This document discusses various extraction methods used to obtain active ingredients from crude drugs using liquid solvents, highlighting the importance of solvent selection and extraction processes. It details techniques such as infusion, decoction, maceration, percolation, and soxhlation, along with factors affecting extraction efficiency. The document also contrasts different methods, their applications, and the significance of controlling variables like temperature and time during extraction.

1. EXTRACTION
METHODS
• Preseted by;- Laxmi Kumari, B.Pharm (UIPS), Dehradun

2. EXTRACTION
 Extraction is the process of extracting active ingredients (desired
chemical constituents) from the crude drugs using a liquid solvent.
 It is the separation of medicinally active tissues from inert or
inactive components in plants or animals using specific solvents.
 Solvent
 Can be Polar or Non-polar
 Depends on the nature of secondary metabolite
• Example;
Polar Solvent Non-polar Solvent
• Water • Benzene
• Alcohol • Chloroform
• Acetone • Diethyl ether

3.  IDEAL PROPERTIES OFTHE SOLVENT
 Must be highly selective for the compound to be extracted
 Inert with the extracted compound or with other compounds in
the plant material
 Cost effective
 Be harmless to man & eco-friendly
CHOICE OF EXTRACTION METHODS DEPENDS ON;
 Size of Sample
 Quantity of the extract required
 Choice of solvent
 The time taken for extraction
 Cost

4.  STEPS FOR EXTRACTION;
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Collection of
fresh plant
material
Drying Powder Extraction

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TERMS USED IN EXTRACTION
 MENSTRUUM;
Solvent or solvent mixture used for extraction.
 MISCELLA /Extract;
Solution containing extracted substances.
MARC;
Inert insoluble material that remains after extraction.
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6.  DRYING OF CRUDE DRUGS;
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 To prevent microbiological contamination, it is necessary.
 Drugs should be dried below 60°C unless otherwise specified.
• Lowered heat exposure
• Less chance to chemical alteration
Shade drying
• Use less intense sun light
• Economic, Most efficient
Sun drying
• Less explored yet
• Expensive, Used for expensive drugs
Far infrared drying
• Low Pressure rapid drying method
• For thermolabile compounds
Vacuum Drying
• Often used
Oven/Hot air drying

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Size reduction
• Maximum surface area
• Mesh size is 30-40 optimum
Extraction
• Maceration, Infusion, Percolation, soxhlation etc.
Filtration
• With the help of musciline cloth, filter paper, filter press
Concentration
• By evaporation of solvent
Drying
• Spray drying

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 Extraction;
 Extraction is the process of efficiently dissolving & separating the desired chemical constituents from the
crude drug with the use of solvent.
 Types Of Extraction
1. Solid Extraction
 The name refers to the separation of solid components from solid substance by using
appropriate solvent. This type of extraction is generally performed before any further
separation or processing..
2. Solvent Extraction
 The liquid-liquid extraction is one in which phytoconstituents that are extracted
by solid extraction process are partitioned between any two immiscible solvents.
 Ideally this process needs to be carried out after solid extraction process & it is
considered as purification process.
 On a laboratory scale Solvent extraction is carried out in a separating funnel.

9.  Mechanism Of Extraction
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 During the extraction of phytoconstituents from the plant material;
• Initially solvent penetrates into the solid matrix,
• After that, the solubilisation of solutes in the solvent takes place,
• Later on the solute (soluble phytoconstituents ) diffuses out of the solid matrix,
• And finally extracted solute are separated out by solvent evaporation.
 Factors Affecting Extraction Of Crude Drugs
1. The quantity & the chemical nature of the drug
2. Nature and volume of the solvents
3. Particle size of the powder of crude drug
4. Ratio of the mixing of Solvent to the sample
5. Duration of extraction
6. Temperature at which extraction is carried out
7. pH of the extracting solvent
8. Lipophilicity of the solvent mixture

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Conventional methods of
extraction
Infusion
Cold infusion
Hot infusion
Decoction Maceration
Simple
Maceration
Maceration
with
adjustment
Multiple
Maceration
Percolation
Simple
Percolation
Percolation
process for
concentrated
preparation
Reserve
Percolation
process
Modified
Percolation
process
Continuous
Percolation
process
Digestion

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1. INFUSION
 Very simple method of extraction
 Used for volatile ingredients, vitamins , & soft ingredients
 Water (Cold or Hot) used as a solvent
 Only applicable for Soft drugs & drug containing water soluble constituents
 The aqueous solution of active constituents of a crude drug is termed as Fresh Infusion.
Note;- Cold water is used as menstruum (solvent) in Cold Infusion while Hot/ boiling water is used as
menstruum in Hot Infusion but the drug not boiled
Drug + menstruum (Cold/
boiling Water)
Stand for stated period
(usually 15 – 20 min &
sometimes over night)
Shaking or
occasional stirring is
done if required
Filtered & the marc is
not pressed
Filtrate is called
Infusion
Example;- Cold infusion of cumin & Hot infusion of lepton green tea, etc.

12. 2. DECOCTION
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 Crude drug is boiled in a specified volume of water for a stated time period (10-15min) & then filtered.
 Suitable for drugs that are hard and woody in nature such as seed, wood etc. containing thermo-stable
chemical constituents.
 Mainly useful for making Herbal Tea.
Drug + Menstruum ( Water)
Boiled for
specified time
Filtered & Marc is pressed
Filtrate is called Decoction

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3. MACERATION
 In this method of extraction the crushed or powdered crude drug is soaked in the suitable solvent.
 The extraction time can vary from several minutes to weeks with occasional shaking or stirring at room
temperature.
 This process is normally used for the preparation of tinctures or extracts & menstruum is usually alcoholic,
hydroalcohlic in case of tincture or may be aqueous.
 The drug extracted by this process are either organized or unorganized drugs.
I. Simple maceration - A process for tinctures made from organized drugs e.g. roots, stems,
leaves etc.
II. Maceration with adjustment - A process for tinctures made from unorganized drugs such
as oleo-resins and gum resins. The marc is not pressed.
III. Multiple maceration - A process to prepare concentrated extract. It includes ‘Double
maceration’ and ‘Triple maceration’.
Types of Maceration
 Example;- Tincture of Benzoin etc.

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 Process of Maceration;
Solid sample + Menstruum
In a closed vessel
Stand for 7 days
Shaking of stirring
Mixing the liquid obtained
The mixture is strained
& the marc is pressed

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 This process is a modified form of maceration where the drug is extracted by heating at a particular pressure.
This will increase the penetration power of the menstruum, so that there is complete extraction of the drug.
 The apparatus is known as ‘Digestor’ is a vessel made up of metal.
 The drug is treated with menstruum for a definite period under specified condition of temperature and
pressure.
i) No solvent residues
ii) Eco-friendly extraction procedure
4. DIGESTION
5. Percolation
 Percolation means ‘pass through’. It implies a slow passage of the menstruum under the influence of gravity
through the drug powder & during this movement it goes on extracting the drug molecules layer wise.
 In this process the drug plant material is extracted by fresh solvent.
 The extraction is continued until the sufficient compound is extracted. If necessary, the same material can be
re-extracted with a second solvent.
 This method is suitable for heat-sensitive, hard & woody drugs, not suitable for drug which may block the
percolator.

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 Types of Percolation
1. Simple Percolation
2. Reserved Percolation
3. Hot Percolation
Example;- Preparation which are made by Simple Percolation
• Tincture of belladonna
• Compound tincture of cardamom
• Strong tincture of ginger
A percolator ( a narrow , cone-shaped vessel open at both ends ) is generally used. The process
consist of three steps;-
I. Imbibition;
 Moistening the drug with a little Menstruum for 4 hours. During this period the drug swells & menstruum
penetrates the cell wall.
II. Maceration
 Moistened drug is kept in contact with the menstruum for 24 hours with occasional shaking where in the
menstruum dissolves & get saturated with the soluble constituents of the crude drug.
III. Percolation
 It consist of the downward displacement of saturated menstruum formed in the maceration & extraction
of the remaining active constituents present in the sample by the slow passage of the menstruum.

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Process of percolation
Imbibition of the
crude drug
Maceration- Add
sufficient amount of the
menstruum above the
drug & allowed to stand
for 24 hrs.
Percolation- Outlet
opened, Percolate
is collected drop
wise
After collecting 3/4th of the
required volume of the
finished product, marc is
pressed
Percolating the liquid while
mixing it. Add sufficient
menstruum to produce the
required volume
Following a period of
standing, the combined
liquid is filtrated.
Imbibed/moistened drug
packed up to 2/3rd capacity
of the Percolator
Add sufficient amount of
menstruum to saturate the
material
When the liquid comes to
drop from the percolator,
close the outlet

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 CONTINUOUS HOT PERCOLATION PROCESS / SOXHLET
EXTRACTION /SOXHLATION;
 This process is used for those drugs
 Where the penetration of the menstruum into the cellular tissues is very slow,
 The solute is not readily soluble into the solvent,
 The quantity of the menstruum is very less.
Fig;- Soxhlet Extractor
 In such cases Soxhlet extractor is used where
small volume of hot menstruum is passed over
the drug and again to dissolve out the active
constituents until the drug is exhausted. The
process is known as Soxhlation.

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 The plant material is continually washed with new solvent during the Soxhlet extraction. However, the
boiling solvent containing the extracted analytes creates the fresh solvent.
 Meaning that through the process of evaporation and subsequent condensation, the same amount of
solvent is made to flow through the extractor that contains the drug.
 Working of Soxhlet Apparatus;
 The Coarsely powdered crud drug is placed in a porous bag or “ thimble”
made of strong filter paper, which is then placed in Soxhlet extractor.
 Place the RBF (Round Bottom Flask) on the heating mantle with the
extracting solvent added.The RBF is heated, causing the solvent vapours to
condense in the condenser.
 Condensed vapours drip into a thimble containing crude medicine, which is
then extracted.
 When the level of liquid in chamber rises to the top of siphon tube, the liquid
contents of siphon chamber drop into flask.
 During each cycle, pure hot solvent dissolves some of the phytoconstituents
& siphoned back to the round bottom flask.

21. DIFFERENCE BETWEEN MACERATION AND PERCOLATION
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S.NO. MACERATION PERCOLATION
1. Both drug and solvent are mixed
together &kept aside for 7-14 days
The solvent is allowed to pass through the column of
the drug
2. Duration time is more Duration time is Less
3. There is no necessity of the drug to be
packed
The drug should be packed in layer to get rid of air gaps
4. More amount of menstruum is required Less amount of menstruum is required
5. Doesn’t require temperature, Except
Digestion
Heat is required
6. More API cannot be extracted Maximum possible amount of API can be extracted
7. The clarity of the preparation is low The clarity of the preparation is low

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Differences between Infusion and Decoction
S.No. Component Infusion Decoction
1. Plant Soft structures (Eg: Senna
Leaves)
Hard Woody structures( Eg: cinchona
bark)
2. Menstruum Boiling (or) Cold Water Boiling Water
3. Procedure Infusing the drug with cold or
hot water
Boiling the drug with water
4. Time Calculated as soon as water is
added
Calculated as soon as water begins to
boil.
5. Adjustment of
final volume
No adjustment Calculated as soon as water begins to
boil.
6. Apparatus Infusion earthware pot Any covered apparatus
7. Storage Used fresh within 12 Hours Used fresh and when stored in
refrigerator used within few days

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