1. Pharmaceutical Inorganic chemistry
UNIT-III (Part-I)
Gastrointestinal agents
Presented By
Ms. Pooja D. Bhandare
(Assistant Professor)
DADASAHEB BALPANDE COLLEGE OF PHARMACY BESA NAGPUR
2. Gastrointestinal agents
Introduction:
• The digestive system is the gastrointestinal tract (GIT)
• It starts from the esophagus to the anus.
• The main portion of GIT includes the stomach, small inte
stine, large intestine and the rectum with the exit anus.
• Whenever the functions of GIT go wrong, disease occurs.
3. Disease of GIT:
• Inadequate secretion of acid in the stomach causes achlorhydria or
hypochlorhydria.
• When excess of acid secretion takes place in stomach, this causes imbalance of
acid – enzyme ratio, which causes hyperacidity or ulcer.
• There may occur accumulation of toxic substances or gases.
• There may occur inadequate absorption of fluids and minerals from large
intestine, which causes diarrhoea.
• There may occur insufficient peristaltic movement of large intestine, thereby
causing constipation.
• There may occur inadequate secretion of saliva, thereby making the food to
swallow with difficulty.
• There may occur ingestion of poisonous substance accidentally or
intentionally by some person.
• It is possible to correct the above conditions by administration of suitable
drugs, which are called the GASTROINTESTINAL AGENTS.
4. • Hyperchlorhydria/ hyperacidity
Whenever excess secretion of acid takes place in the stomach, this causes the
imbalance in acid enzyme ratio, thereby finally leading to hyperacidity and ulcers.
Antacids are used in treatment of Hyperchlorhydria.
• Hypochlorhydria
Whenever inadequate secretion of acid takes place in the stomach, this causes
achlorhydria or hypochlorhydria. Acidifying agents/acidifiers are used in
treatment of Hypochlorhydria
5. • Acidifying agents/acidifiers: The drugs or agents which are used to increase metabolic
acidosis and gastric hydrochloric acid. They are also known as acidifying reagents or
acidifiers. e.g. Dilute HCl
• Antacids: These are drugs or substances which are alkaline substances and used for
neutralizing excess acid in the stomach of the patients suffering from hyperacidity. e.g
Sodium bicarbonate, aluminium hydroxide gel, Magnesium carbonate, milk of
magnesia, Tribasic Calcium Phosphate, Magnesium hydroxide.
• Protective and adsorbents:
These are chemically inert substances which are used in the treatment of mild diarrhoea
or dysentery of GIT because of their ability to adsorb gases, toxins and bacteria.
e.g Bismuth subcarbonate, Bismuth subnitrate milk of Bismuth.
6. • Cathartics: Cathartics may be defined as the drugs which bring about
defecation. They are beneficial in constipation and for expulsion of intestinal
parasites. e.g magnesium hydroxide sodium potassium tartrate.
• Purgatives: Purgatives are also cathartics which act similarly but are generally
mild in their nature of action. Potassium bitartrate
• Laxatives They are mild type of purgatives. They give rise to same effect but
vary in nature and mechanism of action. e.g Magnesium sulphate and sodium
phosphate
7. Detail Classification:
A. Acidifying Reagent or Acidifiers
1) Gastric acidifiers Eg. Dilute HCl
2) Urinary acidifier
3) Systemic acidifier
4) Acids
B. Antacids
1) Systemic (absorbable) antacids eg. Sodium bicarbonate
2) Non-Systemic (non-absorbable) antacids
a) Aluminium containing antacids e.g Aluminium hydroxide, Aluminium phosphate
b) Calcium containing antacids e.g Calcium carbonate, Tri basic calcium phosphate
c) Magnesium containing antacids e.g Magnesium carbonate, magnesium hydroxide.
d) Combination antacid preparations e.g. Aluminium hydroxide gel and magnesium
hydroxide Aluminium hydroxide gel and magnesium trisilicate
9. A. Acidifying reagents/acidifiers:
• These are drugs or agents which are able to increase acidity in GIT. Some of the
drugs are used to increase metabolic acidosis whereas some of these are used to
increase the gastric hydrochloric acid. They are also known as acidifying
reagents or acidifiers.
• Gastric acidifiers: These are drugs which are used to restore temporarily the
acidity of stomach in patients suffering from hypochlorhydria.
• Urinary acidifiers: These are the drugs which are used to render acidic urine to
enable treatment of some type of urinary tract disorders.
• Systemic acidifiers: These are the drugs which are able to neutralize the
alkaline body fluids, particularly blood, in patients who are suffering from
systemic alkalosis.
• Acids: Acids are used as pharmaceutical aids in the preparation, laboratory
quality control etc.
10. Ammonium Chloride*
Molecular formula NH4Cl Molar mass 53.49 g/mol
Synonym Sal ammoniac
Solutions of ammonium chloride are mildly acidic.
Physical Properties Appearance: White solid, hygroscopic Odor: Odourless Taste: Cooling saline Density:
1.5274 g/cm3 Melting point: 3380 C (decomposes, sublimes) Solubility: free soluble in water and glycerol,
Sparingly soluble in alcohol
Prepration
Ammonium chloride prepared through the Solvay process: Barine solution(Nacl) is saturated with ammonia to
remove traces of impurities like Mg and Fe. The solution is now filtered and passed through the carbonating tower.
In this it is allowed to come in contact with current CO2 and the tower is cooled to enhance perception (sodium
bicarbonate is less soluble in water below 15°). The precipitate is filtered out and dried.
CO2 + 2 NH3 + 2 NaCl + H2O 2 NH4Cl + Na2CO3
11. 2. Commercially it is prepared by neutralizing ammonia with HCl. The Solution is evaporated
till crude, crystalline mass of ammonium chloride is obtained.
NH3 + HCl NH4Cl
Ammonium chloride
The crude salt is purified by crystallization.
3. Ammonium chloride is produced by heating ammonium sulphate with sodium chloride.
2NaCl + (NH4 ) 2SO4 2NH3 + 2HCl + Na2SO 4
sodium chloride ammonium sulphate
Reactions
- Ammonium chloride appears to sublime upon heating but actually decomposes into ammonia
and hydrogen chloride gas: NH4Cl → NH3 + HCl
- Ammonium chloride reacts with a strong base, like sodium hydroxide, to release ammonia
gas:
NH4Cl + NaOH → NH3 + NaCl + H2O
- Similarly, ammonium chloride also reacts with alkali metal carbonates at elevated
temperatures, giving ammonia and
alkali metal chloride: 2 NH4Cl + Na2CO3 → 2 NaCl + CO2 + H2O + 2 NH3
12. Assay: Dissolve 1.000 g of Ammonium chloride in 20 ml of water and add a mixture of 5 ml
of formaldehyde solution, with few drops of phenolphthalein solution. After 1 min to 2 min,
titrate slowly with 1M sodium hydroxide. 1 ml of 1M sodium hydroxide is equivalent to 53.49
mg of NH4Cl.
Uses: -
• Ammonium chloride is used as an expectorant in cough medicine. Its expectorant action is
caused by irritative action on the bronchial mucosa, which causes the production of excess
respiratory tract fluid, which presumably is easier to cough up. –
• Ammonium salts are an irritant to the gastric mucosa and may induce nausea and vomiting. -
Ammonium chloride is used as a systemic acidifying agent in treatment of severe metabolic
alkalosis.
• The main application of ammonium chloride is as a nitrogen source in fertilizers.
• Ammonium chloride is used as a flux in preparing metals to be tin coated, galvanized or
soldered.
Dose: 1 to 2 gm (As systemic acidifier); 0.3 to 0.5 gm (Expectorant)
Storage: Store in highly closed container.
13. Dilute Hydrochloric acid:
• Formula : HCl (10%w/w) Mol. Wt: 36.46
Ingredients:
Hydrochloric acid and purified water.Hydrochloric acid is commonly known as spirit of salt
because it was first of all prepared by distilling sea salt with Sulphuric acid.
It is an aqueous solution of hydrogen chloride in water and is having not less than 35% w/w
and not more than 38 % of HCl.
Preparation:
1. It is manufactured by the action of sulphuric acid on sodium chloride. Calculated quantities of
concentrated sulphuric acid and sodium chloride are heated in the cast ion pans of a salt cake
furnace. The hydrochloric acid gas is formed which is passed in a tower , which is sprayed with
water. The dilute hydrochloric acid is collected at the bottom. It is again circulated to the tower
to absorb more hydrogen chloride so that it gets concentrated. The acid so produced is then
purified. NaHSO 4 formed in the process is mixed with some more quantity of sodium chloride,
and heated strongly in the maffle furnace to get more hydrogen chloride gas.
14. NaCl + H 2SO4 NaHSO4 + HCl
NaHSO4 + NaCl Na 2SO 4 + HCl
• During the manufacture of caustic soda by electrolysis of sodium chloride s
olution, large quantities of hydrogen and chlorine are obtained as by‐produ
cts. These gases are combined to yield hydrogen chloride.
• H2 + Cl2 2HCl
• Properties:
1. It is a colourless liquid , strongly acidic.
2. It is miscible with water, alcohol having a specific gravity of 1.18
3. It is a strong acid and attacks metals, forming their hydrochlorides with th
e evolution of hydrogen gas.
4. Even in high diluted form, it is very strongly acidic to litmus.
15. Identification:
• After neutralization, it gives reactions which are characteristic of chlorid.
• When it is added to KMnO 4 solution, chlorine gas is liberated.
Test for purity:
It has to be tested for As, Heavy metals, sulphate, sulphite, free chlorine, bromide and i
odide and residue on ignition.
Assay:
4 g of HClis transferred into a stoppered flask which is having 40 mL of water.
Now the solution is titrated with 1 N NaOH, using Methyl orange as an indicator
NaOH + HCl NaCl + H 2 O
Storage:
It should be stored in well closed container of glass or other material at a temperature no
t exceeding 30 °C.
Uses:
• It is mainly used as a pharmaceutical aid or as an acidifying agent.
• Used as gastric acidifier when levels of hydrochloric acid in gastric juice are low.
• Externally used as a solvent, catalyst in basic pharmaceutical and as acidifier.
16. B. ANTACIDS:
• These are drugs which are usually alkaline substances and are used to neutralize the excess
acid in the stomach of patients suffering from hyperacidity.(a condition in which the level of
acid in the gastric juices is excessive, causing discomfort.)
• Production of gastric HCl is a continuous process. It means use of antacids is also a
continuous process.
• Strong alkaline bases will damage the mucosal layer.
• The action of antacids should be gradual without evoking rebound acidity. Also antacids
should no have any side effects.
• Antacids give symptomatic relief from pain by neutralizing excess of hydrochloric acid. So
they find use in treatment of ulcers by reducing pain.
17. Antacids are classified as follows:
1) Systemic (absorbable) antacids: These are soluble, readily absorbable and capable
of producing systemic electrolytic alteration and alkalosis. eg. Sodium bicarbonate
2) Non-Systemic (non-absorbable) antacids: These are not absorbed to a significant
extent and thus do not alter an appreciable systemic effect. This group is further divided
into following:
a) Aluminium containing antacids e.g Aluminium hydroxide, Aluminium phosphate,
Basic aluminium carbonate, Dihydroxyaluminium aminoacetate
b) Calcium containing antacids e.g Calcium carbonate, Tri basic calcium phosphate
c) Magnesium containing antacids e.g Magnesium carbonate, magnesium hydroxide,
magnesium citrate, magnesium oxide, magnesium peroxide, magnesium trisilicate,
magnesium phosphate.
d) Combination antacid preparations e.g. Aluminium hydroxide gel and magnesium
hydroxide Aluminium hydroxide gel and magnesium trisilicate Semithicone containing
antacids Calcium carbonate containing antacids
18. Ideal requirements of Antacids:
• It should be insoluble in water and has fine particle form.
• It should not be absorbable or cause systemic alkalosis.
• It should be able to exert its effect gradually and over a long period of time.
• It should not be a laxative or cause constipation.
• It should not cause any side effect.
• It should be stable and readily available.
• The reaction between antacid and gastric hydrochloric acid should not produce large
volume of gas.
• The antacid should buffer in the pH range 4-6.
• Antacid should probably inhibit pepsin, the proteolytic enzyme.
Antacid preparations are administered as oral suspension, mixtures, tablets, chewable
tablets, capsules, and oral products.
Evaluation of antacid activity is done by acid neutralizing test.
19. Combinationsof antacidstherapy:
Requirement of combinations of antacids therapy:
• Systemic Antacid leads to alkalosis, may worsen edema and congestive heart failure
because of sodium ion load, thereby they are not frequently used.
• Whereas non-systemic antacid are more potent and effective as compare to systemic
antacid, but They are insoluble and poorly absorbed systemically.
• In Magnesium salt, Magnesium carbonate is most water soluble and reacts with HCl
at a slow rate, while Magnesium hydroxide has low solubility and has the power to
absorb and inactivate pepsin and to protect the ulcer base.
• Aluminium hydroxide is a weak and slow reacting antacid. The aluminium ions
relax smooth muscles and cause constipation.
20. • Calcium carbonate is a potent antacid with rapid acid neutralizing capacity, but
on long term use, it can cause hypercalcemia, hypercalciuria and formation of
calcium stone in kidney.
• 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 is constipative in nature.
21. Aluminium hydroxide gel
• It is an aqueous white viscous suspension of hydrated aluminium oxide having
varying amounts of basic aluminium carbonate.
• The preparation may sometimes have methyl oil, peppermint oil, glycerine,
sucrose or saccharin as flavouring and sweetening agents and upto 0.05%
sodium benzoate as preservative.
Preparation:
It is prepared by adding hot solution of potash alum slowly with constant
stirring to a hot solution of sodium carbonate. After complete removal of CO2,
the precipitated aluminium hydroxide is filtered.
22. It is washed properly with hot water until it gets free from sulphate ion and
the precipitate is suspended in distilled water to the required strength.
3Na2CO3 + 2KAI(SO 4)2 +3H2O‐‐‐‐‐‐‐‐‐‐3Na2SO4+ K2SO4 + 2Al(OH) 3 + 3CO2
sodium carbonate potash alum aluminium hydroxide
Precaution: Alum solution is added to solution of sodium carbonate and not
vice versa.
Properties:
• It is a white viscous suspension.
• Aluminium hydroxide gel gives astringent aluminium chloride when it
reacts with gastric hydrochloric acid. This results in nausea, vomiting and
constipation.
Al(OH)3 + 3HCl ‐‐‐‐‐‐‐‐‐‐‐‐ > AlCl3 + 3H2O
astringent aluminium chloride
23. • Aluminium hydroxide gel is a popular antacid and brings about neutralization
of gastric acid by following mechanism.
• Al(OH)3 + 3H 2O ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ [Al (H 2O) 3 (OH) 3]
• [Al (H 2O) 3 (OH) 3] + H 3 O + ‐‐‐‐‐‐‐‐‐‐‐ [Al (H 2O) 4 (OH) 2]+ + H 2 O
• [Al (H 2O) 4 (OH) 2]+ + H 3 O + ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ [Al (H 2O) 5(OH)]+2 +H2O
• [Al (H 2O) 5 (OH)]+2 + H 3 O + ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ [Al (H 2O) 6 (OH)]+3 + H 2 O
24. Mechanism:
• Aluminium hydroxide gel is non-absorbable and exert very little systemic effect.
• If the gel is formed by precipitation in a carbonate or bicarbonate reaction mixture,
there may be some evolution of CO2 when the carbonate or bicarbonate anions react
with gastric acid. But this reaction is very slow , so patient will not feel discomfort.
• Other drugs should not be taken with antacid, simultaneously, as there is loss of
antacid property.
• End product of neutralization of aluminium hydroxide gel with hydrochloric acid is
Aluminium chloride, which is water soluble astringent salt. This may cause
constipation, nausea, vomiting.
25. Assay:
• An accurately weighed amount of sample is dissolved in a mixture of hydrochloric acid and water by
warming on a water bath.
• 20 mL solution is taken in a conical flask and 40 mL of 0.05 N disodium edetate is added to it,
followed by water and few drops of methyl red.
• To this solution, 1 N NaOH solution is added to neutralize this solution. This can be identified by
color change red to yellow.
• Now flask is warmed on a water bath for 30 minutes.
• To this 3 g of hexamine is added.
• Also 0.5 ml xylenol orange solution is added as an indicator.
• This mixture is tirated with standard 0.05 M Lead nitrate solution until a violet color appears at the
end point due to formation of lead xylenol orange complex.
26. Uses
• It is a very effective slow acting antacid.
• Al(OH)3 + 3 HCl ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ AlCl3 + 3HCl Base Acid
• It does not get absorbed in alimentary canal and does not produce carbondioxide.
• Used in treatment of intestinal toxaemia and hyperchlorhydria.
• It does not cause systemic alkalosis.
Test for acid consuming capacity:
1. An accurately weighed quantity of gel (1.5 ml) is taken in a flask.
2. To it 50 ml of 0.1 N HCl is added. 3.
3. The contents are shaken at 37 °C for 1 hour.
4. The solution is titrated for excess HCl with 0.1 N NaOH using bromophenol
blue as an indicator.
Storage:
• It is stored in well closed containers and should not be allowed to freeze.
• For attractiveness it is usually dispensed in blue or amber colour bottles.
27. Sodium bicarbonate*
• Molecular formula: NaHCO3
• Molar mass: 84.01 g/mol
• Synonym: Baking soda; Bread soda, Cooking soda, Bicarbonate of soda
• 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: 69 g/L (00C); 96 g/L (200C); 165 g/L
(600C); 236 g/L (1000 C)
Refractive index : 1.583
28. Preparation
• On small scale , 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
• On an industrial scale it is obtained by Solvay process. Barine solution(Nacl) is saturated with
ammonia to remove traces of impurities like Mg and Fe. The solution is now filtered and
passed through the carbonating tower. In this it is allowed to come in contact with current
CO2 and the tower is cooled to enhance perception (sodium bicarbonate is less soluble in
water below 15°). The precipitate is filtered out and dried.
29. CO2 + H2O → H2CO3
NH3 + H2CO3 → NH4HCO3
NaCl + NH4HCO3 → NaHCO3 + NH4Cl
Identification :It gives the reaction of sodium and carbonate Its 1 % w/v solution has
pH not more than 8.6.
Test of Purity: It is tested for alkalinity, Al, Ca, insoluble matter, As, Fe, heavy metals,
chloride, sulphate and ammonium compound.
Assay
• Weigh accurately 1gm of Sodium bicarbonate and dissolve in 20 ml of water, titrate
the solution with 0.5N sulphuric acid using methyl orange as indicator.
• - Each ml of 0.5N sulphuric acid ≡ 0.0425gm of NaHCO3
• Storage: Store in air tight container.
30. 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.
Dose: 300 mg to 2 g per day in divided dose.
31. Magnesium hydroxide mixture
Molecular formula: Mg(OH)2
Molar mass: 58.31 g/mol
• Mg2+ Salts or Oxide or Hydroxide acts as both antacids and laxative agents
• Properties:
Appearance : White amorphous powder
Odor : Odorless Taste : Tasteless
• Preparation -Combining a solution of many magnesium salts with basic
water induces precipitation of solid
Mg(OH)2: Mg2+ + 2 OH− → Mg(OH)2
• Laboratory Preparation: MgCO3 + 2 NaOH → Mg(OH)2 + Na2CO3
32. • 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).
33. Milk of Magnesia
• Milk of Magnesia is a suspension of Magnesium Hydroxide.
• Milk of Magnesia, Double-Strength Milk of Magnesia, and Triple-Strength
Milk of Magnesia contain not less than 90.0 percent and not more than 115.0
percent of the labeled amount of Mg(OH)2, the labeled amount being 80, 160,
and 240 mg of Mg(OH)2 per mL, respectively as per USP Monographs.
Packaging and storage: Preserve in tight containers, preferably at a temperature
not exceeding 350C . Avoid freezing.
Labeling:
• (i) Double- or Triple-Strength Milk of Magnesia is so labeled, or may be
labeled as 2× or 3× Concentrated Milk of Magnesia, respectively.
• (ii) “SHAKE WELL BEFORE USED”
34. Uses:
• Milk of Magnesia is used for a short time to treat occasional constipation,
it is used as Laxative.
• Milk of Magnesia is also used to treat symptoms caused by too much
stomach acid such as heartburn, upset stomach or indigestion.
35. C. ANTIMICROBIALS
Anti microbial is a broad terminology describing activity against microbes.
Specific terminology gives exact mode of action.
1.Antiseptics are substances that kill or prevent the growth of microorganism. This is specific for
preparation intended to be used for living tissues.
2.Disinfectant is prevent infection by the destruction of pathogenic microorganism. It is generally
used to inanimate objects.
3.Germicide is an agent which kills microorganisms. More specific terminologies like
‘bactericide’(against bacteria),‘fungicide’(against fungi),virucide (against virus)denotes exact
action.
• Bacteriostatics is an agent which function by inhibiting the growth of bacteria. Thus
bacteriostatic agents do not kill but stops the growth of bacteria
36. Mechanism of Action
Inorganic compounds generally exhibit antimicrobial action by three different
mechanism. They are
1. Oxidation mechanism
2. Halogenation mechanism
3. Protein precipitation
1. Oxidation Mechanism: This belongs to class of peroxides, peroxyacids,
oxygen liberating like permanganate.
• They act on proteins containing sulphhydryl group and oxidizes free
sulfhydryl to disulphide bridge and inactivate its function.
• These infective agent brings about oxidation of active functional group
present in protein & enzyme vital to growth & survilance of microorganism.
• This cause the change on conformation of protein
37. 2. Halogenation Mechanisms: Compounds which liberates chlorine or
hypochlorite or iodine act by this mechanism. They act on peptide linkages and
alter its property.
• The destruction of specific function of protein results in death of microorganism.
• Most of enzymes are proteineous in nature, protein molecule composed of
variety of amino acids connected through the peptide(-CONH-)linkage.
• Antiseptic have hypohalite functional group exerts their antimicrobial activity
by chlorination of peptide linkage in protein molecule.
3. Protein Precipitation: Many cations exhibit protein binding or protein
precipitation.
• The interaction with protein occurs through polar group of protein which acts as
ligands and metal cation as Lewis acid.
• The complex formed may be strong chelate leading to inactivation of proteins.
38. POTASSIUM PERMANGANATE
• Mol. Formula-KMnO4 Mol. Wt. 158
It is having Not less than 99% of KMnO4
Preparation
• Manganese dioxide is fused with solid potassium hydroxide along with
potassium chlorate, a green mass potassium manganate is obtained. The mass
is cooled is extracted with water and filtered.
3MnO2+6KOH + KClO3D 3K2MnO4+ KCl +3H2O
The filtrate is treated with carbon dioxide followed by chlorine. By this
potassium manganite is converted in to potassium permanganate.
Physical Properties
It occurs in the form of deep, dark purple, monoclinic prismatic crystals and
moderately soluble in water. The taste is sweet and astringent.
39. Chemical Properties
• It is very powerful oxidizing agent both in dry state and in solution. Explosions
may occur when it comes in contact with organic or other readily oxidizable
materials.
• It act as an oxidizing agent because it produces nascent oxygen in solution.
2KMnO4+3H2SO4 K2SO4+2MnSO4+3H2O+5(O)(acid solution)
2KMnO4+H2O 2MnO2+2KOH+3(O)(Alkaline (or) neutral solution)
• Use
1. It is used as local anti-infective.
2. It is used as mouthwash and gargle (more than 1 in 1000solution).
3. It is also used as stomach wash in the treatment of Narcotic drug poisoning.
40. BORIC ACID
M.F. H3 BO3
Synonym : Ortho Boric Acid
Preparation : (i) Laboratory Method
Adding a mixture of concentrated sulphuric acid and water to a boiling solution of
borax, the solution is allowed to cool. The boric acid is filtered and then washed until
they become free from sulphate ions.
Na2 B4O7 + H2SO4 + 5H2O → Na2 SO4 + 4H3 BO3
Physical Properties
i. White odorless, crystalline powder, soft to touch.
ii. Slightly acidic to taste.
iii. Freely soluble in boiling water, boiling alcohol and glycerin
41. Chemical Properties
i. Boric acid is a weak acid.
ii. On heating tetra boric acid produces the boric acid anhydride, boron trioxide
B2O3 H2 B4O7 (160 °C) → 2B2O3 + H2O
(Boron trioxide)
• Boric acid is assayed by titrimetric method. It is a very weak acid.
• UseAssay : Anti infective.
42. HYDROGEN PEROXIDE (H2O2)*
Preparation
• It is prepared by adding a paste of barium peroxide in ice cold water to a
calculated quantity of ice cold dilute sulphuric acid. The in soluble barium
sulphate is filtered off.
BaO2+H2SO4 BaSO4¯+H2O2
• It is also manufactured by electrolysis process. Electrolysis of sulphuric acid to
proxy sulphuric acid which is hydrolysed to give the product. Sulphuric acid is
oxidized to give peroxydisulphuric acid (H2S2O8)
43. Properties:
• Hydrogen peroxide solution is a colorless liquid with slightly acidic taste. The
solution is decomposes in contact with oxidizable matter, reducing agent, when
made alkaline or even on standing.
2H2O2 2H2O + O2
• The solution is stabilized by the addition of small amount of acid and adjusting the
pH between 2 and 3. Polyvalent metal ions catalyzede composition of hydrogen
peroxide and complexing agent prevent it by acting as stabilizer.
• Hydrogen peroxide acts as oxidizing or reducing agent depending upon the chemical
environment.
44. Assay
• It is estimated by titration with potassium permanganate in presence of 4N sulphuric acid. Potassium
permanganate is reduced to manganese sulphate. This determination depends on mutual oxidation–
reduction as expressed by following equations.
2KMnO4+3H2SO4 K2SO4+ 2MnSO4+ 3H2O + 5(O)
H2O2+(O) H2O + O2
• Hydrogen peroxide is oxidized to oxygen by nascent oxygen produced from the reaction between
potassium permanganate and dilute sulphuric acid. The appearance of permanent pale pink color
indicates the end point.
Use
1.Used as an Antiseptic and topical Anti-infective.
2.It is used to clean the wounds and ears.
45. CHLORINATED LIME [Ca(OCl) Cl]*
Syn: Bleaching powder Calcium choro hypochlorite.
Preparation
• It is obtained by the action of chlorine on calcium hydroxide. Slaked lime is
spread on stable shelves in a container and chlorine gas is introduced at the top
of the chamber and passed through the contents of the shelves. This is done at
25°C to minimize the formation of calcium chloride.
Ca(OH)2+Cl2 Ca(OCl) Cl +H2O
Properties
• It is dull white powder with characteristic odour, on exposure to air it absorbs
moisture and decomposes by liberating chlorine. It is sparingly soluble in water
and in soluble in alcohol.
• When bleaching powder is added to water hypochlorite goes into solution and
oxygen is liberated. The oxidizing and bleaching properties are shown.
46. • When bleaching powder is added to water hypochlorite goes into solution and
oxygen is liberated. The oxidizing and bleaching properties are shown.
Use:
1.It is used as disinfectant, deodorant.
2.Commonly used in chlorination of water and in treatment of swimming tank.
47. IODINE (I2)
Preparation
• Iodine is manufactured by extracting kelp (sea weed ash) with water and the solution is
concentrated. The sulphate and chloride of sodium and potassium are crystallized out, leaving
soluble sodium and potassium iodides in the mother liquor.
• Sulphuric acid is added to the mother liquor and Sulphur which is liberated from small
amount of thiosulphate and sulphide is allowed to settle. The mother liquor is decanted and to
this MnO2 is then added and the Iodine is distilled out.
2NaI+3H2SO4+MnO2 MnSO4+2NaHSO4+I2+2H2O
.
48. Physical Properties
• It occurs as heavy, bluish-black rhombic plates with metallicluster.
• It melts at higher temperature.
• It is practically insoluble in water but soluble in alcohol.
• It is freely soluble in chloroform and ether.
Chemical Properties
• It combines directly with some non-metals and with many metals.
2P+3I2 2PI3
Fe+I2 FeI2
• Reducing agent reacts with aqueous iodine solution and gets oxidized.
• Iodine reacts with alkali to form an iodide and iodate when heated.
3I2+6NaOH 2NaI+NaIO3+3H2O
49. SOLUTIONS OF IODINE
• Iodineisinsolubleinwaterbutitissolubleinwaterinpresenceofpotassiumorsodiumiodi
deduetotheformationofpolyiodides.Thefollowingarethesolutionpreparationscontai
ningiodine.
1.Strong iodine solution (10% W/V solution ofiodine)
2.Weak iodine solution (2% W/V solution of iodine)
3.Aqueous iodine solution (5% W/V solution of iodine)
4.Iodine tincture USP.
5.Mandl’spaint.
• Use: All the above solutions are used as antiseptics and disinfectants.
50. POVIDONE –IODINE (PVP –IODINE)
• (Polyvinyl Pyrrol idone –Iodine Complex)
• It is a complex of polyvinyl pyrrol-idone and iodine containing not less than
9% and not more than 12% W/V of available I2(iodine).
• Thecomplexisyellowishbrownamorphouspowderandhasslightcharacteristicodo
ur,itsaqueoussolutionisacidtolitmus
• Uses
• Major advantages over other iodine preparation is lack of tissue irritation.
Solutions are used for surgical scrubs and for pre operative antisepsis for the
skin.
• It is also used in gargles and mouth washes for the treatment of infections in
the oral cavity.
51. D. Cathartics
• Cathartics are drugs used to relieve constipation or bring out
defecation. The term laxative is used for mild cathartic whereas
purgatives is used for strong cathartics.
52. Magnesium sulphate (MgSO4 . 7H2O)
MOL WT- 246.5
• It is having not less than 99% and not more than 100% of magnesium sulphate.
Preparations-
• It is obtained by the action of dilute sulphuric acid on magnesium carbonate or
magnesium oxide.
MgCO3 + H2SO4 MgSO4 + H2O +CO2
• The solution is filtered and the filtrate is evaporated to crystallisation.
• It is manufactured by the action of sulphuric acid on magnesite or dolomite.
MgCO3.CaCO3 + 2H2SO4 MgSO4 + CaSO4 + 2CO2 + 2H2O
• The liquid is filtered and the filtrate is evaporated to crystallisation.
• It is also prepared from magnesium hydroxide occurred in brine after extraction of
bromine. To this magnesium hydroxide salts, sulphur dioxide and air are passed
which forms magnesium sulphate.
• 2Mg (OH)2 + 2SO2 + O2 2MgSO4 + 2H2O
53. Properties
• It occurs as odourless crystals having a cool, saline bitter taste. It effloresces in warm dry air.
• It is soluble in water and sparingly soluble in alcohol. When gently heated, it loses some of its
water of hydration and gets converted into the monohydrate which becomes anhydrous at 2000 C.
Uses
• Magnesium sulphate is given orally in dilute solutions. About 5g gives rise to laxative effect. Due
to bitter and nauseating taste it is given in fruit juices.
• The mechanism of action is that magnesium sulphate does not get absorbed from intestinal tract
and thus retains water. The hydrostatic pressor is able to promote peristalsis movement of bowel. It
is used in patients with impaired renal function.
Dose- 10-15g
54. Sodium Orthophosphate (Na2HPO4 . 12H2O)
MOL WT- 358.14
• It is dodecahydrate of disodium hydrogen orthophosphate. It contains not less than
98.5% and not more than 101.0% of Na2HPO4.
Preparation
1. It is obtained by adding sodium carbonate to a hot solution of phosphoric acid.
H3PO4 + Na2CO3 Na2HPO4 + H2O + CO2
• The solution is neutralised, concentrated and the crystals are separated out by
centrifuging, washed and dried.
2. It is also obtained from calcium phosphate which is treated with sulphuric acid,
yields calcium sulphate and monobasic calcium phosphate.
Ca3 (PO4)2 + 2H2SO4 Ca (H2PO4)2 + 2CaSO4
• Now the filtrate is treated with sodium carbonate when dibasic calcium phosphate
gets deposited leaving sodium phosphate in solution.
55. Ca (H2PO4)2 + Na2CO3 CaHPO4 + Na2HPO4 + CO2 + H2O
• The solution is filtered off. The crystals of sodium phosphate are obtained by
concentrating the solution and crystallisation.
• Properties
• It occurs in the form of colourless transparent crystals, having a saline taste.
• It is odourless and effloresces in air.
• It is soluble in water but insoluble in alcohol. On heating over 3000 C it is converted
into sodium pyrophosphate.
2 Na2HPO4 Na2P2O7 + H2O
Uses
It is used as a saline laxative.
It is a cathartic and buffering agent.
Storage
It is stored in tightly closed containers.
Dose- 2-16g
56. Kaolin (Al2O3 .2SiO2 .2H2O)
• It is a native hydrated aluminium silicate which is freed from most of its impurities by dried.
• Preparation-
It is prepared from natural clay by powdering and separating particles by electrical
sedimentation. It must be purified from gritty particles and other impurities.
Properties-
It is light, white powder free from gritty particles. It is odourless, tasteless and having greasy
or soapy to the touch.
Uses-
It finds use in mixtures which are intended for dysentery, diarrhoea and for symptomatic
treatment of cholitis, cholera etc. • It is used in the treatment of food and alkaloid poisoning, as
it adsorbs toxins. • It finds use in dusting powder, cosmetic preparations etc.
Storage-
It is stored in well-closed containers.
Dose- 15-75g
57. Bentonite (Al2O3 .4SiO2 .H2O)
• It is a colloidal hydrated aluminium silicate which occurs naturally. It is obtained
from the naturally occurring sources. Bentonite is having SiO2 , Al2O3 , Fe2O3 ,
CaO, MgO and some sodium and potassium.
Properties-
• It occurs as a very fine, pale or cream coloured powder.
• It is odourless, free from grit and has slightly earthy taste.
• It is almost insoluble in water but swells to about 12 times its volume after
neutralisation.
• Uses-
• It is a good pharmaceutical aid and is used as a protective colloid to stabilise
emulsions. Mainly it is used to suspend other insoluble powders.
• It finds use as an emulsifier for oil in water emulsions.
• It is also used as a base for many pharmaceutical preparations including plasters and
ointments.
• It is an ingredient of calamine lotion which is used as a protective.
58. • Swelling factor-
It is measured by dropping from the top. Add 2g of bentonite in 10 portions at
intervals of 2minutes to 100ml of water in a 100ml graduated cylinder about
3cm in diameter. Allow each portions to settle before adding the next and let it
stand for 1day. Bentonite swells up at the bottom and it should occupy an
apparent volume of not less than 24ml.
