The document discusses various extraction and percolation processes used to produce galenicals from plant materials. It describes common solvents like water and alcohol and their advantages and disadvantages. Infusion, maceration, and percolation processes are explained in detail along with modifications like multiple maceration, reserve percolation, and continuous hot percolation. Different processes are used depending on the nature of the drug and solubility of active constituents.

1. Mr. G.A.Shete

2.  Extraction:
 The treatment of plant or animal tissues with solvent, whereby the medicinally
active constituents are dissolved, & most of the inert matter remains
undissolved.
 The solvent used for extraction is known as “Menstrum”.
 The inert soluble material that remains after extraction is called “Marc”.
 The various processes used for extraction are:
 Infusion
 Decoction
 Maceration
 Percolation
 Digestion

3.  Galenicals
 A standard medicinal preparation (as an extract or tincture) containing usually
one or more active constituents of a plant and made by infusion decoction,
maceration or percolation process that leaves the inert and other undesirable
constituents of the plant undissolved.
 Infusion
 It consists of pouring water over the drugs & then allowing it to keep in contact
with water for the 15 minutes, with occasional stirring & finally filtering off
the liquid. The marc is not pressed. The boiling water is commonly used as a
solvent, since it has a greater solvent action than cold water.
 There 2 types of Infusion
 Fresh Infusions
 Concentrated Infusions

5.  Advantages of Water as Menstrum
 It is cheap & easily available.
 Non –toxic
 Non inflammable.
 It has wide solvent action.
 Disadvantages of Water as Menstrum
 It dissolves wide range of substances which are undesirable & may interfere
with the clarity of preparation or decomposition of the preparation.
 Water helps in the growth of mould & bacteria.
 Water causes hydrolysis of many substances.
 Large amount of heat is required to concentrate the aqueous preparations than
non-aqueous preparations.

6.  Advantages of Alcohol as Menstrum
 The mould and bacteria cannot grow in an alcoholic solution (20% or more).
 It is neutral and hence extraction products obtained are compatible with other
products.
 It is non-toxic in the concentration mostly present in the preparations.
 A small amount of heat is required to concentrate the alcoholic preparations.
 It dissolves selective active ingredients of drugs.
 Disadvantages of Alcohol as Menstrum
 Costly.

7.  Difference between Simple Maceration & Maceration with adjustment
Sr No Simple Maceration Maceration with adjustment
1 Drug along with whole of Menstrum is used in
maceration process
Drug along with 4/5th of the Menstrum
is used in the maceration process.
2 The period of Maceration is 7 days The period of Maceration is 2 to 7 days
3 Strain off the liquid and press the marc Decant the liquid and marc is not pressed
4 Mix the pressed liquid with the macerate and
clarify by filtration. Filtrate is not adjusted to
volume.
Filter the liquid and pass the remaining 1/5th of
Menstrum through filter to make up the volume.
5 Final volume is not adjusted Final volume is adjusted
6 Example of tincture: Tincture of orange,
Tincture of capsicum, tincture of lemon.
Example of tincture: Tincture of tolu, Tincture of
catechu, compound tincture of benzoin.

8.  Simple Maceration Process
 Simple maceration is a maceration process for tinctures made from organized
drugs. In this process, the drug is placed with the whole of the menstruum in a
closed vessel for seven days. During this period, shaking is done occasionally.
After seven days, the liquid is strained and marc is pressed. The expressed liquid
is mixed with strained liquid. It is then filtered to make a clear liquid. The final
volume is not adjusted. The tinctures made by simple maceration process are
Tincture of Orange, Tincture of Lemon, Tincture of Squill, etc.
 Maceration with adjustment:
 This process is carried out for unorganized drug.
 Method:
 Place unorganized drug with 4/5th of the menstruum in a close vessel for 2-7
days. Shake the vessel occasionally. After stipulated period filter the liquid and
make up the final volume with the remaining i.e. 1/5th of the menstruum. (Do not
press the marc)

9.  Justification:
 The period of maceration can be reduced from 7 to 2 days in few cases. As
unorganized drugs behave like simple chemicals which dissolves in the solvent
very easily and quickly The marc left is gummy, it does not retain the menstruum
thus not pressed. The final volume is made up with 1/5th of menstruum. As marc
is not pressed there is no change in concentration of the preparation.
 Multiple Maceration
 This is done to achieve maximum extraction of active constituents as well as
complete exhaustion of drugs.
 Double Maceration:
 It is carried in the same way as simple maceration. The menstruum is divided in
two parts. The quantity of menstruum required for two macerations are calculated
as.

10.  Volume of menstruum req. = Total Vol. of menstruum – Vol. to be retained by drug
for first maceration 2 + Vol to be retained by drug.
 Volume of menstruum req. for second maceration = Total Vol. of menstruum – Vol. of
menstruum used for first maceration.
 In Double maceration drug is macerated for 48 hr for first maceration and 24 hr for
second maceration.
 Strain the liquid and press the marc.
 Mix the liquid obtain from two maceration and keep it for 14 days and then filter.
 Ex. Concentrated infusion of orange and gentian infusion.

11.  Triple Maceration Process
 In this maceration process, the drug is macerated thrice by using the
menstruum which is divided into three parts in such a manner that the same
volume is used for each maceration.
 The quantity of menstruum required for three macerations is calculated as
follows:
 Volume of menstruum required for first maceration =
 Total vol. of menstrum - Vol. to be retained by the drug +Vol. to be retained
3 by the drug
 Volume of menstruum used for 2nd and 3rd maceration =
 Total vol. of menstruum - Vol. of menstruum used in first maceration
2

12.  Procedure for Triple Maceration
 The whole of the drug is macerated for one hour with part of menstruum
required for first maceration and strained.
 Macerate again for one hour with a part of menstruum required for second
maceration and strained.
 Macerate again for one hour with a part of menstruum required for third
maceration and strained.
 Press the marc lightly. Then combine the liquids obtained from second and
third maceration and evaporate it to a specified extent.
 Mix it with the liquid obtained from first maceration. Add alcohol 90% equal
to l/4th of the volume of the finished product. Adjust volume with water. Allow
it to stand for 14 days and filter.

13.  Percolation Processes
 Simple Percolation Processes
 a. Imbibition:
 Drug is kept is moistened with sufficient quantity of menstruum. Allow to
stand for 4 hr.
 Significance:
 It allow the swelling of tissue of drug before packing.
 It is imbibed for uniform packing in percolator.
 It allows the entrapped air to escape.
 Quantity of menstrum required can be reduced.
 b. Maceration:
 The moistened drug is left in contact with menstruum for 24 hrs.
 During this period, menstruum dissolves the active constituents of the drug.

14.  c. Percolation:
 It consists of downward displacement of the saturated menstrum formed in
maceration and extraction.
 After collecting 3/4th volume of product then marc is pressed.
 Mix the liquids.

15.  Percolation process for concentrated preparations :
 Reserve percolation:
 In this process a part of percolate, generally 3/4th volume of the finished
preparation is reserved.(contains high solute concentration)
 Then the percolation process is continued till the drug is completely exhausted.
 The percolate is subjected to evaporation or distillation to convert in to soft
extract.
 Distillation will help to recover the costly solvent.
 Hence the major portion of active constituents of the drugs are saved from
deterioration
 This soft extract is dissolved in reserve portion of percolate and sufficient
menstruum is added to make up the volume.

16.  Modified Percolation:
 In percolation process for tinctures drug percolate (d/p) ratio is 1:4.The drug/percolate
ratio is reduced to 1:3 by modifying percolation process. Thus saves lot of heat, time
and menstrum.
 It is proved that the menstrum remaining in contact with the drug dissolves more active
constituents than the flowing menstrum. Hence simple percolation process requires
more menstrum to exhaust t the drug. But if continuous percolation stage has suitable
breaks by short maceration stages, the d/p ratio can be reduced to 1:3
 e.g .In Simple Percolation process:
 Drug→ Imbibition → Maceration → Percolation
 (200gm) (4hrs.) ( for 24 hrs.) collect the Percolate,i.e.3/4th of
 the volume of finished product.

17.  In modified percolation process:
 Drug → Imbibition → Maceration → Percolation-
 (1000gm) (for 24 hrs.) collect 1000ml of percolate
 → Maceration → Percolation-
(for 12 hrs.) collect 1000ml of percolate
 → Maceration → Percolation-
(for 12 hrs.) collect 1000ml of percolate
 Drug : Percolate
 1000gm : 3000ml i.e. d/p = 1:3
 After exhaustion of the drug, the percolate is evaporated and then mixed with main
percolate. Final volume is made by adding more menstrum.

18.  Continuous Hot Percolation Process or Soxhlet Extraction or Soxhelation:
 When active constituents of the drug are not freely soluble in the solvent or difficult
to be displaced from the cells of the drug, then it becomes necessary to extract the
crude drug by the action of hot menstrum for a considerable length of time.The fixed
oils from seeds & alkaloids from the drug are extracted by continuous hot
percolation using benzene, chloroform etc.
 Apparatus:
 It consists of 3 parts i.e.
 Flask containing the boiling solvent
 Soxhlet Extractor in which the drug to be extracted is packed. It has a side tube
which carries the vapours of the solvent from the flask to the condenser & a syphon
tube which syphons over the extract from Soxhlet extractor to the flask.
 A Condenser in which the vapours of the solvent are condensed again into solvent.

19.  Procedure:
 The drug to be extracted is packed in a paper cylinder made from a filter paper & it
is placed in the body of Soxhlet extractor. The solvent is placed in the flask. When
solvent is boiled on heating the flask, it gets converted into vapours. These vapours
enter into the condenser through the side tube & get condensed into hot liquid which
falls on the column of the drug.
 When the extractor gets filled with the solvent, the level of syphon tube also raises
up to its top. The solvent containing active constituents of the drug in the syphon
tube syphon over & run into the flask, thus emptying the body of extractor. This
alteration of filling & emptying the body of extractor goes on continuously.
 The soluble active constituents of the drug remain in the flask while the solvent is
repeatedly volatilized. The process of filling & emptying of the extractor is repeated
until the drug is exhausted. Normally the process is repeated about 15 times for
complete exhaustion of the drug.

21.  Limitation:
 Physical character of the drug: If the drug would block the soxhlet apparatus then
this process cannot be used for extraction. Eg opium. Gum, resin, orange peel, etc.
 Solvent: Only pure solvents or constant boiling mixtures can be used.
 Chemical constituents of the drug: The process is unsuitable for drugs having
thermolabile active constituents such as enzymes, alkaloids, anthraquinone
derivatives, esters, etc.