Pharmaceutical inorganic chemistry B.Pharm 1st year[1st sem] Unit-4

1. Unit- 4
EXPECTORANTS
Expectorants are drugs which enhance the secretion of the sputum by the air passages so that it is easier to remove the phlegm through
coughing. They are used in cough mixtures for this purpose they act either by increasing the bronchiole secretion or by making it less
viscous (mucolytic agents) Drugs such as ipecacuanha in small doses act as stimulant expectorants. They irritate the lining of the stomach
which stimulates the production of sputum by the glands in the bronchial mucous membrane.
Potassium iodide stimulates the gastric mucosa and increases the bronchiole secretion. Ammonium chloride acts like potassium iodide but
is less potent antimony potassium tartrate also used as expectorant.
Potassium iodide is an inorganic compound with the chemical formula [KI].
• This white salt is the most commercially significant iodide compound, with approximately 37,000 tons produced in1985.
• It is less hygroscopic (absorbs water less readily) than sodium iodide, making it easier to work with.
• Aged and impure samples are yellow because of aerial oxidation of the iodide to elemental iodine.
4KI + 2CO2 + O2→ 2K2CO3 + 2I2
AMMONIUM CHLORIDE
Preparation:
Ammonium chloride is made by reacting hydrochloric acid with ammonia the solution is evaporated to dryness. The product is
purified by recrystallisation or by sublimation.
NH3+HCl→NH4Cl
Assay:
Formaldehyde, previously neutralised to phenolphthalein, is added to the solution of the substance. It fixes the
ammonia in ammonium chloride as hexamine. the liberated hydrochloric acid is titrated against0.1 M sodium
hydroxide, using phenolphthalein as indicator.
A modified Volhard method was used in IP ‘66’. A solution of the substance acidifies with nitric acid is shaken with
a measured volume of n/10 silver Nitrate, nitrobenzene being previously added. Nitrobenzene is added to coagulate
the precipitate of silver chloride, so that it will not interfere with the titration later of excess of silver nitrate which is
determined by titration with N/10 ammonium thiocyanate, using ferric ammonium sulphate as indicator.

2. AgNO3+NH4Cl→AgCl+NH4NO3
AgNO3+NH4SCN → AgSCN+NH4NO3
Ammonium Silver
Thiocyanate Thiocyanate
The following is the reaction taking place at the end point when red ferric thiocyanate is formed (by reaction
of ammonium thiocyanate with the indicator ammonium sulphate
FeNH4(SO4)2
+3NH4SCN = Fe (SCN)3
+ 2(NH4)2
SO4
Emetics
Definition
An emetic is a drug which induces vomiting. Emetics act either directly by stimulation of the chemoreceptor trigger zone, located
in the area of medulla oblongata located in the brainstem in cerebellum or by inducing irritant action on gastrointestinal tract.
• Emetics takes a valuable part in poisoning cases.
• Emetics are added to cough preparations in low doses to stimulate flow of respiratory tract secretions.
• Inorganic compounds such as copper sulphate, sodium chloride, zinc sulphate and sodium potassium tartrate are used.
Copper sulphate
Properties
• Molecular Formula; (CuSO4.5H2O)
• Molecular Weight- 249.7
• Colour: Deep blue, crystals of pentahydrate or as blue crystalline granules or powder

3. • Solubility: Soluble in water and very soluble in in boiling water, slowly soluble in glycerol and almost insoluble
in alcohol.
• Stability: The salt has been stable to heat up to 60℃.
Assay
• An accurately weighed quantity of copper sulphate is dissolved in water. To this a slight excess of potassium
iodide is added followed by acetic acid.
• The liberated iodine is titrated with standard sodium thiosulphate solution by using starch as an indicator.
• The titration is continued until faint blue colour persists. 2g of potassium thiocyanate is then added and the
titration is continued until the blue colour disappears.
Preparation
• It is obtained by roasting copper containing sulphide ore in presence of air or by heating copper in a furnace with
sulphur. The mixture of copper sulphate and CuO formed in the above process is treated with dilute sulphuric
acid. The resulting solution is filtered, concentrated and allowed to crystallise when crystals of copper sulphate
separate out.
• It is also obtained by treating granulated copper in the presence of air with sulphuric acid.
• The solution is filtered and evaporated to crystallisation when crystals of copper sulphate separate out.
Uses
• It finds use as an emetic in a dose of 300mg in 30ml of water. But its use as an emetic can be dangerous because
of large and corrosive doses.
• It is used as chemical antidote in phosphorous poisoning.
• It is used as fungicide.
• It is an ingredient of Benedict’s and Fehling’s solution.
Sodium potassium tartrate (Rochelle salt)
Properties-
Molecular formula-C4H4KNaO6.4H2O
Mol wt.- 283.23

4. Colour: White colourless crystalline powder
Odour: Odourless
Solubility: Freely soluble in water and insoluble in alcohol
Taste: Saline
Preparation
• The starting material is tartar with a minimum tartaric acid content 68 %.
• This is first dissolved in water. It is then saponified with hot caustic soda to pH 8, decolorized with activated charcoal,
and chemically purified before being filtered.
• The filtrate is evaporated at 100 °C and salt is separated.
Uses:
• It is used as emetics
• It is used in effervescent powder.
• It is also used as laxative to relief from constipation
Astringent
Astringents are locally applied protein precipitants which have a low cell permeability so that the action is limited essentially
to the cell surface and the interstitial spaces.
Most topical astringents are salts of aluminium, zinc & to some extent Zirconium.
The action does not result in the death of the cell, only the permeability of the cell membrane is reduced.
Astringents are therapeutically used as
(i) Styptic, to arrest haemorrhage (to stop bleeding from small cuts) by promoting coagulation of blood and constricting small
capillaries;
(ii) antiperspirant to decrease sweating by constricting pores at the surface of the
skin;
(iii) to reduce inflammation by restriction of the blood supply to the surface of mucous membranes;
(iv) promote healing and toughen the skin;

5. (v) deodorant by virtue of interaction with odorous fatty acids liberated or produced by the action of bacteria on lipids in
sweat and by an action suppressing bacterial growth, partly due to a decrease in pH; and
(vi) direct action on skin to remove unwanted tissue (this requires a higher concentration or a stronger protein precipitant,
often termed as corrosive).
Alum: KAI(SO4)2 12H2O
Mol wt.- 474.33
(Aluminium Potassium Sulphate) Mol Wt.- 453.33
(Aluminium Ammonium Sulphate), Mol Wt.- 474.39
Alum can be either the ammonium or the potassium salt & should be labelled on container which salt is present.
Preparation:
official alums are prepared by adding a hot, concentrated
solution of either potassium or ammonium sulphate to a
hot solution of an equimolecular proportion of
aluminium sulphate.
The alums separate out as crystals on cooling.
Properties:
Colour: colourless
Nature: large crystals, crystalline fragments or as a white powder.
odour: odourless
Taste: with a sweetish strongly astringent taste.
Solubility: Alums are freely soluble in water, but slowly dissolve in glycerin, and insoluble in alcohol.
Chemical properties:
Acidic to litmus When heated, it melts and at about 200°C loses its water of crystallization with the formation of the
anhydrous salt.
Storage: To be stored in airtight containers.
Uses:
• Alum precipitates proteins and is a powerful astringent.

6. • Dilute solutions (l to 4%) have been· used as astringent mouthwashes and gargles but they have a destructive action on
teeth.
• A 2% solution has been used for application to the skin to reduce excessive perspiration.
• Stronger solutions (5 to 10%) are used to harden skin by athletes, especially as footbath to toughen the skin of the feet.
• strong solution is used as a styptic for minor cuts and abrasions.
• (0.5 to 5%), lotions and douches, some vulvovaginal
• cleansing and deodorant preparations.
ZINC SULPHATE
Chemical formula: ZnS04.7H20
Synonym: White Vitriol
Preparations
• For industrial scale, zinc sulphide is heated in presence of air under specified conditions. The heated mass is
dissolved in hot water, filter the solution concentrated for crystallization.
• Metallic zinc granules are digested with H2SO4.
• The sol is filtered & treated with chlorine to oxidize any ferrous impurity into ferric sulphate which is then
precipitated by hydroxide & removed. The filtrate is concentrated & crystallized
Properties:
• Colour: colourless,
• Nature: transparent crystals or as crystalline powder.
• Odour: Odourless
• Taste: metallic and astringent.
• Solubility: very soluble in water. It is freely soluble in glycerin, but is insoluble in alcohol
Chemical Properties:
• Aqueous solutions of zinc sulphate are acid to litmus
• It forms double salts with ammonium & Potassium Sulphate
• When strongly heated it decomposes
• Storage: It should be stored in tightly closed containers.
• Incompatibility: It is incompatible with alkali carbonates and hydroxide and with astringent infusions and decoctions.

7. Uses:
• Zinc ions exhibit mild germicidal astringent & styptic action (The action is dependent due to slow release of zinc ions
from salt or sol.)
• Insoluble zinc ions used in topical agents as protectives.
• ZnSO4 sol 0.1-1% used ophthalmic
• Internally it is used as an emetic
• Insoluble Zn complex are mainly used in bandages, adhesive, tapes etc.
Poison and Antidotes
Poison:
• Any substance that is harmful to your body or any substance that cause disturbances in organisms.
• You might swallow it, inhale it, inject it or absorb through skin.
Background
In regard to poison sources, poisons (chemicals) can be divided into three broad groups:
1. Agricultural and industrial chemicals
2. Drugs and health care products.
3. Biological poisons
The most common poisons:
• Pain medicine, Iron pills, anticonvulsants & antidepressants
• Cleaning substances (household substances) e.g. Antimicrobials,
• Toilet cleaners, rust removers,
• Pesticides e.g. chemicals to kill bugs & other pests
• Cosmetics & personal care products e.g. nail glue remover & nail
• primer, coloring substances like lipsticks, nail polish etc
• Topical preparations e.g. topical anesthetics which keeps the
• blood from carrying oxygen to the tissues.
• Bites and stings e.g. snakes, ticks, spider, bees, insects bites etc
• or also called Venom (Animal poison delivered subcutaneously)
• Carbon monoxide & hydrocarbons like gasoline, kerosene,

8. • lighter fluid, furniture polish & paint thinner.
1. Agricultural and industrial chemicals
• The majority of agricultural chemicals are pesticides, which include insecticides, herbicides, fungicides, fumigants,
and rodenticides.
• The term industrial chemicals is used to refer to chemicals used in industry, like hydrocarbons, chlorinated
hydrocarbons, aldehydes, ketones, alcohols, esters etc. as well as chemicals found in or near households.
• Poisoning with industrial chemicals occurs most often by either through skin (percutaneous) or inhalation routes.
2. Drugs and health care products
• Pain medicine, Iron pills, anticonvulsants & antidepressants & cosmetics etc
3. Biotoxins or Biological poisons: can be conveniently grouped into 3 major categories:
1. Microbial toxins- poisons produced by bacteria like blue green algae, dinoflagellates, golden brown algae etc.
2. Phytotoxins-poisons produced by plants.
3. Zootoxins-Poisons produced by animal.
Substances used to counteract the action of these chemicals or form of poisoning are called
“Antidote”
Antidote
Types of Antidotes based on mechanism of action:
• Physiological antidote (Counteracts the physiological effects of poison): e.g. Sodium Nitrite converts haemoglobin
into methemoglobin in order to bind cyanide and converts more toxic cyanide to less toxic cyanomethaemoglobin.
• Nitrite + oxyhemoglobin → methemoglobin + cyanide
(toxic)
↓
Cyanomethemoglobin
(less toxic)

9. Types of Antidotes based on mechanism of action:
• Mechanical Antidote (prevents the Absorption of the poison into the poison into the body): E.g. Activated charcoal
adsorbs the poison prior absorption by means inactivates and precipitates the toxic materials by insoluble salts,
thereby preventing their absorption.
• Chemical antidote (Acts by changing the Chemical nature of the poison): e.g., sodium thiosulphate causes
conversion of systematic Toxic cyanide to non-toxic thiocyanide.
Antidotes in most common use:
• Cyanide poisoning: Sodium Nitrite (NaNO2), Sodium Thiosulphate (Na2S2O3)
• Universal Antidote: Activated Charcoal
Activated Charcoal
• It is similar to common charcoal but is made especially for medical use.
• During its preparation the wood charcoal is treated with various substances like steam, air, CO2, Oxygen, ZnCl2,
Sulphuric acid or phosphoric acid – helps charcoal to develop many internal spaces or "pores".
• These pores help activated charcoal trap chemicals – strong adsorptive agent.
• It is an odourless, tasteless, fine black powder.
• It is NOT soluble in water or any other solvents.
• Helpful to absorbed effectively all heavy metals, viruses, bacterial & fungal toxins by binding poisons within the
GIT. This allows their transfer out of the body in a harmless form.
• The most common drug poisoning is from aspirin, charcoal should be given within the first 30 min of an overdose or
aspirin poisoning.
• Powdered form of it reaches its maximum rate of absorption rapidly within one min compare to other forms.
• It is mainly known both for its use in drug overdoses and chemical poisonings.
• It acts to purify & cleanse the body due to its amazing ability to attract poisons to itself.
Uses:
• Activated charcoal is used in treating poisoning and
overdoses through oral injection.

10. • It is also used in air purification, gold purification, metal extraction, water purification, medicine, sewage treatment, air
filters in gas masks and to treat a condition of pregnancy in which the normal flow of bile is affected (cholestasis),
Prevent gas, Reduce high cholesterol & to Prevent a hangover.
• Side effects:
Constipation and black stools. Rare, side effects are a slowing or blockage of the intestinal tract & dehydration. Stomach
cramps & swelling of the abdomen.
• Dose:
Adults :25-100g & children:25-50g
Sodium Nitrite (NaNO2)
Sodium nitrite is the inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline
powder that is very soluble in water and is hygroscopic. It contains not less than 97.0% & not more than 101.0% of
sodium nitrite. It can act as both oxidising & reducing agent.
• When it reacts with oxidising agent, nitric oxide (NO) is the product in acidic solution & nitrogen gas is in neutral to
alkaline solution.
Uses: it is used as antidote for cyanide poisoning
Side effects: head pain, blurred vision.
Dose: 30 –120mg.
It gives pale brown fumes of nitrous acid with dilute acids
2NaNO2 + H2SO4 → Na2SO4 + 2 HNO2
3HNO2 ↔ HNO3 + 2 NO↑ + H2O
2NO + O2 → 2NO2
Method of Analysis: About 10 ml of 1% w/v aqueous solution is added by a pipette to 0.1 N KMnO4 solution acidified with
sulfuric acid. The formed unstable nitrous acid (HNO2) readily breaks down into nitric oxide &
nitrogen dioxide.
2HNO2 → NO + NO2 + H2O
Nitrous acid also behaves as a reducing agent for it may be oxidised to nitric acid by KMnO4.

11. • A known excess 25 ml of 0.1N oxalic acid is added & then mixture, after it is heated is back titrated with 0.1N KMnO4.
Oxalic acid is quantitatively oxidised on warming.
NaNO2 + H2SO4 → HNO2+ NaHSO4
HNO2 + O → HNO3
H2C2O4 + O → H2O + 2CO2↑
Factor: Each ml of 0.1 N KMnO4 is equivalent to 0.00345g of NaNO2.
USE
The main USE of sodium nitrite is for the industrial production of organonitrogen compounds.
• It is a reagent for conversion of amines into diazo compounds, which are key precursors to many dyes, such as diazo dyes.
• Nitroso compounds are produced from nitrites. These are used in the rubber industry.
• sodium nitrite is used as spoilage or disease causing microorganisms.
• its effectiveness depends on several factors including residual nitrite level, pH, salt concentration, reductants present and
iron content.
Sodium Thiosulphate (Na2S2O3)
Sodium thiosulfate is a colorless, water-soluble salt. It is a calcium-chelating agent and has many medical uses in removing
toxic substances from the body.
• Depending on the medical condition being treated, the salt can be injected, taken orally, or applied to the skin. It is also
used in some vital tests for kidney patients to glean information without doing harm.
• This compound is combined with sodium nitrite and used as an antidote for cyanide poisoning in both children and
adults.
• Sodium thiosulfate reacts with the cyanide and forms sodium thiocyanate, a nontoxic substance that can then be
excreted harmlessly from the body.
• The salt is also used to treat arsenic poisoning. Studies show that it can be useful in removing excess copper from
patients too.
• Uses: It is used as an antidote to cyanide poisoning. Thiosulfate acts as a sulfur donor for the conversion of cyanide to
thiocyanate (which can then be safely excreted in the urine), catalyzed by the enzyme rhodanese.
• Side effects: muscle cramps, blurred vision, pain in joints & vomiting.

12. • Dose: 12.5gms in adults…..and 7gms for children
Preparation
• The obtained solution of sodium bisulfite is place in a 600 ml beaker and cautiously treated with 53 g of sodium
carbonate.
2NaHSO3 + Na2CO3 → 2Na2SO3 + CO2 + H2O
• The solution is boiled for 15 min then is treated with 48 g powdered sulfur wetted with small amount of ethanol and
gently boiled under reflux for an hr & a half or longer.
Na2SO3 + S →2Na2S2O3
• The obtained solution is filtered & the solution is left at room temperature in a crystallizing dish to set to crystallize.
Method of Analysis
Assay: Sodium thiosulphate can analyse by using ceric ammonium sulphate and KMnO4 solution.
Haematinics

13. The total body content of iron is estimated to be about 3 – 4g
• Major portion (70%) of body iron is present in haemoglobin and myoglobin.
• Haemoglobin helps to carry oxygen from lungs to tissues & carbon dioxide from tissue to lungs.
• Balance amount of iron consists of storage iron, transport iron & enzyme iron.
• In normal adults about 1 g of iron is lost from the body daily.
• Average daily intake of iron in a normal adult is about 14 mg.
Preferred Compounds:
• Ferrous Sulphate (20% hydrated salt and dried salt 32% or 65 mg)
• Ferrous Gluconate (12% iron or 28 – 36mg).
Other: Ferrous fumarate, Ferrous succinate, Ferric ammonium citrate, Iron hydroxide etc
• Preferred route: Oral
• Dosage: 200 mg daily in 3 divided doses (3 -5mg/Kg for children)
Adverse Drug Reactions: Epigastric pain, heart burn, nausea, vomiting, staining of teeth, metallic taste, bloating, colic,
Constipation
Ferrous Sulphate
Description: Bluish green crystalline powder with metallic & astringent taste.
• It undergoes slow oxidation upon exposure to the moist air to brown coloured ferric sulphate. Hence tablets of ferrous
sulphate are sugar coated in order to prevent air oxidation.
• It is soluble in water and insoluble in ethanol
• When heated at higher temp. it decomposes to ferric oxide, SO2 & H2SO4.
2(FeSO4.7H2O) →Fe2O3 + SO2+ H2SO4 + 13H2O
Preparation: FeSO4 is prepared by adding excess of dil. H2SO4 to iron fillings
Fe + H2SO4 → FeSO4 + H2(gas)

14. The crystals of FeSO4 is efflorescent in dry air and exposure to moist air undergoes slow oxidation become coated with
brown basic ferric sulphate, to that the salt should be kept in well closed container.
Ferrous Gluconate
Description: Yellowish grey or pale greenish yellow fine powder having slight odour of burnt sugar.
• It is soluble in water and insoluble in ethanol
• Usual dose is 300 mg thrice a day
Preparation: Gluconic acid is preaped by oxidation of glucose and then dissolving ferrous carbonate in a calculated amount
of gluconic acid. BaCl2 is used to precipitate BaSO4 which is removed by filtration.
Assay: As same as FeSO4. It is assayed by use of ceric ammonium sulphate.
Uses: To treat iron deficiency anaemia