Evaluation of crude drugs

Drug evaluation may be defined as the determination of identity, purity and quality of a drug.

Vegetable or animal drugs that consist of natural substances that have undergone only the processes of collection and drying.

Natural substances:

1- Plant origin: leaves, flowers, seeds and barks. Or vegetable saps, extracts and secretions. 2- Animal origin: whole animals, glands or organs, extracts and secretions.

Drug evaluation may be defined as the determination of identity, purity and quality of a drug.

Identity – identification of biological source of the drug.

Quality – the quantity of the active constituents present.

Purity – the extent of foreign organic material present in a crude drug.

METHODS OF DRUG EVALUATION

The evaluation of a drug is drug done by studying its various properties. The various properties are:

(1) Organoleptic evaluation (Morphological)

(2) Microscopic evaluation

(3) Physical evaluation

(4) Chemical evaluation

(5) Analytical evaluation

(6) Biological evaluation

1.Organoleptic (Morphological) Evaluation:

• This refers to drug evaluation by means of organs of sense and includes other sensory organs like color, odour, taste ,size ,shape and texture.

• It includes the study of morphology and other sensory characters.

S. No.CharacterExample
1.Brown ColourCinnamon
2.Sweet taste Liquorice
3.Fractured surface Cinchona
4.Bark Kurchi
5.FruitsFennels

2. Microscopic evaluation: This method allows a more detailed examination of a drug and it can be used to identify organized drugs by their known histological characters.

This can be done by powdering, cutting thin sections of the drug or preparing a macerate or other suitable method.

Parameter for Evaluation of Crude Drug:

  1. Palisade Ratio
  2. Stomata
  3. Stomatal Number
  4. Stomatal Index
  5. Vein-islet Number
  6. Vein-termination Number
  7. Trichomes or plant hairs
  8. Calcium oxalate crystals Methods for Quantitative Microscopy: 1.Lycopodium spore method 2. Physical Evaluation 3. Chemical Evaluation 4. Biological Evaluation