Crude Drugs (Pharmacognosy) MANIK

Lecturer
Departmentof Pharmacy,NUB
1103: Pharmacognosy-I

CRUDE DRUG
• Crude drugs are vegetable or animal drugs that consist
of natural substances that have undergone only the
processes of collection and drying which
• Crude drugs comprise of whole plants and herbs, their
morphological or anatomical parts, saps, extracts,
secretions and other constituents; whole animals, their
anatomical parts, glands or other organs, extracts,
secretions and other constituents of their organ.
• Examples: Acacia, Agar, Benzoin, Beeswax, Cinchona,
Cinnamon, Digitalis, Datura, Jalap, Kino, Ephedra,
Linseed, Fennel, Mustard, Ginger, Isapagol, Nutmeg, etc.
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Terminologies
• Constituents: These are chemical substances that are
present in the cells of some plant or animal organs.
Constituents that exert some physiological or
pharmacological actions on living organisms are referred to
as “active constituents” or “active principles”.
• Extractive: The crude mixture of chemical constituents that
are removed from plant or animals by various extraction
process are called extractives.
• Menstruum: Extraction removes only those substances that
can be dissolved in the liquid or liquid mixture referred to as
the solvent, or, more specifically, as the menstruum.
• Marc: The undissolved portion of the drug that remains after
the extraction process is completed is called the marc.
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Terminologies
• Indigenous: Plants and animals growing or living in their
native countries are said to be indigenous to those
region.
• Example: Pinus palustris is native to the Southeastern
United States.
• Naturalized: Plants or animals are said to be naturalized
when they grow or live comfortably in a foreign land or in
a locality other than their native homes.
• Example: Datura stramonium, which was introduced into
the United States from Europe.
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Examples: Acacia, Agar, Benzoin, Beeswax, Cinchona, Cinnamon, Digitalis, Datura, Jalap,
Kino,Ephedra, Linseed,Fennel,Ginger, Isapagol, Mustard, Nutmeg, etc.
Advantages:
It is simple method, in this system location, tracing and addition of the drug is easy,
No technical person is required for handling the system.
Disadvantages:
Scientific nature of the drug cannot be identified by this method, whether they are organized or
unorganized drug.
This system does not help in distinguishing the drugs of plant, animal and mineral source.
(Original source is not clear)
Classification
Crude drugs may be classified according to (1) Alphabetical (2) Morphological,
(3)Taxonomical, (4) Chemical and (5) Pharmacological character.
Alphabetical classification: The crude drugs are arranged according to the alphabetical
order/form of their Latin and Englishnames. Some of the Pharmacopoeias and reference books
which classify crude drugs according to this system are: British Pharmacopoeia (BP)
(English);British Pharmacopoeia Codex (BPC) (English); United States of Pharmacopoeia
(USP) (English)
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According to morphology and structural organization, the crude drugs
are further classified as
(i) Organized (Cellular)crude drugs:
The drugs obtained from the direct parts of the plants and containing
cellular tissues are called as organized drugs.
e.g. rhizomes, barks, leaves, fruits, entire plants, hair and fibers.
(i) Unorganized (Acellular) crude drugs:
The drugs which are prepared from plants by some intermediate
physical processes such as incision, drying, or extraction with a
solvent and not containing any cellular plant tissues are called as
unorganized drugs.
e.g. Aloe juice. Opium latex.
Morphological Classification: The arrangement of drugs according to the part of the
plant used (such as leaves, stems, roots, barks, flowers, seeds. etc.) is known as
morphological classification.
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The organized crude drugs are further divided into two
groups:-
(a) Drugs from over-ground organs: which include all
drugs that are derived from the over-ground or aerial
parts or organs of plants.
(b) Drugs from underground organs: which include all
drugs that are derived from underground or subterranean
parts or organs of plants.
Advantages:
• This system of classification is more convenient for practical study especially when
the chemical nature of the drug is not clearly understood.
• This type of classification is very useful in identifying the adulterants used.
Disadvantages:
• There is no co-relation of chemical constituents with the therapeutic actions.
• When different parts of the plant contain different chemical constituents, it is difficult
to classify them.
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Taxonomical Classification:
In this system, crude drugs are arranged
according to the taxonomical studies. The drugs
are arranged according to their phylum, order,
family, genus and species .
Taxonomical Classification
Thus all the drugs
obtained from
plants of the
family
Umbelliferae are
grouped together
as umbelliferous
drugs, those from
Solanaceae are
grouped together
as Solanaceous
drugs and so on.
Advantages:
• Easy for the classification of crude
drugs.
• It will provide proper idea about
species and varieties of the organism.
Disadvantages:
• There is no co-relation of chemical
constituents and biological activity of
the drugs.
• The system fails to recognize the
organised / unorganised nature of
crude drugs in their morphological
studies.
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Chemical Classification:
In this system, the crude drugs are divided into groups
according to their principal chemical constituents.
Thus all alkaloid containing drugs are put into one group
regardless of other consideration. Similarly all crude drugs
containing glycosides are grouped together and so on.
Since the pharmacological actions and the therapeutic uses
of drugs depend on chemical constituents, this system of
classification appears to be ideal one not only for study but
also for storage.
Chemical Classification
Advantages:
• Known chemical constituents
are easy to study the drug.
• Popular approach for
phytochemical study.
Disadvantages:
• Drugs of different origin are
grouped under similar chemical
titles.
• This type of classification
makes no proper placement of
drugs containing two different
types of chemicals.
Eg: Certain drugs are found to
contain alkaloids and glycosides
(Cinchona), Fixed oil and volatile
oil (Nutmeg) of equal importance
together and hence it is difficult to
categorize them properly
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Pharmacological (therapeutic) Classification:
Grouping of drug according to their
pharmacological action or of most important
constituent or their therapeutic use is termed as
pharmacological or therapeutic classification.
In this system, all the cathartic drugs are brought
together regardless of their morphology,
taxonomy or chemical relationship.
Thus cardiotonic drugs include Digitalis. Squill
and Strophanthus. Senna leaves an Castor oil
are termed as purgative drugs.
Pharmacological Classification
Advantages:
• The special advantage is that if
even chemical constituents of the
crude drugs are not known they can
be classified properly on the basis of
therapeutic or pharmacological uses.
Disadvantages:
• The main drawback of this
classification is that a drug can be
placed in various classes according
to its therapeutic use. Thus
Cinchona can be grouped in
antimalarial and antiarrhythmic
categories.
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There are 6 steps of preparations of drugs
for commercial Markets --
1. Collection
2. Harvesting
3. Drying
4. Garbing
5. Quality control
6. Packaging, storage and preservation.
Preparation of Drugs for Commercial Markets
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Collection
• The drugs should be collected from the cultivated plants, because the cultivated
plants always ensures a true natural source and a reliable product.
• This may or may not be the case when drugs are collected from wild plants.
• Carelessness or ignorance on the part of the collector can result in complete or
partial substitution. So it is better to collect the plant by skilled persons.
• The proper time of collection is also an important factor, because the nature and
quantity of the constituents vary according to the season.
The most advantageous collection time is
• When the part of the plant that constitutes the drug contains the highest amount
of active principles and
• When the material will dry to give the maximum quality and appearance.
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There are certain rules for the collection of various drug
• Leaves and flowering tops should be collected during the
active reproductive process of plants, i.e. from the beginning
of the flowering to early fruiting.
• Flower should be collected prior to or just about the time of
pollination.
• Fruits may be collected when they are fully mature but unripe
(e.g., black pepper) or when fully ripe (Umbelliferous fruits).
• Seeds should be collected when they are fully mature and
have ripened, but before the fruits open.
• Barks are generally collected at the end of the winter season.
• Roots and rhizomes of annual plants should be collected
before flowering.
➢ Biennials in winter at the end of the first years growth.
➢ Perennials should also be collected in winter at the end of
the second or third year’s growth.
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Harvesting
The mode of harvesting varies
depending upon the drug produced
and the pharmaceutical requirements
of each drug.
Some drugs may be collected by-
i) Hand labor
ii) Mechanical devices
With some drugs, where the skillful
selection of plant parts is an
important factor (digitalis),
mechanical means cannot replace
hand labor.
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Drying
Drying is a very important and essential step for the
preparation of crude drugs for the commercial market.
Drying fixes the constituents, facilitates grinding and
milling, and converts the drug into a more convenient form
for commercial handling
Proper and successful drying consists of two principles or
processes. These are-
Control of temperature and
Regulation of air flow.
Control of the drying operation is determined by the nature
of the material to be dried and by the desired appearance
of the finished product.
Curing: Curing is a special drying processes required to
bring about necessary changes in the constituents of some
natural products. For example fermentation or sweating.
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There are two methods for drying the drugs
1.Natural Heat 2. Artificial Heat
Natural Heat: It can also be termed as regulation of air flow.
It can be of two types.
These are-
(a) Sun drying: Sun drying is applicable for those drugs
which are not affected by the direct heat of sunlight.
(b) Shade drying: It is employed to those drugs which are
heat sensitive and color of the drugs should be retained.
Artificial heat: The artificial drying has the advantage over
air and sun drying that it stops the enzymatic action more
rapidly.
For example due to the moisture in the fresh leaves of
digitalis, if the leaves are allowed to dry naturally rapid
hydrolysis of the glycoside occur. Thus artificial drying is
essential for a high grade product.
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Garbling
Garbling consists of the removal of
extraneous matter, such as other parts of the
plant, dirt and added adulterants.
This step is done to some extent during
collection.
For example in leaf drugs stems must be
removed.
Incase of roots and rhizomes ,overground
stems must be removed.
Garbling is done in two times.
During collection of the crude drug. (pre
garbling)
After drying and before packaging. (Final
garbling)
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Quality Control
Quality Control: Quality Control, QC, is the set of
activities that control the quality of product.
i) Preliminary examination for the general
appearance of the sample by using microscopical
and sensory characters.
ii) Determination of foreign organic matters by
manually picking out the extraneous matters from
their sample and finding out their proportional
quantity.
iii) Determination of the amount of moisture present in
the dried drug by “loss on drying” method.
iv) Some quantitative chemical tests to determine the
amount of active principle in the sample.
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Packaging, storage and preservation
Packaging: The packaging of drugs facilitates
transportation, storage and ultimate use for
manufacturing purposes.
So the proper selection of packaging is an important
step for the protection of the drug’s quality, purity and
also for the economy of space.
are usually baled with
power balers into a solid compact mass which is then
sewn into a burlap cover.
are packed into water
proof container.
are packed into barrels.
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1.Moisture:
2.Light:
3.Air:
4.Temperatur
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Adulteration involves
1. Incorporation of impurities,
2. Spoilage,
3. Deterioration,
4. Admixture,
5. Sophistication and
6. Substitution.
Adulterated drugs means the drugs which do not fulfill the
official requirements of purity, quality and standard due to
substitution with spurious, inferior, defective or harmful
substances.
Adulteration of Crude Drugs
Definition: The term adulteration is defined as substituting
original crude drug partially or wholly with other similar
looking substances. The substance, which is mixed, is free
from or inferior in chemical and therapeutic property
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Classification
Adulteration can be divided in to two groups:
1. Undeliberate adulteration
2. Deliberate (Intentional) adulteration
1. Undeliberate (Incidental) adulteration: When the act of adulteration takes place
due to various unintentional reasons.
2. Deliberate adulteration: When adulteration is done intentionally to cheat others.
Undeliberate adulteration of the crude drugs occurs due to.
(a). Faulty collection: i.e. wrong time of collection.
(b). Imperfect preparation: i.e. improper drying, packing.
(c). Incorrect storage in improperly built storehouse.
These results in -
Inferior, Deteriorated,
Spoiled and Admixed drugs.
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An inferior drug is a substandard drug, which contains less
quantity of the active principle.
Example: Datura stramonium containing less than 0.25% of
total alkaloid are regarded as inferior stramonium.
A deteriorated drug is one in which the active constituents
have been partially destroyed by over aging, moisture, heat,
fungi, insects or by other means.
e.g. over roasted coffee beans, moldy Ergot etc.
A crude drug is regarded as spoiled, when its quality or
usefulness is impaired or destroyed by the action of fungi,
bacteria, insects and rodents to render it unfit for human
consumption.
An admixed drug is one in which other plant parts of the same
plants got mixed through accidents, ignorance or carelessness.
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It is the most serious illegal act of adulteration and may be called the true type of adulteration.
This type of adulteration is done intentionally to defraud and involves conditions like- Admixture,
Deterioration, Sophistication and Substitution.
The admixture type of deliberate adulteration is accomplished by deliberately mixing related or
unrelated cheaper substances to the genuine drug in order to increase its bulk or weight or
expressed qualities (color, odor, taste etc.)
Admixture involves a number of different conditions, which include the following:
i. Addition of worthless heavy materials such as pieces of stone, iron lead etc. to increase its
weight.
ii. Addition of artificially manufactured unnecessary substances to the genuine drug to
increase its bulk and weight. e.g. ergot has often been admixed with small masses of flour
dough.
iii. Addition of inferior commercial varieties of the same drug to the genuine drug to increase
its bulk and weight.
For example: African or Japanese ginger is often mixed with medicinal or official Ginger and
sold at a higher price as Official Ginger.
iv. Addition of synthetic substances to fortify inferior drugs.
For example: Citral is added to enhance the odor of substandard lemon oil.
v. Addition of powdered waste produces of similar colors to powders of genuine drugs.
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Deliberate deterioration: It is done by partially abstracting their
active principles using processes like distillation and solvent
extraction.
For example: In Spent Clove, a portion of the volatile oil is removed
by distillation from whole Cloves.
Sophistication: Sophistication is the deliberate addition of spurious
or inferior material with intent to defraud.
Example: A sophisticated Ginger powder is made by mixing debris of
Ginger powder with proportionate quantities of Wheat flour (to provide
the starchy nature), Curcuma powder (to incorporate the cream
colour), and Capsicum powder (to restore or enhance the pungent
taste and odour).
Substitution: It is a serious type of deliberate adulteration in which an
entirely different article is used or supplied in place of genuine article.
Example: Official Alexandrian Senna (Cassia acutifolia) is often
substituted by leaves of Cassia auriculata or Dog Senna.
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Evaluation of Drugs
Evaluation of drugs means the identification of the plant
and determination of quality and purity of the crude drug
The identification of a drug can be established by –
i. Its actual collection from a plant or animal that has been
positively identified.
ii. Comparison of unknown sample to a published drug and
to authentic drug samples.
The evaluation of a drug involves a number of methods
that may be classified as follows:
1. Organoleptic
2. Microscopic
3. Biologic
4. Chemical
5. Physical
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1. Organoleptic: Organoleptic evaluation means study of a drug with
the help of organs of sense which includes its external morphology,
colour, odour, taste, sound of its fracture, etc.
For e.g. Morphology of a drug, such as shape and size, colour and
external markings, fracture and internal colour, odour and taste are
examined.
2. The microscopic evaluation of drugs is done with the aid of
microscopes. It is not only essential to the study of adulterants in
powdered plant and animal drugs but also is indispensable in the
identification of the pure powdered drug.
3. The Biological evaluation: In this type of evaluation, the extent of
pharmacologic activity of certain drugs is taken as the basis of quality.
Since living organisms or their isolated tissues are used, the assays are
called biologic assays or bioassays.
For example: antibiotics, toxoids and vitamins are assayed by this
method.
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4. Chemical evaluation of drugs :
Chemical evaluation involves the determination of active constituents
by a chemical process. It is done by the-
i. Qualitative chemical test: To determine quality and purity.
ii. Quantitative chemical assays: To identify crude drug and their
constituents.
Titrimetric assay, iodine value, saponification value, acid value, acetyl
value, ester value, peroxide value, hydroxyl value and ash value are
determined. For many drugs, the chemical assay represents the best
method of determining the official potency.
5. The physical evaluation:
Physical constants are extensively applied to the active principles of
drugs, such as alkaloids, volatile oils, fixed oils, and others.
Physical constants such as elasticity in fibres, viscosity of drugs
containing gums, swelling factor of mucilage containing materials,
melting and boiling points and water contents (loss on drying at 110°C)
are some important parameters used in the evaluation of drugs.
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Crude Drugs (Pharmacognosy) MANIK

Crude Drugs (Pharmacognosy) MANIK

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