Impurity is the undesirable foreign material which may be toxic or non toxic present in the pharmaceutical substance.
Impurity is the substance or the matter which does not form a part of the medicinal or pharmaceutical substance or drugs.
Sources of impurities include
1. Raw materials used in the manufacturer.
2. Process used in the manufacturer.
3. Material of the plant.
4. Inadequate storage.
5. Accidental substitutions/deliberate adulteration with spurious/ useless substance.
6. Manufacturing hazards.
This ppt also explain Effects of impurities in pharmacopoeial substance.
2. Impurity
Impurity is the undesirable foreign material
which may be toxic or non toxic present in
the pharmaceutical substance.
Impurity is the substance or the matter
which does not form a part of the medicinal
or pharmaceutical substance or drugs.
Presentation Title 2
3. 1. Raw materials used in the
manufacturer.
2. Process used in the manufacturer.
3. Material of the plant.
4. Inadequate storage.
5. Accidental substitutions/deliberate
adulteration with spurious/ useless
substance.
6. Manufacturing hazards.
Sources of impurities
4. 1. Raw materials used in
the manufacturer
Traces of raw materials may come in
the final product
e.g.
1. Traces of some sodium compounds
in sodium chloride or the traces of
chloride.may be present in them if not
prepared carefully.
2. Metallic zinc may be present as on
impurity in zinc oxide sample as zinc
oxide can be prepared by heating
metallic zinc(raw materials)
2. Process used in the
manufacture
1. Tap water is invariably used in
various processes. This tap water
contains chloride, calcium &
magnesium, which may contaminate
the substance which is to be
manufactured.
2. Due to the wide use of strong acids in
the manufacture of medicinal
substances chloride & sulphate ions
are very Commonly occuring
impurities. 4
5. Presentation Title
3. Material of the plant 4. Inadequate storage
1. The equipment or utensils used in the
manufacturing processes are made of
metals like copper, aluminium, iron, zinc,
nickel. & tin or stainless steel.
2. Due to action of the solvents on the
material of the equipment or utensils,
traces of the equipment or utensils, traces
of the metals are introduced as impurities
in the compound
2. Decomposition of the product during
storage
Many chemical substances undergo
changes decomposition due to careless
storage.
a) Due to careless storage, ferrous sulphate
is slowly converted into Insoluble ferric
oxide by air & moisture.
b) Bismuth / carbonate blackens on long
exposure to sunlight.
1. Filth: stored products may become
contaminated with dust, the bodies of
insects and even animal and insect excreta.
6. Presentation Title
5. Accidental substitutions/deliberate adulteration with spurious/useless
substance
1. Accidental substitution can take place if toxic substances are stocked with other
substances or compound due to incomplete saponification there may be presence
of alkali impurities.
2. Deliberate adulteration or substitution with cheaper drugs or varities is a
possibility.
e.g.
a) Asafoetida can be adulterated with wheat, flour stones..
b) In honey, commerical sugar can be an adulterant.
c) Acacia powder can be adulterated with clay
7. Presentation Title
6. Manufacturing Hazards
i) Particulate Contamination: Accidental inclusion of dirt or glass, porcelain,
metallic or plastic fragments from sieves, granulating, tableting and filling
machines or even from product containers, may come from either bulk material
used in formulation or from improperly cleaned equipment or containers, but is
more likely to be present due to wear and tear of equipment.
ii) Process Errors: Gross errors arising from incomplete solution of a solute in a
liquid preparation should probably be detected readily by normal analytical
control procedures.
iii) Cross Contamination: The handling of powders, granules and tablets in bulk
quantities, frequently create a considerable amount of air-borne dust, which if
not controlled, leads to cross contamination of products, particularly of
steroidal and other synthetic hormones and antibiotics like penicillin.
8. Presentation Title
6. Manufacturing Hazards
(iv) Microbial Contamination: Liquid
preparations and creams for topical application to
broken skin or mucous membrane are liable to
bacterial, mould and fungal contamination from
the atmosphere.
(v) Packing Errors: Products of similar
appearance, such as tablets of same size, colour
and shape packed in similar containers can cause
danger through mislabelling.
9. Effects of impurities in pharmacopoeial substance
The impurities which produce toxic effect on body, if present beyond the prescribed
limit, e.g. Lead and arsenic impurities.
Impurities which are harmless but if present beyond a limit in pharmaceutical substance,
lowers the active strength of that substance. e.g. Impurities of sodium salts in potassium
salts.
Impurities which, if present, beyond the limit, affect the storage capacity of the
pharmaceuticals, e.g., Presence of moisture beyond limit, may activate the free flowing
property of a substance or may decompose it.
Impurities causing technical difficulties, while using the substance, in which it is present.
e.g. Presence of carbonate impurity in the ammonia solution.
Impurities such as taste, odour or colour or appearance which are easily detectable by the
senses and make the substance unaesthetic or unhygienic, e.g. Phenolic impurities
present in sodium salicylate, alter its colour. Traces of magnesium salts in sodium
chloride render it damp and change its appearance
