Sources of Impurities in Medicinal agent

 Sources of Impurities in
Medicinal agent

The origin of impurities in drugs is from various sources and phases of
t
he synthetic process and
p
reparation of pharmaceutical
dos
age forms.

Majority of the impurities are characteristics
of the
synthetic route of
the
manufacturing process.

There are
several possibilities of
synthesizing a drug; it is possible that the same product of different sources may
give
rise to different impurities.

Organic  impurities  

may  arise  from
 starting 
materials, by products,
synthetic intermediates
a
nd degradation products.

Inorganic impurities may be derived from the manufacturing process and
are
normally known and identified as
reagents, ligands, inorganic salts, heavmetals, catalysts, filter aids and charcoaetc. 

Sources of organic
impurities:

  • Impurities
    o
    riginating from drug
    substance synthetic processes
  • Starting materials
    and intermediates
  •  Impurities
    in the
    starting materials
  •  Reagents, ligands
    and catalysts
  •  Byproducts of the synthesis
  •  Products of overreaction
  •  Products of side reactions
  •  Impurities
    o
    riginating from degradation of the
    drug substance.

 Limit Test

Limit test is defined as quantitative or semi quantitative test designed to identifand control small quantities of impurity which is likely to be present in the substance.

Limit test is generally carried out to determine the inorganic impurities present in compound.

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