QUALITY CONTROL OF

CRUDE DRUGS

Physical and Biological Evaluation

By
Dr. Kamran Javed Naquvi
Associate Professor,
Faculty of Pharmaceutical Sciences (FPhS),
Rama University, Kanpur.

PHYSICAL EVALUATION

Physical constants are sometimes taken into
consideration to evaluate certain drugs. These
include moisture content, specific gravity, optical
rotation, refractive index, melting point, viscosity
and solubility in different solvents.

 Moisture content

Determined by heating the drug at 105 ºC in an
oven to constant weight.

 Aloe: NMT 10 %; Ergot: NMT 8 %

 Digitalis: NMT 5 %; Acacia: NMT 15 %

 Viscosity

Viscosity of a liquid is constant at given
temperature and is an index of composition. It
can be used as a means of standardising liquid
drugs.

 Liquid paraffin: Viscosity NLT 64 centistrokes
at 37.8 º.

 Melting Point

It is one of the parameters to judge the purity of
crude drugs. In case of pure chemicals, the
melting point is very sharp and constant. Since
the crude drugs from animal or plant origin
contains mixed chemicals, they are prescribed in
certain range of melting point.

 Colophony: 75-85ºC; Kokum butter: 39-42ºC

 Solubility

The presence of adulterant in a drug could be
indicated by solubility studies.

 Castor oil is soluble only in 3 volumes of 90%
alcohol while adulterated form may show good
solubility in alcohol.

 Balsam of Peru is soluble in chloral hydrate
solution.

 Colophony is freely soluble in light petroleum.

 Asafoetida is soluble in carbon disuphide.

 Optical rotation

Certain substances are found to have a property of
rotating the plane of polarised light in pure state or
in solution. Thus they are called as optically active
and this property is called as optical rotation.

 Right side rotation known as dextro rotatory

 Left side rotation known as laevo rotatory

Clove oil : +75º to 80º

Castor oil: +3.5º to 6.0º

Eucalyptus oil: 0º to +10º

Chenopodium oil: -30º to -8º

ASH VALUE

 Ash value is the criterion of purity or identity of
the crude drugs.

 The residue remaining after incineration is the
ash value of the drug, which simply represent
inorganic salts, naturally occurring in drug or
deliberately added to it as a form of adulteration.

 Many a times the crude drugs are admixed with
sand, soil, calcium oxalate, chalk powder.

 Total ash usually consists of phosphate,
carbonates, silicates and silica.

 Cannabis: Total ash-15.0 and acid-insoluble ash-
5.0; Clove: 7.0 and 0.75; Cardamom: 6.0 and 3.5.

EXTRACTIVE VALUES

 Extracts obtained by exhausting crude
drugs are indicative of approximate
measures of their chemical
constituents.

 Different solvents are used for the
extraction because of the diversity of
chemical nature and properties of
content of drugs.

 Water-soluble extractives
This method is applied for the drugs which
contain water-soluble chemical
constituents such as tannins, sugars, Soxhlet

glycosides. Extractor

Senna leaves: NLT 30%; Aloe: NLT 25%;
Linseed: NLT 15%; Ginger: NLT 10%;

 Alcohol-soluble extractives

Alcohol is ideal solvents for extraction of various
chemicals like tannins, resins, flavonoids.

Examples: Aloe: NLT 10%;

Myrrh: NLT 70%

Siam benzoin: NLT 90%;

Sumatra Benzoin NLT 75%

 Ether-Soluble extractives

Used for the evaluation of drugs containing volatile oil.

Examples: Capsicum: NLT 12%;

Nutmeg: 25%

Linseed: 25%

VOLATILE OIL CONTENT

 Pharmaceutical significance of
aromatic drugs are due to their
odorous principles i.e. Volatile oil.

 These drugs are standardized on the
basis of their volatile oil content.

Clove: NLT 15%;

Fennel: NLT 1.4%;

Cardamom seed: NLT 4%;

Fresh lemon peel: NLT 2.5%.
Clevenger
Apparatus

BIOLOGICAL EVALUATION

 Herbal drugs are accessed for their biological
efficacy.

 Hepatoprotective activity

Many drugs, chemicals, industrial pollutants,
hepatitis virus, ethyl alcohol are known to cause
hepatitis, cirrhosis and liver damage.

 Animal: Male/ female albino rats

 Induced by: Carbon tetrachloride, alcohol,
paracetamol, rifampicin (anti-TB drug).

 Standard: Silimarin (Obtained from Milk Thristle)

 Parameters: SGPT, SGOT, Alkalline phosphate

 Histopathological studies of liver.

 Anti-diabetic activity

Many drugs like Karela (Momordica charantia),
Jamun (Syzigium cumini); Methi (Trigonella foenu-
graceum); Gudmar (Gymnema sylvestre) have been
used in traditional system of Medicine for the
treatment of Diabetes mellitus (Type 2)

 Animals: Albino rats, mice, rabbits

 Induction by: Streptozotocin (STZ), Alloxan, i.p

 Standard: metformin, glimeperide, glibenclamide,
gliclazide

 Parameters: Blood sugar by GOD-POD method;

Insulin by ultra sensitive rat ELISA kit;

Lipid profile, TC, TGs, HDL, LDL, VLDL.

 Histopathology of pancreas

 Anti-inflammatory activity
Many plants are used for the treatment of
inflammation in Rheumatoid arthritis, Gout.

 Animals: Mice, rats
 Induced by: Carragenan, isolated from iris

moss Chondus cripus, 0.1 ml 1 % w/v in saline in
rat right hind-paw.

 Drug extract is given orally 1 hour or 30 minutes
i.p before test.

 Volume of paw is measured just after injection
then every after an hour subsequently for 5
times.

 Volume of paw is measured by volume
displacement method using Plethysmometer

 Measurement: 0 = No activity; + = slight;
+ = Pronounced

QUALITY CONTROL

 In short, Quality can be defined as

 It is the character with respect to fineness.

 It refers to the grade of excellence.

 Meeting the requirement of customers.

 Quality control refers to processes involved in
maintaining the quality and validity of a
manufactured product.

 In general, all medicines, whether they are of
synthetic or of plant origin, should fulfill the basic
requirements of being efficacious and safe.

PROBLEMS IN QUALITY CONTROL OF

HERBAL DRUGS

 Herbal drugs are usually mixtures of many
constituents.

 The active principle(s) is (are), in most cases unknown.

 Selective analytical methods or reference compounds
may not be available commercially.

 Plant materials are chemically and naturally
variable.

 The source and quality of the raw material are
variable.

 The methods of harvesting, drying, storage,
transportation, and processing have an effect.

WHO GUIDELINES FOR QUALITY

CONTROL OF HERBAL DRUGS

WHO guidelines for quality control of herbal drugs

Microscopic

QUALITY EVALUATION OF
HERBAL DRUGS

THANK YOU