Pharmaceutical Inorganic Chemistry -B Pharmacy First Year -First semester - B-Pharm first year Pharmaceutical Inorganic Chemistry Unit -I

1.  By Manjusha SK
 Associate professor

2.  The word impurity deals with the state/quality of being impure.
 Impurities are the substances which makes something less pure.
 It is also defined as any unwanted substance existing with active/main
drug.
 The impurities observed in the drug substances may arises with raw
material or during various manufacturing processes or may be due to side
reactions also.
 If a compound contains/have the foreign materials/substances,then such
compound is said to be impure or impurities present in that compound.
 Following are the some effects of impurities,
 1.Impurities may bring about incompatibility with other substances.
 2.Impurities may lower the shelf life of the substance.
 3.Impurities may cause difficulties during formulation and use of the
substances.
 4.Sometimes impurities changes the physical and chemical properties of
the substances.
 5. Imurities may creats the technical problems while preparing the
drug/medicine.
 6.Impurities overall affect the quality of drug and profit also.

3.  Following are the some sources of impurities which arises in any
pharmaceutical preparations/medicines.
1.The raw material used in the manufacturing of drugs/medicines-
 The pharmaceutical preparations/ drugs are prepared from natural
sources/from chemicals.
 If such natural sources/chemicals contains impurities,it passes and
contaminates the final product.
 So it is very essential to verify and check the source of material used
and quality during the manufacturing of pharmaceutical preparations/
drugs.
 Eg.sodium chloride- as it is prepared from rock salts (a natural source)
which consist of small amounts of calcium sulphate and magnesium
chloride,so sodium chloride also contains traces of calcium and
magnecium compound as an impurity.

4. 2.The manufacturing of process/method -
The manufacturing process/method also introduce the new
impurities which leads to the contamination of final product.
 Reagent – The impurities due to the use of reagents,solvants,reaction
vessles and sometimes due to intermediates also.
Eg.the anions like Cl- and SO₄ are common impurities arise due to the
use of hydrochloric acid and sulphuric acid.
 Solvants- The solvants used during manufacturing and purification
process may also leads to contamination of final product.
Eg.water – the main solvent used in various processes contains
number impurities like ca2+,mg2+,Na, Cl- etc.
 Intermediates – It may contaminates the final product.
 Reaction vessels – During manufacturing process some
chemicals undergo metallic reactions with vessles such as
copper,iron,aluminium and even stainless steel.
 So when the inorganic compounds are prepared in these vessels,small
amount of impurities of the metals are likely to be present and that
contaminates the final product.

5. 3.The chemical process used during manufacturing –
 During the pharmaceutical sunstances/drugs
various chemical reactions are carried out like
oxidation,reduction,nitration,sulphonation,halogenation etc.
 So during all these chemical process/reaction various chemicals are
used.
 Eg.water – which is mainly used during all the above chemical
reactions and it contaminates the final product as it contains ca
2+,mg2+,Na, Cl- etc ions impurities.
4.Atmospheric contamination during manufacturing process –
 The atmosphere may consist of different gases and dust/durt
particles like sulphur,silica,plastic fragments,aluminium oxide.
 These dust particles and gases may enter during the manufacturing
process and leads to contamination of final product.
 Eg.sodium hydroxide,it absorb the atmospheric carbondioxide
when it exposed to the atmosphere and leads to contamination of
final product.

6. 5.Manufacturing Hazards –
 There are many possibilities of contamination by impurities even in
well run manufacturing house.
 Sometimes the unwanted Particulate matter can arise by accidental
introduction of dust/durt/glass,metallic,plastic fragments from
various containers/machines like sieve,tabletting,granulatting and
filling machines.
 Eg.metal particles which found in eye ointment due to the packing in
metal tubes.
 Sometimes cross-contamination of the product may occur by the
air-born dust arising due to handling of bulk-large powders,granules
and tablets.
 Cross –contamination arises when two or more products are
manufactured in same premices

7. 6.Storage conditions –
 Depending upon the nature of
chemicals/drugs their storage conditions may vary.
 It depends on nature of material,its quality,size etc.
 There are various types of containers are available in market which
may be made up of plastic,glass,stainless steel,alumunium,iron etc.
 Sometimes the container may react with the stored chemicals/drugs
in it and leads to various physic-chemical changes which are
considered as impurities and responsible for complete loss of final
product.
 Eg.when ferrous sulphate is not stored in well closed container,it
slowly gets changed into insoluble ferric oxide due to presence of
atmospheric air and moisture.
 If the surgical solutions of chlorinated soda is not stored in amber
coloured bottles in cool place ,it leads to deterioration as it reacts
with light and heat.