Extraction refers to processes for the isolation of the active ingredients from drug material. This may be by physical means or by dissolving in a suitable menstruum (liquid solvent eg. water or alcohol). Expression is the physical act of applying pressure to squeeze out oils or juices from plants.

1. Extraction
SANJAY S. PATEL
Professor – Pharmaceutics Department
BMCPER, Modasa.
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2. Topics
• Definition
• Terminology
• Type of extraction
• Theory of extraction
• Solvent use in extraction
• Method of extraction
• Factor affecting choice of extraction process
• Application of extraction in pharmacy
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3. Definition
• Extraction can be defined as the removal of
soluble material from an insoluble residue,
either liquid or solid, by treatment with a
liquid solvent.
• This is mass transfer phenomena.
• Rate of extraction is normally the rate of
diffusion of the solute through the liquid
boundary.
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4. Terminology
• Menstruum: solvent used for extraction purpose
is know as menstruum
• Marc : Residual left after extracting the desired
constituents is know as marc.
• Macerate : It is the solution of soluble
constituent of drug in a menstruum.
• Galenicals : The crud drug extract is impure. It
include infusion, decoctions, etc used for oral or
external use known as galenical.
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5. Type of extraction
• Two types of extraction
1. Liquid – Liquid Extraction
2. Solid – Liquid extraction
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6. Liquid – Liquid Extraction
• Contact with two immiscible solvent.
• A conc. gradient is set up between the phase and
mass transfer will occur until an equilibrium is
achieve.
• Higher mass transfer require large surface area
for contact, sufficient time must be allowed in
the dispersed phase to equilibrium and finally the
liquid are separated.
• In large scale equipment require stirred in tank.
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7. Solid – Liquid extraction
• The extraction of soluble substance from
solid by mean of a solvent is commonly
referred to as leaching.
• Various factor affecting to removal of
soluble substance in insoluble material.
• Solid liquid extraction is important for
medicinal plant material which is good
pharmacological activity.
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8. Theory of extraction
1. Suitable size reduction of the drug:
2. Penetration of the solvent into the drug:
3. Solution of constituent:
4. Escape of the solution from the cells:
5. Separation of solution and exhausted drug:
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9. Suitable size reduction of the drug
Mass transfer theory-maximum surface area
To separate individual cell in drug – but it is not
possible.
Prolong size reduction –decomposition of constituent
(volatile oil).
Degree of size reduction depend on botanical structure
of drug.
Example- belladonna moderate coarse powder contain
higher alkaloids than fine powder.
The cell of drug to be broken it exist penetration of
solvent and escape of soluble matter.
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10. Penetration of the solvent into the drug
Drug in dry state is porous due to shrinkage and pores
contain must be displaced as the solvent enters into
the pores and penetrate into the cell.
In fresh material contain water film when dried shrinkage
occur.
When dried material moistened reverse occur, micellae
take up a liquid once more and tissue swell.
In solvent contain higher hydroxyl group than higher
swelling is occur.
Swelling continues until the pressure caused by the liquid
layer is equal to the cohesive force between micellae.
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11. Solution of constituent:
• Solvent penetrate into cell and formation
of solution of constituent take place.
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12. Escape of the solution from the cells
Broken cell escape of solution is not empeded.
Unbroken cell solution escape depend on diffusion
mechanism.
Rate of diffusion will depend upon on presence of
suitable concentration gradient, boundary layer
thickness, diffusion coefficient of solute in solvent.
1. Agitation
2. Solvent flow rate.
3. Temperate.
Increase temp. decrease Viscosity reduce boundary layer.
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13. Separation of solution and exhausted drug
Immersion drug in bulk solvent.
Drug absorb by solvent and drug is subjected
to pressure to expel as much as solution
possible.
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14. Solvent use in extraction
• There are large number of solvent use for
extraction of drugs.
• The ideal solvent should be selective in dissolving
only the wanted constitutes.
• Ideal quality of solvent
• Cheap, Non toxic
• Stable, Selective
• Plentiful, Low viscosity
• Low specific heat
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15. I. Water as solvent
• Water is solvent for proteins, coloring matter,
gum, sugars, enzymes, glycosides, tannins,
alkaloids salts etc.
• Water is not solvent for waxes, fats, fixed oils,
alkaloids.
• Advantages : cheap, wide solvent action, non
toxic, non inflammable.
• Disadvantages : Non selective, leads to
hydrolysis, bacterial grow in aq. Medium,
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16. II. Alcohol (Ethanol)
• Alcohol is solvent for glycosides, tannins,
alkaloids salts, Resins, volatile oils etc.
• Alcohol is not solvent for Albumin, waxes, fats,
fixed oils, sucrose etc.
• Advantages : non toxic, miscible with water,
bacterial can not grow, higher absorption of drug
etc.
• Disadvantages : costly, hardens the tissues and
therefore delays extraction
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17. III. Water alcohol mixture
IV. Acidifier water
V. Alkalized water
VI. Organic solvent: chloroform, ether,
benzene, etc.
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18. Method of extraction
I. Infusion
II. Decoction
III.Digestion
IV.Maceration
V. Percolation
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19. Infusion
• Vegetable drug containing water soluble & easily extractable
principle.
Drug + water (50ml + 50ml)
Stand for 15 min.
Add 900ml hot water.
Macerate during 30 min.
Separate solvent to marc.
• Use within 12 hrs because microbial attack is there.
• Examples: Infusion of senna
– Infusion of quassia
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20. Decoction
• Vegetable drug containing water soluble & heat stable
constitutes.
Drug + water (50ml + 1000ml)
Boil it for 15 min.
Cool it and liquid strained the marc passed.
• Use within 12 hrs because microbial attack is there.
• Examples: Decoction of irish moss BPC
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21. Digestion
• It is modification of maceration and drug
menstruum mixture is kept hot, between 40 to
60o C.
• in this method volatile menstruum is used, the
vessel is connected to a reflux condenser.
• As temp. is lower than that used for infusion and
decoction , a longer time is required for
extraction
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22. Maceration
• Maceration method based on the
immersion of drug in a bulk of solvent,
with modification to multiple stage
extraction.
• Three types :
1. Simple maceration
2. Modification maceration
3. Multiple maceration
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23. Simple maceration
• Process for organize drug (barks, root)
• Drug + whole of menstruum.
• Shake occasionally during 7 days.
• Strain of liquid and press the mark.
• Mix the liquid clarify.
• Filtrate is not adjusted to volume.
• Examples :
– Tincture of orange.
– Tincture of capsicum.
– Tincture of squill.
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24. Modification maceration
• Process for unorganized drug (gum, gum-resin)
• Drug + 80 % menstruum.
• Shake occasionally during 2-7 days.
• Decant the liquid and do not press the mark.
• Filter the liquid and pass more Mestruum through marc to
volume and wash with mark with fresh menstruum (20%) .
• The conc. And volume obtain is same, so upon adjusting to
final volume do not vary the strength from worker to worker.
• Examples :
– Tincture of myrrh.
– Tincture of tolu.
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25. Multiple maceration
(multistage extractor.)
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26. Process:
1. Fill extractor with drug, add solvent and circulate run off to receiver 1.
2. Fill extractor with drug, add solvent and circulate run off to receiver 2.
3. Fill extractor with drug, add solvent and circulate run off to receiver 3.
4. Remove the drug from extractor and recharge. Retune solution from 1
to extractor. Evaporate solvent.
5. Return solution from 2 to extractor and circulate. Run off to receiver
1.
6. Return solution from 3 to extractor and circulate. Run off to receiver
2.
7. Add fresh solvent to extractor and circulate. Run off to receiver 3.
8. Remove drug from extractor and re change. Repeat cycle.
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27. Percolation
• Percolation is defined as short successive
maceration or extraction by the method of
displacement.
1. Simple percolation
2. Reserved percolation
3. Continuous hot percolation (soxhlet
extraction)
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28. Simple percolation
1. Size reduction
2. Imbibitions
3. Packing
4. Maceration
5. Percolation
6. Pressing the marc
7. Adjustment to volume
8. clarification
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29. Reserved percolation
• It is modification of simple percolation
• Drug percolation ration is 1:1 or 2:1.
Process:
Imbibe for 4 hours macerate for 24 hrs.
Percolate
Reserved the ¾ percolate of finished preparation which
contain major active constitute. The marc is pressed and
mixed with further specified volume of percolate
separately.
Mix the evaporated percolate with that reserved and adjust
to volume with more menstruum.
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30. Continuous hot percolation
(soxhlet extraction)
• It is modification of simple percolation
• It is used for those drug where:
– Penetration of Menstruum is slow in cellular
tissue.
– menstruum is vary less
– Active constitute are not readily soluble into
the menstruum.
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32. Apparatus:
1. The flask holding menstruum.
2. The Extractor
3. The reflux condenser fitted top of the
soxhlet.
Process:
Advantages:
Disadvantages:
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33. Factor affecting choice of extraction process
• Nature of drug :
Hard and tough use percolation.
Soft, parenchymatous and unorganized, use maceration
method.
• Cost of drug
• Therapeutically value of drug
• Stability of drug : Drug is Thermostable.
• Time taken for drug
• Whether drug to be extracted completely or not
• solvent
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34. Application of extraction in
pharmacy
• Extraction is applicable for various analytical
method. (SCF, HPLC, GC, HPTLC. TLC)
• Extraction is use for various preparation.
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