Adulteration of Drugs, Drugs Evaluation and Pharmacopoeial Standards

Adulteration:-

Adulteration are defined as admixture of genuine articles
with spurious or harmful substances.

The action of making something poorer in quality by the
addition of another substance is also known as adulteration.

Example:-

•      Mixture of
Papaya seed with black pepper.

•      Mixture of
power of brick into red chilli powder.

Methods of
adulterating the drugs.

The extent of adulteration depends upon whether the drug is
obtained from other countries.

An adulteration of a drug may be accidental. Adulteration is
very common with drugs which are sold illegally.

Following are the various methods used for drugs
adulteration.

A. Substitution with manufactured materials

B. Substitution with Inferior material

C. Substitution with Exhausted material.

D. Substitution with cheap natural substance.

E. Adulteration with non- plant material.

F. Excessive adventitious matter.

A. Substitution with
manufactured materials:-

This is done with artificially manufactured material which
resembles various drugs in form and appearance.

Example: – Paraffin wax has been coloured yellow to
substitute bee wax.

B. Substitution with
Inferior material:-

• Drug are sometimes adulterated and substituted with standard
commercial material.

• The common example of substitution is adulteration of
cloves by mother cloves.

• Saffron is adulterated with dried flowers of carthamus
tinctorius (Safflower).

C. Substitution with
Exhausted material.

Exhausted material the vegetable residues which remain after
the original material has been use for drug preparation.

Example:-

•      The
substitution of Alexandrian Senna with Arabian Senna.

•      Used of
exhausted Clove and ginger for adulteration.

D. Substitution with
cheap natural substance.

Sometimes drugs are adulterated with cheaper natural
substance which have no relation to the genuine article.

Example Japan wax for bees wax and sterculia gum for
tragcanth.

E. Adulteration with
non- plant material.

Plant material are sometime Adulteration with worthless
non-plant material.

Example: – Pieces of limestone in asafoetida & lead shot
in pieces of opium.

F. Excessive
adventitious matter.

Adulteration involves also the presence of an excessive
quantity of an adventitious material that naturally occurs with the plant.

Examples. Excessive amount of stem in the leaves of lobelia
or stramonium.

Drugs
Evaluation

• Drug Evaluation is defined as the confirmation of its
identity and determination of its quality and purity.

• If adulterated, it also includes the detection of the
Nature of adulteration in the crude drug.

Methods of drug
Evaluation.

The method of drug evaluation are classified as:

1. Organoleptic evaluation

2. Microscopic evaluation

3. Physical evaluation

4. Chemical evaluation

5. Biological evaluation

1. Organoleptic
evaluation:

• The evaluation of drugs by colour, odour, taste, size,
shape etc. Visual examination of morphological characters.

• The study of from of a crude drug is Morphology, while
description of the form is morphography.

2. Microscopic
evaluation:

• This method allows more detailed examination of a drug.

• It can be used to identify organised drugs by their known
histological characters.

• Histological studies are made from very thin sections of
the drugs. The characteristics of cell wall, cell contents, trichomes, etc.

3. Physical
evaluation:

• Physical standard are to be determined for drugs, they may
help in evaluation.

• The following are some physical constants which are use
drug evaluations. Specific gravity, density, optical rotation,

viscocity and solubility in different sovents.

4. Chemical
evaluation

• It is determination of active constituents in a drug by
chemical methods. The following are various methods of chemicals evaluations.

a. Instrumental
methods: They make use of a variety of instruments for evaluations.

Examples: Colorimetry for Alkaloida of solanaceae.

b. Chemical constants
it this method used identifying particular drug.

Example:- Acid value, Iodine value, Easter value

c. Individual
Chemical test: used for identifying particular drug

Example:- Halphen’s test, Copper acetate test.

d. Micro chemical
test: Example:- euginal in clove oil is precipitated as potassium euginate
crystals by adding potassium hydroxide.

5. Biological
evaluation

In this methods the response produce by the rest drug on a
living system in compared with that of the standard

Example:- Cardiac glycosides like digitalis.

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