sulphate.
Methods of Preparation:
1. Magnesium sulphate is prepared from magnesium carbonate and dil. sulfuric acid.
MgCO3 + H2SO4 → MgSO4 + H2O + CO2
2. Magnesium sulphate can also prepare from magnesium oxide and dil. sulfuric acid.
MgO + H2SO4 → MgSO4 + H2O
3. Industrial Method: Magnesium sulphate is prepared from DOLOMITE (MgCO3• CaCO3) by using dil. sulfuric acid
MgCO3•CaCO3 + 2H2SO4 → MgSO4 + CaSO4 + 2H2O + 2CO2

31. Properties:
MgSO4.7H2O MgSO4.H2O
→
Uses:
1. It is widely used as oral saline cathartic.
2. It is used as antidote for barium, barbiturates and other types of poisoning.
3. Due to CNS depressant property of magnesium, it is also used in hypertension and convulsions.
4. It is also used in ventricular tachycardia.
• It occurs as small, odourless and colourless crystals with cool and saline bitter taste.
• It is freely soluble in water and slightly soluble in alcohol.
• When heated gently, it loses most of its water and converted to monohydrate (white powder).
Assay: Weigh accurately about 0.3 g, dissolve in 50 ml of water, add 10 ml of strong ammonia-ammonium chloride
solution and titrate with 0.05 M disodium edetate, using 0.1 g of mordant black II mixture as indicator, until a blue
colour is obtained.
1 ml of 0.05 M disodium edetate is equivalent to 0.00602 g of MgSO4.
Storage: Store protected from moisture.

32. Sodium Orthophosphate
It is one of the phosphates of sodium; which is used as a laxative to cleanse the bowels.
Molecular Formula: Na2HPO4.12H2O
Synonym: Disodium Hydrogen Phosphate
Molecular Weight: 358.14 g
Methods of Preparation:
H3PO4 + 2NaOH Na2HPO4 + 2H2O
→
2. Industrial Preparation- Industrially, it is prepared in a two-step process by treating calcium biphosphate (CaHPO4)
with sodium bisulphate (NaHSO4), which precipitates calcium sulphate and monosodium phosphate (NaH2PO4) remains in
the solution.
CaHPO4 + NaHSO4 NaH2PO4 + CaSO4
→
In the second step, the resulting solution of monosodium phosphate is partially neutralized and finally results in the
formation of sodium orthophosphate.
NaH2PO4 + NaOH Na2HPO4 + H2O
→
1. It is the sodium salt of orthophosphoric acid or phosphoric acid (H3PO4). It is formed by the reaction of orthophosphoric
acid with sodium hydroxide in calculated amount.

33. Chemical Properties:
1. On hydrolysis, it yields sodium hydroxide and phosphoric acid back from which it is formed.
Na2HPO4 + 2H2O H3PO4 + 2NaOH
2. On heating, it gives pyrophosphate.
2Na2HPO4 Na4P2O7 + H2O
→
→
3. On heating with ammonium chloride, table salt is formed.
Na2HPO4 + NH4CI NaCl + Na.NH4HPO4
→
Physical Properties:
• It occurs as colourless, odourless, transparent crystals.
• Its anhydrous salt is hygroscopic in nature.
• It effervescence in air when warmed.
• It is insoluble in alcohol but soluble in water.
• Its aqueous solution has a pH between 8.0-11.0 i.e. moderately basic.

34. Uses:
1. It is widely used as cathartics.
2. In the form of oral solution, it is also used as anti-hypercalcemic.
3. As a pharmaceutical aid, it is used as a buffering agent in various preparations.
4. It is used in conjunction with trisodium phosphate, in water softening treatment.
5. Its presence prevents coagulation, in the preparation of condensed milk.
6. In food industries, it is used to adjust pH.
7. It is used to treat constipation or to clean the bowel before a colonoscopy.
8. It is used as an anti-caking additive in powdered products.
Storage: It should be stored in tightly closed container; protected from moisture.
Assay- Weigh accurately about 4.0 g (w), dissolve in 25 ml of water, add 25.0 ml of 1 M hydrochloric acid and titrate
potentiometrically with 1 M sodium hydroxide to the first inflection of the pH curve (n1 ml). Continue the titration until
the second inflection of the curve is reached; the total volume of sodium hydroxide required is n2 ml. Calculate the
content of Na2HPO4 from the expression 1420(25 - n1)/w (100 - d), where d is the percentage water content.

35. Kaolin
Molecular Formula: Al2O3.2SiO2.2H2O
Molecular Weight: 258
Synonyms: The China Clay, Hydrated Aluminium Silicate
Method of Preparation: It is a hydrated aluminium silicate, widely distributed in nature. It is prepared when the rock is
mined, executed, the impurities are washed with the flow of water and then powdered.
Kaolin is found in two forms: Heavy Kaolin and Light Kaolin. Therefore the rock is elutriated with water and large sized
particles are separated. The turbid liquid is allowed to settle, heavy kaolin containing large particles and colloidal kaolin
containing particles of small size are separated and dried.
Physical Properties:
1. Kaolin is slightly plastic like and is normally white in colour.
2. It has an earthy or clay like taste.
3. Its colour may be tinged grey, yellow brown, blue or red due to presence of impurities.
4. It is soapy to touch and its surface takes high polish on rubbing.
5. Its fusion point range between 1700 - 1800°C.
6. When moistened with water, it produces a darker colour and develops marked clay like odour.

36. Chemical Properties:
1. On heating, kaolin loses water molecules.
2. It is decomposed by prolonged boiling or treatment with concentrated sulphuric acid.
3. If it is first heated to white heat, it becomes more resistant to heat.
Uses:
1. Adsorbent, antidiarrhoeal and increase the bulk of faeces.
2. It adsorbs toxins from alimentary tract and is thus beneficial in diarrhoea.
3. Kaolin has also been used in the treatment of chronic ulcerative colitis.
4. Externally, heavy kaolin has some use as poultice, dusting powder, foot powder and as an ingredient of toilet preparation.
5. It is also used as filtering medium as well as clarifying and decolorizing medium.
6. Sometimes it is also used as tablet diluent.

37. Molecular Formula: Al2O3.4SiO2.H2O
Molecular weight: 422.286 g
Synonym: Clay
Bentonite
Bentonite is a natural, colloidal, hydrated aluminium silicate that has been processed to remove grit and non-swelling
components of the ore.
Description: A very fine, pale buff or cream-coloured to greyish-white powder, free or almost free from gritty particles.
Physical Properties:
1. It is a hydrated material having swelling and absorptive properties.
2. Its powder mask has a binding property.
3. It has excellent plasticity and lubricity.
4. It has high shear and compressive strength.
5. It has low permeability and low compressibility.
6. It has good dry sealing properties.
Bentonite clay has negatively charged molecules, which give adsorptive properties to it and makes it medicinally
useful. It has the ability to pass through the intestinal tract and attract the toxins which are positively charged. When
they are in contact with each other, they swap ions and are bound together and the toxic molecule is absorbed by the
clay molecule.

38. Uses:
1. It is used as cathartics due to its amazing absorption properties.
2. It can remove toxic metals and chemicals following radiation treatments.
3. Promotes healthy bacteria balance and detoxify the digestive system
4. It also supports in liver detoxification
5. As an antidote, it is used in mercury poisoning.
6. It is helpful in removing the internal parasites from digestive system.
7. It is found to be active against free radicals, hence can be used as antioxidant
8. It also helps in colon cleansing.
9. It supports in boosting immune system.
10. As a pharmaceutical aid, it is also used as a binder.

39. These are the agents which are used to destroy or inhibit the growth of pathogenic microorganisms. They are of six
types-
ANTI-MICROBIAL AGENTS
1. Antiseptics- These are the agents which prevent sepsis by destroying or inhibiting the growth of microorganism
on the living tissues. An ideal antiseptic should destroy bacteria, spores, fungi, viruses, or any other
microorganism without causing any harm to the tissue of the host. Antiseptics can also be used in prevention to
the hands of surgeons, dentists, nurses and others in their routine procedure.
2. Disinfectant- These are the substances which prevent infection by the destruction of pathogenic microorganism
and are generally employed for inanimate objects and materials such as instrument, room, hospitals, home
equipment etc.
3. Germicides- These are the substances which kill the microorganisms; the more specific term which is used is
bactericide, fungicide, virucide and amoebicide.
4. Bacteriostatic- Able to restrain or control the multiplication of bacteria, without actually killing them.

40. 5. Sanitizers- These are the disinfectants used to maintain public health standards. Sanitation is mainly concerned
with cleaning or washing away the organism.
6. Sterilization- Sterilization is the process of complete destruction of all living microorganisms, including bacterial
spores. It can be done by physical methods (application of heat or radiation) or by chemical means (use of chemical
disinfectant).
Mechanism of Action of inorganic anti-microbial agents:
Inorganic compounds exhibit their action by
1. Oxidation
2. Halogenation
3. Protein binding or precipitation

41. Oxidation mechanism: Compounds acting by this mechanism belong to class of peroxide, peroxyacids, oxygen
liberating compounds like permanganate and certain oxo halogen anions. These anti-infective agents bring about
oxidation of active functional groups present in proteins or enzymes, which are necessary for the growth, or survival
of microorganisms and also which reducing in nature. These cause a change in the shape of the protein and there by
alter its function. For examples: A free sulfhydryl group has been essential for function of various proteins and
enzymes. If this free sulfhydryl group is destroyed by oxidation into formation of di sulfide group, the microorganism
will die because of the altered protein molecule.
Oxidising
agent

42. Halogenation mechanism: Compounds that are able to liberate the chlorine or hypochlorite or iodine act by this
mechanism. The category of agents act on the peptide linkage and alter its potential and property. The destruction of
specific function of protein causes death of microorganisms. Most of the enzymes are proteineous in nature. A protein
molecule is composed of a variety of amino acids connected through a peptide linkage (-CONH-) if an hypo chlorites
attaches the peptide linkage by replacing the H by Cl then protein molecule will have an altered structure.
(Altered structure)
(Protein structure)
halogenation
Amino acid-CONH- Amino acid Amino acid -COCl-Amino acid.
C
O
N A A
A A
H
C
O
N A A
A A
C l
(Protein structure) (Altered structure)
halogenation

43. Protein precipitation: This type of mechanism involves the interaction of protein with metallic ions having large
charge or radius ratio or strong electrostatic fields. Hence most of the metals belonging to groups IB, IIB, IIIA or
transition metals show protective activity but alkali alkaline earth metals do not show this activity. The nature of
interaction of metal with protein takes place through polar group of protein, which acts as ligand and metal ions as
Lewis acid. The chelate formed may be strong chelate giving rise to inactivation of protein. This action in general non-
specific and at sufficient concentration will react with host as well as with microbial protein. The protein precipitant
properties of metal cations can be altered accordingly to the concentration at the site of action.

44. Potassium Permanganate
Molecular Formula: KMnO4
Molecular Weight: 158.03 g
Synonym: Permanganic acid.
Step 1. Potassium permanganate is prepared by mixing a solution of potassium hydroxide with powdered manganese
dioxide and potassium chlorate. The mixture is boiled, evaporated to yield the residue.
Methods of Preparation
6KOH + 3MnO2 + KClO3 3K2MnO4 +KCl+3H2O
Step 2. By passing chlorine gas through potassium manganate solution.
6K2MnO4 + 3Cl2 6KMnO4 + 6KCl

45. 3K2MnO4 + 2CO2 2KMnO4 + MnO2 + 2K2CO3
Potassium
carbonate
Potassium
manganate
Potassium
permanganate
manganese
dioxide
When carbon dioxide is passed in place of chlorine gas, then two-third of the Potassium manganate gets converted to
potassium permanganate.
Properties:
1. Dark purple prismatic crystal with metallic lustre.
2. Odourless.
3. It decomposes at higher temperature.
4. It is a powerful oxidizing agent.
Potassium
permanganate
Potassium
iodate
2KMnO4 + H2O + KI 2MnO2+ 2KOH+ KIO3

46. Mode of Action: Potassium permanganate releases the nascent oxygen i.e. [O], which by oxidative mechanism inhibits the
actions of microorganism and their growth.
Assay:
Weigh accurately about 0.3 g, dissolve in sufficient water to produce 100.0 ml. To 20.0 ml add 20 ml of water, 1 g of
potassium iodide and 10 ml of 2 M hydrochloric acid and titrate the liberated iodine with 0.1 M sodium thiosulphate
using starch solution, added towards the end of the titration, as indicator.
1 ml of 0.1 M sodium thiosulphate is equivalent to 0.003160 g of KMnO4.
Storage-Store protected from moisture
Uses-
1. Topical anti-infective
2. Used as an antiseptic in mouth wash and for cleaning of ulcers.
3. Treatment of urethritis
4. Antidote
5. Its solution is used in bath for eczema and acute dermatoses patients.

47. Boric Acid
Molecular Formula: H3BO3
Molecular Weight: 61.83
Synonyms: Boracic acid, Orthoboric acid
Methods of Preparation:
1. In laboratory, boric acid is obtained by adding a mixture of concentrated sulphuric acid and water to a boiling
solution of borax.
Na2B4O7 + 5H2O + H2SO4 Na2SO4 + 4H3BO3
Ca2B6O11. 5H2O + 2SO2 + 2H2O 2CaSO3 + 6H3BO3
2. Commercially boric acid is prepared by decomposing certain naturally occurring borates.
Calcium
borate
Borax
Boric
acid
Boric acid
Na2B4O7.10H2O + 2HCI 4H3BO3 + 2NaCl + 5H2O
Borax Boric
acid

48. Physical Properties:
1. Colourless, odourless white crystalline powder.
2. six sided triclinic crystals.
3. slightly acidic or bitter in taste.
4. soluble in water and alcohol.
5. It is stable in air
6. Melting point is 171°C.
Chemical Properties:
1. On heating to 100°C, it loses one molecule of water.
Oxoborinic
acid
H3BO3 HBO2 + H2O
Boric
acid
2. With alkali substance it forms salt due to its acidic nature.
H3BO3 + NaOH NaBO2 + 2H2O
Boric
acid
Sodium
metaborate

49. 3. On reaction with sodium carbonate, it liberates carbon dioxide and borax
4H3BO3 + Na2CO3 Na2B4O7 + CO2 + 6H2O
H3BO3 + C2H5OH B(C2H5O)3 + 3H20
4. Ethanolic solution of boric acid when heated, gives ethyl borate.
Assay- Weigh accurately about 2.0 g, dissolve in a mixture of 50 ml of water and 100 ml of glycerin, previously
neutralised to phenolphthalein solution. Titrate with 1 M sodium hydroxide using phenolphthalein solution as
indicator.
1 ml of 1 M sodium hydroxide is equivalent to 0.06183 g of H3BO3.
Storage: It must be stored in air tight container in a cool place.

50. Uses:
1. Local anti-infective and is used in the preparation of various dusting powders, antiseptic creams, ointments etc.
2. weak bacteriostatic and fungistatic.
3. Its aqueous solution in concentration of 2.5 - 4.5% is used as eye wash, mouth wash and skin lotions.
4. It is used as emollient antiseptic ointment in the treatment of diaper rashes.
5. It is used in the preparation of buffer solutions for topical medications to maintain acidic pH
Hydrogen Peroxide
Molecular Formula: H2O2
Molecular Weight: 34.01gm
Methods of Preparation
1. It is prepared by the action of sulphuric acid on barium peroxide.
BaO2 + H2SO4 BaSO4 + H2O2
2. Hydrogen peroxide solution may be prepared by the reaction of barium peroxide with phosphoric acid.
2BaO2 + 2H3PO4 Ba3(PO4)2 + 3H2O2

51. 3. It can also be prepared by treating sodium peroxide with sulphuric acid.
Na2O2 + H2SO4 Na2SO4 + H2O2
Physical Properties:
1. Hydrogen peroxide solution is colourless and odourless.
2. Its taste is slightly acidic.
3. It readily gets decomposed when come in contact with oxidisable organic metal
2H2O2 2H2O + O2
4. It is a strong oxidizing agent and is miscible with water.
Mode of Action: Potassium permanganate releases the nascent oxygen i.e. [O], which by oxidative mechanism inhibits
the actions of microorganism and their growth.
Storage- Store protected from light in containers resistant to hydrogen peroxide at a temperature not exceeding 30°. If
the solution does not contain a stabilising agent, it should be stored in a refrigerator (2° to 8°). It should not be stored
for long periods.

52. Uses:
1. Strong antiseptic and destroys all pathogenic bacterias.
2. 6% solution of hydrogen peroxide is used as disinfectant.
3. Cleaning of cuts and wounds.
4. To remove ear wax.
5. Effective antidote for phosphorus and cyanide poisoning.
6. Its 1.6% solution is used as deodorant, gargles and mouth wash.
7. It is used for bleaching the hair.
Hydrogen Peroxide Solution (20 Vol) Hydrogen Peroxide Solution (100 Vol)
Hydrogen Peroxide Solution (6 per cent); Dilute
Hydrogen Peroxide Solution
Hydrogen Peroxide Solution (27 per cent);
Strong Hydrogen Peroxide Solution
Assay-To 1.0 ml add 20 ml of 1 M sulphuric acid and
titrate with 0.02 M potassium permanganate.
1 ml of 0.02 M potassium permanganate is
equivalent to 0.001701 g of H2O2 or 0.56 ml of
oxygen.
Assay-Dilute about 1.0 g to 100.0 ml with water. To 10.0 ml
of the resulting solution add 20 ml of 1 M sulphuric acid and
titrate with 0.02 M potassium permanganate.
1 ml of 0.02 M potassium permanganate is equivalent to
0.001701 g of H2O2 or 0.56 ml of oxygen.

53. Chemical formula: Ca(OCl)Cl
Molecular weight: 142.9 8g/mol
Synonym: Calcium hypochlorite, Calcium oxychloride, Bleaching powder
By action of chlorine gas on calcium hydroxide. Calcium hydroxide is spread on the shelves in a suitable
container, then the chlorine gas is introduced at the top of the chamber and then allowed to pass through the
contents of the shelves. This step is carried out at 25°C.
Ca(OH)2 + Cl2 → Ca(OCl) Cl + H2O
Method of preparation:
1. It occurs as a dull white powder having a charteristic odour.
2. When exposed to air, gradually absorbs moisture and gradually gets decomposed.
3. Slightly soluble in water and alcohol.
4. When bleaching powder is put in water, hypochlorite goes out in solution.
Properties-
2Ca(OCl)Cl + CO2 + H2O CaCO3 + CaCl2 + 2HOCl
→
Chlorinated lime

54. Mode of Action: It works by chlorination of microorganism's protein, which ultimately leads to destruction of
protein and cell death.
Assay: Principle: Based on Redox titration, Iodometric titration
The available chlorine in the compound is liberated by the action of acetic acid, then an equivalent weight of
chlorine gas is replaced with iodine by the action of potassium iodide. The liberated iodine is then titrated against
sodium thio sulphate using starch as mucilage until the blue colour changes to colourless.
Ca (OCl)Cl + 2CH3COOH →(CH3COO)2Ca + Cl2 + H2O
Cl2+ 2KI→ I2+ 2KCl
I2+ 2Na2S2O3 → 2NaI + Na2S4O6
Take 4 g of chlorinated lime with small quantity of water and transfer it to 1 L flask and make up the volume to
the mark. Measure 100 ml of this suspension and transfer in another flask. Then it is titrated with 3 gm KI
solution, acidified with 5 ml acetic acid, the liberated iodine is titrated against 0.1 N sodium thiosulphate using
starch solution as an indicator.
Each 1 ml of 0.1 N Na2S2O3 = 0.003545 g of available chlorine.

55. Storage: It should be stored in well closed container as it is slowly decomposed with the loss of chlorine.
Uses:
1. Bactericidal action.
2. Disinfectant in wounds.
3. Cleansing agent for water closets (toilets), drains and effluents.
4. Preparation of detergents.
5. It is powerful bleaching agent and is used in decolorizing most dyes.
Chemical formula: I2
Molecular weight: 253.8 g/mol
Method of Preparation:
Iodine
1. From Seaweed’s ash
2NaI+Cl2 → 2NaCl+I2
2. From Chile saltpeter
2NaIO3 + 5 NaHSO3 2 Na2SO4 + 3 NaHSO4 + I2 + H2O
→
Sodium
iodate
Sodium
hydrogen
sulphite
Sodium
sulphate
Sodium
hydrogen
sulphate

56. 1. Heavy, bluish-black, rhombic prism or plates having metallic lusture
2. Peculiar odour
3. Irritant
4. It volatilises at ordinary temperature
5. Freely soluble in chloroform and ether, soluble in water in presence of potassium iodide
Storage: Store in ground-glass-stoppered containers or in earthenware containers with waxed bungs.
Properties-
1. Counter irritant
2. Disinfectant
3. Proper thyroid functioning
Uses:
Preparations of Iodine
I. Aqueous iodine solution
II. Weak iodine solution
III. Strong iodine solution
IV. Povidone-Iodine solution

57. I. Aqueous iodine solution
Synonym: Lugols solution
Standards: It is having 5%w/v of iodine and 10 % w/v of potassium iodide in purified water
Composition:
• Iodine --- 50g
• Potassium iodide --- 100g
• Purified water sufficient to produce-----1000 ml
Method of preparation: Potassium iodide and iodine are first of dissolved in 100 ml of water with trituration or shaking
process. Then the volume is made upto 1000 ml with purified water.
Properties-
1. Transparent
2. Brown liquid,
3. Having the smell of iodine

58. Storage: It is preserved in well closed container of glass or plastic which are resistant to iodine. It is not stored in metallic
containers because iodine attacks metal.
Uses:
1. Good source of iodine (internally)
2. Externally as germicide, fungicide
II. Weak iodine solution
Synonym: Iodine tincture or tincture of iodine
Standards: It is having 2%w/v of iodine and 2.5 % w/v of potassium iodide in 50 % alcohol
Composition:
• Iodine --- 20g
• Potassium iodide --- 25g
• Alcohol (50%) to produce-----1000 ml
Method of Preparation: Potassium iodide and iodine are first of dissolved in 100 ml of 50 % alcohol. Then the volume is
made up to 1000 ml with 50 % alcohol.
Advantages: Non irritant

59. 1. Transparent
2. Brown liquid
3. Having the smell of iodine
Properties-
Storage condition: It is preserved in well closed container of glass or plastic which are resistant to iodine. It is not
stored in metallic containers because iodine attacks metal.
Uses:
1. Good source of iodine (internally)
2. Externally as germicide, fungicide
3. Well known antiseptic
III. Strong iodine solution
Standards: It is having 10 %w/v of iodine and 6 % w/v of potassium iodide in 90 % alcohol
Composition:
• Iodine --- 100g
• Potassium iodide --- 60g
• Purified water sufficient----100 ml
• Alcohol (90%) to produce-----1000 ml
Disadvantages: Irritant

60. Method of Preparation: Potassium iodide and iodine are first of dissolved in 100 ml purified water. Then the
volume is made up to 1000 ml with 90 % alcohol
Properties-
1. Transparent
2. Brown liquid
3. Having the smell of iodine
Storage condition: It is preserved in well closed container of glass or plastic which are resistant to iodine. It is not
stored in metallic containers because iodine attacks metal.
Uses:
1. Good source of iodine (internally)
2. Externally as germicide, fungicide
3. Well known antiseptic
Disadvantages:
Irritant
IV. Povidone –Iodine solution
It is an aqueous solution of Povidone iodine. It is complex produced by the interaction between iodine and Povidone
(Poly vinyl pyrrolidine). The complex is having about 10 % of iodine.

61. 1. Yellowish brown, amorphous powder,
2. Having a characteristic odour
3. Soluble in water and alcohol
4. The solution is transparent in nature and has reddish brown colour and faint smell of iodine
5. Its aqueous solution is having acidic pH
Properties-
Storage: It is kept in a closed container and remains stable.
1. Bactericidal
2. Disinfection of skin cuts and wounds and even applied on burnt cases also.
Uses:
Advantages:
1. Water solubility
2. Non-irritant
3. Less toxicity

62. References-
1. Anand & Chatwal, Inorganic Pharmaceutical Chemistry.
2. Indian Pharmacopoeia 2018, volume I,II,III.
3. P. Gundu Rao, Inorganic Pharmaceutical Chemistry, 3 rd Edition.
4. N.C. Chaudhry, N.K. Gurbani, Pharmaceutical Chemistry-1, 3 rd Edition.