Transcript Classification of Crude drugs

Classification of Crude drugs
L.A. Dilbreen H. A. Barzanji
1- Alphabateical classification
The crude drugs are arranged according to the alphabetic
order of their Latin or English names.
Some of the pharmacopoeia and reference books which
classify crude drugs according to this system are:
Indian pharmacopoeia(IP)
British pharmacopoeia (BP)
British herbal pharmacopoeia (BHP)
United States Pharmacopoeia and national formulary
(USP/NF)
British pharmaceutical codex
European pharmacopoeia(EP)
Encyclopedia of common natural ingredients used in drugs
and cosmetics
e.g. Acacia, benzoin, cinchona, dill, ergot ……..zedoary
2- Taxonomical (biological)
classification
The drugs are classified according to plants or animals from
which they are obtained in phyla, division, class, order,
families, genus, species, subspecies, etc.
This classification is based on the consideration of natural
relationship or phylogeny among plants or animals. The
crude drugs of plant origin are classified on the basis of one
of the accepted systems of botanical classification.
A large number of plant families have certain distinguishing
characteristics that permit crude drugs from these families
to be studied at one time. thus drugs obtained from plants
having alternate leaves, cymose flowers and fruits that are
berries or capsules (hyoscyamus, datura, belladonna and
stramonium) are considered with other members of
Solanaceae).
In case of animals, all arthropods are grouped, as
are all mammals, fish and other phylogenetic
types.
This system of classification are criticized for its
failure to recognize the organized and
unorganized nature of the crude drug.
At first sight, this classification looks appealing, but
many drugs are not entire plants and represent
parts of the plants that have been processed
systemically.
Further, the system fails to take into account the
chemical nature of active constituents and
therapeutic significance of crude drugs.
e.g.
Phylum: Spermatophyta
Division: Angiospermae
Class: Dicotyledons
Order: Rosales
Family : Leguminosae
Genus: Glycerrhiza
Species: Glycerrhiza glabra
3- Morphological classification:
The crude drugs are grouped according to the
part of the plant or animal represented into
organized and unorganized drugs.
The organized drugs are divided into parts of
plants like leaves, flowers, fruits, seeds, etc.
the unorganized drugs are dried latex, gums,
extracts, etc.
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Seeds: Castor, nux-vomica
Leaves: senna, eucalyptus
Barks: cinchona, cinnamon
Woods: Quassia, Sassafras
Roots: Rauwolfia, Ipecacuanha
Rhizomes: Ginger, Valerian
Flowers: Clove, Pyrethrum
Fruits: Coriander, Fennel
Entire drugs: Ephedra, Ergot
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Dried lattices: Opium, Papain
Resins: Balsam of Tolu, Benzoin
Dried juices: Aloes, Kino
Gums: Acacia, Guar
Dried extracts: Gelatin, Agar
This system of classification is more convenient for
practical study especially when the chemical
nature of the drug is not clearly understood.
4- Chemical classification:
The crude drugs are divided into different
groups according to the chemical nature of
their most important constituent.
Since the pharmacological activity and
therapeutic activity of crude drugs are based
on the nature of their chemical constituents, it
would be appear that chemical classification
of crude drugs is the preferred method of
study.
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Glycosides: Digitalis, liquorice
Alkaloids: Ergot, Cinchona
Tannins: Myrobalan, Ashoka
Volatile oils: Peppermint, Eucalyptus
Lipids: Castor oil, Cod liver oil
Carbohydrates: Acacia, Honey
Resins: Balsam of Tolu, Jalap
Vitamins and Hormones: Oxytocin, Insulin
Proteins and Enzymes: Gelatin, Casein
5- Pharmacological (Therapeutic)
Classification:
This system of classification involves the grouping of
crude drugs according to the pharmacological action of
their active constituent or their therapeutic uses.
Cascara, Castor oil, Senna, Jalap, Colocynth are grouped
together as purgatives or laxatives because of their
common pharmacological action. The drug differing in
mechanism of action, but with the same
pharmacological effect are grouped together.
Some of the drugs could be classified under two
pharmacological leadings, since they exhibit two
different actions, for example, Cinchona is classified
both as antimalarial and bitter tonic.
Ex. drugs acting on GIT
• Bitters: Cinchona, Gentian
• Carminative: Dill, Cardamom
• Emetics: Ipecacuanha
• Bulk laxatives: Agar, Ispaghula
• Purgatives: Senna, Castor oil
Production of crude drugs:
• The crude drug that that reaches the
pharmaceutical manufacturing line will have
passed through various stages, all of which
influence the nature and amount of active
constituents present.
1- Source materials:
• It is imperative that correct identification of the source
material is made.
• Adulteration may be accidental, particularly if
collection is made from wild plants, or it may be
deliberate.
• Failure in this area can result in poisoning (e.g. hemlock
fruits mistaken for other umbilliferous fruits) or
inactive products (e.g. substituition of St. John’s wort
with other vegetable material when demand exceed
supply).
• For pharmacopoeial drugs, precise
macroscopic and microscopic characters are
available.
• For isolation of specific constituents, the
source can vary, e.g. hyoscine obtained from a
number of solanaceous species.
2- Environmental conditions:
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Plant growth and development, and often the
nature and quantity of secondary metabolites,
are affected by:
Temperature
Rainfall
Day-length and radiation characteristic
Altitude
3- Cultivation and wild plants
Crude drugs are now obtained most exclusively cultivated
plants. These include cardamoms, Indian hemp, ginger
and peppermint and spearmint for oil production.
In other cases both wild and cultivated plants are used.
There is a turning into cultivation because wild plants are
• insufficient to meet the demand
• sparse distribution
• inaccessibility
• collection is difficult
• governmental control (e.g. in case of opium)
• some wild plants are in danger of over-exploitation.
4- Collection:
• Drugs may be collected from wild or cultivated plants,
and the task may undertaken by casual, unskilled
native labour (e.g. ipecacuanha) or by skilled workers
in a highly scientific manner (e.g. digitalis, belladonna,
cinchona).
• The season at which each drug is collected is usually a
matter of considerable importance, as the amount, and
sometimes the nature, of active constituents is not
constant throughout the year. e.g. rhubarb is reported
to contain no anthraquinone derivatives in winter but
anthranols which, on the arrival of warmer weather,
are converted by oxidation into anthraquinones.
The age of plant is also of considerable importance
and governs not only the total quantity of active
constituents produced but also the relative
proportions of components of the active mixture.
e.g. Mentha piperita give relatively high proportion
of pulegone in young plants: replaced by
menthone and menthol as leaves mature.
Generally speaking,
• leaves are collected as the flowers are beginning to open
• Flowers just before they are fully expanded
• The underground organs as the aerial parts die down
• Leaves, flowers and fruits should not be collected when
covered with dew or rain.
• Any which are discoloured or attacked by insects or slugs
should be rejected.
• Even with hand picking, it is difficult, certainly expensive, to
get leaves, flowers or fruits entirely free from other parts of
the plant. In cases such as senna leaf and digitalis the
official monographs allow a certain percentage of stalks to
be present or a limited amount of ‘foreign matter’.
Similarly, with roots and rhizomes a certain amount of areal
stem is often collected and is permitted in the case of
Senega root.
• Special machines are used to harvest ergot and lavender
flowers.
• Barks are usually collected after a period of damp weather,
as they then separate mostly from the wood.
• For separation of gums, gum resins, etc., dry weather is
obviously indicated and care should be taken to exclude
vegetable debris as far as possible.
• Underground organs must be freed from soil. Shaking the
drug before, during and after drying, or brushing it , may be
sufficient to separate a sandy soil, but in cases of clay or
other heavy soil; washing is necessary. Before drying, any
wormy or diseased rhizomes or roots should be rejected.
• All large organs should be sliced to facilitate drying.
• Seeds such as nux vomica and cocoa, which are extracted
from mucilaginous fruits, are washed free from pulp before
drying.
5- Drying
• If enzymatic action is to be encouraged, slow
drying at a moderate temperature is necessary.
e.g. ‘vanilla pods’ and ‘gentian roots’.
• If enzymic action is not desired, drying should be
take place as soon as possible after collection.
• Drugs containing volatile oils are liable to lose
their aroma if not dried or if the oil is not distilled
from them immediately, and all moist drugs are
liable to develop mould. For these reasons,
drying apparatus and stills should be situated as
near to the growing plants as possible.
• The duration of drying process varies from a few hours to
many weeks, and in the case of open-air drying depends
very largely on the weather. In suitable climates open-air
drying is used for such drugs as clove, colocynth, cardamom
and cinnamon.
• Even in warm and dry climates arrangements have to be
made for getting the drug under the cover of sheds or
tarpaulins at night or during wet weather. For drying in
sheds the drugs may be suspended in bundles from the
roof, threaded on strings, as in the case of Chinese rhubarb,
or more commonly placed on trays made of sacking or
tinned wire-netting.
• Papers spread on a wooden framework are also used,
particularly for fruits from which it is desired to collect the
seeds
• Drying by artificial heat is more rapid than openair drying and is often necessary in tropical
countries (e.g. west Africa, where the humidity is
very high).
• In Europe continuous belt driers are used for
large crops such as digitalis.
• Alternatively heat may be applied means of open
fires (e.g. nutmegs), stoves or hot-water pipes.
• In all drying sheds there must be a space of at
least 15 cm between superimposed trays, and air
must circulate freely
• As a general rule, leaves, herbs and flowers
may be dried between 20 and 40 oC, and barks
and roots between 30 and 65 oC.
• If leaves and other delicate structures are over
dried, they become very brittle and tend to
break in transit.
• Exactly how far drying is to be carried is a
matter for practical experience.
6- Storage
• Long storage, although often unavoidable, is not to be
recommended,
• Drugs such as Indian hemp and sarsaparilla deteriorate
even when carefully stored.
• Few cases such as cascara bark need long storage
before indicated to be used.
• It has been reported that the content of taxol in Taxus
baccata leaves stored at room temperature for one
year decreased by30-40% , storage in freezer and out
of direct sunlight produced no adverse deterioration.
• Similarly the alkamides of the popular
immunostimulant herb Echinacea purpurea decrease
rapidly on storage.
• drugs stored in the usual containers: sacks, bales,
wooden cases, cardboard boxes and paper bags
reabsorb about 10-12% or more of moisture.
• Plastic sacks will effectively seal the contents.
• Drugs such as digitalis and Indian hemp should
never be allowed to become moist or they lose a
considerable part of their activity. They may kept
in sealed containers with a dehydrating agent.
• Volatile oil should be stored in sealed, wellfilled containers in a cool, dark place.
• Similar remarks apply to fixed oils, particularly
cod-liver oil.
• In order to reduce undesirable microbial
contamination and to prevent the
development of other living organisms, some
plant materials may require sterilization
before storage.