INTRODUCTION FOR EXTRATION

DEFINITION:

                        Extration may be defined as the process in which animal or plant tissue are treated with specific solvents by using extraction process medically active constituents are dissolved out.

METHOD OF EXTRATION:

                   For extraction process there are various method which include the following.

Extraction with organic solvents:

*Percolation

*Maceration

*Extraction using soxhlet apparatus

Extraction with water

          *Infusion

          *Decoction

          *Digestion

          *Steam distillation

Other methods include

          *Super critical fluid extraction and phytonocs

          *Spouted extraction

          *Vertical or turbo extraction

          *Ultra sound extraction

          *Counter current extraction

          *Successive solvent extraction

EXTRATION WITH ORGANIC SOLVENTS:

PERCOLATION:

          Exhaustive extraction or percolation is defined as complete removal of desired extractive substances from the drug substances (material)

GENERAL METHOD FOR EXTRACTING BOTANICALS:

          Moisten 1000gms of powdered botanical with sufficient quantity of prescribed menstrum to render it evenly and distinctly damp

Macerate for 6hrs in light covered containers(this will enable the plant cells to absorb the menstrum)

                                                       

Then pack in cylindrical percolator

Add enough menstrum to saturate powder and leave stratum above it.

When the liquid begins to drop from percolator close. The lower surface cover the percolator and macerate for prescribed time(48hrs)

Then open (hofmann clamp) valve and allow the percolation to proceed slowly.

Collect the preserve first 850ml

Continue percolation by gradually adding more menstrum over the herb until botanical is exhausted.

Recover the alchol from the reminder of percolate and concentrate to soft extract in a vaccum apparatus at a temperature exceed 450 c

Dissolve this residue in the reserved portion of percolate,mix thoroughly add a sufficient quantity of menstrum to make fluid extract measure 1000ml (k)and filter.

MACERATION:

          Maceration is defined as soaking in botanical in suitable solvent for a specified period of time any where from several hours to 3 weeks until solute portions are dissolved in menstrum or maceration is a process of extraction of drug with a solvent with several daily shaking or stirrings at room temperature.

PROCEDURE:

          Solid ingredients+750ml of perscrised solvent.

Allow to stand for a period of atleast one week in warm place with free quent agitation for proper dissolution.

          Filter the mixture.

         

          Residue wash with sufficient quantity of solvent.

          Combine filtrates make upto 1000ml.

ADVANTAGES:

*Small samples are prepared in exactly the same way as technical and production holders.

*highly versatile.

*Drugs passing through smelling(strong)properly or high mucous content can be processed.

HOT CONTINOUS EXTRATION SOXELATION:

          Convinent way to thimble in central plant extract eith pure solvent.

+

PROCEDURE:

          Material is placed in thimble in central compartment with sulphoning device and side arm connected to lower compartment.

          Solvent placed in central compartment

          Solvent is heated to boiling

          Vapour passing through side arm into reflux condenser

          Vapour gets condensed and liquefied and drops into thimble containing the material to be extracted

          Warm solvent percolates through the material and wall of thimble

          The extract is gradually collected in central compartment

          On reaching the top of siphon the entire liquid in central compartment flows through this and back into lower solvent container

          Process in thus repeated.

APPLICATIONS:

          Useful for exhaustive extraction of plant with a particular solvent

                   Eg: defalting or where 100% yield of a particular component is desired.

          Also useful for exhaustive sequential extraction with series of solvents of increased

polarity is desired.

Eg:Hexane,chloroform,and water.

DISADVANTAGES:

Due to continous recycling the extract that collects in lower container is continously being heated that may suffer thermal degradation reaction.

If the operation is carried out on a large scale it may not be suitable for use with solvents with relatively high boiling points such as methanol or water,since the whole apparatus below the condenser needs to be at this temperature for effective movement of solvent vapour.this method is limited for pure solvents or azeotropic mixture.

EXTRATION WITH WATER

INFUSION:

          It is a dilute solution of readily soluble constituents of crude drugs.

PROCEDURE:

          Moisten 60gms of herb cut coarsely ground in 1lit distilled water.

         

          Allow to stand for 15min and then add the balance of litre of boiling water.

          Cover the vessel tightly and allow standing approximately for 30minutes.

          Strain the mixture and pass water to make infusion mixture 1 litre.

          Filter refrigerate or preserve.

DISADVANTAGES:

          Difficult to standardize and are unstable and particularly susceptible to attack by various drugs and bacteria.

2.DECOCTION:

          This process extracts vegetable substances or substances that contain water soluble constituents from crude drugs by boiling in water for 15min.coating straining and passing sufficient cold water through drug to produce required volume.

PROCEDURE:

          Cut the powdered herb(60gms) and place in suitable vessel.

          1lit of cold water preferably distilled is placed over it.

          Cover the vessel well and boil the mixture for 15min.

          Allow to cool and then strain through muslin cloth and pass enough cold water through strainer to make the product measure it.

          Filter,refrigerate or preserve.

3.DIGESTION:

          This is form of maceratin in which gentle heat is used during process of extraction.

ADVANTAGE:

          It is used when moderately elevated temperature is not objectionable and the solvent efficiency of menstrum increased there by.

4.STEAM DISTILLATION,EXPRESSION.EXTRATION AND ENZYMATIC HYDROLYSIS:

METHOD FOR VOLATILE OILS:

METHOD FOR STEAM DISTILLATION AS FOLLOWS:

          *Water distillation

          *water and steam distillation

          *Direct steam distillation

WATER DISTILLATION:

          It is mostly applicable to such material which is dried initially in air and the constituents are not degraded by boiling upto 100Oc 

                   Eg:Turpentine oil

WATER AND STEAM DISTILLATION:

          It is often suitable for such plant material,whether fresh or dried the constituents of which degradation by direct boiling.

          Eg:clove oil,cinnamon oil

DIRECT STEAM DISTILLATION:

          It is invariably applicable to fresh drug that is loaded with sufficient natural moisture and hence no maceration is required.

          Eg:pipperment oil,spearmint oil.

ADVANTAGES:

*Relatively simple equipment.

*No separate filtration step is required to separate,extrated oil from plant material.

DISADVANTAGES:

          Cannot be used where the oil contains hydrolysable substances such as Esters (or) those that are easily oxidized (or) decomposed by heat.

EXPRESSION:

          Expression may be accomplished by four following methods.They are as follows.

                   1. Spooge method.

                   2. Scarification method.

                   3. Rasping process.

                   4. Mechanical process.

EXTRACTION OF VOLATILE OIL: It involves

          *Extraction with volatile solvents.

          *Extration with non-volatile solvents.

EXTRATION WITH VOLATILE SOLVENTS:

          Eg:Hexane,benzene

ADVANTAGES:

          Maintaining an uniform temperature during extraction process ensures retention of more intenses and natural fragnance.

          Flueal concretes-represent an admixture of natural odoriferous components of flowers ,plant waxes,colour pigments and certain albuminous material.

EXTRATION WITH NON-VOLATILE SOLVENTS:

          Three methods adopted for extraction they are as follows

          *Enfleuraga method

          *Pnematic method

          *Maceration method

OTHER METHODS

1)SUPER CRITICAL FLUID EXTRACTION:

          It is process of separating one component from another using super critical fluids as extracting solvent.

ADVANTAGES:

          *Environmental improvement and reduce product contamination.

          *Selectively

          *Speed

DISADVANTAGES:

          *Use of high sophisticated equipment

          *High pressure and high temperature is required.

2)SPOUTED BED EXTRATION:

          This is a process meant for physical removal of pigment layer which gives a better product than thah obtained by solvent extraction.

          Eg:production of annatto powder from seeds of Bixaorellana

3.VORTICO OR TURBO EXTRACTOR:

          A method adopted to reduce the length of time involved is simple maceratin process.

          Eg: cinchona bark.

DISADVANTAGES:

          *Temperature may rise due to high speed stirring.

          *Equilibrium separation of drug residues from miscelles is difficult.

4.ULTRA SOUND EXTRACTION:

          It is defined as frequencies above 20,000 HZ waves used to accelerate extraction.

          Eg:play a major role in decomposition of alkaloid’s in Jaborandi observed after 30s ultra sound treatment on laboratory scale at 20 HZ.

EXTRATION BY ELECTRICAL ENERGY:

          Eg:Extration of scopolamine from seeds and throns of thorn apple.

5.COUNTER-CURRENT METHOD(EXTRACTION):

          It is a process in which plant material is in a contact with charged solvent at same time as fresh solvent is being brought contact in with pre extracted drug.

APPLICATION:

          Alkaloids,Amino acids,Antibiotics,Phenolic including anthroquinone derivates,cardiac glycosides.PGS.Steriods,F.A,essential oils and vitamins.

6.SUCCESSIVE SOLVENT EXTRACTION:

          *This is meant for air dried material.

          *Based on increasing order of polarity.